I've been trying to create a canvas that displays an 11x11 matrix.
const canvas = document.getElementById('canvasGame');
const context = canvas.getContext('2d');
context.scale(10, 10);
context.fillstyle = '#000';
context.fillstyle(0,0, canvas.width, canvas.height);
const matrix = [
[1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1],
[1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1],
[1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1],
[1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1],
[1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1],
[1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1],
[1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1],
[1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1],
[1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1],
[1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1],
[1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1],
[1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1],
];
Depending on the number inside the matrix it will create a rectangle of a certain colour.
I've created a basic function that goes through every entry.
if = 0, white rectangle.
else, black rectangle.
function drawMatrix(matrix){
matrix.forEach((row, y) =>{
row.forEach((value, x) => {
if(value === 0) {
context.fillStyle = 'white';
context.fillRect(x, y, 1, 1);
}
else
{
context.fillStyle = 'black';
context.fillRect(x, y, 1, 1);
}
});
});
}
drawMatrix(matrix);
However when I load my html file with my .js file and my canvas set-up it doesnt load anything apart from the styling I've applied to my canvas.
Screenshot: What it loads.
My HTML, if that matters.
<html>
<head>
<title>Testing Grounds</title>
<style>
body {
background: #345;
color: #fff;
font-family: sans-serif;
font-size: 2em;
text-align: center;
}
canvas {
border: dashed .2em #fff;
height: 90vh;
}
</style>
</head>
<body>
<h1>Test Zone</h1>
<p>Using a canvas to display 11x11 matrix</p>
<canvas id="canvasGame" width="350" height="350"/>
<script src="app.js"></script>
</body>
</html>
Here is also another way...
const canvas1 = document.getElementById('canvas1');
const context1 = canvas1.getContext('2d');
const canvas2 = document.getElementById('canvas2');
const context2 = canvas2.getContext('2d');
//context.scale(canvas.height / 16, canvas.height / 16);
matrix = [
[1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1],
[1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1],
[1, 0, 0, 1, 1, 1, 1, 1, 1, 0, 0, 1],
[1, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 1],
[1, 0, 1, 0, 1, 0, 0, 1, 0, 1, 0, 1],
[1, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 1],
[1, 0, 1, 0, 1, 0, 0, 1, 0, 1, 0, 1],
[1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1],
[1, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 1],
[1, 0, 0, 1, 1, 1, 1, 1, 1, 0, 0, 1],
[1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1],
[1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1],
];
function drawMatrix(matrix) {
z = matrix.map((c) => c.map((c) => c == 0 ? [255, 255, 255, 255] : [0, 0, 0, 255]));
i = new ImageData(Uint8ClampedArray.from(z.flat(2)), 12)
context1.putImageData(i, 0, 0);
context2.scale(16, 16);
context2.webkitImageSmoothingEnabled = false;
context2.mozImageSmoothingEnabled = false;
context2.imageSmoothingEnabled = false;
context2.drawImage(canvas1, 0, 0);
}
drawMatrix(matrix);
<center><canvas hidden id="canvas1" width=12 height=12></canvas></center>
<center><canvas id="canvas2" width=192 height=192></canvas></center>
const canvas = document.getElementById('canvas');
const context = canvas.getContext('2d');
// every drawn pixel will be 16 times bigger
context.scale(canvas.height / 16, canvas.height / 16);
const matrix = [
[1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1],
[1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1],
[1, 0, 0, 1, 1, 1, 1, 1, 1, 0, 0, 1],
[1, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 1],
[1, 0, 1, 0, 1, 0, 0, 1, 0, 1, 0, 1],
[1, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 1],
[1, 0, 1, 0, 1, 0, 0, 1, 0, 1, 0, 1],
[1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1],
[1, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 1],
[1, 0, 0, 1, 1, 1, 1, 1, 1, 0, 0, 1],
[1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1],
[1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1],
];
function drawMatrix(matrix) {
// write all pixels cycling thru rows and columns
matrix.forEach((row, y) => {
row.forEach((value, x) => {
context.fillStyle = value && "black" || "white";
context.fillRect(x, y, 1, 1);
});
});
}
drawMatrix(matrix); // draw the matrix
<center><canvas id="canvas" width=192 height=192></canvas></center>
The rectangles you're creating are 1 by 1 pixel and always in the upper-left. You should calculate the width/height of the rectangle (width / 11, height / 11). Then translate the x and width using those values. Something like the following should work:
function drawMatrix(matrix){
var cellWidth = canvas.width / 11.0;
var cellHeight = vanvas.height / 11.0;
matrix.forEach((row, y) =>{
row.forEach((value, x) => {
context.fillStyle = cellColor(value);
context.fillRect(x * cellWidth, y * cellHeight, cellWidth, cellHeight);
});
});
}
function cellColor(val) {
if(value == 0)
{
return 'white';
}
return 'black';
}
drawMatrix(matrix);
This will calculate the width and height of the cell, loop through each element, and draw the rectangle with either white or black depending on the value.
You should also make sure that the drawMatrix function is called after the body is loaded.
Related
First of all, I have difficulty in explaining because my English is not very good. But I will try to explain as best I can.
I add random photos to the canvasta cells fields with Javascript.
Each plot is equivalent to 20pixels. What I want to do is:
if i and y in the map data are equal to 4;
I want to add the photo I want to a 4x4 area.
In other words, while adding a photo to 20 pixels;
I want to add a photo to a 320pixel area when it is 4x4.
As in the sample photo.
Check Photo
var map = [
[1, 0, 1, 0, 1, 0, 0, 0, 1, 1, 1, 0, 1, 1, 1],
[1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 0, 0],
[1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 0, 0],
[1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 0, 0],
[1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 0, 0],
[1, 0, 1, 0, 1, 0, 0, 0, 1, 1, 1, 0, 1, 1, 1],
[1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1],
[1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1],
[1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1],
[1, 0, 1, 0, 1, 1, 1, 0, 1, 0, 1, 0, 1, 1, 1],
[4, 4, 4, 4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
[4, 4, 4, 4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
[4, 4, 4, 4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
[4, 4, 4, 4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
];
window.onload = function() {
const canvas = document.getElementById("main");
const ctx = canvas.getContext("2d");
ctx.strokeStyle = "transparent";
ctx.lineWidth = 0;
//draw grid
for (let i = 0; i <= 300; i++) {
const x = i*20;
ctx.moveTo(x, 0);
ctx.lineTo(x, canvas.height);
ctx.stroke();
const y = i*20;
ctx.moveTo(0, y);
ctx.lineTo(canvas.width, y);
ctx.stroke();
}
//draw images
const p = ctx.lineWidth / 1; //padding
for (let xCell = 0; xCell < map.length; xCell++) {
for (let yCell = 0; yCell < map[xCell].length; yCell++) {
const x = xCell * 20;
const y = yCell * 20;
const img = new Image();
if (map[xCell][yCell] === 1) {
img.onload = function() {
ctx.drawImage(img, y+p, x+p, 20-p*2, 20-p*2);
};
//TODO: set img.src to your api url instead of the dummyimage url.
img.src = `https://picsum.photos/id/${Math.floor(Math.random() * 10)}${Math.floor(Math.random() * 10)}/200/300`;
}else if(map[xCell][yCell] == 4){
img.onload = function() {
ctx.drawImage(img, y+p, x+p, 20-p*2, 20-p*2);
};
//TODO: set img.src to your api url instead of the dummyimage url.
img.src = `https://picsum.photos/id/${Math.floor(Math.random() * 12)}${Math.floor(Math.random() * 12)}/200/300`;
}
}
}
};
<canvas id="main" width="600" height="630"></canvas>
</canvas>
I solved the problem as below. There are positional errors but I will completely fix them.
Thanks to Lajos Arpad for trying to help.
var defaultMap = [
[1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 1],
[1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 1, 0, 0, 1, 1],
[0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 1, 1],
[0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0],
[0, 0, 1, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0],
[0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0],
[0, 0, 0, 0, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0],
[0, 0, 0, 0, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1],
[0, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1],
[1, 1, 1, 1, 1, 0, 1, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1],
[1, 1, 1, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1],
[1, 1, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1],
[1, 1, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1],
[1, 1, 1, 1, 1, 1, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1],
];
var images = [
{
name: "player 1",
position: [
{
x: [0,4],
y: [4,4]
}
]
},
{
name: "player 2",
position: [
{
x: [5,7],
y: [5,2]
}
]
}
];
window.onload = function() {
const canvas = document.getElementById("main");
const ctx = canvas.getContext("2d");
ctx.strokeStyle = "transparent";
ctx.lineWidth = 0;
//draw grid
for (let i = 0; i <= 300; i++) {
const x = i*40;
ctx.moveTo(x, 0);
ctx.lineTo(x, canvas.height);
ctx.stroke();
const y = i*40;
ctx.moveTo(0, y);
ctx.lineTo(canvas.width, y);
ctx.stroke();
}
const p = ctx.lineWidth / 1;
for (let xCell = 0; xCell < defaultMap.length; xCell++) {
for (let yCell = 0; yCell < defaultMap[xCell].length; yCell++) {
const x = xCell * 20;
const y = yCell * 20;
const img = new Image();
if (defaultMap[xCell][yCell] === 1) {
img.onload = function() {
ctx.drawImage(img, y+p, x+p, 20-p*2, 20-p*2);
};
img.src = `https://besthqwallpapers.com/Uploads/5-6-2020/134999/thumb-black-ground-texture-macro-grunge-textures-black-backgrounds-ground-textures.jpg`;
}
}
}
for (let i = 0; i < images.length; i++) {
var width = 1, height = 1, x = images[i].position[0].x[0], y = images[i].position[0].y[0];
console.log(images[i].name + " x => " + images[i].position[0].x[0])
for(let w = images[i].position[0].x[0]; w < images[i].position[0].x[1]; w++){
width++
}
for(let h = 1; h < images[i].position[0].y[1]; h++){
height++
}
const img = new Image();
img.src = `https://picsum.photos/id/${Math.floor(Math.random() * 12)}${Math.floor(Math.random() * 12)}/200/300`;
img.onload = function() {
console.log(20*images[i].position[0].x[0]+p)
/* ctx.rect(20*i, 20*i, 20*width-p*2, 20*height-p*2)
ctx.fillStyle = "blue";
ctx.fill(); */
ctx.drawImage(img, 20*images[i].position[0].y[0]+p, 20*images[i].position[0].x[0]+p, 20*width-p*2, 20*height-p*2);
};
}
};
<canvas id="main" width="600" height="630"></canvas>
</canvas>
You can compute the value of a multiplier and use that to determine the picture size.
var map = [
[1, 0, 1, 0, 1, 0, 0, 0, 1, 1, 1, 0, 1, 1, 1],
[1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 0, 0],
[1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 0, 0],
[1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 0, 0],
[1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 1, 0, 0],
[1, 0, 1, 0, 1, 0, 0, 0, 1, 1, 1, 0, 1, 1, 1],
[1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1],
[1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1],
[1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1],
[1, 0, 1, 0, 1, 1, 1, 0, 1, 0, 1, 0, 1, 1, 1],
[4, 4, 4, 4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
[4, 4, 4, 4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
[4, 4, 4, 4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
[4, 4, 4, 4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
];
window.onload = function() {
const canvas = document.getElementById("main");
const ctx = canvas.getContext("2d");
ctx.strokeStyle = "transparent";
ctx.lineWidth = 0;
//draw grid
for (let i = 0; i <= 300; i++) {
const x = i*20;
ctx.moveTo(x, 0);
ctx.lineTo(x, canvas.height);
ctx.stroke();
const y = i*20;
ctx.moveTo(0, y);
ctx.lineTo(canvas.width, y);
ctx.stroke();
}
//draw images
const p = ctx.lineWidth / 1; //padding
for (let xCell = 0; xCell < map.length; xCell++) {
for (let yCell = 0; yCell < map[xCell].length; yCell++) {
let multiplier = ((map[xCell][yCell] % 4) ? 1 : 4);
const x = xCell * 20;
const y = yCell * 20;
const img = new Image();
if (map[xCell][yCell] === 1) {
img.onload = function() {
ctx.drawImage(img, y+p, x+p, multiplier * 20-p*2, multiplier * 20-p*2);
};
//TODO: set img.src to your api url instead of the dummyimage url.
img.src = `https://picsum.photos/id/${Math.floor(Math.random() * 10)}${Math.floor(Math.random() * 10)}/200/300`;
}else if(map[xCell][yCell] == 4){
img.onload = function() {
ctx.drawImage(img, y+p, x+p, multiplier * 20-p*2, multiplier * 20-p*2);
};
//TODO: set img.src to your api url instead of the dummyimage url.
img.src = `https://picsum.photos/id/${Math.floor(Math.random() * 12)}${Math.floor(Math.random() * 12)}/200/300`;
}
}
}
};
<canvas id="main" width="600" height="630"></canvas>
</canvas>
I apologize if this is not well explained. I am quite new to JavaScript.
I have a 2D arrayA that is 10x10 and a 2D arrayB that is 5x8. The smaller arrayB is populated with data and the larger arrayA is just populated with 0's by default.
How can i move the data from arrayB to arrayA while still leaving the leftover space of arrayA as 0's?
The end result must be that arrayA should contain all of the data in the same order as arrayB but with the leftover space still just containing 0's.
Assuming I understood the question correctly, you can loop over each value of arrayB and assign it at the same indexes in arrayA:
const arrayA = Array(10).fill(0).map(_ => Array(10).fill(0))
const arrayB = Array(5).fill(0).map(_ => Array(8).fill(1))
for (let y = 0; y < arrayB.length; y++) {
for (let x = 0; x < arrayB[y].length; x++) {
arrayA[y][x] = arrayB[y][x]
}
}
console.log(arrayA.map(v => v.join(', ')).join('\n'))
The console.log is just for readability, to understand how the matrix looks.
A simple Array.map() will do the job:
const arrA = [
[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, 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, 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, 0, 0, 0, 0, 0, 0],
[0, 0, 0, 0, 0, 0, 0, 0, 0, 0],
];
const arrB = [
[0,1,2,3,4],
[0,1,2,3,4],
[0,1,2,3,4],
[0,1,2,3,4],
[0,1,2,3,4],
[0,1,2,3,4],
[0,1,2,3,4],
[0,1,2,3,4],
];
const B2A = () => arrA.map(
(val, index) => val.map(
(subVal, subIndex) => {
if(arrB[index] && arrB[index][subIndex]) return arrB[index][subIndex]
return subVal;
})
)
console.log(B2A());
Use Array.from and iterate, while iterate check if the value exists in filler array. If exists use that value otherwise same array value.
const fill = (arr1, arr2) =>
Array.from(arr1, (arr, row) =>
Array.from(arr, (value, col) => (arr2[row] && arr2[row][col]) || value)
);
const arrA = [
[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, 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, 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, 0, 0, 0, 0, 0, 0],
[0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
];
const arrB = [
[0, 1, 2, 3, 4],
[0, 1, 2, 3, 4],
[0, 1, 2, 3, 4],
[0, 1, 2, 3, 4],
[0, 1, 2, 3, 4],
[0, 1, 2, 3, 4],
[0, 1, 2, 3, 4],
[0, 1, 2, 3, 4]
];
console.log(JSON.stringify(fill(arrA, arrB)));
I was trying to do the 6th day of AdventOfCode.com, when I stumbled upon an annoying problem, that I don't know the cause of. I
var input = ["turn on 7,6 through 9,6","turn on 1,3 through 6,9"];
var grid = 0;
function Create2Darray(dimension) {
var arr = [0];
var arr2 = [0];
for (i=0; i<dimension; i++) {
arr2[i] = 0;
}
for (k=0; k<dimension; k++) {
arr[k] = arr2;
}
return arr;
}
grid = Create2Darray(10);
const p = grid; // THIS IS WHAT IT IS ALL ABOUT
temp = grid[4];
temp[5] = 3;
grid[4] = temp;
p; // outputs [[0, 0, 0, 0, 0, 3, 0, 0, 0, 0], [0, 0, 0, 0, 0, 3, 0, 0, 0, 0], [0, 0, 0, 0, 0, 3, 0, 0, 0, 0], [0, 0, 0, 0, 0, 3, 0, 0, 0, 0], [0, 0, 0, 0, 0, 3, 0, 0, 0, 0], [0, 0, 0, 0, 0, 3, 0, 0, 0, 0], [0, 0, 0, 0, 0, 3, 0, 0, 0, 0], [0, 0, 0, 0, 0, 3, 0, 0, 0, 0], [0, 0, 0, 0, 0, 3, 0, 0, 0, 0], [0, 0, 0, 0, 0, 3, 0, 0, 0, 0]] to console.
// Although we said: const p = grid;
// And at that time, grid was equal to [[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, 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, 3, 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, 0, 0, 0, 0, 0, 0], [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]]
Secondly
this:
temp = grid[4];
temp[5] = 3;
grid[4] = temp;
What I expected was this:
[[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, 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, 3, 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, 0, 0, 0, 0, 0, 0], [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]]
but I got:
[[0, 0, 0, 0, 0, 3, 0, 0, 0, 0], [0, 0, 0, 0, 0, 3, 0, 0, 0, 0], [0, 0, 0, 0, 0, 3, 0, 0, 0, 0], [0, 0, 0, 0, 0, 3, 0, 0, 0, 0], [0, 0, 0, 0, 0, 3, 0, 0, 0, 0], [0, 0, 0, 0, 0, 3, 0, 0, 0, 0], [0, 0, 0, 0, 0, 3, 0, 0, 0, 0], [0, 0, 0, 0, 0, 3, 0, 0, 0, 0], [0, 0, 0, 0, 0, 3, 0, 0, 0, 0], [0, 0, 0, 0, 0, 3, 0, 0, 0, 0]]
What am I doing wrong?
so the core questions:
Why did CONSTANT p change?
Why did ALL the "sub-arrays" within the main arrays change while I only selected the 5th value in the 4th "sub-array"?
About reference/copy
Javascript works "by reference", not "by copy" like C++. This means that after:
var a = [1, 2, 3];
var b = [a, a];
b is an array containing two references to the same array a, not two copies of a. For example after
b[0][0] = 99;
also b[1][0] will be 99 because b[0] and b[1] are references to the very same object.
If you want to build a matrix you need to build each row separately... for example:
var grid = [];
for (var i=0; i<100; i++) {
grid.push(new Array(100));
}
// Now grid is a matrix of 100x100 undefined elements
About const
Declaring a const reference to an array doesn't prevent the array content from being modified, you're only prevented from reassigning grid to reference something else.
A quick way to create a copy of an array is to use slice(0), for example instead of
for (k=0; k<dimension; k++) {
arr[k] = arr2;
}
you could have
for (k=0; k<dimension; k++) {
arr[k] = arr2.slice(0);
}
and then the code works as expected: every row of 2D array has the same content but the rows can be modified independently. See also: What's the point of .slice(0) here?
Though I have been able to create and use animations for small demos in the past using the CreateJS library, i'm currently stumped in trying to understand why Nothing is displaying to the canvas even though I have verified that my animation tiles are all being added. I'm going senile from stepping through the debugger and seeing everything work properly, but getting a completely blank page on reloads.
Any ideas are much appreciated!
var stage, loader;
function tick() {
stage.update();
}
function generateMap(rekeyed_array, spriteSheet, row_length, col_length, tilesize) {
for (var x = 0; x < col_length; x++) {
for (var y = 0; y < row_length; y++) {
// z is a onedimentional value mapped from x and y iterators
spriteInstance = new createjs.Sprite(spriteSheet, rekeyed_array[z]);
var z = x * row_length + y;
spriteInstance.x = tilesize * x;
spriteInstance.y = tilesize * y;
spriteInstance.gotoAndPlay(rekeyed_array[z]);
spriteInstance = spriteInstance.clone();
stage.addChild(spriteInstance);
}
}
console.groupEnd();
stage.update();
}
//Replace Tiled's map data numbers with the actual Game Object's Names
function rekeyTiledMapData(spritemappings, array_to_reindex, rows, cols) {
var reindexedArray = new Array();
for (var y = 0; y < cols; y++) {
for (var x = 0; x < rows; x++) {
// z is a onedimentional value mapped from x and y iterators
var z = y * rows + x;
var currentItem = array_to_reindex[z];
if (typeof spritemappings[currentItem] === "string") {
reindexedArray.push(spritemappings[currentItem]);
} else {
reindexedArray.push(currentItem);
}
}
}
return reindexedArray;
}
function getSpriteData(loadedimg) {
var data = {
framerate: 60,
images: [loadedimg],
frames: [
/*middlearth*/
[592, 654, 70, 70, 0, 0, 0],
/*water*/
[562, 434, 70, 70, 0, 0, 0],
/*doormid*/
[146, 290, 70, 70, 0, 0, 0],
/*doortop*/
[218, 290, 70, 70, 0, 0, 0],
/*grass*/
[736, 362, 70, 70, 0, 0, 0]
],
animations: {
"sand": {
frames: 0,
next: "sand",
speed: 1
},
"water": {
frames: 1,
next: "water",
speed: 1
},
"doormid": [2, 2, "doormid", 1],
"doortop": [3, 3, "doortop", 1],
"grass": [4, 4, "grass", 1],
}
};
return data;
}
var mapdata = [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, 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, 0, 11, 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, 0, 0, 0, 0, 0, 0, 0, 0, 10, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 8, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 6, 6, 6, 7, 7, 7, 6, 6, 6, 6, 0, 0, 0, 0, 0, 0, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5];
var spritemappings = {
'0': "water",
'8': "water",
'7': "water",
'5': "sand",
'6': "grass",
'10': "doortop",
'11': "doormid"
};
function loadLevel(event) {
var tileimage = loader.getResult("tiles");
levelanimations = rekeyTiledMapData(spritemappings, mapdata, 16, 10);
var spritesheet = new createjs.SpriteSheet(getSpriteData(tileimage));
generateMap(levelanimations, spritesheet, 16, 10, 70);
}
function init() {
stage = new createjs.Stage("gameCanvas");
createjs.Ticker.on("tick", tick);
createjs.Ticker.setFPS(60);
loader = new createjs.LoadQueue(false);
loader.addEventListener("complete", loadLevel)
loader.loadManifest({
id: "tiles",
src: "assets/images/level_tiles.png"
});
}
init();
</script>
</head>
<body>
<canvas id="gameCanvas" width="1600" height="900"></canvas>
</body>
If that script is a copy and paste, the script in the head is executed before the body is being created. Thats why you are seeing that it is executing correctly, but nothing is actually happening.
I would copy and paste the script tag in the header down below the canvas element.
I have been creating a game in HTML5 and javascript and have came across a problem.
The game uses a tile system to load the map. Currently my map is saved within a multidimensional array and looks like this:
var map = [ [1, 1, 1, 1, 1, 1, 1, 1, 1, 1],
[1, 3, 0, 0, 0, 0, 0, 0, 0, 1],
[1, 0, 0, 0, 0, 0, 0, 0, 0, 1],
[1, 0, 0, 0, 0, 0, 0, 0, 0, 1],
[1, 0, 0, 0, 0, 0, 0, 0, 0, 1],
[1, 0, 0, 0, 0, 0, 0, 0, 0, 1],
[1, 0, 0, 0, 0, 0, 2, 0, 4, 1],
[1, 0, 0, 0, 0, 0, 2, 0, 4, 1],
[1, 0, 0, 0, 0, 0, 2, 0, 4, 1],
[1, 0, 0, 0, 0, 0, 2, 0, 4, 1],
[1, 0, 0, 0, 0, 0, 2, 0, 4, 1],
[1, 0, 0, 0, 0, 0, 0, 0, 0, 1],
[1, 1, 1, 1, 1, 1, 1, 1, 1, 1]]
I would like to add move levels by using a XML file to update the array.
My XML file currently looks like this:
<TileMaps>
<Level level="1">
<map>[ [1, 1, 1, 1, 1, 1, 1, 1, 1, 1],
[1, 3, 0, 0, 0, 0, 2, 4, 0, 1],
[1, 1, 1, 1, 1, 1, 1, 1, 1, 1]]
</map>
</Level>
<Level level="2">
<map>[ [1, 1, 1, 1, 1, 1, 1, 1, 1, 1],
[1, 3, 0, 0, 0, 0, 0, 0, 0, 1],
[1, 0, 0, 0, 0, 0, 0, 0, 0, 1],
[1, 0, 0, 0, 0, 0, 0, 0, 0, 1],
[1, 0, 0, 0, 0, 0, 0, 0, 0, 1],
[1, 0, 0, 0, 0, 0, 0, 0, 0, 1],
[1, 0, 0, 0, 0, 0, 2, 0, 4, 1],
[1, 0, 0, 0, 0, 0, 2, 0, 4, 1],
[1, 0, 0, 0, 0, 0, 2, 0, 4, 1],
[1, 0, 0, 0, 0, 0, 2, 0, 4, 1],
[1, 0, 0, 0, 0, 0, 2, 0, 4, 1],
[1, 0, 0, 0, 0, 0, 0, 0, 0, 1],
[1, 1, 1, 1, 1, 1, 1, 1, 1, 1]]
</map>
</Level>
</TileMaps>
If anyone could help me load level="1" into my map variable that would be great.
Thanks
Don't use xml, use json. Here's a link to what its about, http://www.json.org/.
While not entirely precise, its pretty safe to think of json as a subset of javascript.
For example:
{
"levels":[
[
[1, 1, 1, 1, 1, 1, 1, 1, 1, 1],
[1, 3, 0, 0, 0, 0, 2, 4, 0, 1],
[1, 1, 1, 1, 1, 1, 1, 1, 1, 1]
],
[
[1, 1, 1, 1, 1, 1, 1, 1, 1, 1],
[1, 3, 0, 0, 0, 0, 0, 0, 0, 1],
[1, 0, 0, 0, 0, 0, 0, 0, 0, 1],
[1, 0, 0, 0, 0, 0, 0, 0, 0, 1],
[1, 0, 0, 0, 0, 0, 0, 0, 0, 1],
[1, 0, 0, 0, 0, 0, 0, 0, 0, 1],
[1, 0, 0, 0, 0, 0, 2, 0, 4, 1],
[1, 0, 0, 0, 0, 0, 2, 0, 4, 1],
[1, 0, 0, 0, 0, 0, 2, 0, 4, 1],
[1, 0, 0, 0, 0, 0, 2, 0, 4, 1],
[1, 0, 0, 0, 0, 0, 2, 0, 4, 1],
[1, 0, 0, 0, 0, 0, 0, 0, 0, 1],
[1, 1, 1, 1, 1, 1, 1, 1, 1, 1]
]
]
}
Use http://jsonlint.org to validate json.
For anyone who wanted to know i fixed this by using the following code:
req=new XMLHttpRequest();
req.open("GET","my.xml",false);
req.send();
xmlDoc = req.responseXML;
map = JSON.parse(xmlDoc.getElementsByTagName('map')[0].firstChild.nodeValue);