<!--
Copyright (c) 2020 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>
<div id="description"></div>
<div id="console"></div>
<script>
"use strict";

// Global declarations so that "shouldBe" can eval with them:
let gl;

(function() {
    description('Check that zero-sized canvases work with WebGL.');

    testZero();

    finishTest();
})();

function testZero() {
    const canvas = document.createElement('canvas');
    canvas.width = 0;
    canvas.height = 0;
    gl = WebGLTestUtils.create3DContext(canvas);

    expectTrue(gl, `Context creation with ${canvas.width}x${canvas.height} canvas should succeed.`);
    shouldBe('gl.drawingBufferWidth', '1');
    shouldBe('gl.drawingBufferHeight', '1');
    shouldBeFalse('gl.isContextLost()');

    const version = gl.getParameter(gl.VERSION);
    expectTrue(version && version.length, `getParameter() should return something.`);

    debug('canvas.width = 2');
    canvas.width = 2;
    shouldBe('gl.drawingBufferWidth', '2');
    shouldBeFalse('gl.isContextLost()');

    debug('canvas.width = 0');
    canvas.width = 0;
    shouldBe('gl.drawingBufferWidth', '1');
    shouldBeFalse('gl.isContextLost()');
}

</script>
</body>
</html>
