out-of-bounds-array-buffers.html (5243B)
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 <!DOCTYPE html> 7 <html> 8 <head> 9 <meta charset="utf-8"> 10 <link rel="stylesheet" href="../../resources/js-test-style.css"/> 11 <script src="../../js/js-test-pre.js"></script> 12 <script src="../../js/webgl-test-utils.js"></script> 13 <title>WebGL Out-of-Bounds Array Buffer Conformance Test</title> 14 </head> 15 <body> 16 <canvas id="canvas" width="8" height="8" style="width: 100px; height: 100px;"></canvas> 17 <div id="description"></div> 18 <div id="console"></div> 19 <script id="vsCheckOutOfBounds" type="x-shader/x-vertex"> 20 precision mediump float; 21 attribute vec2 position; 22 attribute vec4 vecRandom; 23 varying vec4 v_color; 24 25 // Per the spec, each component can either contain existing contents 26 // of the buffer or 0. 27 bool testFloatComponent(float component) { 28 return (component == 0.2 || component == 0.0); 29 } 30 // The last component is additionally allowed to be 1.0. 31 bool testLastFloatComponent(float component) { 32 return testFloatComponent(component) || component == 1.0; 33 } 34 35 void main() { 36 if (testFloatComponent(vecRandom.x) && 37 testFloatComponent(vecRandom.y) && 38 testFloatComponent(vecRandom.z) && 39 testLastFloatComponent(vecRandom.w)) { 40 v_color = vec4(0.0, 1.0, 0.0, 1.0); // green -- We're good 41 } else { 42 v_color = vec4(1.0, 0.0, 0.0, 1.0); // red -- Unexpected value 43 } 44 gl_Position = vec4(position, 0.0, 1.0); 45 } 46 </script> 47 <script> 48 "use strict"; 49 description("This test verifies that out-of-bounds array buffers behave according to spec."); 50 51 var wtu = WebGLTestUtils; 52 var canvas = document.getElementById("canvas"); 53 var gl = wtu.create3DContext(canvas, {antialias: false}); 54 55 var numberOfQuads = 200; 56 57 // Draw out-of-bounds beginning with the start offset passed in. 58 // Ensure that drawArrays flags either no error or INVALID_OPERATION. In the case of INVALID_OPERATION, 59 // no canvas pixels can be touched. In the case of NO_ERROR, all written values must either be the 60 // zero vertex or a value in the vertex buffer. See vsCheckOutOfBounds shader. 61 function drawAndVerifyOutOfBoundsArrays(gl, first, count) { 62 gl.clearColor(0.0, 0.0, 1.0, 1.0); // Start with blue to indicate no pixels touched. 63 gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT); 64 65 gl.drawArrays(gl.TRIANGLES, first, count); 66 var error = gl.getError(); 67 if (error === gl.INVALID_OPERATION) { 68 testPassed("drawArrays flagged INVALID_OPERATION, which is valid so long as all canvas pixels were not touched."); 69 wtu.checkCanvas(gl, [0, 0, 255, 255]); 70 } else if (error === gl.NO_ERROR) { 71 testPassed("drawArrays flagged NO_ERROR, which is valid so long as all canvas pixels are green."); 72 wtu.checkCanvas(gl, [0, 255, 0, 255]); 73 } else { 74 testFailed("Invalid error flagged by drawArrays. Should be INVALID_OPERATION or NO_ERROR"); 75 } 76 } 77 78 // Create a vertex buffer with 200 properly formed triangle quads. These quads will cover the 79 // canvas texture such that every single pixel is touched by the fragment shader. 80 var glQuadBuffer = gl.createBuffer(); 81 gl.bindBuffer(gl.ARRAY_BUFFER, glQuadBuffer); 82 var quadPositions = new Float32Array(numberOfQuads * /*ComponentsPerQuad*/2 * /*VerticesPerQuad*/6); 83 for (var i = 0; i < quadPositions.length; i += /*ComponentsPerQuad*/2 * /*VerticesPerQuad*/6) { 84 quadPositions[i+0] = -1.0; // upper left 85 quadPositions[i+1] = 1.0; 86 quadPositions[i+2] = 1.0; // upper right 87 quadPositions[i+3] = 1.0; 88 quadPositions[i+4] = -1.0; // lower left 89 quadPositions[i+5] = -1.0; 90 quadPositions[i+6] = 1.0; // upper right 91 quadPositions[i+7] = 1.0; 92 quadPositions[i+8] = 1.0; // lower right 93 quadPositions[i+9] = -1.0; 94 quadPositions[i+10] = -1.0; // lower left 95 quadPositions[i+11] = -1.0; 96 } 97 gl.bufferData(gl.ARRAY_BUFFER, quadPositions, gl.STATIC_DRAW); 98 gl.enableVertexAttribArray(0); 99 gl.vertexAttribPointer(0, 2, gl.FLOAT, false, 0, 0); 100 101 102 // Create a small vertex buffer with determined-ahead-of-time "random" values (0.2). This buffer will be 103 // the one read past the end. 104 var glVertexBuffer = gl.createBuffer(); 105 gl.bindBuffer(gl.ARRAY_BUFFER, glVertexBuffer); 106 gl.bufferData(gl.ARRAY_BUFFER, new Float32Array([0.2, 0.2, 0.2, 0.2, 0.2, 0.2]), gl.STATIC_DRAW); 107 gl.enableVertexAttribArray(1); 108 gl.vertexAttribPointer(1, 4, gl.FLOAT, false, 0, 0); 109 110 // Setup the verification program. 111 var glProgram = wtu.setupProgram(gl, ["vsCheckOutOfBounds", wtu.simpleVertexColorFragmentShader], ["position", "vecRandom"]); 112 wtu.glErrorShouldBe(gl, gl.NO_ERROR, "Shader and buffer setup should not generate errors"); 113 114 debug("Test -- Draw off the end of the vertex buffer near the beginning of the out of bounds area."); 115 drawAndVerifyOutOfBoundsArrays(gl, /*first*/6, /*count*/6); 116 117 debug(""); 118 119 debug("Test -- Draw off the end of the vertex buffer near the end of the out of bounds area.") 120 drawAndVerifyOutOfBoundsArrays(gl, /*first*/(numberOfQuads - 1) * 6, /*count*/6); 121 122 var successfullyParsed = true; 123 </script> 124 <script src="../../js/js-test-post.js"></script> 125 </body> 126 </html>