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<!DOCTYPE html>
<html>
<head>
<style type="text/css" media="screen">
canvas {
width: 100px;
height: 100px;
image-rendering: pixelated;
}
#canvas2 {
image-rendering: auto;
}
</style>
<script id="vertexShader" type="x-shader/x-vertex">
attribute vec4 vPosition;
void main() {
gl_Position = vPosition;
}
</script>
<script id="fragmentShader" type="x-shader/x-fragment">
void main() {
gl_FragColor = vec4(0.0, 0.5, 0.0, 1.0);
}
</script>
<script>
if (window.testRunner) {
window.testRunner.overridePreference("WebKitWebGLEnabled", "1");
window.testRunner.dumpAsTextWithPixelResults();
}
function draw(gl) {
var vertices = [ 0.0, 0.8, 0.0,
-0.8, -0.8, 0.0,
0.8, -0.8, 0.0 ];
gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(vertices), gl.STATIC_DRAW);
gl.vertexAttribPointer(0, 3, gl.FLOAT, false, 0, 0); // Load the vertex data
gl.enableVertexAttribArray(0);
gl.drawArrays(gl.TRIANGLES, 0, 3);
gl.flush();
}
function getFragmentShader(gl) {
var shaderNode = document.getElementById("fragmentShader"); // fragmentShader has been defined at the top
var shaderSource = getShaderSource(shaderNode);
var shader = gl.createShader(gl.FRAGMENT_SHADER);
gl.shaderSource(shader, shaderSource);
gl.compileShader(shader);
return shader;
}
function getShaderSource(shaderNode) {
var shaderSource = "";
var node = shaderNode.firstChild;
while (node) {
if (node.nodeType == 3) // Node.TEXT_NODE
shaderSource += node.textContent;
node = node.nextSibling;
}
return shaderSource;
}
function getVertexShader(gl) {
var shaderNode = document.getElementById("vertexShader");
var shaderSource = getShaderSource(shaderNode);
var shader = gl.createShader(gl.VERTEX_SHADER);
gl.shaderSource(shader, shaderSource);
gl.compileShader(shader);
return shader;
}
function initialize(gl) {
var vertexShader = getVertexShader(gl);
var fragmentShader = getFragmentShader(gl);
var shaderProgram = gl.createProgram();
gl.attachShader(shaderProgram, vertexShader);
gl.attachShader(shaderProgram, fragmentShader);
gl.bindAttribLocation(shaderProgram, 0, "vPosition"); // vPosition has been defined at the top
gl.linkProgram(shaderProgram);
gl.useProgram(shaderProgram);
var buffer = gl.createBuffer();
gl.bindBuffer(gl.ARRAY_BUFFER, buffer);
}
function drawCanvas(canvas) {
var gl = canvas.getContext("webgl");
initialize(gl);
draw(gl);
}
function drawAll() {
drawCanvas(document.getElementById("canvas0"));
drawCanvas(document.getElementById("canvas1"));
drawCanvas(document.getElementById("canvas2"));
document.getElementById("canvas1").style.imageRendering = "auto";
document.getElementById("canvas2").style.imageRendering = "pixelated";
}
</script>
</head>
<body onload="drawAll()">
<canvas id="canvas0" width="20" height="20"></canvas>
<canvas id="canvas1" width="20" height="20"></canvas>
<canvas id="canvas2" width="20" height="20"></canvas>
</body>
</html>
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