point-with-gl-pointcoord-in-fragment-shader.html (3193B)
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 Point with gl_PointCoord in Fragment Shader 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 <div id="description"></div> 18 <canvas id="canvas" width="64" height="64"> </canvas> 19 <div id="console"></div> 20 <script id="vs" type="x-shader/x-vertex"> 21 varying vec4 v_color; 22 23 // The X and Y coordinates of the center of the point. 24 attribute vec2 a_vertex; 25 26 uniform float u_pointSize; 27 28 void main(void) { 29 gl_PointSize = u_pointSize; 30 gl_Position = vec4(a_vertex, 0.0, 1.0); 31 32 // The color of the point. 33 v_color = vec4(0.0, 1.0, 0.0, 1.0); 34 } 35 36 </script> 37 <script id="fs" type="x-shader/x-fragment"> 38 precision mediump float; 39 40 varying vec4 v_color; 41 42 void main(void) { 43 // It seems as long as this mathematical expression references 44 // gl_PointCoord, the fragment's color is incorrect. 45 vec2 diff = gl_PointCoord - vec2(.5, .5); 46 if (length(diff) > 0.5) 47 discard; 48 49 // The point should be a solid color. 50 gl_FragColor = v_color; 51 } 52 </script> 53 <script> 54 "use strict"; 55 // Radar 13239314 56 description("This is a regression test for a graphics driver bug affecting end caps on roads in MapsGL."); 57 58 debug(""); 59 60 var wtu = WebGLTestUtils; 61 var canvas = document.getElementById("canvas"); 62 var canvasWidth = canvas.width; 63 var canvasHeight = canvas.height; 64 var output = document.getElementById("console"); 65 var gl = wtu.create3DContext(canvas); 66 67 function runTest() { 68 var pointSizeRange = gl.getParameter(gl.ALIASED_POINT_SIZE_RANGE); 69 // This test can't really run without a maximum point size of at least 2 70 if (pointSizeRange[1] < 2.0) { 71 debug("This test needs a maximum ALIASED_POINT_SIZE_RANGE of at least 2"); 72 return; 73 } 74 75 var vs = wtu.loadShaderFromScript(gl, "vs", gl.VERTEX_SHADER); 76 var fs = wtu.loadShaderFromScript(gl, "fs", gl.FRAGMENT_SHADER); 77 if (!vs || !fs) { 78 testFailed("Loading shaders failed"); 79 return; 80 } 81 82 var program = wtu.setupProgram(gl, [vs, fs], ['a_vertex']); 83 if (!program) { 84 testFailed("Loading program failed"); 85 return; 86 } 87 88 gl.useProgram(program); 89 gl.clearColor(0, 0, 0, 1.0); 90 gl.disable(gl.DEPTH_TEST); 91 gl.clear(gl.COLOR_BUFFER_BIT); 92 93 // uniform float u_pointSize; 94 var uni = gl.getUniformLocation(program, 'u_pointSize'); 95 gl.uniform1f(uni, Math.min(20.0, pointSizeRange[1])); 96 97 // vertex 98 var buffer = gl.createBuffer(); 99 gl.bindBuffer(gl.ARRAY_BUFFER, buffer); 100 var vertexData = new Float32Array([ 101 0, 0, 102 ]); 103 gl.bufferData(gl.ARRAY_BUFFER, vertexData, gl.STATIC_DRAW); 104 gl.enableVertexAttribArray(0); 105 gl.vertexAttribPointer(0, 2, gl.FLOAT, false, 0, 0); 106 107 gl.drawArrays(gl.POINTS, 0, 1); 108 wtu.checkCanvasRect(gl, canvasWidth / 2, canvasHeight / 2, 1, 1, 109 [0, 255, 0, 255], "Center pixel should be green", 2); 110 } 111 112 runTest(); 113 114 debug(""); 115 var successfullyParsed = true; 116 </script> 117 <script src="../../js/js-test-post.js"></script> 118 </body> 119 </html>