lots-of-polys-example.html (2852B)
1 <!-- 2 Copyright (c) 2019 The Khronos Group Inc. 3 Use of this source code is governed by an MIT-style license that can be 4 found in the LICENSE.txt file. 5 --> 6 7 <!DOCTYPE html> 8 <html> 9 <head> 10 <meta charset="utf-8"> 11 <title>WebGL Lots of polygons example.</title> 12 <link rel="stylesheet" href="../resources/js-test-style.css"/> 13 <script src="../js/js-test-pre.js"></script> 14 <script src="../js/webgl-test-utils.js"> </script> 15 </head> 16 <body> 17 <canvas id="example" width="1024" height="1024" style="width: 40px; height: 40px;"> 18 </canvas> 19 <div id="description"></div> 20 <div id="console"></div> 21 <script> 22 "use strict"; 23 window.onload = init; 24 debug("Tests a WebGL program that draws a bunch of large polygons"); 25 26 function init() { 27 if (confirm( 28 "After clicking OK your machine may become unresponsive or crash.")) { 29 main(); 30 } else { 31 debug("cancelled"); 32 } 33 } 34 35 function main() { 36 var wtu = WebGLTestUtils; 37 var canvas = document.getElementById("example"); 38 canvas.addEventListener("webglcontextlost", function(e) { e.preventDefault(); }, false); 39 canvas.addEventListener("webglcontextrestored", function(e) { }, false); 40 41 var gl = wtu.create3DContext(canvas); 42 var program = wtu.setupTexturedQuad(gl); 43 44 assertMsg(gl.getError() == gl.NO_ERROR, "Should be no errors from setup."); 45 46 var tex = gl.createTexture(); 47 gl.enable(gl.BLEND); 48 gl.disable(gl.DEPTH_TEST); 49 50 wtu.fillTexture(gl, tex, 4096, 4096, [0, 192, 128, 255], 0); 51 wtu.glErrorShouldBe(gl, gl.NO_ERROR, "after creating texture"); 52 53 gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST); 54 gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST); 55 gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE); 56 gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE); 57 wtu.glErrorShouldBe(gl, gl.NO_ERROR, "after setting texture params"); 58 59 var loc = gl.getUniformLocation(program, "tex"); 60 wtu.glErrorShouldBe(gl, gl.NO_ERROR, "after getting tex locations"); 61 gl.uniform1i(loc, 0); 62 wtu.glErrorShouldBe(gl, gl.NO_ERROR, "after setting tex uniform"); 63 64 var numQuads = 100000; 65 var indexBuf = new ArrayBuffer(numQuads * 6); 66 var indices = new Uint8Array(indexBuf); 67 for (var ii = 0; ii < numQuads; ++ii) { 68 var offset = ii * 6; 69 indices[offset + 0] = 0; 70 indices[offset + 1] = 1; 71 indices[offset + 2] = 2; 72 indices[offset + 3] = 3; 73 indices[offset + 4] = 4; 74 indices[offset + 5] = 5; 75 } 76 var indexBuffer = gl.createBuffer(); 77 gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, indexBuffer); 78 gl.bufferData(gl.ELEMENT_ARRAY_BUFFER, indices, gl.STATIC_DRAW); 79 wtu.glErrorShouldBe(gl, gl.NO_ERROR, "after creating index buffer"); 80 gl.drawElements(gl.TRIANGLES, numQuads * 6, gl.UNSIGNED_BYTE, 0); 81 wtu.glErrorShouldBe(gl, gl.NO_ERROR, "after drawing"); 82 83 var successfullyParsed = true; 84 } 85 </script> 86 </body> 87 </html>