How to improve WebGL batch render speed

How to improve WebGL batch render speed - javascript

I am writing a small sprite sheet renderer in WebGL, where I render quad with set with and height then I take one big sprite sheet and use the texture coordinates to pick what sprite should be shown on what quad. I do this all in one big object with position and texture coordinates array where i push new items in. I'm also using TWGL library to make WebGL a bit less verbose. Currently this system of batching items into one draw per frame isn't working that well, how can it be improved?
class Render {
constructor(selector) {
this.vertexShaderSource = `#version 300 es
in vec2 position;
in vec2 texcoord;
uniform vec2 u_resolution;
out vec2 v_texCoord;
void main() {
vec2 zeroToOne = position / u_resolution;
vec2 zeroToTwo = zeroToOne * 2.0;
vec2 clipSpace = zeroToTwo - 1.0;
gl_Position = vec4(clipSpace * vec2(1, -1), 0, 1);
v_texCoord = texcoord;
}`;
this.fragmentShaderSource = `#version 300 es
precision highp float;
uniform sampler2D u_image;
in vec2 v_texCoord;
out vec4 outColor;
void main() {
outColor = texture(u_image, v_texCoord);
}`;
this.bufferInfo;
this.gl = document.querySelector(selector).getContext("webgl2");
this.programInfo = twgl.createProgramInfo(this.gl, [this.vertexShaderSource, this.fragmentShaderSource]);
this.textures = [];
this.uniforms = {
u_resolution: [innerWidth, innerHeight],
u_image: null,
}
this.arrays = {
position: [],
texcoord: [],
};
this.gl.canvas.width = innerWidth;
this.gl.canvas.height = innerHeight;
}
loadImage(url, callback) {
const texture = twgl.createTexture(this.gl, { src: url, mag: this.gl.NEAREST }, () => { callback ? callback() : "" });
this.textures.push(texture);
return {
texture: texture,
index: this.textures.length - 1
};
}
clearBuffer() {
this.arrays.position = [];
this.arrays.texcoord = [];
}
setTexture(texture) {
this.uniforms.u_image = texture;
}
addQuad(x, y, width, height, srcWidth, srcHeight, srcX, srcY, realWidth, realHeight) {
const x1 = x;
const x2 = x + width;
const y1 = y;
const y2 = y + height;
this.arrays.position.push(
x1, y1, 0,
x2, y1, 0,
x1, y2, 0,
x1, y2, 0,
x2, y1, 0,
x2, y2, 0,
);
this.arrays.texcoord.push(
srcX / srcWidth / 1, srcY / srcHeight / 1,
(srcX + realWidth) / srcWidth / 1, srcY / srcHeight / 1,
srcX / srcWidth / 1, (srcY + realHeight) / srcHeight / 1,
srcX / srcWidth / 1, (srcY + realHeight) / srcHeight / 1,
(srcX + realWidth) / srcWidth / 1, srcY / srcHeight / 1,
(srcX + realWidth) / srcWidth / 1, (srcY + realHeight) / srcHeight / 1,
);
}
setBuffer() {
this.bufferInfo = twgl.createBufferInfoFromArrays(this.gl, this.arrays);
}
resizeCanvas() {
twgl.resizeCanvasToDisplaySize(this.gl.canvas);
this.gl.viewport(0, 0, this.gl.canvas.width, this.gl.canvas.height);
}
render() {
this.gl.useProgram(this.programInfo.program);
twgl.setUniforms(this.programInfo, this.uniforms);
twgl.setBuffersAndAttributes(this.gl, this.programInfo, this.bufferInfo);
twgl.drawBufferInfo(this.gl, this.bufferInfo);
}
}
const render = new Render("#game");
const texture = render.loadImage("https://i.imgur.com/TQnyNHU.png", () => {
requestAnimationFrame(renderStuff);
render.resizeCanvas();
function renderStuff() {
render.clearBuffer();
render.setTexture(texture);
for(let y = 0; y < 100; y++) {
for(let x = 0; x < 100; x++) {
render.addQuad(x * 48, y * 48, 48, 48, 512, 512, 32, 0, 16, 16);
}
}
render.setBuffer();
render.render();
requestAnimationFrame(renderStuff);
}
});
* {
margin: 0px;
padding: 0px;
}
body, html {
width: 100%;
height: 100%;
}
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<script src="https://cdnjs.cloudflare.com/ajax/libs/twgl.js/4.19.5/twgl.min.js"></script>
<script src="main.js" type="module" defer></script>
<link rel="stylesheet" href="style.css">
<title>Prometeus</title>
</head>
<body>
<canvas id="game"></canvas>
</body>
</html>

Related

webgl how to draw a ring

As shown below, all I can think of is to describe all the points on a circle and then use triangulation to draw a ring with width
I can also think of a way to use overlay. First draw a circle and then draw a circle with a smaller radius
const TAU_SEGMENTS = 360;
const TAU = Math.PI * 2;
export function arc(x0: number, y0: number, radius: number, startAng = 0, endAng = Math.PI * 2) {
const ang = Math.min(TAU, endAng - startAng);
const ret = ang === TAU ? [] : [x0, y0];
const segments = Math.round(TAU_SEGMENTS * ang / TAU);
for(let i = 0; i <= segments; i++) {
const x = x0 + radius * Math.cos(startAng + ang * i / segments);
const y = y0 + radius * Math.sin(startAng + ang * i / segments);
ret.push(x, y);
}
return ret;
}
const gl = container.current.getContext("webgl2");
const program = initProgram(gl);
const position = new Float32Array(arc(0, 0, 1).concat(...arc(0, 0, 0.9)));
let buffer = gl.createBuffer();
gl.bindBuffer(gl.ARRAY_BUFFER, buffer);
gl.bufferData(gl.ARRAY_BUFFER, position, gl.STATIC_DRAW);
let gl_position = gl.getAttribLocation(program, "position");
gl.vertexAttribPointer(gl_position, 2, gl.FLOAT, false, 0, 0);
gl.enableVertexAttribArray(gl_position);
gl.drawArrays(gl.LINE_STRIP, 0, position.length / 2);
The final effect of the code I wrote is as follows. May I ask how I should modify it to become the same as the above picture

You have to add a color attributes for the vertices and you have to draw a gl.TRIANGLE_STRIP primitive instead of a gl.LINE_STRIP primitive.
The color can be calculated from the angle. Map the angle from the range [0, PI] to the range [0, 1] and use the formula for the hue value from the HSL and HSV color space:
function HUEtoRGB(hue) {
return [
Math.min(1, Math.max(0, Math.abs(hue * 6.0 - 3.0) - 1.0)),
Math.min(1, Math.max(0, 2.0 - Math.abs(hue * 6.0 - 2.0))),
Math.min(1, Math.max(0, 2.0 - Math.abs(hue * 6.0 - 4.0)))
];
}
Create vertices in pairs for the inner and outer arcs with the corresponding color attribute:
const TAU_SEGMENTS = 360;
const TAU = Math.PI * 2;
function arc(x0, y0, innerRadius, outerRadius, startAng = 0, endAng = Math.PI * 2) {
const ang = Math.min(TAU, endAng - startAng);
const position = ang === TAU ? [] : [x0, y0];
const color = []
const segments = Math.round(TAU_SEGMENTS * ang / TAU);
for(let i = 0; i <= segments; i++) {
const angle = startAng + ang * i / segments;
const x1 = x0 + innerRadius * Math.cos(angle);
const y1 = y0 + innerRadius * Math.sin(angle);
const x2 = x0 + outerRadius * Math.cos(angle);
const y2 = y0 + outerRadius * Math.sin(angle);
position.push(x1, y1, x2, y2);
let hue = (Math.PI/2 - angle) / (2 * Math.PI);
if (hue < 0) hue += 1;
const rgb = HUEtoRGB(hue);
color.push(...rgb);
color.push(...rgb);
}
return { 'position': position, 'color': color };
}
Create a shader with a color attribute and pass the color attribute from the vertex to the fragment shader:
#version 300 es
precision highp float;
in vec2 position;
in vec4 color;
out vec4 vColor;
void main()
{
vColor = color;
gl_Position = vec4(position.xy, 0.0, 1.0);
}
#version 300 es
precision highp float;
in vec4 vColor;
out vec4 fragColor;
void main()
{
fragColor = vColor;
}
Vertex specification:
const attributes = arc(0, 0, 0.6, 0.9);
position = new Float32Array(attributes.position);
color = new Float32Array(attributes.color);
let position_buffer = gl.createBuffer();
gl.bindBuffer(gl.ARRAY_BUFFER, position_buffer);
gl.bufferData(gl.ARRAY_BUFFER, position, gl.STATIC_DRAW);
let gl_position = gl.getAttribLocation(program, "position");
gl.vertexAttribPointer(gl_position, 2, gl.FLOAT, false, 0, 0);
gl.enableVertexAttribArray(gl_position);
let color_buffer = gl.createBuffer();
gl.bindBuffer(gl.ARRAY_BUFFER, color_buffer);
gl.bufferData(gl.ARRAY_BUFFER, color, gl.STATIC_DRAW);
let gl_color = gl.getAttribLocation(program, "color");
gl.vertexAttribPointer(gl_color, 3, gl.FLOAT, false, 0, 0);
gl.enableVertexAttribArray(gl_color);
Complet and runnable example:
const canvas = document.getElementById( "ogl-canvas");
const gl = canvas.getContext("webgl2");
const program = gl.createProgram();
for (let i = 0; i < 2; ++i) {
let source = document.getElementById(i==0 ? "draw-shader-vs" : "draw-shader-fs").text;
let shaderObj = gl.createShader(i==0 ? gl.VERTEX_SHADER : gl.FRAGMENT_SHADER);
gl.shaderSource(shaderObj, source);
gl.compileShader(shaderObj);
let status = gl.getShaderParameter(shaderObj, gl.COMPILE_STATUS);
if (!status) alert(gl.getShaderInfoLog(shaderObj));
gl.attachShader(program, shaderObj);
gl.linkProgram(program);
}
status = gl.getProgramParameter(program, gl.LINK_STATUS);
if ( !status ) alert(gl.getProgramInfoLog(program));
gl.useProgram(program);
function HUEtoRGB(hue) {
return [
Math.min(1, Math.max(0, Math.abs(hue * 6.0 - 3.0) - 1.0)),
Math.min(1, Math.max(0, 2.0 - Math.abs(hue * 6.0 - 2.0))),
Math.min(1, Math.max(0, 2.0 - Math.abs(hue * 6.0 - 4.0)))
];
}
const TAU_SEGMENTS = 360;
const TAU = Math.PI * 2;
function arc(x0, y0, innerRadius, outerRadius, startAng = 0, endAng = Math.PI * 2) {
const ang = Math.min(TAU, endAng - startAng);
const position = ang === TAU ? [] : [x0, y0];
const color = []
const segments = Math.round(TAU_SEGMENTS * ang / TAU);
for(let i = 0; i <= segments; i++) {
const angle = startAng + ang * i / segments;
const x1 = x0 + innerRadius * Math.cos(angle);
const y1 = y0 + innerRadius * Math.sin(angle);
const x2 = x0 + outerRadius * Math.cos(angle);
const y2 = y0 + outerRadius * Math.sin(angle);
position.push(x1, y1, x2, y2);
let hue = (Math.PI/2 - angle) / (2 * Math.PI);
if (hue < 0) hue += 1;
const rgb = HUEtoRGB(hue);
color.push(...rgb);
color.push(...rgb);
}
return { 'position': position, 'color': color };
}
const attributes = arc(0, 0, 0.6, 0.9);
position = new Float32Array(attributes.position);
color = new Float32Array(attributes.color);
let position_buffer = gl.createBuffer();
gl.bindBuffer(gl.ARRAY_BUFFER, position_buffer);
gl.bufferData(gl.ARRAY_BUFFER, position, gl.STATIC_DRAW);
let gl_position = gl.getAttribLocation(program, "position");
gl.vertexAttribPointer(gl_position, 2, gl.FLOAT, false, 0, 0);
gl.enableVertexAttribArray(gl_position);
let color_buffer = gl.createBuffer();
gl.bindBuffer(gl.ARRAY_BUFFER, color_buffer);
gl.bufferData(gl.ARRAY_BUFFER, color, gl.STATIC_DRAW);
let gl_color = gl.getAttribLocation(program, "color");
gl.vertexAttribPointer(gl_color, 3, gl.FLOAT, false, 0, 0);
gl.enableVertexAttribArray(gl_color);
gl.enable( gl.DEPTH_TEST );
gl.clearColor( 0.0, 0.0, 0.0, 1.0 );
//vp_size = [gl.drawingBufferWidth, gl.drawingBufferHeight];
vp_size = [window.innerWidth, window.innerHeight];
vp_size = [256, 256]
canvas.width = vp_size[0];
canvas.height = vp_size[1];
gl.viewport( 0, 0, canvas.width, canvas.height );
gl.clearColor(1, 1, 1, 1);
gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);
gl.drawArrays(gl.TRIANGLE_STRIP, 0, attributes.position.length / 2);
<script id="draw-shader-vs" type="x-shader/x-vertex">#version 300 es
precision highp float;
in vec2 position;
in vec4 color;
out vec4 vColor;
void main()
{
vColor = color;
gl_Position = vec4(position.xy, 0.0, 1.0);
}
</script>
<script id="draw-shader-fs" type="x-shader/x-fragment">#version 300 es
precision highp float;
in vec4 vColor;
out vec4 fragColor;
void main()
{
fragColor = vColor;
}
</script>
<canvas id="ogl-canvas" style="border: none"></canvas>

How to avoid transparency overlap using the latest Mapbox-gl-js version?

I have been playing around with the shadows from building geometries example at (https://bl.ocks.org/andrewharvey/9490afae78301c047adddfb06523f6f1) and have been able to blend the transparent layers to become one uniform alpha value with an older version of mapbox-gl-js.
However when I change the mapbox-gl-js version to v0.54.0 or higher it no longer blends the shadows to be a uniform value. I have experimented with gl.blendFunc() and gl.blendFuncSeparate() but still seem to get a mixture of weird anti-aliasing issues or overlapping opacities.
How could I avoid this transparency issue and get a similar result to the first example provided.
0.53.1:
1.6.1:
Code using version 0.53.1:
<!DOCTYPE html>
<html>
<head>
<title>Mapbox GL JS debug page</title>
<meta charset='utf-8'>
<meta name="viewport" content="width=device-width, initial-scale=1.0, user-scalable=no">
<link href='https://api.tiles.mapbox.com/mapbox-gl-js/v0.53.1/mapbox-gl.css' rel='stylesheet' />
<style>
body { margin: 0; padding: 0; }
html, body, #map { height: 100%; }
#time { position: absolute; width: 90%; top: 10px; left: 10px; }
</style>
</head>
<body>
<div id='map'></div>
<input id='time' type='range' min="0" max="86400" />
<script src='https://api.tiles.mapbox.com/mapbox-gl-js/v0.53.1/mapbox-gl.js'></script>
<script src='https://unpkg.com/suncalc#1.8.0/suncalc.js'></script>
<!-- <script src='/debug/access_token_generated.js'></script> -->
<script>
mapboxgl.accessToken = 'pk.eyJ1IjoiYWxhbnRnZW8tcHJlc2FsZXMiLCJhIjoiY2pzcTA4NjRiMTMxczQzcDFqa29maXk3bSJ9.pVYNTFKfcOXA_U_5TUwDWw';
var map = window.map = new mapboxgl.Map({
container: 'map',
zoom: 15,
center: [-74.0059, 40.7064],
style: 'mapbox://styles/mapbox/streets-v11',
hash: true
});
var date = new Date();
var time = date.getHours() * 60 * 60 + date.getMinutes() * 60 + date.getSeconds();
var timeInput = document.getElementById('time');
timeInput.value = time;
timeInput.oninput = () => {
time = +timeInput.value;
date.setHours(Math.floor(time / 60 / 60));
date.setMinutes(Math.floor(time / 60) % 60);
date.setSeconds(time % 60);
map.triggerRepaint();
};
map.addControl(new mapboxgl.NavigationControl());
class BuildingShadows {
constructor() {
this.id = 'building-shadows';
this.type = 'custom';
this.renderingMode = '3d';
this.opacity = 0.5;
}
onAdd(map, gl) {
this.map = map;
const vertexSource = `
uniform mat4 u_matrix;
uniform float u_height_factor;
uniform float u_altitude;
uniform float u_azimuth;
attribute vec2 a_pos;
attribute vec4 a_normal_ed;
attribute lowp vec2 a_base;
attribute lowp vec2 a_height;
void main() {
float base = max(0.0, a_base.x);
float height = max(0.0, a_height.x);
float t = mod(a_normal_ed.x, 2.0);
vec4 pos = vec4(a_pos, t > 0.0 ? height : base, 1);
float len = pos.z * u_height_factor / tan(u_altitude);
pos.x += cos(u_azimuth) * len;
pos.y += sin(u_azimuth) * len;
pos.z = 0.0;
gl_Position = u_matrix * pos;
}
`;
const fragmentSource = `
void main() {
gl_FragColor = vec4(0.0, 0.0, 0.0, 0.5);
}
`;
const vertexShader = gl.createShader(gl.VERTEX_SHADER);
gl.shaderSource(vertexShader, vertexSource);
gl.compileShader(vertexShader);
const fragmentShader = gl.createShader(gl.FRAGMENT_SHADER);
console.log(gl.FRAGMENT_SHADER)
console.log(fragmentShader)
console.log(fragmentSource)
gl.shaderSource(fragmentShader, fragmentSource);
gl.compileShader(fragmentShader);
this.program = gl.createProgram();
gl.attachShader(this.program, vertexShader);
gl.attachShader(this.program, fragmentShader);
gl.linkProgram(this.program);
gl.validateProgram(this.program);
this.uMatrix = gl.getUniformLocation(this.program, "u_matrix");
this.uHeightFactor = gl.getUniformLocation(this.program, "u_height_factor");
this.uAltitude = gl.getUniformLocation(this.program, "u_altitude");
this.uAzimuth = gl.getUniformLocation(this.program, "u_azimuth");
this.aPos = gl.getAttribLocation(this.program, "a_pos");
this.aNormal = gl.getAttribLocation(this.program, "a_normal_ed");
this.aBase = gl.getAttribLocation(this.program, "a_base");
this.aHeight = gl.getAttribLocation(this.program, "a_height");
}
render(gl, matrix) {
gl.useProgram(this.program);
const source = this.map.style.sourceCaches['composite'];
const coords = source.getVisibleCoordinates().reverse();
const buildingsLayer = map.getLayer('3d-buildings');
const context = this.map.painter.context;
const {lng, lat} = this.map.getCenter();
const pos = SunCalc.getPosition(date, lat, lng);
gl.uniform1f(this.uAltitude, pos.altitude);
gl.uniform1f(this.uAzimuth, pos.azimuth + 3 * Math.PI / 2);
map.setLight({
anchor: 'map',
position: [1.5, 180 + pos.azimuth * 180 / Math.PI, 90 - pos.altitude * 180 / Math.PI],
'position-transition': {duration: 0},
color: '#fdb'
// color: `hsl(20, ${50 * Math.cos(pos.altitude)}%, ${ 200 * Math.sin(pos.altitude) }%)`
}, {duration: 0});
this.opacity = Math.sin(Math.max(pos.altitude, 0)) * 0.9;
// ADDED: normalises the colour of the shadows
gl.blendFunc(gl.SRC_COLOR, gl.CONSTANT_COLOR)
gl.enable(gl.BLEND)
for (const coord of coords) {
const tile = source.getTile(coord);
const bucket = tile.getBucket(buildingsLayer);
if (!bucket) continue;
const [heightBuffer, baseBuffer] = bucket.programConfigurations.programConfigurations['3d-buildings']._buffers;
gl.uniformMatrix4fv(this.uMatrix, false, coord.posMatrix);
gl.uniform1f(this.uHeightFactor, Math.pow(2, coord.overscaledZ) / tile.tileSize / 8);
for (const segment of bucket.segments.get()) {
const numPrevAttrib = context.currentNumAttributes || 0;
const numNextAttrib = 2;
for (let i = numNextAttrib; i < numPrevAttrib; i++) gl.disableVertexAttribArray(i);
const vertexOffset = segment.vertexOffset || 0;
gl.enableVertexAttribArray(this.aPos);
gl.enableVertexAttribArray(this.aNormal);
gl.enableVertexAttribArray(this.aHeight);
gl.enableVertexAttribArray(this.aBase);
bucket.layoutVertexBuffer.bind();
gl.vertexAttribPointer(this.aPos, 2, gl.SHORT, false, 12, 12 * vertexOffset);
gl.vertexAttribPointer(this.aNormal, 4, gl.SHORT, false, 12, 4 + 12 * vertexOffset);
heightBuffer.bind();
gl.vertexAttribPointer(this.aHeight, 1, gl.FLOAT, false, 4, 4 * vertexOffset);
baseBuffer.bind();
gl.vertexAttribPointer(this.aBase, 1, gl.FLOAT, false, 4, 4 * vertexOffset);
bucket.indexBuffer.bind();
context.currentNumAttributes = numNextAttrib;
gl.drawElements(gl.TRIANGLES, segment.primitiveLength * 3, gl.UNSIGNED_SHORT, segment.primitiveOffset * 3 * 2);
}
}
}
}
map.on('load', () => {
map.removeLayer('building');
map.addLayer({
'id': '3d-buildings',
'source': 'composite',
'source-layer': 'building',
'type': 'fill-extrusion',
'minzoom': 14,
'paint': {
'fill-extrusion-color': '#ddd',
'fill-extrusion-height': ["number", ["get", "height"], 5],
'fill-extrusion-base': ["number", ["get", "min_height"], 0],
'fill-extrusion-opacity': 1
}
}, 'road-label');
map.addLayer(new BuildingShadows(), '3d-buildings');
});
</script>
</body>
</html>
Code using version 1.6.1:
<!DOCTYPE html>
<html>
<head>
<title>Mapbox GL JS debug page</title>
<meta charset='utf-8'>
<meta name="viewport" content="width=device-width, initial-scale=1.0, user-scalable=no">
<link href='https://api.tiles.mapbox.com/mapbox-gl-js/v1.6.1/mapbox-gl.css' rel='stylesheet' />
<style>
body { margin: 0; padding: 0; }
html, body, #map { height: 100%; }
#time { position: absolute; width: 90%; top: 10px; left: 10px; }
</style>
</head>
<body>
<div id='map'></div>
<input id='time' type='range' min="0" max="86400" />
<script src='https://api.tiles.mapbox.com/mapbox-gl-js/v1.6.1/mapbox-gl.js'></script>
<script src='https://unpkg.com/suncalc#1.8.0/suncalc.js'></script>
<!-- <script src='/debug/access_token_generated.js'></script> -->
<script>
mapboxgl.accessToken = 'pk.eyJ1IjoiYWxhbnRnZW8tcHJlc2FsZXMiLCJhIjoiY2pzcTA4NjRiMTMxczQzcDFqa29maXk3bSJ9.pVYNTFKfcOXA_U_5TUwDWw';
var map = window.map = new mapboxgl.Map({
container: 'map',
zoom: 15,
center: [-74.0059, 40.7064],
style: 'mapbox://styles/mapbox/streets-v11',
hash: true
});
var date = new Date();
var time = date.getHours() * 60 * 60 + date.getMinutes() * 60 + date.getSeconds();
var timeInput = document.getElementById('time');
timeInput.value = time;
timeInput.oninput = () => {
time = +timeInput.value;
date.setHours(Math.floor(time / 60 / 60));
date.setMinutes(Math.floor(time / 60) % 60);
date.setSeconds(time % 60);
map.triggerRepaint();
};
map.addControl(new mapboxgl.NavigationControl());
class BuildingShadows {
constructor() {
this.id = 'building-shadows';
this.type = 'custom';
this.renderingMode = '3d';
this.opacity = 0.5;
}
onAdd(map, gl) {
this.map = map;
const vertexSource = `
uniform mat4 u_matrix;
uniform float u_height_factor;
uniform float u_altitude;
uniform float u_azimuth;
attribute vec2 a_pos;
attribute vec4 a_normal_ed;
attribute lowp vec2 a_base;
attribute lowp vec2 a_height;
void main() {
float base = max(0.0, a_base.x);
float height = max(0.0, a_height.x);
float t = mod(a_normal_ed.x, 2.0);
vec4 pos = vec4(a_pos, t > 0.0 ? height : base, 1);
float len = pos.z * u_height_factor / tan(u_altitude);
pos.x += cos(u_azimuth) * len;
pos.y += sin(u_azimuth) * len;
pos.z = 0.0;
gl_Position = u_matrix * pos;
}
`;
const fragmentSource = `
void main() {
gl_FragColor = vec4(5.0, 0.0, 0.0, 0.1);
}
`;
const vertexShader = gl.createShader(gl.VERTEX_SHADER);
gl.shaderSource(vertexShader, vertexSource);
gl.compileShader(vertexShader);
const fragmentShader = gl.createShader(gl.FRAGMENT_SHADER);
gl.shaderSource(fragmentShader, fragmentSource);
gl.compileShader(fragmentShader);
this.program = gl.createProgram();
gl.attachShader(this.program, vertexShader);
gl.attachShader(this.program, fragmentShader);
gl.linkProgram(this.program);
gl.validateProgram(this.program);
this.uMatrix = gl.getUniformLocation(this.program, "u_matrix");
this.uHeightFactor = gl.getUniformLocation(this.program, "u_height_factor");
this.uAltitude = gl.getUniformLocation(this.program, "u_altitude");
this.uAzimuth = gl.getUniformLocation(this.program, "u_azimuth");
this.aPos = gl.getAttribLocation(this.program, "a_pos");
this.aNormal = gl.getAttribLocation(this.program, "a_normal_ed");
this.aBase = gl.getAttribLocation(this.program, "a_base");
this.aHeight = gl.getAttribLocation(this.program, "a_height");
}
render(gl, matrix) {
gl.useProgram(this.program);
const source = this.map.style.sourceCaches['composite'];
const coords = source.getVisibleCoordinates().reverse();
const buildingsLayer = map.getLayer('3d-buildings');
const context = this.map.painter.context;
const {lng, lat} = this.map.getCenter();
const pos = SunCalc.getPosition(date, lat, lng);
gl.uniform1f(this.uAltitude, pos.altitude);
gl.uniform1f(this.uAzimuth, pos.azimuth + 3 * Math.PI / 2);
map.setLight({
anchor: 'map',
position: [1.5, 180 + pos.azimuth * 180 / Math.PI, 90 - pos.altitude * 180 / Math.PI],
'position-transition': {duration: 0},
color: '#fdb'
// color: `hsl(20, ${50 * Math.cos(pos.altitude)}%, ${ 200 * Math.sin(pos.altitude) }%)`
}, {duration: 0});
this.opacity = Math.sin(Math.max(pos.altitude, 0)) * 0.9;
// ADDED: New Attempt to normalise the colour of the shadows
gl.depthMask(false);
gl.enable(gl.BLEND)
gl.blendFuncSeparate(gl.SRC_ALPHA, gl.ONE_MINUS_SRC_ALPHA, gl.ONE, gl.ONE_MINUS_SRC_ALPHA);
for (const coord of coords) {
const tile = source.getTile(coord);
const bucket = tile.getBucket(buildingsLayer);
if (!bucket) continue;
const [heightBuffer, baseBuffer] = bucket.programConfigurations.programConfigurations['3d-buildings']._buffers;
gl.uniformMatrix4fv(this.uMatrix, false, coord.posMatrix);
gl.uniform1f(this.uHeightFactor, Math.pow(2, coord.overscaledZ) / tile.tileSize / 8);
for (const segment of bucket.segments.get()) {
const numPrevAttrib = context.currentNumAttributes || 0;
const numNextAttrib = 2;
for (let i = numNextAttrib; i < numPrevAttrib; i++) gl.disableVertexAttribArray(i);
const vertexOffset = segment.vertexOffset || 0;
gl.enableVertexAttribArray(this.aPos);
gl.enableVertexAttribArray(this.aNormal);
gl.enableVertexAttribArray(this.aHeight);
gl.enableVertexAttribArray(this.aBase);
bucket.layoutVertexBuffer.bind();
gl.vertexAttribPointer(this.aPos, 2, gl.SHORT, false, 12, 12 * vertexOffset);
gl.vertexAttribPointer(this.aNormal, 4, gl.SHORT, false, 12, 4 + 12 * vertexOffset);
heightBuffer.bind();
gl.vertexAttribPointer(this.aHeight, 1, gl.FLOAT, false, 4, 4 * vertexOffset);
baseBuffer.bind();
gl.vertexAttribPointer(this.aBase, 1, gl.FLOAT, false, 4, 4 * vertexOffset);
bucket.indexBuffer.bind();
context.currentNumAttributes = numNextAttrib;
gl.drawElements(gl.TRIANGLES, segment.primitiveLength * 3, gl.UNSIGNED_SHORT, segment.primitiveOffset * 3 * 2);
}
}
}
}
map.on('load', () => {
map.removeLayer('building');
map.addLayer({
'id': '3d-buildings',
'source': 'composite',
'source-layer': 'building',
'type': 'fill-extrusion',
'minzoom': 14,
'paint': {
'fill-extrusion-color': '#ddd',
'fill-extrusion-height': ["number", ["get", "height"], 5],
'fill-extrusion-base': ["number", ["get", "min_height"], 0],
'fill-extrusion-opacity': 1
}
}, 'road-label');
map.addLayer(new BuildingShadows(), '3d-buildings');
});
</script>
</body>
</html>

There are various variations but
draw all the shadows into the stencil buffer then draw one quad with the stencil test on so that it only draws where the stencil is set?
draw all the shadows opaquely into a texture. draw the texture as a quad over the map.
draw all the shadows into the depth buffer. draw one quad with the depth test set so it only draws where there were shadows.
also
draw the shadows with the depth test or stencil test on such that no pixel can be drawn more than once.
Various related examples:
Stencil buffer in WebGL
WebGL – Use mesh as mask for background image
Is there a way in WebGL to quickly invert the stencil buffer?

Three.js (GLSL) — Canvas resize

I am trying to preserve the proportions at least a little when the window is resized to smaller sizes at the CodePen here. Currently it turns out to be really hard to see the lines and the interaction on mobile. Do you have a solution for this? Maybe it makes sense to double the scale on resize based on the window but I am a bit lost on how I can implement it.
The responsible part of the JS:
onWindowResize();
window.addEventListener('resize', onWindowResize, false);
}
function onWindowResize(event) {
container.style.height = window.innerHeight+"px";
container.style.width = window.innerWidth+"px";
canvasWidth = container.offsetWidth;
canvasHeight = container.offsetHeight;
//send new size value to the shader and resize the window
uniforms.resolution.value.x = canvasWidth;
uniforms.resolution.value.y = canvasHeight;
//var res = canvasWidth / cols;
//rows = canvasHeight / res;
uniforms.colsrows.value.x = cols;
uniforms.colsrows.value.y = rows;//rows;
renderer.setSize(canvasWidth, canvasHeight);
}
Here is the pen:
//Create var for the contenair, the webGL 3D scene, uniforms to bind into shader and timer
var container;
var camera, scene, renderer;
var uniforms;
var startTime;
var cols = 50.;
var rows = 50.0;
init(); //init scene
animate(); //updateScene
function init() {
//get contenaire
container = document.getElementById('container');
//Create THREE.JS scene and timer
startTime = Date.now();
camera = new THREE.Camera();
camera.position.z = 1;
scene = new THREE.Scene();
//create a simple plance
var geometry = new THREE.PlaneBufferGeometry(16, 9);
//create uniform table which provide all our GLSL binding
uniforms = {
time: { type: "f", value: 1.0 },
resolution: { type: "v2", value: new THREE.Vector2() },
colsrows: {type: "v2", value: new THREE.Vector2()},
mouse: {type: "v2", value: new THREE.Vector2()}
};
//create THREE.JS material
var material = new THREE.ShaderMaterial( {
//set shaders and uniforms into material
uniforms: uniforms,
vertexShader: document.getElementById('vertexShader').textContent,
fragmentShader: document.getElementById('fragmentShader').textContent
} );
//create mesh, add it to the scene
var mesh = new THREE.Mesh(geometry, material);
scene.add(mesh);
//create renderer and add it to the DOM
renderer = new THREE.WebGLRenderer();
container.appendChild(renderer.domElement);
//check window for resize This will give us the proper resolution values to bind
onWindowResize();
window.addEventListener('resize', onWindowResize, false);
}
function onWindowResize(event) {
container.style.height = window.innerHeight+"px";
container.style.width = window.innerWidth+"px";
canvasWidth = container.offsetWidth;
canvasHeight = container.offsetHeight;
//send new size value to the shader and resize the window
uniforms.resolution.value.x = canvasWidth;
uniforms.resolution.value.y = canvasHeight;
//var res = canvasWidth / cols;
//rows = canvasHeight / res;
uniforms.colsrows.value.x = cols;
uniforms.colsrows.value.y = rows;//rows;
renderer.setSize(canvasWidth, canvasHeight);
}
function animate() {
render();
requestAnimationFrame(animate);
}
function render() {
var currentTime = Date.now();
var elaspedSeconds = (currentTime - startTime) / 1000.0;
var maxTime = 4.0;
var normTime = (elaspedSeconds % maxTime) / maxTime;
uniforms.time.value = elaspedSeconds * 1.0;
renderer.render(scene, camera);
}
function move(ev){
mx = ev.clientX
my = ev.clientY;
// console.log(mx+" , "+my);
uniforms.mouse.value.x = mx;
uniforms.mouse.value.y = my;
}
document.addEventListener('mousemove', move)
html, body {
margin: 0;
height: 100%;
background : #1a1a1a;
}
canvas {
display: block;
cursor: none;
}
#container{
background : black;
color : white;
margin: auto;
width : 500px;
height : 500px;
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/three.js/110/three.min.js"></script>
<div id="container"></div>
<!-- GLSL SCRIPT -->
<!-- vertex shader -->
<script id="vertexShader" type="x-shader/x-vertex">
void main() {
gl_Position = vec4(position, 1.0);
}
</script>
<!-- fragment shader -->
<script id="fragmentShader" type="x-shader/x-fragment">
#define TWO_PI 6.28318530718
#define EPSILON 0.000011
uniform vec2 resolution;
uniform float time;
uniform vec2 colsrows;
uniform vec2 mouse;
float HueToRGB(float f1, float f2, float hue)
{
if (hue < 0.0)
hue += 1.0;
else if (hue > 1.0)
hue -= 1.0;
float res;
if ((6.0 * hue) < 1.0)
res = f1 + (f2 - f1) * 6.0 * hue;
else if ((2.0 * hue) < 1.0)
res = f2;
else if ((3.0 * hue) < 2.0)
res = f1 + (f2 - f1) * ((2.0 / 3.0) - hue) * 6.0;
else
res = f1;
return res;
}
vec3 HSLToRGB(vec3 hsl)
{
vec3 rgb;
if (hsl.y == 0.0)
rgb = vec3(hsl.z); // Luminance
else
{
float f2;
if (hsl.z < 0.5)
f2 = hsl.z * (1.0 + hsl.y);
else
f2 = (hsl.z + hsl.y) - (hsl.y * hsl.z);
float f1 = 2.0 * hsl.z - f2;
rgb.r = HueToRGB(f1, f2, hsl.x + (1.0/3.0));
rgb.g = HueToRGB(f1, f2, hsl.x);
rgb.b= HueToRGB(f1, f2, hsl.x - (1.0/3.0));
}
return rgb;
}
mat2 rotate2d(float _angle){
return mat2(cos(_angle),-sin(_angle),
sin(_angle),cos(_angle));
}
vec2 rotateFrom(vec2 uv, vec2 center, float angle){
vec2 uv_ = uv - center;
uv_ = rotate2d(angle) * uv_;
uv_ = uv_ + center;
return uv_;
}
float random(float value){
return fract(sin(value) * 43758.5453123);
}
float random(vec2 tex){
return fract(sin(dot(tex.xy, vec2(12.9898, 78.233))) * 43758.5453123);
}
vec2 random2D(vec2 uv){
uv = vec2(dot(uv, vec2(127.1, 311.7)), dot(uv, vec2(269.5, 183.3)));
//return -1.0 + 2.0 * fract(sin(uv) * 43758.5453123);
return fract(sin(uv) * 43758.5453123); //return without offset on x, y
}
vec3 random3D(vec3 uv){
uv = vec3(dot(uv, vec3(127.1, 311.7, 120.9898)), dot(uv, vec3(269.5, 183.3, 150.457)), dot(uv, vec3(380.5, 182.3, 170.457)));
return -1.0 + 2.0 * fract(sin(uv) * 43758.5453123);
}
float cubicCurve(float value){
return value * value * (3.0 - 2.0 * value); // custom cubic curve
}
vec2 cubicCurve(vec2 value){
return value * value * (3.0 - 2.0 * value); // custom cubic curve
}
vec3 cubicCurve(vec3 value){
return value * value * (3.0 - 2.0 * value); // custom cubic curve
}
float noise(vec2 uv){
vec2 iuv = floor(uv);
vec2 fuv = fract(uv);
vec2 suv = cubicCurve(fuv);
float dotAA_ = dot(random2D(iuv + vec2(0.0)), fuv - vec2(0.0));
float dotBB_ = dot(random2D(iuv + vec2(1.0, 0.0)), fuv - vec2(1.0, 0.0));
float dotCC_ = dot(random2D(iuv + vec2(0.0, 1.0)), fuv - vec2(0.0, 1.0));
float dotDD_ = dot(random2D(iuv + vec2(1.0, 1.0)), fuv - vec2(1.0, 1.0));
return mix(
mix(dotAA_, dotBB_, suv.x),
mix(dotCC_, dotDD_, suv.x),
suv.y);
}
float noise(vec3 uv){
vec3 iuv = floor(uv);
vec3 fuv = fract(uv);
vec3 suv = cubicCurve(fuv);
float dotAA_ = dot(random3D(iuv + vec3(0.0)), fuv - vec3(0.0));
float dotBB_ = dot(random3D(iuv + vec3(1.0, 0.0, 0.0)), fuv - vec3(1.0, 0.0, 0.0));
float dotCC_ = dot(random3D(iuv + vec3(0.0, 1.0, 0.0)), fuv - vec3(0.0, 1.0, 0.0));
float dotDD_ = dot(random3D(iuv + vec3(1.0, 1.0, 0.0)), fuv - vec3(1.0, 1.0, 0.0));
float dotEE_ = dot(random3D(iuv + vec3(0.0, 0.0, 1.0)), fuv - vec3(0.0, 0.0, 1.0));
float dotFF_ = dot(random3D(iuv + vec3(1.0, 0.0, 1.0)), fuv - vec3(1.0, 0.0, 1.0));
float dotGG_ = dot(random3D(iuv + vec3(0.0, 1.0, 1.0)), fuv - vec3(0.0, 1.0, 1.0));
float dotHH_ = dot(random3D(iuv + vec3(1.0, 1.0, 1.0)), fuv - vec3(1.0, 1.0, 1.0));
float passH0 = mix(
mix(dotAA_, dotBB_, suv.x),
mix(dotCC_, dotDD_, suv.x),
suv.y);
float passH1 = mix(
mix(dotEE_, dotFF_, suv.x),
mix(dotGG_, dotHH_, suv.x),
suv.y);
return mix(passH0, passH1, suv.z);
}
float drawLine(vec2 uv, vec2 p1, vec2 p2, float r)
{
//from https://www.shadertoy.com/view/MtlSDr
vec2 l = p2 - p1;
float L = length(l);
float L2 = L*L;
float d1 = length(uv - p1);
float d2 = length(uv - p2);
float d = min(d1, d2);
float ds = dot(uv - p1, l);
if (ds >= 0.0 && ds <= L2)
{
vec2 n = vec2(-l.y, l.x) / L;
d = min(d, abs(dot(uv - p1, n)));
}
return 1.0 - smoothstep(0.0, 0.01, d - r);
}
vec2 fishey(vec2 uv, vec2 center, float ratio, float dist){
vec2 puv = uv + vec2(1.0);
//center coords
vec2 m = vec2(center.x, center.y/ratio) + vec2(1.0);
//vector from center to current fragment
vec2 d = puv - m;
// distance of pixel from center
float r = sqrt(dot(d, d));
//amount of effect
float power = ( TWO_PI / (2.0 * sqrt(dot(m, m)))) * mix(0.1, 0.4, pow(dist, 0.75));
//radius of 1:1 effect
float bind;
if (power > 0.0) bind = sqrt(dot(m, m));//stick to corners
//else {if (ratio < 1.0) bind = m.x; else bind = m.y;}//stick to borders
//Weird formulas
vec2 nuv;
if (power > 0.0)//fisheye
nuv = m + normalize(d) * tan(r * power) * bind / tan( bind * power);
else if (power < 0.0)//antifisheye
nuv = m + normalize(d) * atan(r * -power * 10.0) * bind / atan(-power * bind * 10.0);
else
nuv = puv;//no effect for power = 1.0
return nuv - vec2(1.0);
}
vec4 addGrain(vec2 uv, float time, float grainIntensity){
float grain = random(fract(uv * time)) * grainIntensity;
return vec4(vec3(grain), 1.0);
}
void main(){
vec2 ouv = gl_FragCoord.xy / resolution.xy;
vec2 uv = ouv;
float ratio = resolution.x / resolution.y;
vec2 nmouse = vec2(mouse.x, mouse.y) / resolution.xy;
nmouse.y = 1.0 - nmouse.y;
float maxDist = 0.35;
float blurEdge = maxDist * 0.5;
float blurEdge2 = maxDist * 1.0;
vec2 mouseToUV = (uv - nmouse) / vec2(1.0, ratio);
float mouseDistance = 1.0 - smoothstep(maxDist - blurEdge, maxDist, length(mouseToUV));
float mouseDistance2 = 1.0 - smoothstep(maxDist - blurEdge2, maxDist, length(mouseToUV));
uv = fishey(uv, nmouse, ratio, mouseDistance2);
uv = rotateFrom(uv, vec2(0.5), time * 0.1);
//animate y
//wave
uv.y /= ratio;
vec2 basedUV = uv + vec2(1.0);
float complexityX = 10.0;
float complexityY = 10.0;
float maxAmp = mix(0.05, 0.75, mouseDistance);
float amp = 0.01 * mouseDistance + noise(vec3(basedUV.x * complexityX, basedUV.y * complexityY, time * 0.1)) * maxAmp;
float theta = time + mouseDistance + basedUV.y * (TWO_PI);
uv.x = fract(uv.x + sin(theta) * amp);
//divide into cols rows
vec2 nuv = uv * colsrows;
vec2 fuv = fract(nuv);
vec2 iuv = floor(nuv);
float minSpeed = 1.0;
float maxSpeed = 5.0;
float speed = minSpeed + random(floor(uv.x * colsrows.x)) * (maxSpeed - minSpeed);
fuv.y = fract(fuv.y + time * speed);
//draw dash line
float minWeight = 0.005 + random(vec2(iuv.x, 0.0)) * 0.05;
float strokeWeight = mix(minWeight, minWeight * 5.0, mouseDistance);
float dlineWidth = mix(1.0, 0.25 - strokeWeight, mouseDistance);//0.5 - strokeWeight;
float dline = drawLine(fuv, vec2(0.5, 0.5 - dlineWidth * 0.5), vec2(0.5, 0.5 + dlineWidth * 0.5), strokeWeight);
float randIndexHue = random(vec2(iuv.x + floor(time), 0.0));
float noiseHue = noise(vec3(randIndexHue, randIndexHue, time));
float hue = mix(0.111, 0.138, randIndexHue + (noiseHue * 0.5));
vec4 grain = addGrain(ouv, time, 0.15);
//vec3 color = HSLToRGB(vec3(hue, 1.0, 0.5));
//vec3 bgColor = HSLToRGB(vec3(0.772, mix(0.75, 1.0, mouseDistance), mix(0.1, 0.25, mouseDistance)));
vec3 color = vec3(1.0);
vec3 bgColor = vec3(0.0);
float val = dline * (mouseDistance * 0.5 + 0.5);
vec3 albedo = mix(bgColor, color, val);
gl_FragColor = vec4(albedo, 1.0) + grain;
}
</script>

The thickness of the lines is computed in drawLine and depends on the parameters to smoothstep:
float drawLine(vec2 uv, vec2 p1, vec2 p2, float r)
{
// [...]
return 1.0 - smoothstep(0.0, 0.01, d - r);
}
Increase the parameter to edge1, to generate "thicker" lines (e.g. 0.1):
float drawLine(vec2 uv, vec2 p1, vec2 p2, float r)
{
// [...]
return 1.0 - smoothstep(0.0, 0.1, d - r);
}
You can add an additional uniform variable for the line:
uniform float thickness;
float drawLine(vec2 uv, vec2 p1, vec2 p2, float r)
{
// [...]
return 1.0 - smoothstep(0.0, thickness, d - r);
}
uniforms = {
// [...]
thickness: { type: "f", value: 0.1 },
};

how to achieve this motion blur shader effect?

I tried to create the snow effect like the one on the bottom page of this link http://blog.edankwan.com/post/my-first-christmas-experiment. Everything else works fine But just can't make the motion blur effect work. Any ideas?
the texture sprite used to achieve the motion blur effect
here is the code:
(function(global) {
var img = 'https://i.imgur.com/hlmsgWA.png'
var renderer, scene, camera
var w = 800, h = 320
var uniforms
var geometry
var texture, material
var gui
var conf = {
amount: 200,
speed: 0.5,
time: 0
}
var obj = {
init: function() {
renderer = new THREE.WebGLRenderer({
antialias: true
})
renderer.setPixelRatio(window.devicePixelRatio)
renderer.setSize(w, h)
camera = new THREE.Camera
scene = new THREE.Scene()
geometry = new THREE.BufferGeometry()
var positions = []
for(var i = 0, l = conf.amount; i < l; i++) {
positions[i * 3] = Math.random() * 800 - 400
positions[i * 3 + 1] = i
positions[i * 3 + 2] = Math.random() * 800
}
geometry.addAttribute('position', new THREE.Float32BufferAttribute(positions, 3))
var vs = document.getElementById('vertexShader').textContent
var fs = document.getElementById('fragmentShader').textContent
uniforms = {
u_amount: {
type: 'f',
value: conf.amount
},
u_speed: {
type: 'f',
value: conf.speed
},
u_time: {
type: 'f',
value: conf.time
},
u_resolution: {
type: 'vec2',
value: new THREE.Vector2(w, h)
},
u_texture : {
value: new THREE.TextureLoader().load(img)
}
}
material = new THREE.ShaderMaterial({
uniforms: uniforms,
vertexShader: vs,
fragmentShader: fs,
transparent: true
})
var points = new THREE.Points(geometry, material)
scene.add(points)
document.body.appendChild(renderer.domElement)
this.render()
this.createGui()
},
createGui: function() {
gui = new dat.GUI()
gui.add(conf, 'speed', -1, 1)
},
render: function() {
requestAnimationFrame(this.render.bind(this))
uniforms.u_time.value += conf.speed * 0.003
renderer.render(scene, camera)
}
}
obj.init()
})(window)
<script id="vertexShader" type="x-shader/x-vertex">
precision highp float;
vec3 getPosOffset(float ratio, float thershold) {
return vec3(
cos((ratio * 80.0 + 10.0) * thershold) * 20.0 * thershold,
(sin((ratio * 90.0 + 30.0) * thershold) + 1.0) * 5.0 * thershold + mix(500.0, -500.0, ratio / thershold),
sin((ratio * 70.0 + 20.0) * thershold) * 20.0 * thershold
);
}
uniform vec2 u_resolution;
uniform float u_amount;
uniform float u_speed;
uniform float u_time;
varying float v_alpha;
varying float v_rotation;
varying float v_index;
void main() {
float indexRatio = position.y / u_amount;
float thershold = 0.7 + indexRatio * 0.3;
float ratio = mod(u_time - indexRatio * 3.0, thershold);
float prevRatio = mod(u_time - u_speed - indexRatio * 3.0, thershold);
vec3 offsetPos = getPosOffset(ratio, thershold);
vec3 prevOffsetPos = getPosOffset(prevRatio, thershold);
vec3 pos = position;
pos += offsetPos;
float perspective = (2000.0 - pos.z) / 2000.0;
pos.x *= perspective;
pos.y *= perspective;
float delta = length(offsetPos.xy - prevOffsetPos.xy);
float maxDelta = 2.7;
v_index = floor(pow(clamp(delta, 0.0, maxDelta) / maxDelta, 5.0) * 15.99);
v_rotation = atan((offsetPos.x - prevOffsetPos.x) / (offsetPos.y - prevOffsetPos.y));
pos.x *= 2.0 / u_resolution.x;
pos.y *= 2.0 / u_resolution.y;
pos.z = 0.0;
gl_Position = projectionMatrix * modelViewMatrix * vec4(pos, 1.0);
gl_PointSize = 24.0 * perspective;
v_alpha = perspective;
}
</script>
<script id="fragmentShader" type="x-shader/x-fragment">
uniform sampler2D u_texture;
varying float v_rotation;
varying float v_index;
varying float v_alpha;
void main() {
vec2 coord = gl_PointCoord.xy;
coord = vec2(
clamp(cos(v_rotation) * (coord.x - 0.5) + sin(v_rotation) * (coord.y - 0.5) + 0.5, 0.0, 1.0),
clamp(cos(v_rotation) * (coord.y - 0.5) - sin(v_rotation) * (coord.x - 0.5) + 0.5, 0.0, 1.0)
);
float index = floor(v_index + 0.5);
coord.y = - coord.y + 4.0;
coord.x += (index - floor(index / 4.0) * 4.0);
coord.y -= floor(index / 4.0);
coord *= 0.25;
vec4 color = texture2D(u_texture, coord);
color.a *= v_alpha;
gl_FragColor = color;
}
</script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/three.js/99/three.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/dat-gui/0.7.3/dat.gui.js"></script>
http://blog.edankwan.com/post/my-first-christmas-experiment.

In snippet code you treat variable speed differently in your update loop and in vertex shader.
Update: uniforms.u_time.value += conf.speed * 0.003
Shader usage: float prevRatio = mod(u_time - u_speed - indexRatio * 3.0, thershold);
You'll get desired result if you change u_speed to u_speed * 0.003 in shader code (or better move that multiplication to definition in javascript).
Fast way to debug such things - pass your values to output color and check if it is what you expect.
==================
If someone wants to make tails with non-flat curvature - you can store last N points of each particle path. Then you can fully compute trail mesh geometry on CPU and stream it to GPU.
Or another way: you can upload all paths to single Uniform Buffer Object and find right point to fetch with pointId and uv of tail mesh vertex.

Bump Mapping with javascript and glsl

/**
* A class creating buffers for a textured box to render it with WebGL
*/
class RasterTextureBox {
/**
* Creates all WebGL buffers for the textured box
* 6 ------- 7
* / | / |
* 3 ------- 2 |
* | | | |
* | 5 -----|- 4
* | / | /
* 0 ------- 1
* looking in negative z axis direction
* #param {WebGLContext} gl - The canvas' context
* #param {Vector} minPoint - The minimal x,y,z of the box
* #param {Vector} maxPoint - The maximal x,y,z of the box
*/
constructor(gl, minPoint, maxPoint, texture) {
this.gl = gl;
const mi = minPoint;
const ma = maxPoint;
let vertices = [
// front
mi.x, mi.y, ma.z, ma.x, mi.y, ma.z, ma.x, ma.y, ma.z,
ma.x, ma.y, ma.z, mi.x, ma.y, ma.z, mi.x, mi.y, ma.z,
// back
ma.x, mi.y, mi.z, mi.x, mi.y, mi.z, mi.x, ma.y, mi.z,
mi.x, ma.y, mi.z, ma.x, ma.y, mi.z, ma.x, mi.y, mi.z,
// right
ma.x, mi.y, ma.z, ma.x, mi.y, mi.z, ma.x, ma.y, mi.z,
ma.x, ma.y, mi.z, ma.x, ma.y, ma.z, ma.x, mi.y, ma.z,
// top
mi.x, ma.y, ma.z, ma.x, ma.y, ma.z, ma.x, ma.y, mi.z,
ma.x, ma.y, mi.z, mi.x, ma.y, mi.z, mi.x, ma.y, ma.z,
// left
mi.x, mi.y, mi.z, mi.x, mi.y, ma.z, mi.x, ma.y, ma.z,
mi.x, ma.y, ma.z, mi.x, ma.y, mi.z, mi.x, mi.y, mi.z,
// bottom
mi.x, mi.y, mi.z, ma.x, mi.y, mi.z, ma.x, mi.y, ma.z,
ma.x, mi.y, ma.z, mi.x, mi.y, ma.z, mi.x, mi.y, mi.z
];
const vertexBuffer = gl.createBuffer();
gl.bindBuffer(gl.ARRAY_BUFFER, vertexBuffer);
gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(vertices), gl.STATIC_DRAW);
this.vertexBuffer = vertexBuffer;
this.elements = vertices.length / 3;
let cubeTexture = gl.createTexture();
let cubeImage = new Image();
cubeImage.onload = function () {
gl.bindTexture(gl.TEXTURE_2D, cubeTexture);
gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, gl.RGBA, gl.UNSIGNED_BYTE, cubeImage);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE);
gl.bindTexture(gl.TEXTURE_2D, null);
}
cubeImage.src = texture;
this.texBuffer = cubeTexture;
let uv = [
// front
0, 0, 1, 0, 1, 1,
1, 1, 0, 1, 0, 0,
// back
0, 0, 1, 0, 1, 1,
1, 1, 0, 1, 0, 0,
// right
0, 0, 1, 0, 1, 1,
1, 1, 0, 1, 0, 0,
// top
0, 0, 1, 0, 1, 1,
1, 1, 0, 1, 0, 0,
// left
0, 0, 1, 0, 1, 1,
1, 1, 0, 1, 0, 0,
// bottom
0, 0, 1, 0, 1, 1,
1, 1, 0, 1, 0, 0,
];
let uvBuffer = this.gl.createBuffer();
gl.bindBuffer(gl.ARRAY_BUFFER, uvBuffer);
gl.bufferData(this.gl.ARRAY_BUFFER, new Float32Array(uv),
gl.STATIC_DRAW);
this.texCoords = uvBuffer;
}
render(shader) {
this.gl.bindBuffer(this.gl.ARRAY_BUFFER, this.vertexBuffer);
const positionLocation = shader.getAttributeLocation("a_position");
this.gl.enableVertexAttribArray(positionLocation);
this.gl.vertexAttribPointer(positionLocation, 3, this.gl.FLOAT, false, 0, 0);
// Bind the texture coordinates in this.texCoords
// to their attribute in the shader
this.gl.bindBuffer(this.gl.ARRAY_BUFFER, this.texCoords);
const texCoordLocation = shader.getAttributeLocation("a_texCoord");
this.gl.enableVertexAttribArray(texCoordLocation);
this.gl.vertexAttribPointer(texCoordLocation, 2, this.gl.FLOAT, false, 0, 0);
this.gl.activeTexture(gl.TEXTURE0);
this.gl.bindTexture(gl.TEXTURE_2D, this.texBuffer);
shader.getUniformInt("sampler").set(0);
this.gl.drawArrays(this.gl.TRIANGLES, 0, this.elements);
this.gl.disableVertexAttribArray(positionLocation);
//disable texture vertex attrib array
this.gl.disableVertexAttribArray(texCoordLocation);
}
}
/**
* Class representing a 4x4 Matrix
*/
class Matrix {
constructor(mat) {
this.data = new Float32Array(16);
for (let row = 0; row < 4; row++) {
for (let col = 0; col < 4; col++) {
this.data[row * 4 + col] = mat[col * 4 + row];
}
}
}
getVal(row, col) {
return this.data[col * 4 + row];
}
setVal(row, col, val) {
this.data[col * 4 + row] = val;
}
static translation(translation) {
let m = Matrix.identity();
m.setVal(0, 3, translation.x);
m.setVal(1, 3, translation.y);
m.setVal(2, 3, translation.z);
return m;
}
static rotation(axis, angle) {
let m = Matrix.identity()
let sin = Math.sin(angle);
let cos = Math.cos(angle);
if (axis.x != 0) {
m.setVal(1, 1, cos);
m.setVal(1, 2, -sin);
m.setVal(2, 1, sin);
m.setVal(2, 2, cos);
} else if (axis.y != 0) {
m.setVal(0, 0, cos);
m.setVal(0, 2, sin);
m.setVal(2, 0, -sin);
m.setVal(2, 2, cos);
} else {
m.setVal(0, 0, cos);
m.setVal(0, 1, -sin);
m.setVal(1, 0, sin);
m.setVal(1, 1, cos);
}
return m;
}
static scaling(scale) {
let m = Matrix.identity();
m.setVal(0, 0, scale.x);
m.setVal(1, 1, scale.y);
m.setVal(2, 2, scale.z);
return m;
}
/**
* Constructs a lookat matrix
* #param {Vector} eye - The position of the viewer
* #param {Vector} center - The position to look at
* #param {Vector} up - The up direction
* #return {Matrix} The resulting lookat matrix
*/
static lookat(eye, center, up) {
let fBig = center.sub(eye);
// Vom Eye zum Center Punkt
let f = fBig.normalised();
// UP-Vektor
let upNorm = up.normalised();
// Kreuzprodukt
let s = f.cross(upNorm);
let u = s.normalised().cross(f);
// s, u und f sind die Vektoren des Kamerakoordinatensystems
// Lookat Matrix, 3x3 betrifft Rotation und Skalierung
let mat = new Matrix([
s.x, s.y, s.z, 0,
u.x, u.y, u.z, 0, -f.x, -f.y, -f.z, 0,
0, 0, 0, 1
]);
// Noch weitere Berechnungen? Translation
let trans = Matrix.translation(eye.mul(-1));
mat = mat.mul(trans);
return mat;
}
static frustum(left, right, bottom, top, near, far) {
// TODO [exercise 9]
const n2 = 2 * near;
const rpl = right + left;
const rml = right - left;
const tpb = top + bottom;
const tmb = top - bottom;
const fpn = far + near;
const fmn = far - near;
const n2f = n2 * far;
return new Matrix([
n2 / rml, 0, rpl / rml, 0,
0, n2 / tmb, tpb / tmb, 0,
0, 0, -fpn / fmn, -n2f / fmn,
0, 0, -1, 0
]);
}
static perspective(fovy, aspect, near, far) {
// frustum Methode verwenden. Foliensatz 10
const top = near * Math.tan((Math.PI / 180) * (fovy / 2));
const bottom = -top;
const right = top * aspect;
const left = -right;
return Matrix.frustum(left, right, bottom, top, near, far);
}
/**
* Returns the identity matrix
*/
static identity() {
return new Matrix([
1, 0, 0, 0,
0, 1, 0, 0,
0, 0, 1, 0,
0, 0, 0, 1
]);
}
mul(other) {
if (other instanceof Matrix) {
// [exercise 7]
let m = Matrix.identity();
for (let row = 0; row < 4; row++) {
for (let col = 0; col < 4; col++) {
let sum = 0;
for (let i = 0; i < 4; i++) {
sum += this.getVal(row, i) * other.getVal(i, col);
}
m.setVal(row, col, sum);
}
}
return m;
} else {
let v = [0, 0, 0, 0];
for (let row = 0; row < 4; row++) {
for (let i = 0; i < 4; i++) {
v[row] += this.getVal(row, i) * other.valueOf()[i];
}
}
return new Vector(v[0], v[1], v[2], v[3]);
}
}
transpose() {
let m = Matrix.identity();
for (let row = 0; row < 4; row++) {
for (let col = 0; col < 4; col++) {
m.setVal(row, col, this.getVal(col, row));
}
}
return m;
}
invert() {
let mat = this.data;
let dst = new Float32Array(16); //ret.getValues();
let tmp = new Float32Array(12);
/* temparray for pairs */
let src = new Float32Array(16); //new float[16];
/* array of transpose source matrix */
let det;
for (let i = 0; i < 4; i++) {
src[i] = mat[i * 4];
src[i + 4] = mat[i * 4 + 1];
src[i + 8] = mat[i * 4 + 2];
src[i + 12] = mat[i * 4 + 3];
}
tmp[0] = src[10] * src[15];
tmp[1] = src[11] * src[14];
tmp[2] = src[9] * src[15];
tmp[3] = src[11] * src[13];
tmp[4] = src[9] * src[14];
tmp[5] = src[10] * src[13];
tmp[6] = src[8] * src[15];
tmp[7] = src[11] * src[12];
tmp[8] = src[8] * src[14];
tmp[9] = src[10] * src[12];
tmp[10] = src[8] * src[13];
tmp[11] = src[9] * src[12];
dst[0] = tmp[0] * src[5] + tmp[3] * src[6] + tmp[4] * src[7];
dst[0] -= tmp[1] * src[5] + tmp[2] * src[6] + tmp[5] * src[7];
dst[1] = tmp[1] * src[4] + tmp[6] * src[6] + tmp[9] * src[7];
dst[1] -= tmp[0] * src[4] + tmp[7] * src[6] + tmp[8] * src[7];
dst[2] = tmp[2] * src[4] + tmp[7] * src[5] + tmp[10] * src[7];
dst[2] -= tmp[3] * src[4] + tmp[6] * src[5] + tmp[11] * src[7];
dst[3] = tmp[5] * src[4] + tmp[8] * src[5] + tmp[11] * src[6];
dst[3] -= tmp[4] * src[4] + tmp[9] * src[5] + tmp[10] * src[6];
dst[4] = tmp[1] * src[1] + tmp[2] * src[2] + tmp[5] * src[3];
dst[4] -= tmp[0] * src[1] + tmp[3] * src[2] + tmp[4] * src[3];
dst[5] = tmp[0] * src[0] + tmp[7] * src[2] + tmp[8] * src[3];
dst[5] -= tmp[1] * src[0] + tmp[6] * src[2] + tmp[9] * src[3];
dst[6] = tmp[3] * src[0] + tmp[6] * src[1] + tmp[11] * src[3];
dst[6] -= tmp[2] * src[0] + tmp[7] * src[1] + tmp[10] * src[3];
dst[7] = tmp[4] * src[0] + tmp[9] * src[1] + tmp[10] * src[2];
dst[7] -= tmp[5] * src[0] + tmp[8] * src[1] + tmp[11] * src[2];
tmp[0] = src[2] * src[7];
tmp[1] = src[3] * src[6];
tmp[2] = src[1] * src[7];
tmp[3] = src[3] * src[5];
tmp[4] = src[1] * src[6];
tmp[5] = src[2] * src[5];
tmp[6] = src[0] * src[7];
tmp[7] = src[3] * src[4];
tmp[8] = src[0] * src[6];
tmp[9] = src[2] * src[4];
tmp[10] = src[0] * src[5];
tmp[11] = src[1] * src[4];
dst[8] = tmp[0] * src[13] + tmp[3] * src[14] + tmp[4] * src[15];
dst[8] -= tmp[1] * src[13] + tmp[2] * src[14] + tmp[5] * src[15];
dst[9] = tmp[1] * src[12] + tmp[6] * src[14] + tmp[9] * src[15];
dst[9] -= tmp[0] * src[12] + tmp[7] * src[14] + tmp[8] * src[15];
dst[10] = tmp[2] * src[12] + tmp[7] * src[13] + tmp[10] * src[15];
dst[10] -= tmp[3] * src[12] + tmp[6] * src[13] + tmp[11] * src[15];
dst[11] = tmp[5] * src[12] + tmp[8] * src[13] + tmp[11] * src[14];
dst[11] -= tmp[4] * src[12] + tmp[9] * src[13] + tmp[10] * src[14];
dst[12] = tmp[2] * src[10] + tmp[5] * src[11] + tmp[1] * src[9];
dst[12] -= tmp[4] * src[11] + tmp[0] * src[9] + tmp[3] * src[10];
dst[13] = tmp[8] * src[11] + tmp[0] * src[8] + tmp[7] * src[10];
dst[13] -= tmp[6] * src[10] + tmp[9] * src[11] + tmp[1] * src[8];
dst[14] = tmp[6] * src[9] + tmp[11] * src[11] + tmp[3] * src[8];
dst[14] -= tmp[10] * src[11] + tmp[2] * src[8] + tmp[7] * src[9];
dst[15] = tmp[10] * src[10] + tmp[4] * src[8] + tmp[9] * src[9];
dst[15] -= tmp[8] * src[9] + tmp[11] * src[10] + tmp[5] * src[8];
det = src[0] * dst[0] + src[1] * dst[1] + src[2] * dst[2] + src[3] * dst[3];
if (det == 0.0) {
throw new Error("singular matrix is not invertible");
}
/* calculate matrix inverse */
det = 1 / det;
for (let j = 0; j < 16; j++) {
dst[j] *= det;
}
let ret = Matrix.identity();
ret.data = dst;
return ret;
}
}
/**
* Class representing a vector in 4D space
*/
class Vector {
/**
* Create a vector
* #param {number} x - The x component
* #param {number} y - The y component
* #param {number} z - The z component
* #param {number} w - The w component
* #return {number} The resulting vector
*/
constructor(x, y, z, w) {
this.data = [x, y, z, w];
}
//has getter and setter
add(other) {
return new Vector(
this.x + other.x,
this.y + other.y,
this.z + other.z,
this.w + other.w
);
}
sub(other) {
return new Vector(
this.x - other.x,
this.y - other.y,
this.z - other.z,
this.w - other.w
);
}
mul(other) {
return new Vector(
this.x * other,
this.y * other,
this.z * other,
this.w
);
}
div(other) {
return new Vector(
this.x / other,
this.y / other,
this.z / other,
this.w
);
}
dot(other) {
if (other instanceof Vector) {
return this.x * other.x + this.y * other.y + this.z * other.z;
} else {
throw new Error("Dot product only works with vectors!");
}
}
cross(other) {
if (other instanceof Vector) {
return new Vector(
this.y * other.z - this.z * other.y,
this.z * other.x - this.x * other.z,
this.x * other.y - this.y * other.x,
0
);
} else {
throw new Error("Dot product only works with vectors!");
}
}
valueOf() {
return this.data;
}
normalised() {
const l = this.length;
return this.div(l);
}
equals(other) {
return (
Math.abs(this.x - other.x) <= Number.EPSILON &&
Math.abs(this.y - other.y) <= Number.EPSILON &&
Math.abs(this.z - other.z) <= Number.EPSILON &&
((!this.w && !other.w) || Math.abs(this.w - other.w) <= Number.EPSILON)
);
}
get length() {
return Math.sqrt(this.x * this.x + this.y * this.y + this.z * this.z);
}
}
/**
* Class representing a Node in a Scenegraph
*/
class Node {
/**
* Accepts a visitor according to the visitor pattern
* #param {Visitor} visitor - The visitor
*/
accept(visitor) { }
}
/**
* Class representing a GroupNode in the Scenegraph.
* A GroupNode holds a transformation and is able
* to have child nodes attached to it.
* #extends Node
*/
class GroupNode extends Node {
/**
* Constructor
* #param {Matrix} mat - A matrix describing the node's transformation
*/
constructor(mat) {
super();
this.matrix = mat;
// TODO [exercise 8]
this.children = [];
}
/**
* Accepts a visitor according to the visitor pattern
* #param {Visitor} visitor - The visitor
*/
accept(visitor) {
// TODO [exercise 8]
visitor.visitGroupNode(this);
}
/**
* Adds a child node
* #param {Node} childNode - The child node to add
*/
add(childNode) {
// TODO [exercise 8]
this.children.push(childNode);
}
}
/**
* Class representing a Textured Axis Aligned Box in the Scenegraph
* #extends Node
*/
class TextureBoxNode extends Node {
constructor(minPoint, maxPoint, texture) {
super();
this.minPoint = minPoint;
this.maxPoint = maxPoint;
this.texture = texture;
}
accept(visitor) {
// TODO [exercise 8]
visitor.visitTextureBoxNode(this);
}
}
//Texture Fragment Shader
precision mediump float;
uniform sampler2D sampler;
varying vec2 v_texCoord;
void main( void ) {
//gl_FragColor = vec4( 0.0, 0.0, 0.5, 1.0 );
// Read fragment color from texture
// TODO [exercise 9]
gl_FragColor = texture2D(sampler, vec2(v_texCoord.s, v_texCoord.t));
}
//Texture Vertex Shader
attribute vec3 a_position;
attribute vec2 a_texCoord;
varying vec2 v_texCoord;
uniform mat4 M;
uniform mat4 V;
uniform mat4 P;
void main() {
gl_Position = P * V * M * vec4( a_position, 1.0 );
v_texCoord = a_texCoord;
}
// Phong Vertex Shader
attribute vec3 a_position;
attribute vec3 a_normal;
// Pass color as attribute and forward it
// to the fragment shader
attribute vec4 a_color;
uniform mat4 M;
uniform mat4 V;
uniform mat4 P;
uniform mat4 N; // normal matrix
varying vec3 v_normal;
// Pass the vertex position in view space
// to the fragment shader
// TODO [exercise 9]
varying vec4 v_position;
varying vec4 v_color;
void main() {
gl_Position = P * V * M * vec4( a_position, 1.0 );
// Pass the color and transformed vertex position through
v_position = gl_Position;
v_color = a_color;
v_normal = (N * vec4(a_normal, 0)).xyz;
}
//Phong Fragment Shader
//precision mediump float;
// TODO [exercise 5]
//void main( void ) {
//gl_FragColor = vec4( 0.0, 0.0, 0.5, 1.0 );
// TODO [exercise 5]
//}
// Wird mindestens einmal pro Pixel ausgefuehrt
precision mediump float;
// TODO [exercise 5]
varying vec4 v_color;
varying vec4 v_position;
varying vec3 v_normal;
const vec3 lightPos = vec3(0.2,-1.0,-1.0);
const float shininess = 16.0;
const float k_a = 1.0;
const float k_d = 0.6;
const float k_s = 0.3;
// Farbe von Vertex shader durchreichen und Interpolieren
void main( void ) {
// Rot, Gruen, Blau, Alpha
//gl_FragColor = vec4( 0.0, 0.0, 0.5, 1.0 );
// TODO [exercise 5]
vec3 vertPos = vec3(v_position) / v_position.w;
vec3 N = normalize(v_normal);
vec3 L = normalize(lightPos - vertPos);
vec4 L_j = vec4(1,1,1,1);
vec4 diffuse = L_j * max(dot(N, L), 0.0);
vec3 R = reflect(-L, N);
vec3 V = normalize(-vertPos);
float specAngle = max(dot(R, V), 0.0);
vec4 specular = L_j * pow(specAngle, shininess);
vec4 color = vec4(k_a * v_color + k_d * diffuse + k_s * specular);
gl_FragColor = color;
}
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>ICG-11 Animation</title>
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css" integrity="sha384-BVYiiSIFeK1dGmJRAkycuHAHRg32OmUcww7on3RYdg4Va+PmSTsz/K68vbdEjh4u"
crossorigin="anonymous">
</head>
<body>
<div class="container text-center">
<h1>ICG Animation</h1>
<hr>
<p>Implement a Rasteriser with WebGL using a Scenegraph.</p>
<canvas id="rasteriser" width="500" height="500"></canvas>
<script src="vector.js"></script>
<script src="raster-texture-box.js"></script>
<script src="matrix.js"></script>
<script src="nodes.js"></script>
<script src="rastervisitor.js"></script>
<script src="shader.js"></script>
<script src="animation-nodes.js"></script>
<script>
const canvas = document.getElementById("rasteriser");
const gl = canvas.getContext("webgl");
// construct scene graph
const sg = new GroupNode(Matrix.scaling(new Vector(0.2, 0.2, 0.2)));
const gn1 = new GroupNode(Matrix.translation(new Vector(1, 1, 0)));
sg.add(gn1);
let gn2 = new GroupNode(Matrix.translation(new Vector(-.7, -0.4, .1)));
sg.add(gn2);
const cube = new TextureBoxNode(
new Vector(-1, -1, -1, 1),
new Vector(1, 1, 1, 1),
'diffuse.png'
);
gn2.add(cube);
// setup for rendering
const setupVisitor = new RasterSetupVisitor(gl);
setupVisitor.setup(sg);
const visitor = new RasterVisitor(gl);
let camera = {
eye: new Vector(-.5, .5, -1, 1),
center: new Vector(0, 0, 0, 1),
up: new Vector(0, 1, 0, 0),
fovy: 60,
aspect: canvas.width / canvas.height,
near: 0.1,
far: 100
};
const phongShader = new Shader(gl,
"phong-vertex-perspective-shader.glsl",
"phong-fragment-shader.glsl"
);
visitor.shader = phongShader;
const textureShader = new Shader(gl,
"texture-vertex-perspective-shader.glsl",
"texture-fragment-shader.glsl"
);
visitor.textureshader = textureShader;
let animationNodes = [
new RotationNode(gn2, new Vector(0, 0, 1))
];
function simulate(deltaT) {
for (animationNode of animationNodes) {
animationNode.simulate(deltaT);
}
}
let lastTimestamp = performance.now();
function animate(timestamp) {
simulate(timestamp - lastTimestamp);
visitor.render(sg, camera);
lastTimestamp = timestamp;
window.requestAnimationFrame(animate);
}
Promise.all(
[textureShader.load(), phongShader.load()]
).then(x =>
window.requestAnimationFrame(animate)
);
</script>
</div>
</body>
</html>
Hey there I`m trying since a while now to add a second texture
to my cube and do some bump mapping. But I am a progam beginner, so its kinda hard for me. All my maths for the matrix and vector are in the same named js.files. I also have to kinds of shaders, the texture and the phong shader. Now everyone says I have to calculate my normals, but how do I do that? And where?
Looking forward for your help!

With a normal map as in the question, Bump mapping can be performed. At bump mapping the normal vector of a fragment is read from a normal map and used for the light calculations.
In general the incident light vector is transformed into texture space. This is the "orientation" of the normal map on the object (fragment). In order to set up a 3x3 orientation matrix that describes the orientation of the map, the tangent vector and the bi-tangent vector as well as the normal vector must be known. If there is no tangent vector and no bi-tangent vector, the vectors can be approximated by the partial derivative of the vertex position and the texture coordinate in the fragment shader.
So at least the texture coordinate and the normal vector attribute are required. In the fragment shader the calculations are done in world space respectively texture space. The vertex shader is straight forward:
precision highp float;
attribute vec3 a_position;
attribute vec3 a_normal;
attribute vec2 a_texCoord;
varying vec3 w_pos;
varying vec3 w_nv;
varying vec2 o_uv;
uniform mat4 P;
uniform mat4 V;
uniform mat4 M;
void main()
{
o_uv = a_texCoord;
w_nv = normalize(mat3(M) * a_normal);
vec4 worldPos = M * vec4(a_position, 1.0);
w_pos = worldPos.xyz;
gl_Position = P * V * worldPos;
}
In the fragment shader, the normal vector is read from the normal map:
vec3 mapN = normalize(texture2D(u_normal_map, o_uv.st).xyz * 2.0 - 1.0);
The light vector is transformed to texture space:
vec3 L = tbn_inv * normalize(u_light_pos - w_pos);
With this vector the light calculations can be performed:
float kd = max(0.0, dot(mapN, L));
To calculate the matrix which transforms form world space to texture space, the partial derivative functions (dFdx, dFdy) are required. This causes that the "OES_standard_derivatives" has to be enabled (or "webgl2" context):
gl = canvas.getContext( "experimental-webgl" );
var standard_derivatives = gl.getExtension("OES_standard_derivatives");
The algorithm to calculate the tangent vector and binormal vector is explained in another answer - How to calculate Tangent and Binormal?.
Final fragment shader:
#extension GL_OES_standard_derivatives : enable
precision mediump float;
varying vec3 w_pos;
varying vec3 w_nv;
varying vec2 o_uv;
uniform vec3 u_light_pos;
uniform sampler2D u_diffuse;
uniform sampler2D u_normal_map;
void main()
{
vec3 N = normalize(w_nv);
vec3 dp1 = dFdx( w_pos );
vec3 dp2 = dFdy( w_pos );
vec2 duv1 = dFdx( o_uv );
vec2 duv2 = dFdy( o_uv );
vec3 dp2perp = cross(dp2, N);
vec3 dp1perp = cross(N, dp1);
vec3 T = dp2perp * duv1.x + dp1perp * duv2.x;
vec3 B = dp2perp * duv1.y + dp1perp * duv2.y;
float invmax = inversesqrt(max(dot(T, T), dot(B, B)));
mat3 tm = mat3(T * invmax, B * invmax, N);
mat3 tbn_inv = mat3(vec3(tm[0].x, tm[1].x, tm[2].x), vec3(tm[0].y, tm[1].y, tm[2].y), vec3(tm[0].z, tm[1].z, tm[2].z));
vec3 L = tbn_inv * normalize(u_light_pos - w_pos);
vec3 mapN = normalize(texture2D(u_normal_map, o_uv.st).xyz * 2.0 - 1.0);
float kd = max(0.0, dot(mapN, L));
vec3 color = texture2D(u_diffuse, o_uv.st).rgb;
vec3 light_col = (0.0 + kd) * color.rgb;
gl_FragColor = vec4(clamp(light_col, 0.0, 1.0), 1.0);
}
And will produce bump mapping like this:
If the tangent vector is know the calculation of tbn_inv matrix can be simplified very much:
mat3 tm = mat3(normalize(w_tv), normalize(cross(w_nv, w_tv)), normalize(w_nv));
mat3 tbn_inv = mat3(vec3(tm[0].x, tm[1].x, tm[2].x), vec3(tm[0].y, tm[1].y, tm[2].y), vec3(tm[0].z, tm[1].z, tm[2].z));
If you want Parallax mapping like in this Example then a displacement map is required, too.
The white areas on this map are pushed "into" the object. The algorithm is described in detail at LearnOpengl - Parallax Mapping.
The idea is that each fragment is associated to a height of the displacement map. This can be imagined as a rectangular pillar standing on the fragment. The view ray is tracked until a displaced fragment is hit.
For a high performance algorithm samples are taken of the displacement texture. When a fragment is identified, then the corresponding fragment of the e normal map and the diffuse texture is read. This gives a 3 dimensional look of the geometry. Note this algorithm is bot able to handle silhouettes.
Final fragment shader with steep parallax mapping:
#extension GL_OES_standard_derivatives : enable
precision mediump float;
varying vec3 w_pos;
varying vec3 w_nv;
varying vec2 o_uv;
uniform float u_height_scale;
uniform vec3 u_light_pos;
uniform vec3 u_view_pos;
uniform sampler2D u_diffuse;
uniform sampler2D u_normal_map;
uniform sampler2D u_displacement_map;
vec2 ParallaxMapping (vec2 texCoord, vec3 viewDir)
{
float numLayers = 32.0 - 31.0 * abs(dot(vec3(0.0, 0.0, 1.0), viewDir));
float layerDepth = 1.0 / numLayers;
vec2 P = viewDir.xy / viewDir.z * u_height_scale;
vec2 deltaTexCoords = P / numLayers;
vec2 currentTexCoords = texCoord;
float currentLayerDepth = 0.0;
float currentDepthMapValue = texture2D(u_displacement_map, currentTexCoords).r;
for (int i=0; i<32; ++ i)
{
if (currentLayerDepth >= currentDepthMapValue)
break;
currentTexCoords -= deltaTexCoords;
currentDepthMapValue = texture2D(u_displacement_map, currentTexCoords).r;
currentLayerDepth += layerDepth;
}
vec2 prevTexCoords = currentTexCoords + deltaTexCoords;
float afterDepth = currentDepthMapValue - currentLayerDepth;
float beforeDepth = texture2D(u_displacement_map, prevTexCoords).r - currentLayerDepth + layerDepth;
float weight = afterDepth / (afterDepth - beforeDepth);
return prevTexCoords * weight + currentTexCoords * (1.0 - weight);
}
void main()
{
vec3 N = normalize(w_nv);
vec3 dp1 = dFdx( w_pos );
vec3 dp2 = dFdy( w_pos );
vec2 duv1 = dFdx( o_uv );
vec2 duv2 = dFdy( o_uv );
vec3 dp2perp = cross(dp2, N);
vec3 dp1perp = cross(N, dp1);
vec3 T = dp2perp * duv1.x + dp1perp * duv2.x;
vec3 B = dp2perp * duv1.y + dp1perp * duv2.y;
float invmax = inversesqrt(max(dot(T, T), dot(B, B)));
mat3 tm = mat3(T * invmax, B * invmax, N);
mat3 tbn_inv = mat3(vec3(tm[0].x, tm[1].x, tm[2].x), vec3(tm[0].y, tm[1].y, tm[2].y), vec3(tm[0].z, tm[1].z, tm[2].z));
vec3 view_dir = tbn_inv * normalize(w_pos - u_view_pos);
vec2 uv = ParallaxMapping(o_uv, view_dir);
if (uv.x > 1.0 || uv.y > 1.0 || uv.x < 0.0 || uv.y < 0.0)
discard;
vec3 L = tbn_inv * normalize(u_light_pos - w_pos);
vec3 mapN = normalize(texture2D(u_normal_map, uv.st).xyz * 2.0 - 1.0);
float kd = max(0.0, dot(mapN, L));
vec3 color = texture2D(u_diffuse, uv.st).rgb;
vec3 light_col = (0.1 + kd) * color.rgb;
gl_FragColor = vec4(clamp(light_col, 0.0, 1.0), 1.0);
}
The result is much more impressive:
(function loadscene() {
var gl, progDraw, vp_size;
var bufCube = {};
var diffuse_tex = 1;
var height_tex = 2;
var normal_tex = 3;
function render(deltaMS){
var height_scale = 0.3 * document.getElementById("height").value / 100.0;
// setup view projection and model
vp_size = [canvas.width, canvas.height];
camera.Update( vp_size );
var prjMat = camera.Perspective();
var viewMat = camera.LookAt();
var modelMat = camera.AutoModelMatrix();
gl.viewport( 0, 0, vp_size[0], vp_size[1] );
gl.enable( gl.DEPTH_TEST );
gl.clearColor( 0.0, 0.0, 0.0, 1.0 );
gl.clear( gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT );
gl.frontFace(gl.CCW)
gl.cullFace(gl.BACK)
gl.enable(gl.CULL_FACE)
// set up draw shader
ShProg.Use( progDraw );
ShProg.SetF3( progDraw, "u_view_pos", camera.pos )
ShProg.SetF3( progDraw, "u_light_pos", [0.0, 5.0, 5.0] )
ShProg.SetF1( progDraw, "u_height_scale", height_scale );
ShProg.SetI1( progDraw, "u_diffuse", diffuse_tex );
ShProg.SetI1( progDraw, "u_displacement_map", height_tex );
ShProg.SetI1( progDraw, "u_normal_map", normal_tex );
ShProg.SetM44( progDraw, "P", prjMat );
ShProg.SetM44( progDraw, "V", viewMat );
ShProg.SetM44( progDraw, "M", modelMat );
// draw scene
VertexBuffer.Draw( bufCube );
requestAnimationFrame(render);
}
function initScene() {
canvas = document.getElementById( "canvas");
gl = canvas.getContext( "experimental-webgl" );
var standard_derivatives = gl.getExtension("OES_standard_derivatives"); // dFdx, dFdy
if (!standard_derivatives)
alert('no standard derivatives support (no dFdx, dFdy)');
//gl = canvas.getContext( "webgl2" );
if ( !gl )
return null;
progDraw = ShProg.Create(
[ { source : "draw-shader-vs", stage : gl.VERTEX_SHADER },
{ source : "draw-shader-fs", stage : gl.FRAGMENT_SHADER }
] );
if ( !progDraw.progObj )
return null;
progDraw.inPos = ShProg.AttrI( progDraw, "a_position" );
progDraw.inNV = ShProg.AttrI( progDraw, "a_normal" );
progDraw.inUV = ShProg.AttrI( progDraw, "a_texCoord" );
// create cube
let Pos = [ -1,-1,1, 1,-1,1, 1,1,1, -1,1,1, -1,-1,-1, 1,-1,-1, 1,1,-1, -1,1,-1 ];
let Col = [ 1,0,0, 1,0.5,0, 1,0,1, 1,1,0, 0,1,0, 0, 0, 1 ];
let NV = [ 0,0,1, 1,0,0, 0,0,-1, -1,0,0, 0,1,0, 0,-1,0 ];
let TV = [ 1,0,0, 0,0,-1, -1,0,0, 0,0,1, 1,0,0, -1,0,0 ];
var cubeHlpInx = [ 0,1,2,3, 1,5,6,2, 5,4,7,6, 4,0,3,7, 3,2,6,7, 1,0,4,5 ];
var cubePosData = [];
for ( var i = 0; i < cubeHlpInx.length; ++ i ) cubePosData.push(Pos[cubeHlpInx[i]*3], Pos[cubeHlpInx[i]*3+1], Pos[cubeHlpInx[i]*3+2] );
var cubeNVData = [];
for ( var i1 = 0; i1 < 6; ++ i1 ) {
for ( i2 = 0; i2 < 4; ++ i2 ) cubeNVData.push(NV[i1*3], NV[i1*3+1], NV[i1*3+2]);
}
var cubeTVData = [];
for ( var i1 = 0; i1 < 6; ++ i1 ) {
for ( i2 = 0; i2 < 4; ++ i2 ) cubeTVData.push(TV[i1*3], TV[i1*3+1], TV[i1*3+2]);
}
var cubeColData = [];
for ( var is = 0; is < 6; ++ is ) {
for ( var ip = 0; ip < 4; ++ ip ) cubeColData.push(Col[is*3], Col[is*3+1], Col[is*3+2]);
}
var cubeTexData = []
for ( var i = 0; i < 6; ++ i ) cubeTexData.push( 0, 0, 1, 0, 1, 1, 0, 1 );
var cubeInxData = [];
for ( var i = 0; i < cubeHlpInx.length; i += 4 ) cubeInxData.push( i, i+1, i+2, i, i+2, i+3 );
bufCube = VertexBuffer.Create(
[ { data : cubePosData, attrSize : 3, attrLoc : progDraw.inPos },
{ data : cubeNVData, attrSize : 3, attrLoc : progDraw.inNV },
//{ data : cubeTVData, attrSize : 3, attrLoc : progDraw.inTV },
{ data : cubeTexData, attrSize : 2, attrLoc : progDraw.inUV },
//{ data : cubeColData, attrSize : 3, attrLoc : progDraw.inCol },
],
cubeInxData, gl.TRIANGLES );
Texture.LoadTexture2D( diffuse_tex, "https://raw.githubusercontent.com/Rabbid76/graphics-snippets/master/resource/texture/woodtiles.jpg" );
Texture.LoadTexture2D( height_tex, "https://raw.githubusercontent.com/Rabbid76/graphics-snippets/master/resource/texture/toy_box_disp.png" );
Texture.LoadTexture2D( normal_tex, "https://raw.githubusercontent.com/Rabbid76/graphics-snippets/master/resource/texture/toy_box_normal.png" );
camera = new Camera( [0, 3, 0], [0, 0, 0], [0, 0, 1], 90, vp_size, 0.5, 100 );
window.onresize = resize;
resize();
requestAnimationFrame(render);
}
function resize() {
//vp_size = [gl.drawingBufferWidth, gl.drawingBufferHeight];
vp_size = [window.innerWidth, window.innerHeight];
//vp_size = [256, 256];
canvas.width = vp_size[0];
canvas.height = vp_size[1];
}
function Fract( val ) {
return val - Math.trunc( val );
}
function CalcAng( deltaTime, interval ) {
return Fract( deltaTime / (1000*interval) ) * 2.0 * Math.PI;
}
function CalcMove( deltaTime, interval, range ) {
var pos = self.Fract( deltaTime / (1000*interval) ) * 2.0
var pos = pos < 1.0 ? pos : (2.0-pos)
return range[0] + (range[1] - range[0]) * pos;
}
function IdentM44() {
return [ 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1 ];
};
function RotateAxis(matA, angRad, axis) {
var aMap = [ [1, 2], [2, 0], [0, 1] ];
var a0 = aMap[axis][0], a1 = aMap[axis][1];
var sinAng = Math.sin(angRad), cosAng = Math.cos(angRad);
var matB = matA.slice(0);
for ( var i = 0; i < 3; ++ i ) {
matB[a0*4+i] = matA[a0*4+i] * cosAng + matA[a1*4+i] * sinAng;
matB[a1*4+i] = matA[a0*4+i] * -sinAng + matA[a1*4+i] * cosAng;
}
return matB;
}
function Rotate(matA, angRad, axis) {
var s = Math.sin(angRad), c = Math.cos(angRad);
var x = axis[0], y = axis[1], z = axis[2];
matB = [
x*x*(1-c)+c, x*y*(1-c)-z*s, x*z*(1-c)+y*s, 0,
y*x*(1-c)+z*s, y*y*(1-c)+c, y*z*(1-c)-x*s, 0,
z*x*(1-c)-y*s, z*y*(1-c)+x*s, z*z*(1-c)+c, 0,
0, 0, 0, 1 ];
return Multiply(matA, matB);
}
function Multiply(matA, matB) {
matC = IdentM44();
for (var i0=0; i0<4; ++i0 )
for (var i1=0; i1<4; ++i1 )
matC[i0*4+i1] = matB[i0*4+0] * matA[0*4+i1] + matB[i0*4+1] * matA[1*4+i1] + matB[i0*4+2] * matA[2*4+i1] + matB[i0*4+3] * matA[3*4+i1]
return matC;
}
function Cross( a, b ) { return [ a[1] * b[2] - a[2] * b[1], a[2] * b[0] - a[0] * b[2], a[0] * b[1] - a[1] * b[0], 0.0 ]; }
function Dot( a, b ) { return a[0]*b[0] + a[1]*b[1] + a[2]*b[2]; }
function Normalize( v ) {
var len = Math.sqrt( v[0] * v[0] + v[1] * v[1] + v[2] * v[2] );
return [ v[0] / len, v[1] / len, v[2] / len ];
}
Camera = function( pos, target, up, fov_y, vp, near, far ) {
this.Time = function() { return Date.now(); }
this.pos = pos;
this.target = target;
this.up = up;
this.fov_y = fov_y;
this.vp = vp;
this.near = near;
this.far = far;
this.orbit_mat = this.current_orbit_mat = this.model_mat = this.current_model_mat = IdentM44();
this.mouse_drag = this.auto_spin = false;
this.auto_rotate = true;
this.mouse_start = [0, 0];
this.mouse_drag_axis = [0, 0, 0];
this.mouse_drag_angle = 0;
this.mouse_drag_time = 0;
this.drag_start_T = this.rotate_start_T = this.Time();
this.Ortho = function() {
var fn = this.far + this.near;
var f_n = this.far - this.near;
var w = this.vp[0];
var h = this.vp[1];
return [
2/w, 0, 0, 0,
0, 2/h, 0, 0,
0, 0, -2/f_n, 0,
0, 0, -fn/f_n, 1 ];
};
this.Perspective = function() {
var n = this.near;
var f = this.far;
var fn = f + n;
var f_n = f - n;
var r = this.vp[0] / this.vp[1];
var t = 1 / Math.tan( Math.PI * this.fov_y / 360 );
return [
t/r, 0, 0, 0,
0, t, 0, 0,
0, 0, -fn/f_n, -1,
0, 0, -2*f*n/f_n, 0 ];
};
this.LookAt = function() {
var mz = Normalize( [ this.pos[0]-this.target[0], this.pos[1]-this.target[1], this.pos[2]-this.target[2] ] );
var mx = Normalize( Cross( this.up, mz ) );
var my = Normalize( Cross( mz, mx ) );
var tx = Dot( mx, this.pos );
var ty = Dot( my, this.pos );
var tz = Dot( [-mz[0], -mz[1], -mz[2]], this.pos );
return [mx[0], my[0], mz[0], 0, mx[1], my[1], mz[1], 0, mx[2], my[2], mz[2], 0, tx, ty, tz, 1];
};
this.AutoModelMatrix = function() {
return this.auto_rotate ? Multiply(this.current_model_mat, this.model_mat) : this.model_mat;
};
this.Update = function(vp_size) {
if (vp_size)
this.vp = vp_size;
var current_T = this.Time();
this.current_model_mat = IdentM44()
var auto_angle_x = Fract( (current_T - this.rotate_start_T) / 13000.0 ) * 2.0 * Math.PI;
var auto_angle_y = Fract( (current_T - this.rotate_start_T) / 17000.0 ) * 2.0 * Math.PI;
this.current_model_mat = RotateAxis( this.current_model_mat, auto_angle_x, 0 );
this.current_model_mat = RotateAxis( this.current_model_mat, auto_angle_y, 1 );
};
}
var Texture = {};
Texture.HandleLoadedTexture2D = function( texture, flipY ) {
gl.activeTexture( gl.TEXTURE0 + texture.unit );
gl.bindTexture( gl.TEXTURE_2D, texture.obj );
gl.pixelStorei( gl.UNPACK_FLIP_Y_WEBGL, flipY != undefined && flipY == true );
gl.texImage2D( gl.TEXTURE_2D, 0, gl.RGBA, gl.RGBA, gl.UNSIGNED_BYTE, texture.image );
gl.texParameteri( gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.LINEAR );
gl.texParameteri( gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR );
gl.texParameteri( gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.REPEAT );
gl.texParameteri( gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.REPEAT );
return texture;
}
Texture.LoadTexture2D = function( unit, name ) {
var texture = {};
texture.obj = gl.createTexture();
texture.unit = unit;
texture.image = new Image();
texture.image.setAttribute('crossorigin', 'anonymous');
texture.image.onload = function () {
Texture.HandleLoadedTexture2D( texture, false )
}
texture.image.src = name;
return texture;
}
var ShProg = {
Create: function (shaderList) {
var shaderObjs = [];
for (var i_sh = 0; i_sh < shaderList.length; ++i_sh) {
var shderObj = this.Compile(shaderList[i_sh].source, shaderList[i_sh].stage);
if (shderObj) shaderObjs.push(shderObj);
}
var prog = {}
prog.progObj = this.Link(shaderObjs)
if (prog.progObj) {
prog.attrInx = {};
var noOfAttributes = gl.getProgramParameter(prog.progObj, gl.ACTIVE_ATTRIBUTES);
for (var i_n = 0; i_n < noOfAttributes; ++i_n) {
var name = gl.getActiveAttrib(prog.progObj, i_n).name;
prog.attrInx[name] = gl.getAttribLocation(prog.progObj, name);
}
prog.uniLoc = {};
var noOfUniforms = gl.getProgramParameter(prog.progObj, gl.ACTIVE_UNIFORMS);
for (var i_n = 0; i_n < noOfUniforms; ++i_n) {
var name = gl.getActiveUniform(prog.progObj, i_n).name;
prog.uniLoc[name] = gl.getUniformLocation(prog.progObj, name);
}
}
return prog;
},
AttrI: function (prog, name) { return prog.attrInx[name]; },
UniformL: function (prog, name) { return prog.uniLoc[name]; },
Use: function (prog) { gl.useProgram(prog.progObj); },
SetI1: function (prog, name, val) { if (prog.uniLoc[name]) gl.uniform1i(prog.uniLoc[name], val); },
SetF1: function (prog, name, val) { if (prog.uniLoc[name]) gl.uniform1f(prog.uniLoc[name], val); },
SetF2: function (prog, name, arr) { if (prog.uniLoc[name]) gl.uniform2fv(prog.uniLoc[name], arr); },
SetF3: function (prog, name, arr) { if (prog.uniLoc[name]) gl.uniform3fv(prog.uniLoc[name], arr); },
SetF4: function (prog, name, arr) { if (prog.uniLoc[name]) gl.uniform4fv(prog.uniLoc[name], arr); },
SetM33: function (prog, name, mat) { if (prog.uniLoc[name]) gl.uniformMatrix3fv(prog.uniLoc[name], false, mat); },
SetM44: function (prog, name, mat) { if (prog.uniLoc[name]) gl.uniformMatrix4fv(prog.uniLoc[name], false, mat); },
Compile: function (source, shaderStage) {
var shaderScript = document.getElementById(source);
if (shaderScript)
source = shaderScript.text;
var shaderObj = gl.createShader(shaderStage);
gl.shaderSource(shaderObj, source);
gl.compileShader(shaderObj);
var status = gl.getShaderParameter(shaderObj, gl.COMPILE_STATUS);
if (!status) alert(gl.getShaderInfoLog(shaderObj));
return status ? shaderObj : null;
},
Link: function (shaderObjs) {
var prog = gl.createProgram();
for (var i_sh = 0; i_sh < shaderObjs.length; ++i_sh)
gl.attachShader(prog, shaderObjs[i_sh]);
gl.linkProgram(prog);
status = gl.getProgramParameter(prog, gl.LINK_STATUS);
if ( !status ) alert(gl.getProgramInfoLog(prog));
return status ? prog : null;
} };
var VertexBuffer = {
Create: function(attribs, indices, type) {
var buffer = { buf: [], attr: [], inx: gl.createBuffer(), inxLen: indices.length, primitive_type: type ? type : gl.TRIANGLES };
for (var i=0; i<attribs.length; ++i) {
buffer.buf.push(gl.createBuffer());
buffer.attr.push({ size : attribs[i].attrSize, loc : attribs[i].attrLoc });
gl.bindBuffer(gl.ARRAY_BUFFER, buffer.buf[i]);
gl.bufferData(gl.ARRAY_BUFFER, new Float32Array( attribs[i].data ), gl.STATIC_DRAW);
}
gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, buffer.inx);
gl.bufferData(gl.ELEMENT_ARRAY_BUFFER, new Uint16Array( indices ), gl.STATIC_DRAW);
gl.bindBuffer(gl.ARRAY_BUFFER, null);
gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, null);
return buffer;
},
Draw: function(bufObj) {
for (var i=0; i<bufObj.buf.length; ++i) {
gl.bindBuffer(gl.ARRAY_BUFFER, bufObj.buf[i]);
gl.vertexAttribPointer(bufObj.attr[i].loc, bufObj.attr[i].size, gl.FLOAT, false, 0, 0);
gl.enableVertexAttribArray( bufObj.attr[i].loc);
}
gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, bufObj.inx);
gl.drawElements(bufObj.primitive_type, bufObj.inxLen, gl.UNSIGNED_SHORT, 0);
for (var i=0; i<bufObj.buf.length; ++i)
gl.disableVertexAttribArray(bufObj.attr[i].loc);
gl.bindBuffer( gl.ARRAY_BUFFER, null );
gl.bindBuffer( gl.ELEMENT_ARRAY_BUFFER, null );
} };
initScene();
})();
html,body { margin: 0; overflow: hidden; }
#gui { position : absolute; top : 0; left : 0; }
<script id="draw-shader-vs" type="x-shader/x-vertex">
precision highp float;
attribute vec3 a_position;
attribute vec3 a_normal;
attribute vec2 a_texCoord;
varying vec3 w_pos;
varying vec3 w_nv;
varying vec2 o_uv;
uniform mat4 P;
uniform mat4 V;
uniform mat4 M;
void main()
{
o_uv = a_texCoord;
w_nv = normalize(mat3(M) * a_normal);
vec4 worldPos = M * vec4(a_position, 1.0);
w_pos = worldPos.xyz;
gl_Position = P * V * worldPos;
}
</script>
<script id="draw-shader-fs" type="x-shader/x-fragment">
#extension GL_OES_standard_derivatives : enable
precision mediump float;
varying vec3 w_pos;
varying vec3 w_nv;
varying vec2 o_uv;
uniform float u_height_scale;
uniform vec3 u_light_pos;
uniform vec3 u_view_pos;
uniform sampler2D u_diffuse;
uniform sampler2D u_normal_map;
uniform sampler2D u_displacement_map;
vec2 ParallaxMapping (vec2 texCoord, vec3 viewDir)
{
float numLayers = 32.0 - 31.0 * abs(dot(vec3(0.0, 0.0, 1.0), viewDir));
float layerDepth = 1.0 / numLayers;
vec2 P = viewDir.xy / viewDir.z * u_height_scale;
vec2 deltaTexCoords = P / numLayers;
vec2 currentTexCoords = texCoord;
float currentLayerDepth = 0.0;
float currentDepthMapValue = texture2D(u_displacement_map, currentTexCoords).r;
for (int i=0; i<32; ++ i)
{
if (currentLayerDepth >= currentDepthMapValue)
break;
currentTexCoords -= deltaTexCoords;
currentDepthMapValue = texture2D(u_displacement_map, currentTexCoords).r;
currentLayerDepth += layerDepth;
}
vec2 prevTexCoords = currentTexCoords + deltaTexCoords;
float afterDepth = currentDepthMapValue - currentLayerDepth;
float beforeDepth = texture2D(u_displacement_map, prevTexCoords).r - currentLayerDepth + layerDepth;
float weight = afterDepth / (afterDepth - beforeDepth);
return prevTexCoords * weight + currentTexCoords * (1.0 - weight);
}
void main()
{
vec3 N = normalize(w_nv);
vec3 dp1 = dFdx( w_pos );
vec3 dp2 = dFdy( w_pos );
vec2 duv1 = dFdx( o_uv );
vec2 duv2 = dFdy( o_uv );
vec3 dp2perp = cross(dp2, N);
vec3 dp1perp = cross(N, dp1);
vec3 T = dp2perp * duv1.x + dp1perp * duv2.x;
vec3 B = dp2perp * duv1.y + dp1perp * duv2.y;
float invmax = inversesqrt(max(dot(T, T), dot(B, B)));
mat3 tm = mat3(T * invmax, B * invmax, N);
mat3 tbn_inv = mat3(vec3(tm[0].x, tm[1].x, tm[2].x), vec3(tm[0].y, tm[1].y, tm[2].y), vec3(tm[0].z, tm[1].z, tm[2].z));
vec3 view_dir = tbn_inv * normalize(w_pos - u_view_pos);
vec2 uv = ParallaxMapping(o_uv, view_dir);
if (uv.x > 1.0 || uv.y > 1.0 || uv.x < 0.0 || uv.y < 0.0)
discard;
vec3 L = tbn_inv * normalize(u_light_pos - w_pos);
vec3 mapN = normalize(texture2D(u_normal_map, uv.st).xyz * 2.0 - 1.0);
float kd = max(0.0, dot(mapN, L));
vec3 color = texture2D(u_diffuse, uv.st).rgb;
vec3 light_col = (0.1 + kd) * color.rgb;
gl_FragColor = vec4(clamp(light_col, 0.0, 1.0), 1.0);
}
</script>
<body>
<div>
<form id="gui" name="inputs">
<table>
<tr>
<td> <font color=#CCF>height scale</font> </td>
<td> <input type="range" id="height" min="0" max="100" value="50"/></td>
</tr>
</table>
</form>
</div>
<canvas id="canvas" style="border: none;" width="100%" height="100%"></canvas>

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