<!-- Any copyright is dedicated to the Public Domain.
http://creativecommons.org/publicdomain/zero/1.0/ -->
<!doctype html>
<html>
<head>
<meta charset="utf-8"/>
<title>WebGL editor test page</title>
</head>
<body>
<canvas id="canvas" width="1024" height="1024"></canvas>
<script type="text/javascript;version=1.8">
"use strict";
let canvas, gl;
let customFramebuffer;
let customRenderbuffer;
let customTexture;
window.onload = function() {
canvas = document.querySelector("canvas");
gl = canvas.getContext("webgl", { preserveDrawingBuffer: true });
gl.clearColor(1.0, 0.0, 0.0, 1.0);
gl.clear(gl.COLOR_BUFFER_BIT);
customFramebuffer = gl.createFramebuffer();
gl.bindFramebuffer(gl.FRAMEBUFFER, customFramebuffer);
customRenderbuffer = gl.createRenderbuffer();
gl.bindRenderbuffer(gl.RENDERBUFFER, customRenderbuffer);
gl.renderbufferStorage(gl.RENDERBUFFER, gl.DEPTH_COMPONENT16, 1024, 1024);
customTexture = gl.createTexture();
gl.bindTexture(gl.TEXTURE_2D, customTexture);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST);
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.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, 1024, 1024, 0, gl.RGBA, gl.UNSIGNED_BYTE, null);
gl.framebufferTexture2D(gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.TEXTURE_2D, customTexture, 0);
gl.framebufferRenderbuffer(gl.FRAMEBUFFER, gl.DEPTH_ATTACHMENT, gl.RENDERBUFFER, customRenderbuffer);
gl.viewport(128, 256, 384, 512);
gl.clearColor(0.0, 1.0, 0.0, 1.0);
gl.clear(gl.COLOR_BUFFER_BIT);
drawScene();
}
function drawScene() {
gl.clearColor(0.0, 0.0, 1.0, 1.0);
gl.clear(gl.COLOR_BUFFER_BIT);
window.requestAnimationFrame(drawScene);
}
</script>
</body>
</html>