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<!--
Copyright (c) 2019 The Khronos Group Inc.
Use of this source code is governed by an MIT-style license that can be
found in the LICENSE.txt file.
-->
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>WebGL Transform Feedback Conformance Tests</title>
<link rel="stylesheet" href="../../resources/js-test-style.css"/>
<script src="../../js/js-test-pre.js"></script>
<script src="../../js/webgl-test-utils.js"></script>
</head>
<body>
<div id="description"></div>
<canvas id="canvas" style="width: 50px; height: 50px;"> </canvas>
<div id="console"></div>
<script id="vshader" type="x-shader/x-vertex">#version 300 es
in vec4 in_data;
uniform int flag;
out vec4 out_data;
void main(void) {
if (flag > 0) {
out_data = in_data + vec4(2.0, 3.0, 4.0, 5.0);
}
}
</script>
<script id="fshader" type="x-shader/x-fragment">#version 300 es
precision mediump float;
out vec4 out_color;
void main(void) {
out_color = vec4(1.0, 1.0, 1.0, 1.0);
}
</script>
<script>
"use strict";
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.");
debug("");
var wtu = WebGLTestUtils;
var canvas = document.getElementById("canvas");
var gl = wtu.create3DContext(canvas, null, 2);
if (!gl) {
testFailed("WebGL context does not exist");
} else {
testPassed("WebGL context exists");
debug("");
debug("Testing transform feedback works fine");
runTest(1);
debug("");
debug("Testing unwritten output variables default to zero");
runTest(0);
}
function runTest(flag) {
var in_data = [
1.0, 2.0, 3.0, 4.0,
2.0, 4.0, 8.0, 16.0,
0.75, 0.5, 0.25, 0.0
];
var in_buffer = gl.createBuffer();
gl.bindBuffer(gl.ARRAY_BUFFER, in_buffer);
gl.bufferData(gl.ARRAY_BUFFER, new Float32Array(in_data), gl.STATIC_DRAW);
var out_buffer = gl.createBuffer();
gl.bindBuffer(gl.TRANSFORM_FEEDBACK_BUFFER, out_buffer);
gl.bufferData(gl.TRANSFORM_FEEDBACK_BUFFER, Float32Array.BYTES_PER_ELEMENT * in_data.length, gl.STATIC_DRAW);
// Create the transform feedback program
var program = wtu.setupTransformFeedbackProgram(gl, ["vshader", "fshader"],
["out_data"], gl.SEPARATE_ATTRIBS,
["in_data"]);
var loc = gl.getUniformLocation(program, "flag");
if (!program || !loc) {
testFailed("Fail to set up the program");
return;
}
gl.uniform1i(loc, flag);
wtu.glErrorShouldBe(gl, gl.NO_ERROR, "Set up program should succeed");
// Draw the the transform feedback buffers
var tf = gl.createTransformFeedback();
gl.enableVertexAttribArray(0);
gl.bindBuffer(gl.ARRAY_BUFFER, in_buffer);
gl.vertexAttribPointer(0, 4, gl.FLOAT, false, 16, 0);
gl.bindTransformFeedback(gl.TRANSFORM_FEEDBACK, tf);
gl.bindBufferBase(gl.TRANSFORM_FEEDBACK_BUFFER, 0, out_buffer);
gl.enable(gl.RASTERIZER_DISCARD);
gl.beginTransformFeedback(gl.POINTS);
gl.drawArrays(gl.POINTS, 0, 3);
gl.endTransformFeedback();
gl.disable(gl.RASTERIZER_DISCARD);
gl.bindBufferBase(gl.TRANSFORM_FEEDBACK_BUFFER, 0, null);
// Verify the output buffer contents
var expected_data;
if (flag > 0) {
expected_data = [
3.0, 5.0, 7.0, 9.0,
4.0, 7.0, 12.0, 21.0,
2.75, 3.5, 4.25, 5.0
];
} else {
expected_data = [
0.0, 0.0, 0.0, 0.0,
0.0, 0.0, 0.0, 0.0,
0.0, 0.0, 0.0, 0.0
];
}
gl.bindBuffer(gl.TRANSFORM_FEEDBACK_BUFFER, out_buffer);
wtu.checkFloatBuffer(gl, gl.TRANSFORM_FEEDBACK_BUFFER, expected_data);
}
debug("");
var successfullyParsed = true;
</script>
<script src="../../js/js-test-post.js"></script>
</body>
</html>