negative-one-index.html (2966B)
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>-1 Index Rendering Test</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="50" height="50"> 18 </canvas> 19 <div id="description"></div> 20 <div id="console"></div> 21 <script id="vshader" type="x-shader/x-vertex"> 22 attribute vec4 vPosition; 23 void main() 24 { 25 gl_Position = vPosition; 26 } 27 </script> 28 29 <script id="fshader" type="x-shader/x-fragment"> 30 void main() 31 { 32 gl_FragColor = vec4(0.0,1.0,0.0,1.0); 33 } 34 </script> 35 36 <script> 37 "use strict"; 38 function init() 39 { 40 description(document.title); 41 42 var wtu = WebGLTestUtils; 43 var gl = wtu.create3DContext("example"); 44 var contextVersion = wtu.getDefault3DContextVersion(); 45 var program = wtu.setupProgram(gl, ["vshader", "fshader"], ["vPosition"]); 46 47 var vertexObject = gl.createBuffer(); 48 gl.bindBuffer(gl.ARRAY_BUFFER, vertexObject); 49 var vertexData = new Float32Array(65536 * 3); 50 vertexData[0 * 3 + 0] = 0.0; 51 vertexData[0 * 3 + 1] = 0.5; 52 vertexData[0 * 3 + 2] = 0.0; 53 vertexData[1 * 3 + 0] = -0.5; 54 vertexData[1 * 3 + 1] = -0.5; 55 vertexData[1 * 3 + 2] = 0.0; 56 vertexData[65535 * 3 + 0] = 0.5; 57 vertexData[65535 * 3 + 1] = -0.5; 58 vertexData[65535 * 3 + 2] = 0.0; 59 gl.bufferData(gl.ARRAY_BUFFER, vertexData, gl.STATIC_DRAW); 60 gl.enableVertexAttribArray(0); 61 gl.vertexAttribPointer(0, 3, gl.FLOAT, false, 0, 0); 62 63 var indices = new Uint16Array([0, 1, -1]); 64 var indexBuffer = gl.createBuffer(); 65 gl.bindBuffer(gl.ELEMENT_ARRAY_BUFFER, indexBuffer); 66 gl.bufferData(gl.ELEMENT_ARRAY_BUFFER, indices, gl.STATIC_DRAW); 67 68 gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT); 69 gl.drawElements(gl.TRIANGLES, 3, gl.UNSIGNED_SHORT, 0); 70 71 if (contextVersion <= 1) { 72 // This should render a green triangle in the middle of the canvas. 73 // Some implementations may incorrectly interpret the -1 index as 74 // a primitive restart and not render anything. 75 76 // Test several locations 77 // First line should be all black 78 wtu.checkCanvasRect(gl, 0, 0, 50, 1, [0, 0, 0, 0]); 79 80 // Line 15 should be green for at least 10 pixels starting from row 20 81 wtu.checkCanvasRect(gl, 20, 15, 10, 1, [0, 255, 0, 255]); 82 83 // Last line should be all black 84 wtu.checkCanvasRect(gl, 0, 49, 50, 1, [0, 0, 0, 0]); 85 } else { 86 // For WebGL 2, PRIMITIVE_RESTART_FIXED_INDEX is always enabled. 87 // Nothing should be drawn on the canvas. 88 wtu.checkCanvasRect(gl, 0, 0, 50, 50, [0, 0, 0, 0]); 89 } 90 } 91 92 init(); 93 var successfullyParsed = true; 94 </script> 95 <script src="../../js/js-test-post.js"></script> 96 97 </body> 98 </html>