framebuffer-bindings-affected-by-to-data-url.html

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Copyright (c) 2019 The Khronos Group Inc.

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<meta charset="utf-8">

<title>Verifies than GL framebuffer bindings do not change by toDataURL()</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>

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<canvas id="example" width="50" height="50"></canvas>

<div id="description"></div>

<div id="console"></div>

<script>

"use strict";

description("Verifies than GL framebuffer bindings do not change by toDataURL()");

var wtu = WebGLTestUtils;

function test() {

  var glCanvas = document.getElementById("example");

  var gl = wtu.create3DContext(glCanvas, {preserveDrawingBuffer: true, premultipliedAlpha: true});

  if (!gl) {

    testFailed("context does not exist");

    return;

  var program = wtu.setupColorQuad(gl);

  // Clear backbuffer in red.

  gl.clearColor(1.0, 0.0, 0.0, 1.0);

  gl.clear(gl.COLOR_BUFFER_BIT);

  wtu.checkCanvas(gl, [255, 0, 0, 255], "should be red");

  var fbo = gl.createFramebuffer();

  var tex = gl.createTexture();

  gl.bindTexture(gl.TEXTURE_2D, tex);

  gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, 50, 50, 0, gl.RGBA, gl.UNSIGNED_BYTE, null);

  gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST);

  gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST);

  gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE);

  gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE);

  gl.bindFramebuffer(gl.FRAMEBUFFER, fbo);

  gl.framebufferTexture2D(gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.TEXTURE_2D, tex, 0);

  if (gl.checkFramebufferStatus(gl.FRAMEBUFFER) != gl.FRAMEBUFFER_COMPLETE) {

    return;

  // Clear the FBO in green.

  gl.clearColor(0.0, 1.0, 0.0, 1.0);

  gl.clear(gl.COLOR_BUFFER_BIT);

  // backbuffer is still in red.

  gl.bindFramebuffer(gl.FRAMEBUFFER, null);

  wtu.checkCanvas(gl, [255, 0, 0, 255], "should be red");

  gl.bindFramebuffer(gl.FRAMEBUFFER, fbo);

  // toDataURL() calls must not bind backbuffer.

  glCanvas.toDataURL();

  // Calling twice caused a bug due to wrong cache impl; crbug.com/445848

  glCanvas.toDataURL();

  // It must applies to the FBO, not backbuffer.

  gl.clear(gl.COLOR_BUFFER_BIT);

  // backbuffer must be in red, not green.

  gl.bindFramebuffer(gl.FRAMEBUFFER, null);

  wtu.checkCanvas(gl, [255, 0, 0, 255], "should be red");

test();

var successfullyParsed = true;

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