dom/canvas/test/webgl-conf/checkout/conformance2/transform_feedback/unwritten-output-defaults-to-zero.html

   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 Transform Feedback Conformance Tests</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" style="width: 50px; height: 50px;"> </canvas>
  19 <div id="console"></div>
  20 <script id="vshader" type="x-shader/x-vertex">#version 300 es
  21 in vec4 in_data;
  22 uniform int flag;
  23 out vec4 out_data;
  24 void main(void) {
  25     if (flag > 0) {
  26         out_data = in_data + vec4(2.0, 3.0, 4.0, 5.0);
  27     }
  28 }
  29 </script>
  30 <script id="fshader" type="x-shader/x-fragment">#version 300 es
  31 precision mediump float;
  32 out vec4 out_color;
  33 void main(void) {
  34     out_color = vec4(1.0, 1.0, 1.0, 1.0);
  35 }
  36 </script>
  37 <script>
  38 "use strict";
  39 description("This test verifies if an output variable is specified to be streamed to a transform feedback buffer but not actually written, the value defaults to 0.");
  40
  41 debug("");
  42
  43 var wtu = WebGLTestUtils;
  44 var canvas = document.getElementById("canvas");
  45 var gl = wtu.create3DContext(canvas, null, 2);
  46
  47 if (!gl) {
  48     testFailed("WebGL context does not exist");
  49 } else {
  50     testPassed("WebGL context exists");
  51
  52     debug("");
  53     debug("Testing transform feedback works fine");
  54     runTest(1);
  55
  56     debug("");
  57     debug("Testing unwritten output variables default to zero");
  58     runTest(0);
  59 }
  60
  61 function runTest(flag) {
  62     var in_data = [
  63         1.0, 2.0, 3.0, 4.0,
  64         2.0, 4.0, 8.0, 16.0,
  65         0.75, 0.5, 0.25, 0.0
  66     ];
  67
  68     var in_buffer = gl.createBuffer();
  69     gl.bindBuffer(gl.ARRAY_BUFFER, in_buffer);
  70     gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(in_data), gl.STATIC_DRAW);
  71
  72     var out_buffer = gl.createBuffer();
  73     gl.bindBuffer(gl.TRANSFORM_FEEDBACK_BUFFER, out_buffer);
  74     gl.bufferData(gl.TRANSFORM_FEEDBACK_BUFFER, Float32Array.BYTES_PER_ELEMENT * in_data.length, gl.STATIC_DRAW);
  75
  76     // Create the transform feedback program
  77     var program = wtu.setupTransformFeedbackProgram(gl, ["vshader", "fshader"],
  78         ["out_data"], gl.SEPARATE_ATTRIBS,
  79         ["in_data"]);
  80     var loc = gl.getUniformLocation(program, "flag");
  81     if (!program || !loc) {
  82         testFailed("Fail to set up the program");
  83         return;
  84     }
  85     gl.uniform1i(loc, flag);
  86     wtu.glErrorShouldBe(gl, gl.NO_ERROR, "Set up program should succeed");
  87
  88     // Draw the the transform feedback buffers
  89     var tf = gl.createTransformFeedback();
  90
  91     gl.enableVertexAttribArray(0);
  92     gl.bindBuffer(gl.ARRAY_BUFFER, in_buffer);
  93     gl.vertexAttribPointer(0, 4, gl.FLOAT, false, 16, 0);
  94
  95     gl.bindTransformFeedback(gl.TRANSFORM_FEEDBACK, tf);
  96     gl.bindBufferBase(gl.TRANSFORM_FEEDBACK_BUFFER, 0, out_buffer);
  97
  98     gl.enable(gl.RASTERIZER_DISCARD);
  99     gl.beginTransformFeedback(gl.POINTS);
 100
 101     gl.drawArrays(gl.POINTS, 0, 3);
 102
 103     gl.endTransformFeedback();
 104     gl.disable(gl.RASTERIZER_DISCARD);
 105
 106     gl.bindBufferBase(gl.TRANSFORM_FEEDBACK_BUFFER, 0, null);
 107
 108     // Verify the output buffer contents
 109     var expected_data;
 110     if (flag > 0) {
 111         expected_data = [
 112             3.0, 5.0, 7.0, 9.0,
 113             4.0, 7.0, 12.0, 21.0,
 114             2.75, 3.5, 4.25, 5.0
 115         ];
 116     } else {
 117         expected_data = [
 118             0.0, 0.0, 0.0, 0.0,
 119             0.0, 0.0, 0.0, 0.0,
 120             0.0, 0.0, 0.0, 0.0
 121         ];
 122     }
 123     gl.bindBuffer(gl.TRANSFORM_FEEDBACK_BUFFER, out_buffer);
 124     wtu.checkFloatBuffer(gl, gl.TRANSFORM_FEEDBACK_BUFFER, expected_data);
 125 }
 126
 127 debug("");
 128 var successfullyParsed = true;
 129 </script>
 130 <script src="../../js/js-test-post.js"></script>
 131
 132 </body>
 133 </html>