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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">
<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>
<canvas id="testbed" width="400" height="400" style="width: 40px; height: 40px;"></canvas>
<div id="description"></div>
<div id="console"></div>
<script>
"use strict";
var wtu = WebGLTestUtils;
description('Verify renderbuffers are initialized to 0 before being read in WebGL');
var gl = wtu.create3DContext("testbed");
if (!gl) {
testFailed('canvas.getContext() failed');
} else {
// Set the clear color to green. It should never show up.
gl.clearColor(0, 1, 0, 1);
runTest(gl, gl.canvas.width, gl.canvas.height, 0);
runTest(gl, gl.canvas.width, gl.canvas.height, 1);
runTest(gl, gl.canvas.width, gl.canvas.height, 0);
runTest(gl, gl.canvas.width, gl.canvas.height, 1);
// Testing buffer clearing won't change the clear values.
var clearColor = gl.getParameter(gl.COLOR_CLEAR_VALUE);
shouldBe("clearColor", "[0, 1, 0, 1]");
wtu.glErrorShouldBe(gl, gl.NO_ERROR, 'should be no errors');
}
function runTest(gl, width, height, order)
{
wtu.checkCanvasRect(gl, 0, 0, width, height, [0,0,0,0],
"internal buffers have been initialized to 0");
// fill the back buffer so we know that reading below happens from
// the renderbuffer.
gl.clear(gl.COLOR_BUFFER_BIT);
var fbo = gl.createFramebuffer();
gl.bindFramebuffer(gl.FRAMEBUFFER, fbo);
var colorbuffer = gl.createRenderbuffer();
gl.bindRenderbuffer(gl.RENDERBUFFER, colorbuffer);
switch (order) {
case 0:
allocStorage(width, height);
attachBuffer(colorbuffer);
break;
case 1:
attachBuffer(colorbuffer);
allocStorage(width, height);
break;
}
function allocStorage(width, height) {
gl.renderbufferStorage(gl.RENDERBUFFER, gl.RGBA4, width, height);
wtu.glErrorShouldBe(gl, gl.NO_ERROR, 'should be no error after renderbufferStorage(internalformat = RGBA4).');
}
function attachBuffer(colorbuffer) {
gl.framebufferRenderbuffer(gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.RENDERBUFFER, colorbuffer);
}
if (gl.checkFramebufferStatus(gl.FRAMEBUFFER) != gl.FRAMEBUFFER_COMPLETE) {
testFailed('Framebuffer incomplete.');
return;
}
wtu.checkCanvasRect(gl, 0, 0, width, height, [0,0,0,0],
"user buffers have been initialized to 0");
gl.deleteFramebuffer(fbo);
gl.deleteRenderbuffer(colorbuffer);
// this clear should not matter we are about to resize
gl.clear(gl.COLOR_BUFFER_BIT);
gl.canvas.width += 1;
gl.canvas.height += 1;
debug('');
}
var successfullyParsed = true;
</script>
<script src="../../js/js-test-post.js"></script>
</body>
</html>