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| <!DOCTYPE html> |
| <html> |
| <head> |
| <meta charset="utf-8"> |
| <title>OffscreenCanavs context attribute preserveDrawingBuffer</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> |
| <script src="../../js/tests/canvas-tests-utils.js"></script> |
| </head> |
| <body> |
| <div id="description"></div> |
| <div id="console"></div> |
| <script> |
| "use strict"; |
| description("This test checks whether OffscreenCanvas webgl context honors the preserveDrawingBuffer flag."); |
| |
| function getPixelsFromOffscreenWebgl(preserveFlag) { |
| var canvas = document.createElement("canvas"); |
| var offscreenCanvas = transferredOffscreenCanvasCreation(canvas, 10, 10); |
| var gl = offscreenCanvas.getContext("webgl", {preserveDrawingBuffer: preserveFlag}); |
| |
| // Draw some color on gl and commit |
| gl.clearColor(1, 0, 1, 1); |
| gl.clear(gl.COLOR_BUFFER_BIT); |
| gl.commit(); |
| |
| var pixels = new Uint8Array(4); |
| gl.readPixels(0, 0, 1, 1, gl.RGBA, gl.UNSIGNED_BYTE, pixels); |
| return pixels; |
| } |
| |
| if (!window.OffscreenCanvas) { |
| testPassed("No OffscreenCanvas support"); |
| } else { |
| // Test if OffscreenCanvas.webgl retains context if preserveDrawingBuffer is true. |
| var pixelsPreserve = getPixelsFromOffscreenWebgl(true); |
| shouldBe(pixelsPreserve, [255,0,255,255]); |
| |
| // Test if OffscreenCanvas.webgl loses context if presereDrawingbuffer is false. |
| var pixelsNoPreserve = getPixelsFromOffscreenWebgl(false); |
| shouldBe(pixelsNoPreserve, [0,0,0,0]); |
| } |
| |
| var successfullyParsed = true; |
| |
| </script> |
| <script src="../../js/js-test-post.js"></script> |
| </body> |
| </html> |
