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qubbit/gist:f1e1e783dbd241a5ac8ddb061f6d5f16

Forked from elnaqah/gist:5070979
Created July 10, 2020 08:29
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cube with texture webgl tutorial
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gistfile1.txt
<html>
<head>
<title>Learning WebGL</title>
<meta http-equiv="content-type" content="text/html; charset=ISO-8859-1">
<script type="text/javascript" src="glMatrix-0.9.5.min.js"></script>
<script type="text/javascript" src="webgl-utils.js"></script>
<script id="shader-fs" type="x-shader/x-fragment">
precision mediump float;
varying vec4 vColor;
varying vec2 vTextureCoord;
uniform sampler2D uSampler;
void main(void)
{
gl_FragColor=texture2D(uSampler,vTextureCoord);
}
</script>
<script id="shader-vs" type="x-shader/x-vertex">
attribute vec3 aVertexPosition;
attribute vec4 aVertexColor;
attribute vec2 aTextureCoord;
uniform mat4 uMVMatrix;
uniform mat4 uPMatrix;
varying vec4 vColor;
varying vec2 vTextureCoord;
void main(void)
{
gl_Position=uPMatrix * uMVMatrix * vec4(aVertexPosition,1.0);
vColor=aVertexColor;
vTextureCoord=aTextureCoord;
}
</script>
<script type="text/javascript">
function handleLoadedTexture(texture)
{
gl.bindTexture(gl.TEXTURE_2D, texture);
gl.pixelStorei(gl.UNPACK_FLIP_Y_WEBGL,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.NEAREST);
gl.texParameteri(gl.TEXTURE_2D,gl.TEXTURE_MIN_FILTER,gl.NEAREST);
gl.bindTexture(gl.TEXTURE_2D,null);
}
var myTexture;
function initTexture()
{
myTexture=gl.createTexture();
myTexture.image=new Image();
myTexture.image.onload= function() {
handleLoadedTexture(myTexture);
}
myTexture.image.src="nehe.gif";
}
var mvMatrix=mat4.create();
var pMatrix=mat4.create();
var mvMatrixStack=[];
function mvPushMatrix()
{
var copy=mat4.create();
mat4.set(mvMatrix,copy);
mvMatrixStack.push(copy);
}
function mvPopMatrix()
{
if (mvMatrixStack.length==0) {
throw "ya 3am mesh pop";
}
mvMatrix=mvMatrixStack.pop();
}
function setUniforms()
{
gl.uniformMatrix4fv(shaderProgram.pMatrixUniform,false,pMatrix);
gl.uniformMatrix4fv(shaderProgram.mvMatrixUniform,false,mvMatrix);
}
function getShader(gl,id)
{
var shaderScript=document.getElementById(id);
if(!shaderScript)
{
return null;
}
var str="";
var script=shaderScript.firstChild;
while(script){
if(script.nodeType==3)
{
str+=script.textContent;
}
script=script.nextSibling;
}
var shader;
if(shaderScript.type == "x-shader/x-fragment")
{
shader=gl.createShader(gl.FRAGMENT_SHADER);
}
else if(shaderScript.type == "x-shader/x-vertex" )
{
shader=gl.createShader(gl.VERTEX_SHADER);
}
else
{
return null;
}
gl.shaderSource(shader,str);
gl.compileShader(shader);
if(!gl.getShaderParameter(shader,gl.COMPILE_STATUS))
{
alert(gl.getShaderInfoLog(shader));
return null;
}
return shader;
}
var shaderProgram;
var gl;
function initShaders()
{
var fragementShader=getShader(gl,"shader-fs");
var vertexShader=getShader(gl,"shader-vs");
shaderProgram=gl.createProgram();
gl.attachShader(shaderProgram,vertexShader);
gl.attachShader(shaderProgram,fragementShader);
gl.linkProgram(shaderProgram);
if(!gl.getProgramParameter(shaderProgram,gl.LINK_STATUS))
{
alert("cloud not initialise shaders");
}
gl.useProgram(shaderProgram);
shaderProgram.vertexPositionAttribute=gl.getAttribLocation(shaderProgram,"aVertexPosition");
gl.enableVertexAttribArray(shaderProgram.vertexPositionAttribute);
// shaderProgram.vertexColorAttribute=gl.getAttribLocation(shaderProgram,"aVertexColor");
// gl.enableVertexAttribArray(shaderProgram.vertexColorAttribute);
shaderProgram.textureCoordsAttribute=gl.getAttribLocation(shaderProgram,"aTextureCoord");
gl.enableVertexAttribArray(shaderProgram.textureCoordsAttribute);
shaderProgram.samplerUniform=gl.getUniformLocation(shaderProgram,"uSampler");
shaderProgram.pMatrixUniform=gl.getUniformLocation(shaderProgram,"uPMatrix");
shaderProgram.mvMatrixUniform=gl.getUniformLocation(shaderProgram,"uMVMatrix");
}
function initGL(canvas)
{
try{
gl=canvas.getContext("experimental-webgl");
gl.viewportWidth=canvas.width;
gl.viewportHeight=canvas.height;
}
catch(e){}
if(!gl)
{
alert("mafesh webgl");
}
}
var cubeVertexPositionBuffer;
var cubeVertexColorBuffer;
var cubeVertexIndicesBuffer;
var cubeVertexTextureCoordBuffer;
function initBuffer()
{
cubeVertexPositionBuffer=gl.createBuffer();
gl.bindBuffer(gl.ARRAY_BUFFER,cubeVertexPositionBuffer);
vertices = [
// Front face
-1.0, -1.0, 1.0,
1.0, -1.0, 1.0,
1.0, 1.0, 1.0,
-1.0, 1.0, 1.0,
// Back face
-1.0, -1.0, -1.0,
-1.0, 1.0, -1.0,
1.0, 1.0, -1.0,
1.0, -1.0, -1.0,
// Top face
-1.0, 1.0, -1.0,
-1.0, 1.0, 1.0,
1.0, 1.0, 1.0,
1.0, 1.0, -1.0,
// Bottom face
-1.0, -1.0, -1.0,
1.0, -1.0, -1.0,
1.0, -1.0, 1.0,
-1.0, -1.0, 1.0,
// Right face
1.0, -1.0, -1.0,
1.0, 1.0, -1.0,
1.0, 1.0, 1.0,
1.0, -1.0, 1.0,
// Left face
-1.0, -1.0, -1.0,
-1.0, -1.0, 1.0,
-1.0, 1.0, 1.0,
-1.0, 1.0, -1.0
];
gl.bufferData(gl.ARRAY_BUFFER,new Float32Array(vertices),gl.STATIC_DRAW);
cubeVertexPositionBuffer.itemSize=3;
cubeVertexPositionBuffer.numItems=24;
cubeVertexColorBuffer=gl.createBuffer();
gl.bindBuffer(gl.ARRAY_BUFFER,cubeVertexColorBuffer);
var colors=[
[1.0, 0.0, 0.0, 1.0], // Front face
[1.0, 1.0, 0.0, 1.0], // Back face
[0.0, 1.0, 0.0, 1.0], // Top face
[1.0, 0.5, 0.5, 1.0], // Bottom face
[1.0, 0.0, 1.0, 1.0], // Right face
[0.0, 0.0, 1.0, 1.0] // Left face
];
var unpackedColors=[];
for (var i in colors) {
var color=colors[i];
for(var j=0;j<4 ; j++)
{
unpackedColors=unpackedColors.concat(color);
}
}
gl.bufferData(gl.ARRAY_BUFFER,new Float32Array(unpackedColors),gl.STATIC_DRAW);
cubeVertexColorBuffer.itemSize=4;
cubeVertexColorBuffer.numItems=24;
cubeVertexIndicesBuffer=gl.createBuffer();
gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER,cubeVertexIndicesBuffer);
var cubeVertexIndices=[
0,1,2, 0,2,3,
4,5,6, 4,6,7,
8,9,10, 8,10,11,
12,13,14, 12,14,15,
16,17,18, 16,18,19,
20,21,22, 20,22,23
]
gl.bufferData(gl.ELEMENT_ARRAY_BUFFER,new Uint16Array(cubeVertexIndices),gl.STATIC_DRAW);
cubeVertexIndicesBuffer.itemSize=1;
cubeVertexIndicesBuffer.numItems=36;
cubeVertexTextureCoordBuffer=gl.createBuffer();
gl.bindBuffer(gl.ARRAY_BUFFER,cubeVertexTextureCoordBuffer);
var textureCoords = [
// Front face
0.0, 0.0,
1.0, 0.0,
1.0, 1.0,
0.0, 1.0,
// Back face
1.0, 0.0,
1.0, 1.0,
0.0, 1.0,
0.0, 0.0,
// Top face
0.0, 1.0,
0.0, 0.0,
1.0, 0.0,
1.0, 1.0,
// Bottom face
1.0, 1.0,
0.0, 1.0,
0.0, 0.0,
1.0, 0.0,
// Right face
1.0, 0.0,
1.0, 1.0,
0.0, 1.0,
0.0, 0.0,
// Left face
0.0, 0.0,
1.0, 0.0,
1.0, 1.0,
0.0, 1.0,
];
gl.bufferData(gl.ARRAY_BUFFER,new Float32Array(textureCoords),gl.STATIC_DRAW);
cubeVertexTextureCoordBuffer.itemSize=2;
cubeVertexTextureCoordBuffer.numItems=24;
}
function degree_to_redian(degree)
{
return degree*Math.PI/180.0;
}
function drawScene()
{
gl.viewport(0,0,gl.viewportWidth,gl.viewportHeight);
gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);
mat4.perspective(45,gl.viewportWidth/gl.viewportHeight,0.1,100.0,pMatrix);
mat4.identity(mvMatrix);
mat4.translate(mvMatrix,[0.0,0.0,-7.0]);
mat4.rotate(mvMatrix,degree_to_redian(rTri),[1.0,1.0,1.0]);
gl.bindBuffer(gl.ARRAY_BUFFER,cubeVertexPositionBuffer);
gl.vertexAttribPointer(shaderProgram.vertexPositionAttribute,cubeVertexPositionBuffer.itemSize,gl.FLOAT,false,0,0);
gl.bindBuffer(gl.ARRAY_BUFFER,cubeVertexTextureCoordBuffer);
gl.vertexAttribPointer(shaderProgram.textureCoordsAttribute,cubeVertexTextureCoordBuffer.itemSize,gl.FLOAT,false,0,0);
gl.activeTexture(gl.TEXTURE0);
gl.bindTexture(gl.TEXTURE_2D,myTexture);
gl.uniform1i(shaderProgram.samplerUniform,0);
// gl.bindBuffer(gl.ARRAY_BUFFER,cubeVertexColorBuffer);
// gl.vertexAttribPointer(shaderProgram.vertexColorAttribute,cubeVertexColorBuffer.itemSize,gl.FLOAT,false,0,0);
gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER,cubeVertexIndicesBuffer);
setUniforms();
gl.drawElements(gl.TRIANGLES,cubeVertexIndicesBuffer.numItems,gl.UNSIGNED_SHORT,0);
//gl.drawArrays(gl.TRIANGLES_STRIPS,0,cubeVertexPositionBuffer.numItems);
}
function webGLStart()
{
var canvas=document.getElementById("canvas");
initGL(canvas);
initShaders();
initBuffer();
initTexture();
gl.clearColor(0.0,0.0,0.0,1.0);
gl.enable(gl.DEPTH_TEST)
//drawScene();
tick();
}
var rTri=0;
var lastTime = 0;
function animate() {
var timeNow = new Date().getTime();
if (lastTime != 0) {
var elapsed = timeNow - lastTime;
rTri += (90 * elapsed) / 1000.0;
}
lastTime = timeNow;
}
function tick()
{
requestAnimFrame(tick);
drawScene();
animate();
}
</script>
</head>
<body onload="webGLStart()">
<canvas id="canvas" style="border: none;" width="500" height="500"></canvas>
</body>
</html>
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