I am trying to create some scales measuring sound frequency for a music visualiser project. They are meant to display 4 different frequencies ( bass, lowMid, highMid and treble in a 2x2 grid pattern. I'm nearly there I have my rectangles but the needle which measures and shows the frequency itself is only iterating for the top row x and not the bottom row. I'm pretty new to JavaScript so I'm sure it could be something very simple that I'm missing.
// draw the plots to the screen
this.draw = function() {
//create an array amplitude values from the fft.
var spectrum = fourier.analyze();
//iterator for selecting frequency bin.
var currentBin = 0;
push();
fill('#f0f2d2');
//nested for loop to place plots in 2*2 grid.
for(var i = 0; i < this.plotsDown; i++) {
for(var j = 0; j < this.plotsAcross; j++) {
//calculate the size of the plots
var x = this.pad * j * 10;
var y = height/20 * i * 10;
var w = (width - this.pad) / this.plotsAcross;
var h = (height - this.pad) / this.plotsDown;
//draw a rectangle at that location and size
rect(x, y, w, h);
//add on the ticks
this.ticks((x + w/2), h, this.frequencyBins[i])
var energy = fourier.getEnergy(this.frequencyBins[currentBin]);
//add the needle
this.needle(energy, (x + w/2), h)
currentBin++;
}
}
pop();
};
I'm worked with Three.JS before, but not on meshes. I think I am approaching my problem the right way, but I'm not sure.
The Goal
I'm trying to make a 3D blobby object that has specific verticies. The direction of the verticies are fixed, but their radius from center varies. You can imagine it sort of like an audio equalizer, except radial and in 3D.
I'm open to scrapping this approach and taking a totally different one if there's some easier way to do this.
Current Progress
I took this example and cleaned/modified it to my needs. Here's the HTML and JavaScript:
HTML (disco-ball.html)
<!DOCTYPE html>
<html>
<head>
<title>Disco Ball</title>
<script type="text/javascript" src="../libs/three.js"></script>
<script type="text/javascript" src="../libs/stats.js"></script>
<script type="text/javascript" src="../libs/ConvexGeometry.js"></script>
<script type="text/javascript" src="../libs/dat.gui.js"></script>
<style type='text/css'>
/* set margin to 0 and overflow to hidden, to go fullscreen */
body { margin: 0; overflow: hidden; }
</style>
</head>
<body>
<div id="Stats-output"></div>
<div id="WebGL-output"></div>
<script type="text/javascript" src="01-app.js"></script>
</body>
</html>
And the JavaScript (01-app.js):
window.onload = init;
const PARAMS = {
SHOW_SURFACE : true,
SHOW_POINTS : true,
SHOW_WIREFRAME : true,
SHOW_STATS : true
};
// once everything is loaded, we run our Three.js stuff.
function init() {
var renderParams = {
webGLRenderer : createWebGLRenderer(),
step : 0,
rotationSpeed : 0.007,
scene : new THREE.Scene(),
camera : createCamera(),
};
// Create the actual points.
var points = getPoints(
100, // Number of points (approximate)
10, // Unweighted radius
// Radius weights for a few points. This is a multiplier.
[2,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2]
);
if (PARAMS.SHOW_STATS) {
renderParams.stats = initStats();
}
if (PARAMS.SHOW_SURFACE) {
renderParams.surface = getHullMesh(points);
renderParams.scene.add(renderParams.surface);
}
if (PARAMS.SHOW_POINTS) {
renderParams.sphereGroup = getSphereGroup(points);
renderParams.scene.add(sphereGroup);
}
render(renderParams);
}
function render(params) {
if (params.stats) {
params.stats.update();
}
if (params.sphereGroup) {
params.sphereGroup.rotation.y = params.step;
}
params.step += params.rotationSpeed;
if (params.surface) {
params.surface.rotation.y = params.step;
}
// render using requestAnimationFrame
requestAnimationFrame(function () {render(params)});
params.webGLRenderer.render(params.scene, params.camera);
}
// ******************************************************************
// Helper functions
// ******************************************************************
function getPoints (count, baseRadius, weightMap) {
// Because this is deterministic, we can pass in a weight map to adjust
// the radii.
var points = distributePoints(count,baseRadius,weightMap);
points.forEach((d,i) => {
points[i] = new THREE.Vector3(d[0],d[1],d[2]);
});
return points;
}
// A deterministic function for (approximately) evenly distributing n points
// over a sphere.
function distributePoints (count, radius, weightMap) {
// I'm not sure why I need this...
count *= 100;
var points = [];
var area = 4 * Math.PI * Math.pow(radius,2) / count;
var dist = Math.sqrt(area);
var Mtheta = Math.round(Math.PI / dist);
var distTheta = Math.PI / Mtheta
var distPhi = area / distTheta;
for (var m = 0; m < Mtheta; m++) {
let theta = (Math.PI * (m + 0.5)) / Mtheta;
let Mphi = Math.round((2 * Math.PI * Math.sin(theta)) / distPhi);
for (var n = 0; n < Mphi; n++) {
let phi = ((2 * Math.PI * n) / Mphi);
// Use the default radius, times any multiplier passed in through the
// weightMap. If no multiplier is present, use 1 to leave it
// unchanged.
points.push(createPoint(radius * (weightMap[points.length] || 1),theta,phi));
}
}
return points;
}
function createPoint (radius, theta, phi) {
var x = radius * Math.sin(theta) * Math.cos(phi);
var y = radius * Math.sin(theta) * Math.sin(phi);
var z = radius * Math.cos(theta);
return [Math.round(x), Math.round(y), Math.round(z)];
}
function createWebGLRenderer () {
// create a render and set the size
var webGLRenderer = new THREE.WebGLRenderer();
webGLRenderer.setClearColor(new THREE.Color(0xEEEEEE, 1.0));
webGLRenderer.setSize(window.innerWidth, window.innerHeight);
webGLRenderer.shadowMapEnabled = true;
// add the output of the renderer to the html element
document.getElementById("WebGL-output").appendChild(webGLRenderer.domElement);
return webGLRenderer;
}
function createCamera () {
// create a camera, which defines where we're looking at.
var camera = new THREE.PerspectiveCamera(45, window.innerWidth / window.innerHeight, 0.1, 1000);
// position and point the camera to the center of the scene
camera.position.x = -30;
camera.position.y = 40;
camera.position.z = 50;
camera.lookAt(new THREE.Vector3(0, 0, 0));
return camera;
}
function getSphereGroup (points) {
sphereGroup = new THREE.Object3D();
var material = new THREE.MeshBasicMaterial({color: 0xFF0000, transparent: false});
points.forEach(function (point) {
var spGeom = new THREE.SphereGeometry(0.2);
var spMesh = new THREE.Mesh(spGeom, material);
spMesh.position.copy(point);
sphereGroup.add(spMesh);
});
return sphereGroup;
}
function getHullMesh (points) {
// use the same points to create a convexgeometry
var surfaceGeometry = new THREE.ConvexGeometry(points);
var surface = createMesh(surfaceGeometry);
return surface;
}
function createMesh(geom) {
// assign two materials
var meshMaterial = new THREE.MeshBasicMaterial({color: 0x666666, transparent: true, opacity: 0.25});
meshMaterial.side = THREE.DoubleSide;
var wireFrameMat = new THREE.MeshBasicMaterial({color: 0x0000ff});
wireFrameMat.wireframe = PARAMS.SHOW_WIREFRAME;
// create a multimaterial
var mesh = THREE.SceneUtils.createMultiMaterialObject(geom, [meshMaterial, wireFrameMat]);
return mesh;
}
function initStats() {
var stats = new Stats();
stats.setMode(0); // 0: fps, 1: ms
// Align top-left
stats.domElement.style.position = 'absolute';
stats.domElement.style.left = '0px';
stats.domElement.style.top = '0px';
document.getElementById("Stats-output").appendChild(stats.domElement);
return stats;
}
What I'm Missing
You can see that there are two points on the "ball" for which I've doubled the radius (big spikes). Of course, since I'm using a ConvexGeometry, the shape is convex... so a number of the points are hidden. What kind of ... non-convex geometry can I use to make those points no longer be hidden?
I would like to subdivide the mesh a bit so it's not simply vertex-to-vertex, but a bit smoother. How can I do that (the spikes less spikey and more blobby)?
I'd like to modify the mesh so different points spike different amounts every few seconds (I have some data arrays that describe how much). How do I modify the geometry after its been made? Ideally with some kind of tweening, but I can do without of that's extremely hard =)
Thanks!
Smooth and animate a mesh.
Three provides a huge range of options. These are just suggestions, your best bet is to read the Three documentation start point and find what suits you.
A mesh is just a set of 3D points and an array of indexes describing each triangle. Once you have built the mesh you only need to update the verts and let Three update the shader attributes, and the mesh normals
Your questions
Q1. Use Three.Geometry for the mesh.
Q2. As you are building the mesh you can use the curve helpers eg Three.CubicBezierCurve3 or Three.QuadraticBezierCurve3 or maybe your best option Three.SplineCurve
Another option is to use a modifier and create the simple mesh and then let Three subdivide the mesh for you. eg three example webgl modifier subdivision
Though not the fastest solution, if the vert count is low it will do this each frame without any loss of frame rate.
Q3. Using Three.Geometry you can can set the mesh morph targets, an array of vertices.
Another option is to use a modifier, eg three example webgl modifier subdivision
Or you can modify the vertices directly each frame.
for ( var i = 0, l = geometry.vertices.length; i < l; i ++ ) {
geometry.vertices[ i ].x = ?;
geometry.vertices[ i ].y = ?;
geometry.vertices[ i ].z = ?;
}
mesh.geometry.verticesNeedUpdate = true;
How you do it?
There are a zillion other ways to do this. Which is the best will depend on the load and amount of complexity you want to create. Spend some time and read the doc's, and experiment.
What I would do! maybe?
I am not too sure what you are trying to achieve but the following is a way of getting some life into the animation rather than the overdone curves that seem so ubiquitous these days.
So if the vert count is not too high I would use a Three.BufferGeometry and modify the verts each frame. Rather than use curves I would weight subdivision verts to follow a polynomial curve f(x) = x^2/(x^2 + (1-x)^2) where x is the normalized distance between two control verts (note don't use x=0.5 rather subdivide the mesh in > 2 times)
EG the two control points and two smoothing verts
// two control points
const p1 = {x,y,z};
const p2 = {x,y,z};
// two weighted points
// dx,dy,dz are deltas
// w is the weighted position s-curve
// wa, and wd are acceleration and drag coefficients. Try to keep their sum < 1
const pw1 = {x, y, z, dx, dy, dz, w : 1/3, wa : 0.1,wd : 0.7};
const pw2 = {x, y, z, dx, dy, dz, w : 2/3, wa : 0.1,wd : 0.7};
// Compute w
pw1.w = Math.pow(pw1.w,2) / ( Math.pow(pw1.w,2) + Math.pow(1 - pw1.w,2));
pw2.w = Math.pow(pw2.w,2) / ( Math.pow(pw2.w,2) + Math.pow(1 - pw2.w,2));
Then for each weighted point you can find the new delta and update the position
// do for x,y,z
x = (p2.x - p1.x); // these points are updated every frame
// get the new pw1 vert target position
x = p1.x + x * w;
// get new delta
pw1.dx += (x - pw1.x) * pw1.wa; // set delta
pw1.dx *= pw1.wd;
// set new position
pw1.x += pw1.dx;
Do for all weighted points then set geometry.vertices
The wa,wd coefficients will change the behaviour of the smoothing, you will have to play with these values to suit your own taste. Must be 0 <= (wa,wd) < 1 and the sum should be wa + wd < 1. High sumed values will result in oscillations, too high and the oscillations will be uncontrolled.
jsfiddle here: http://jsfiddle.net/yw0w18m3/2/
I'm using paper.js to make a background image that looks somthing like this:
Basically, I'm creating a couple thousand triangles over a loop and rotating them on every other iteration.
function Tri(x, y, rotate) {
var tri = new Path([
new Point((x - 42), (y - 48)),
new Point((x - 42), y),
new Point(x, (y - 24)),
new Point((x - 42), (y - 48))
]);
tri.fillColor = {
hue: Math.random() * 360,
saturation: 0,
brightness: ( (( Math.random() ) * .95) + .3 )
};
if(rotate) { tri.rotate(180); }
}
for (var i = 0; i < 2000; i++) {
rotate = false;
if( i % 2 ) {
rotate = true;
}
new Tri(x, y, rotate);
x = x + 42;
if( x > (winWidth + 42) ) {
x = 0 ;
y = y + 24;
}
}
There seems to be a brief 1-2 second pause/freeze though while the shapes are being drawn. Is there a more efficient way to draw all the shapes first (or push to an array) then add that to the canvas all at once?
I based my code off of the example here: http://paperjs.org/examples/candy-crash/ (click "source" in the upper right corner).
Any help is much appreciated.
Thanks!
I would end up creating two triangles, one rotated, so they don't have to be built from new points each time. Then choose the correct triangle based on the rotation variable and clone it, as opposed to create points and a triangle from scratch each time. Finally, just change the position of the cloned triangle.
Last, I would correct the maxTri so it doesn't do more than it needs to. The paren should follow the 48, not the 24. You're doing an order of magnitude more triangles than needed.
Here's a link to the sketch.paperjs.org solution I created based on your code. I find sketch easier to use than jsfiddle for paper examples.
proto1 = new Path([
new Point(0, -24),
new Point(0, 24),
new Point(42, 0)
]);
proto1.closed = true;
proto2 = proto1.clone();
proto2.rotate(180);
function putTriangle(pos, rotate) {
var tri = (rotate ? proto2 : proto1).clone();
tri.position = pos;
tri.position = tri.position.subtract([21, 0])
tri.fillColor = {
hue: Math.random() * 360,
saturation: 0,
brightness: Math.random() * 0.5 + 0.5
}
}
var tris = [],
x = 42,
y = 24,
rotate,
winWidth = paper.view.size.width,
winHeight = paper.view.size.height,
rows = (winHeight + 48) / 24,
cols = (winWidth + 42) / 42,
numTri = rows * cols,
numTriOrig = (winWidth + 42) / 42 * (winHeight + 48 / 24);
//console.log(numTri, numTriOrig);
x = 0;
y = 0;
for (var row = 0; row < rows; row++) {
rowrotate = row % 2;
for (var col = 0; col <= cols; col++) {
rotate = rowrotate ^ col % 2;
putTriangle([x,y], rotate);
x += 42;
}
x = 0;
y = y + 24;
}
Two thoughts:
I see you use rotate to transform you triangles into place. This is an expensive operation. You could replace the rotate with a less geometric & more arithmetic calculation of the triangles orientation.
Also, I see is that the fill color is being changed with each triangle and state changes (like fill) are modestly expensive. You could group all the similarly colored triangles and draw them in a single batch.
I am creating a Tangram puzzle game using Javascript. And I need to detect when a user has drawn a circle (or circle like shape) with their finger. I have been able to gather hundreds (if not thousands) of x and y points with:
var touchX = event.targetTouches[0].pageX - canvas.offsetLeft;
var touchY = event.targetTouches[0].pageY - canvas.offsetTop;
I then push each x and y coordinate into an array:
touchMoveX.push(touchX);
touchMoveY.push(touchY);
I then loop through each array and create two points:
for(var i = 0; i < touchMoveX.length; i++)
{
for(var l=0; l < touchMoveY.length; l++)
{
var xPosition = touchMoveX[i];
var yPosition = touchMoveY[l];
var v1x = touchMoveX[i];
var v2x = touchMoveX[i + 1];
var v1y = touchMoveY[l];
var v2y = touchMoveY[l + 1];
Then using those two points, I use the following formula to figure out the angle between these two points in degrees:
var v1 = {x: v1x, y: v1y}, v2 = {x: v2x, y: v2y},
angleRad = Math.acos( (v1.x * v2.x + v1.y * v2.y) /
(Math.sqrt(v1.x*v1.x + v1.y*v1.y) * Math.sqrt(v2.x*v2.x + v2.y*v2.y) ) ),
angleDeg = angleRad * 180 / Math.PI;
I then sum up all of the angles and see if they are around 360 degrees.
But the above code I have described isn't working very well. Does someone out there have a better way to do this? Thank you very much.
yeah compute the average of all points (giving you a cheaply approximated center) then check if more than a certain percent of points are within a certain threshold. You can tune those values to adjust the precision until it feels right.
edit: Didn't consider that the circle could have multiple sizes, but you could just add another step computing the average of all distances. Adjusted the example for that.
var totalAmount = touchMoveX.length;
// sum up all coordinates and divide them by total length
// the average is a cheap approximation of the center.
var averageX = touchMoveX.reduce( function ( previous, current) {
return previous + current;
} ) / totalAmount ;
var averageY = touchMoveY.reduce( function ( previous, current) {
return previous + current;
} ) / totalAmount ;
// compute distance to approximated center from each point
var distances = touchMoveX.map ( function ( x, index ) {
var y = touchMoveY[index];
return Math.sqrt( Math.pow(x - averageX, 2) + Math.pow(y - averageY, 2) );
} );
// average of those distance is
var averageDistance = distances.reduce ( function ( previous, current ) {
return previous + current;
} ) / distances.length;
var min = averageDistance * 0.8;
var max = averageDistance * 1.2;
// filter out the ones not inside the min and max boundaries
var inRange = distances.filter ( function ( d ) {
return d > min && d < max;
} ).length;
var minPercentInRange = 80;
var percentInRange = inRange.length / totalAmount * 100;
// by the % of points within those boundaries we can guess if it's circle
if( percentInRange > minPercentInRange ) {
//it's probably a circle
}
EDIT: So apparently, PI is finite in JavaScript (which makes sense). But that leaves me with a major problem. What's the next best way to calculate the angles I need?
Alright, first, my code:
http://jsfiddle.net/joshlalonde/vtfyj/34/
I'm drawing cubes that open up to a 120 degree angle.
So the coordinates are calculated based on (h)eight and theta (120).
On line 46, I have a for loop that contains a nested for loop used for creating rows/columns.
It's somewhat subtle, but I noticed that the lines aren't matching up exactly. The code for figuring out each cubes position is on line 49. One of the things in the first parameter (my x value) for the origin of the cube is off. Can anyone help figure out what it is?
var cube = new Cube(
origin.x + (j * -w * (Math.PI)) +
(i * w * (Math.PI))
, origin.y + j * (h / 2) +
i * (h / 2) +
(-k*h), h);
Sorry if that's confusing. I,j, and k refer to the variable being incremented by the for loops. So basically, a three dimensional for loop.
I think the problem lies with Math.PI.
The width isn't the problem, or so I believe. I originally used 3.2 (which I somehow guessed and it seemed to line up pretty good. But I have no clue what the magical number is). I'm guessing it has to do with the angle being converted to Radians, but I don't understand why Math.PI/180 isn't the solution. I tried multiple things. 60 (in degrees) * Math.PI/180 doesn't work. What is it for?
EDIT: It might just be a JavaScript related math problem. The math is theoretically correct but can't be calculated correctly. I'll accept the imperfection to spare myself from re-writing code in unorthodox manners. I can tell it would take a lot to circumvent using trig math.
There are 2 problems...
Change line 35 to var w=h*Math.sin(30);. The 30 here matches the this.theta / 4 in the Cube getWidthmethod since this.theta equals 120.
Use the following code to generate the position of your new cube. You don't need Math.Pi. You needed to use both the cube width and height in your calculation.
var cube = new Cube(
origin.x+ -j*w - i*h,
origin.y + -j*w/2 + i*h/2,
h);
Alright I found the solution!
It's really simple - I was using degrees instead of radians.
function Cube(x, y, h) {
this.x = x
this.y = y
this.h = h;
this.theta = 120*Math.PI/180;
this.getWidth = function () {
return (this.h * Math.sin(this.theta / 2));
};
this.width = this.getWidth();
this.getCorner = function () {
return (this.h / 2);
};
this.corner = this.getCorner();
}
So apparently Javascript trig functions use Radians, so that's one problem.
Next fix I made was to the offset of each point in the cube. It doesn't need one! (o.O idk why. But whatever it works. I left the old code just in case I discover why later on).
function draw() {
var canvas = document.getElementById("canvas");
var ctx = canvas.getContext("2d");
ctx.fillStyle = "#000";
ctx.fillRect(0, 0, canvas.width, canvas.height); // Draw a black canvas
var h = 32;
var width = Math.sin(60*Math.PI/180);
var w = h*width;
var row = 9; // column and row will always be same (to make cube)
var column = row;
var area = row * column;
var height = 1;
row--;
column--;
height--;
var origin = {
x: canvas.width / 2,
y: (canvas.height / 2) - (h * column/2) + height*h
};
var offset = Math.sqrt(3)/2;
offset = 1;
for (var i = 0; i <= row; i++) {
for (var j = 0; j <= column; j++) {
for (var k = 0; k <= height; k++) {
var cube = new Cube(
origin.x + (j * -w * offset) +
(i * w * offset)
, origin.y + (j * (h / 2) * offset) +
(i * (h / 2) * offset) +
(-k*h*offset), h);
var cubes = {};
cubes[i+j+k] = cube; // Store to array
if (j == column) {
drawCube(2, cube);
}
if (i == row) {
drawCube(1, cube);
}
if (k == height) {
drawCube(0,cube);
}
}
}
}
}
See the full Jsfiddle here: http://jsfiddle.net/joshlalonde/vtfyj/41/