LayoutTests/fast/canvas/webgl/context-attributes-alpha-depth-stencil-antialias.html - WebKit - Git at Google


 <!DOCTYPE html>
 <html>
 <head>
 <meta charset="utf-8">
 <script src="../../../resources/js-test.js"></script>
 <script src="resources/webgl-test.js"></script>
 <script id="vshader" type="x-shader/x-vertex">
 attribute vec3 pos;
 attribute vec4 colorIn;
 varying vec4 color;

 void main()
 {
     color = colorIn;
     gl_Position = vec4(pos.xyz, 1.0);
 }
 </script>

 <script id="fshader" type="x-shader/x-fragment">
 precision mediump float;

 varying vec4 color;

 void main()
 {
     gl_FragColor = color;
 }
 </script>

 <script>
 var successfullyParsed = false;

 // These four declarations need to be global for "shouldBe" to see them
 var gl;
 var contextAttribs = null;
 var pixel = [0, 0, 0, 1];
 var correctColor = null;
 var framebuffer;
 var fbHasColor;
 var fbHasDepth;
 var fbHasStencil;

 function init()
 {
     if (window.initNonKhronosFramework) {
         window.initNonKhronosFramework(true);
     }

     if (window.internals)
         window.internals.settings.setWebGLErrorsToConsoleEnabled(false);

     description('Verify WebGLContextAttributes are working as specified, including alpha, depth, stencil, antialias, but not premultipliedAlpha');

     runTest();
 }

 function getWebGL(canvasWidth, canvasHeight, contextAttribs, clearColor, clearDepth, clearStencil)
 {
     var canvas = document.createElement("canvas");
     if (!canvas)
         return null;
     canvas.width = canvasWidth;
     canvas.height = canvasHeight;

     gl = create3DContext(canvas, contextAttribs);
     if (!gl)
         return null;

     var program = createProgram(gl, "vshader", "fshader", ["pos", "colorIn"]);
     if (!program)
         return null;

     gl.useProgram(program);

     gl.enable(gl.DEPTH_TEST);
     gl.enable(gl.STENCIL_TEST);
     gl.disable(gl.BLEND);

     gl.clearColor(clearColor[0], clearColor[1], clearColor[2], clearColor[3]);
     gl.clearDepth(clearDepth);
     gl.clearStencil(clearStencil);
     gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT | gl.STENCIL_BUFFER_BIT);

     framebuffer = gl.createFramebuffer();
     gl.bindFramebuffer(gl.FRAMEBUFFER, framebuffer);
     var texture = gl.createTexture();
     gl.bindTexture(gl.TEXTURE_2D, texture);
     gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, gl.canvas.width, gl.canvas.height, 0, gl.RGBA, gl.UNSIGNED_BYTE, null);
     gl.framebufferTexture2D(gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.TEXTURE_2D, texture, 0);
     fbHasStencil = false;
     fbHasDepth = false;
     fbHasColor = gl.checkFramebufferStatus(gl.FRAMEBUFFER) == gl.FRAMEBUFFER_COMPLETE;
     if (fbHasColor) {
       var depthStencil = gl.createRenderbuffer();
       gl.bindRenderbuffer(gl.RENDERBUFFER, depthStencil);
       gl.renderbufferStorage(gl.RENDERBUFFER, gl.DEPTH_STENCIL, gl.canvas.width, gl.canvas.height);
       gl.framebufferRenderbuffer(gl.FRAMEBUFFER, gl.DEPTH_STENCIL_ATTACHMENT, gl.RENDERBUFFER, depthStencil);
       fbHasDepth = gl.checkFramebufferStatus(gl.FRAMEBUFFER) == gl.FRAMEBUFFER_COMPLETE;
       if (!fbHasDepth) {
         gl.framebufferRenderbuffer(gl.FRAMEBUFFER, gl.DEPTH_STENCIL_ATTACHMENT, gl.RENDERBUFFER, null);
         shouldBe('gl.checkFramebufferStatus(gl.FRAMEBUFFER)', 'gl.FRAMEBUFFER_COMPLETE');
       } else {
         fbHasStencil = true;
       }
     }
     gl.bindFramebuffer(gl.FRAMEBUFFER, null);
     glErrorShouldBe(gl, gl.NO_ERROR, "should be no errors");

     return gl;
 }

 function drawAndReadPixel(gl, vertices, colors, x, y)
 {
     var colorOffset = vertices.byteLength;

     var vbo = gl.createBuffer();
     gl.bindBuffer(gl.ARRAY_BUFFER, vbo);
     gl.bufferData(gl.ARRAY_BUFFER, colorOffset + colors.byteLength, gl.STATIC_DRAW);
     gl.bufferSubData(gl.ARRAY_BUFFER, 0, vertices);
     gl.bufferSubData(gl.ARRAY_BUFFER, colorOffset, colors);

     gl.vertexAttribPointer(0, 3, gl.FLOAT, false, 0, 0);
     gl.enableVertexAttribArray(0);
     gl.vertexAttribPointer(1, 4, gl.UNSIGNED_BYTE, true, 0, colorOffset);
     gl.enableVertexAttribArray(1);

     gl.drawArrays(gl.TRIANGLES, 0, vertices.length / 3);

     var buf = new Uint8Array(1 * 1 * 4);
     gl.readPixels(x, y, 1, 1, gl.RGBA, gl.UNSIGNED_BYTE, buf);
     return buf;
 }

 function testAlpha(alpha, is_default_test)
 {
     if (is_default_test) {
         debug("Testing default alpha = true");
         alpha = true;

         shouldBeNonNull("gl = getWebGL(1, 1, { depth: false, stencil: false, antialias: false }, [ 0, 0, 0, 0 ], 1, 0)");
         shouldBeTrue("gl.getParameter(gl.ALPHA_BITS) >= 8");
     } else {
         debug("Testing alpha = " + alpha);

         if (alpha) {
             shouldBeNonNull("gl = getWebGL(1, 1, { alpha: true, depth: false, stencil: false, antialias: false }, [ 0, 0, 0, 0 ], 1, 0)");
             shouldBeTrue("gl.getParameter(gl.ALPHA_BITS) >= 8");
         } else {
             shouldBeNonNull("gl = getWebGL(1, 1, { alpha: false, depth: false, stencil: false, antialias: false }, [ 0, 0, 0, 0 ], 1, 0)");
             shouldBeTrue("gl.getParameter(gl.ALPHA_BITS) == 0");
         }
     }

     shouldBeTrue("gl.getParameter(gl.RED_BITS) >= 8");
     shouldBeTrue("gl.getParameter(gl.GREEN_BITS) >= 8");
     shouldBeTrue("gl.getParameter(gl.BLUE_BITS) >= 8");
     shouldBeTrue("gl.getParameter(gl.DEPTH_BITS) == 0");
     shouldBeTrue("gl.getParameter(gl.STENCIL_BITS) == 0");

     shouldBeNonNull("contextAttribs = gl.getContextAttributes()");
     shouldBeTrue("contextAttribs.alpha == " + alpha);

     var buf = new Uint8Array(1 * 1 * 4);
     gl.readPixels(0, 0, 1, 1, gl.RGBA, gl.UNSIGNED_BYTE, buf);
     pixel[0] = buf[0];
     pixel[1] = buf[1];
     pixel[2] = buf[2];
     pixel[3] = buf[3];
     correctColor = (contextAttribs.alpha ? [0, 0, 0, 0] : [0, 0, 0, 255]);
     shouldBe("pixel", "correctColor");

     if (fbHasColor) {
       gl.bindFramebuffer(gl.FRAMEBUFFER, framebuffer);
       gl.clearColor(0.5, 0.5, 0.5, 0.5);
       gl.clear(gl.COLOR_BUFFER_BIT);
       gl.readPixels(0, 0, 1, 1, gl.RGBA, gl.UNSIGNED_BYTE, buf);
       pixel[0] = buf[0];
       pixel[1] = buf[1];
       pixel[2] = buf[2];
       pixel[3] = buf[3];
       shouldBeTrue("Math.abs(pixel[0] - 127) <= 1 && Math.abs(pixel[1] - 127) <= 1 && Math.abs(pixel[2] - 127) <= 1 && Math.abs(pixel[3] - 127) <= 1");
       gl.bindFramebuffer(gl.FRAMEBUFFER, null);
     }
 }

 function testDepth(depth, is_default_test)
 {
     if (is_default_test) {
         debug("Testing default depth = true");
         depth = true;
         shouldBeNonNull("gl = getWebGL(1, 1, { stencil: false, antialias: false }, [ 0, 0, 0, 1 ], 1, 0)");
         shouldBeTrue("gl.getParameter(gl.DEPTH_BITS) >= 16");
     } else {
         debug("Testing depth = " + depth);
         if (depth) {
             shouldBeNonNull("gl = getWebGL(1, 1, { depth: true, stencil: false, antialias: false }, [ 0, 0, 0, 1 ], 1, 0)");
             shouldBeTrue("gl.getParameter(gl.DEPTH_BITS) >= 16");
         } else {
             shouldBeNonNull("gl = getWebGL(1, 1, { depth: false, stencil: false, antialias: false }, [ 0, 0, 0, 1 ], 1, 0)");
             shouldBeTrue("gl.getParameter(gl.DEPTH_BITS) == 0");
         }
     }
     shouldBeTrue("gl.getParameter(gl.RED_BITS) >= 8");
     shouldBeTrue("gl.getParameter(gl.GREEN_BITS) >= 8");
     shouldBeTrue("gl.getParameter(gl.BLUE_BITS) >= 8");
     shouldBeTrue("gl.getParameter(gl.ALPHA_BITS) >= 8");

     shouldBeNonNull("contextAttribs = gl.getContextAttributes()");

     gl.depthFunc(gl.NEVER);

     var vertices = new Float32Array([
          1.0,  1.0, 0.0,
         -1.0,  1.0, 0.0,
         -1.0, -1.0, 0.0,
          1.0,  1.0, 0.0,
         -1.0, -1.0, 0.0,
          1.0, -1.0, 0.0]);
     var colors = new Uint8Array([
         255, 0, 0, 255,
         255, 0, 0, 255,
         255, 0, 0, 255,
         255, 0, 0, 255,
         255, 0, 0, 255,
         255, 0, 0, 255]);

     var buf = drawAndReadPixel(gl, vertices, colors, 0, 0);
     pixel[0] = buf[0];
     pixel[1] = buf[1];
     pixel[2] = buf[2];
     pixel[3] = buf[3];
     correctColor = (contextAttribs.depth ? [0, 0, 0, 255] : [255, 0, 0, 255]);
     shouldBe("pixel", "correctColor");

     if (fbHasDepth) {
       gl.bindFramebuffer(gl.FRAMEBUFFER, framebuffer);
       gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);
       var buf = drawAndReadPixel(gl, vertices, colors, 0, 0);
       pixel[0] = buf[0];
       pixel[1] = buf[1];
       pixel[2] = buf[2];
       pixel[3] = buf[3];
       shouldBe("pixel", "[0, 0, 0, 255]");
       gl.bindFramebuffer(gl.FRAMEBUFFER, null);
     }
 }

 function testStencilAndDepth(stencil, depth, is_default_test)
 {
     if (is_default_test) {
         debug("Testing default stencil = false and default depth = true");
         stencil = false;
         depth = true;
         var creationString =
             "gl = getWebGL(1, 1, { antialias: false }, [ 0, 0, 0, 1 ], 1, 0)";
         shouldBeNonNull(creationString);
     } else {
         debug("Testing stencil = " + stencil + ", depth = " + depth);
         var creationString =
             "gl = getWebGL(1, 1, { depth: " + depth + ", stencil: " + stencil + ", antialias: false }, [ 0, 0, 0, 1 ], 1, 0)";
         shouldBeNonNull(creationString);
     }

     shouldBeTrue("gl.getParameter(gl.RED_BITS) >= 8");
     shouldBeTrue("gl.getParameter(gl.GREEN_BITS) >= 8");
     shouldBeTrue("gl.getParameter(gl.BLUE_BITS) >= 8");
     shouldBeTrue("gl.getParameter(gl.ALPHA_BITS) >= 8");
     if (depth)
         shouldBeTrue("gl.getParameter(gl.DEPTH_BITS) >= 16");
     else
         shouldBeTrue("gl.getParameter(gl.DEPTH_BITS) == 0");

     if (stencil)
         shouldBeTrue("gl.getParameter(gl.STENCIL_BITS) >= 8");
     else
         shouldBeTrue("gl.getParameter(gl.STENCIL_BITS) == 0");

     shouldBeNonNull("contextAttribs = gl.getContextAttributes()");
     if (!depth && contextAttribs.depth) {
         testFailed("WebGL implementation provided a depth buffer when it should not have");
     }
     if (!contextAttribs.depth)
         depth = false;
     if (!stencil && contextAttribs.stencil) {
         testFailed("WebGL implementation provided a stencil buffer when it should not have");
     }
     if (!contextAttribs.stencil)
         stencil = false;

     gl.depthFunc(gl.ALWAYS);

     gl.stencilFunc(gl.NEVER, 1, 1);
     gl.stencilOp(gl.KEEP, gl.KEEP, gl.KEEP);

     var vertices = new Float32Array([
          1.0, 1.0, 0.0,
         -1.0, 1.0, 0.0,
         -1.0, -1.0, 0.0,
          1.0, 1.0, 0.0,
         -1.0, -1.0, 0.0,
          1.0, -1.0, 0.0]);
     var colors = new Uint8Array([
         255, 0, 0, 255,
         255, 0, 0, 255,
         255, 0, 0, 255,
         255, 0, 0, 255,
         255, 0, 0, 255,
         255, 0, 0, 255]);

     var buf = drawAndReadPixel(gl, vertices, colors, 0, 0);
     pixel[0] = buf[0];
     pixel[1] = buf[1];
     pixel[2] = buf[2];
     pixel[3] = buf[3];
     correctColor = (stencil ? [0, 0, 0, 255] : [255, 0, 0, 255]);
     shouldBe("pixel", "correctColor");

     if (fbHasStencil) {
       gl.bindFramebuffer(gl.FRAMEBUFFER, framebuffer);
       gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);
       var buf = drawAndReadPixel(gl, vertices, colors, 0, 0);
       pixel[0] = buf[0];
       pixel[1] = buf[1];
       pixel[2] = buf[2];
       pixel[3] = buf[3];
       shouldBe("pixel", "[0, 0, 0, 255]");
       gl.bindFramebuffer(gl.FRAMEBUFFER, null);
     }
 }

 function testAntialias(antialias, is_default_test)
 {
     if (is_default_test) {
         debug("Testing default antialias = true");
         antialias = true;
         shouldBeNonNull("gl = getWebGL(2, 2, { depth: false, stencil: false, alpha: false }, [ 0, 0, 0, 1 ], 1, 0)");
     } else {
         debug("Testing antialias = " + antialias);
         if (antialias)
             shouldBeNonNull("gl = getWebGL(2, 2, { depth: false, stencil: false, alpha: false, antialias: true }, [ 0, 0, 0, 1 ], 1, 0)");
         else
             shouldBeNonNull("gl = getWebGL(2, 2, { depth: false, stencil: false, alpha: false, antialias: false }, [ 0, 0, 0, 1 ], 1, 0)");
     }
     shouldBeNonNull("contextAttribs = gl.getContextAttributes()");

     var vertices = new Float32Array([
          1.0, 1.0, 0.0,
         -1.0, 1.0, 0.0,
         -1.0, -1.0, 0.0]);
     var colors = new Uint8Array([
         255, 0, 0, 255,
         255, 0, 0, 255,
         255, 0, 0, 255]);
     var buf = drawAndReadPixel(gl, vertices, colors, 0, 0);
     pixel[0] = buf[0];
     shouldBe("pixel[0] != 255 && pixel[0] != 0", "contextAttribs.antialias");
 }

 function runDefaultTests(run_default_tests)
 {
     if (run_default_tests) {
         debug("Testing default values for attributes");
         testAlpha(true, run_default_tests);
         testDepth(true, run_default_tests);
         testStencilAndDepth(true, true, run_default_tests);
         testAntialias(true, run_default_tests);
     } else {
         testAlpha(true, run_default_tests);
         testAlpha(false, run_default_tests);
         testDepth(true, run_default_tests);
         testDepth(false, run_default_tests);
         testStencilAndDepth(true, false, run_default_tests);
         testStencilAndDepth(false, false, run_default_tests);
         testStencilAndDepth(true, true, run_default_tests);
         testStencilAndDepth(false, true, run_default_tests);
         testAntialias(true, run_default_tests);
         testAntialias(false, run_default_tests);
     }
 }

 function runTest()
 {
     runDefaultTests(false);
     runDefaultTests(true);
     finishTest();
 }

 </script>
 </head>
 <body onload="init()">
 <div id="description"></div>
 <div id="console"></div>
 </body>
 </html>

	<!DOCTYPE html>
	<html>
	<head>
	<meta charset="utf-8">
	<script src="../../../resources/js-test.js"></script>
	<script src="resources/webgl-test.js"></script>
	<script id="vshader" type="x-shader/x-vertex">
	attribute vec3 pos;
	attribute vec4 colorIn;
	varying vec4 color;

	void main()
	{
	color = colorIn;
	gl_Position = vec4(pos.xyz, 1.0);
	}
	</script>

	<script id="fshader" type="x-shader/x-fragment">
	precision mediump float;

	varying vec4 color;

	void main()
	{
	gl_FragColor = color;
	}
	</script>

	<script>
	var successfullyParsed = false;

	// These four declarations need to be global for "shouldBe" to see them
	var gl;
	var contextAttribs = null;
	var pixel = [0, 0, 0, 1];
	var correctColor = null;
	var framebuffer;
	var fbHasColor;
	var fbHasDepth;
	var fbHasStencil;

	function init()
	{
	if (window.initNonKhronosFramework) {
	window.initNonKhronosFramework(true);
	}

	if (window.internals)
	window.internals.settings.setWebGLErrorsToConsoleEnabled(false);

	description('Verify WebGLContextAttributes are working as specified, including alpha, depth, stencil, antialias, but not premultipliedAlpha');

	runTest();
	}

	function getWebGL(canvasWidth, canvasHeight, contextAttribs, clearColor, clearDepth, clearStencil)
	{
	var canvas = document.createElement("canvas");
	if (!canvas)
	return null;
	canvas.width = canvasWidth;
	canvas.height = canvasHeight;

	gl = create3DContext(canvas, contextAttribs);
	if (!gl)
	return null;

	var program = createProgram(gl, "vshader", "fshader", ["pos", "colorIn"]);
	if (!program)
	return null;

	gl.useProgram(program);

	gl.enable(gl.DEPTH_TEST);
	gl.enable(gl.STENCIL_TEST);
	gl.disable(gl.BLEND);

	gl.clearColor(clearColor[0], clearColor[1], clearColor[2], clearColor[3]);
	gl.clearDepth(clearDepth);
	gl.clearStencil(clearStencil);
	gl.clear(gl.COLOR_BUFFER_BIT \| gl.DEPTH_BUFFER_BIT \| gl.STENCIL_BUFFER_BIT);

	framebuffer = gl.createFramebuffer();
	gl.bindFramebuffer(gl.FRAMEBUFFER, framebuffer);
	var texture = gl.createTexture();
	gl.bindTexture(gl.TEXTURE_2D, texture);
	gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, gl.canvas.width, gl.canvas.height, 0, gl.RGBA, gl.UNSIGNED_BYTE, null);
	gl.framebufferTexture2D(gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.TEXTURE_2D, texture, 0);
	fbHasStencil = false;
	fbHasDepth = false;
	fbHasColor = gl.checkFramebufferStatus(gl.FRAMEBUFFER) == gl.FRAMEBUFFER_COMPLETE;
	if (fbHasColor) {
	var depthStencil = gl.createRenderbuffer();
	gl.bindRenderbuffer(gl.RENDERBUFFER, depthStencil);
	gl.renderbufferStorage(gl.RENDERBUFFER, gl.DEPTH_STENCIL, gl.canvas.width, gl.canvas.height);
	gl.framebufferRenderbuffer(gl.FRAMEBUFFER, gl.DEPTH_STENCIL_ATTACHMENT, gl.RENDERBUFFER, depthStencil);
	fbHasDepth = gl.checkFramebufferStatus(gl.FRAMEBUFFER) == gl.FRAMEBUFFER_COMPLETE;
	if (!fbHasDepth) {
	gl.framebufferRenderbuffer(gl.FRAMEBUFFER, gl.DEPTH_STENCIL_ATTACHMENT, gl.RENDERBUFFER, null);
	shouldBe('gl.checkFramebufferStatus(gl.FRAMEBUFFER)', 'gl.FRAMEBUFFER_COMPLETE');
	} else {
	fbHasStencil = true;
	}
	}
	gl.bindFramebuffer(gl.FRAMEBUFFER, null);
	glErrorShouldBe(gl, gl.NO_ERROR, "should be no errors");

	return gl;
	}

	function drawAndReadPixel(gl, vertices, colors, x, y)
	{
	var colorOffset = vertices.byteLength;

	var vbo = gl.createBuffer();
	gl.bindBuffer(gl.ARRAY_BUFFER, vbo);
	gl.bufferData(gl.ARRAY_BUFFER, colorOffset + colors.byteLength, gl.STATIC_DRAW);
	gl.bufferSubData(gl.ARRAY_BUFFER, 0, vertices);
	gl.bufferSubData(gl.ARRAY_BUFFER, colorOffset, colors);

	gl.vertexAttribPointer(0, 3, gl.FLOAT, false, 0, 0);
	gl.enableVertexAttribArray(0);
	gl.vertexAttribPointer(1, 4, gl.UNSIGNED_BYTE, true, 0, colorOffset);
	gl.enableVertexAttribArray(1);

	gl.drawArrays(gl.TRIANGLES, 0, vertices.length / 3);

	var buf = new Uint8Array(1 * 1 * 4);
	gl.readPixels(x, y, 1, 1, gl.RGBA, gl.UNSIGNED_BYTE, buf);
	return buf;
	}

	function testAlpha(alpha, is_default_test)
	{
	if (is_default_test) {
	debug("Testing default alpha = true");
	alpha = true;

	shouldBeNonNull("gl = getWebGL(1, 1, { depth: false, stencil: false, antialias: false }, [ 0, 0, 0, 0 ], 1, 0)");
	shouldBeTrue("gl.getParameter(gl.ALPHA_BITS) >= 8");
	} else {
	debug("Testing alpha = " + alpha);

	if (alpha) {
	shouldBeNonNull("gl = getWebGL(1, 1, { alpha: true, depth: false, stencil: false, antialias: false }, [ 0, 0, 0, 0 ], 1, 0)");
	shouldBeTrue("gl.getParameter(gl.ALPHA_BITS) >= 8");
	} else {
	shouldBeNonNull("gl = getWebGL(1, 1, { alpha: false, depth: false, stencil: false, antialias: false }, [ 0, 0, 0, 0 ], 1, 0)");
	shouldBeTrue("gl.getParameter(gl.ALPHA_BITS) == 0");
	}
	}

	shouldBeTrue("gl.getParameter(gl.RED_BITS) >= 8");
	shouldBeTrue("gl.getParameter(gl.GREEN_BITS) >= 8");
	shouldBeTrue("gl.getParameter(gl.BLUE_BITS) >= 8");
	shouldBeTrue("gl.getParameter(gl.DEPTH_BITS) == 0");
	shouldBeTrue("gl.getParameter(gl.STENCIL_BITS) == 0");

	shouldBeNonNull("contextAttribs = gl.getContextAttributes()");
	shouldBeTrue("contextAttribs.alpha == " + alpha);

	var buf = new Uint8Array(1 * 1 * 4);
	gl.readPixels(0, 0, 1, 1, gl.RGBA, gl.UNSIGNED_BYTE, buf);
	pixel[0] = buf[0];
	pixel[1] = buf[1];
	pixel[2] = buf[2];
	pixel[3] = buf[3];
	correctColor = (contextAttribs.alpha ? [0, 0, 0, 0] : [0, 0, 0, 255]);
	shouldBe("pixel", "correctColor");

	if (fbHasColor) {
	gl.bindFramebuffer(gl.FRAMEBUFFER, framebuffer);
	gl.clearColor(0.5, 0.5, 0.5, 0.5);
	gl.clear(gl.COLOR_BUFFER_BIT);
	gl.readPixels(0, 0, 1, 1, gl.RGBA, gl.UNSIGNED_BYTE, buf);
	pixel[0] = buf[0];
	pixel[1] = buf[1];
	pixel[2] = buf[2];
	pixel[3] = buf[3];
	shouldBeTrue("Math.abs(pixel[0] - 127) <= 1 && Math.abs(pixel[1] - 127) <= 1 && Math.abs(pixel[2] - 127) <= 1 && Math.abs(pixel[3] - 127) <= 1");
	gl.bindFramebuffer(gl.FRAMEBUFFER, null);
	}
	}

	function testDepth(depth, is_default_test)
	{
	if (is_default_test) {
	debug("Testing default depth = true");
	depth = true;
	shouldBeNonNull("gl = getWebGL(1, 1, { stencil: false, antialias: false }, [ 0, 0, 0, 1 ], 1, 0)");
	shouldBeTrue("gl.getParameter(gl.DEPTH_BITS) >= 16");
	} else {
	debug("Testing depth = " + depth);
	if (depth) {
	shouldBeNonNull("gl = getWebGL(1, 1, { depth: true, stencil: false, antialias: false }, [ 0, 0, 0, 1 ], 1, 0)");
	shouldBeTrue("gl.getParameter(gl.DEPTH_BITS) >= 16");
	} else {
	shouldBeNonNull("gl = getWebGL(1, 1, { depth: false, stencil: false, antialias: false }, [ 0, 0, 0, 1 ], 1, 0)");
	shouldBeTrue("gl.getParameter(gl.DEPTH_BITS) == 0");
	}
	}
	shouldBeTrue("gl.getParameter(gl.RED_BITS) >= 8");
	shouldBeTrue("gl.getParameter(gl.GREEN_BITS) >= 8");
	shouldBeTrue("gl.getParameter(gl.BLUE_BITS) >= 8");
	shouldBeTrue("gl.getParameter(gl.ALPHA_BITS) >= 8");

	shouldBeNonNull("contextAttribs = gl.getContextAttributes()");

	gl.depthFunc(gl.NEVER);

	var vertices = new Float32Array([
	1.0, 1.0, 0.0,
	-1.0, 1.0, 0.0,
	-1.0, -1.0, 0.0,
	1.0, 1.0, 0.0,
	-1.0, -1.0, 0.0,
	1.0, -1.0, 0.0]);
	var colors = new Uint8Array([
	255, 0, 0, 255,
	255, 0, 0, 255,
	255, 0, 0, 255,
	255, 0, 0, 255,
	255, 0, 0, 255,
	255, 0, 0, 255]);

	var buf = drawAndReadPixel(gl, vertices, colors, 0, 0);
	pixel[0] = buf[0];
	pixel[1] = buf[1];
	pixel[2] = buf[2];
	pixel[3] = buf[3];
	correctColor = (contextAttribs.depth ? [0, 0, 0, 255] : [255, 0, 0, 255]);
	shouldBe("pixel", "correctColor");

	if (fbHasDepth) {
	gl.bindFramebuffer(gl.FRAMEBUFFER, framebuffer);
	gl.clear(gl.COLOR_BUFFER_BIT \| gl.DEPTH_BUFFER_BIT);
	var buf = drawAndReadPixel(gl, vertices, colors, 0, 0);
	pixel[0] = buf[0];
	pixel[1] = buf[1];
	pixel[2] = buf[2];
	pixel[3] = buf[3];
	shouldBe("pixel", "[0, 0, 0, 255]");
	gl.bindFramebuffer(gl.FRAMEBUFFER, null);
	}
	}

	function testStencilAndDepth(stencil, depth, is_default_test)
	{
	if (is_default_test) {
	debug("Testing default stencil = false and default depth = true");
	stencil = false;
	depth = true;
	var creationString =
	"gl = getWebGL(1, 1, { antialias: false }, [ 0, 0, 0, 1 ], 1, 0)";
	shouldBeNonNull(creationString);
	} else {
	debug("Testing stencil = " + stencil + ", depth = " + depth);
	var creationString =
	"gl = getWebGL(1, 1, { depth: " + depth + ", stencil: " + stencil + ", antialias: false }, [ 0, 0, 0, 1 ], 1, 0)";
	shouldBeNonNull(creationString);
	}

	shouldBeTrue("gl.getParameter(gl.RED_BITS) >= 8");
	shouldBeTrue("gl.getParameter(gl.GREEN_BITS) >= 8");
	shouldBeTrue("gl.getParameter(gl.BLUE_BITS) >= 8");
	shouldBeTrue("gl.getParameter(gl.ALPHA_BITS) >= 8");
	if (depth)
	shouldBeTrue("gl.getParameter(gl.DEPTH_BITS) >= 16");
	else
	shouldBeTrue("gl.getParameter(gl.DEPTH_BITS) == 0");

	if (stencil)
	shouldBeTrue("gl.getParameter(gl.STENCIL_BITS) >= 8");
	else
	shouldBeTrue("gl.getParameter(gl.STENCIL_BITS) == 0");

	shouldBeNonNull("contextAttribs = gl.getContextAttributes()");
	if (!depth && contextAttribs.depth) {
	testFailed("WebGL implementation provided a depth buffer when it should not have");
	}
	if (!contextAttribs.depth)
	depth = false;
	if (!stencil && contextAttribs.stencil) {
	testFailed("WebGL implementation provided a stencil buffer when it should not have");
	}
	if (!contextAttribs.stencil)
	stencil = false;

	gl.depthFunc(gl.ALWAYS);

	gl.stencilFunc(gl.NEVER, 1, 1);
	gl.stencilOp(gl.KEEP, gl.KEEP, gl.KEEP);

	var vertices = new Float32Array([
	1.0, 1.0, 0.0,
	-1.0, 1.0, 0.0,
	-1.0, -1.0, 0.0,
	1.0, 1.0, 0.0,
	-1.0, -1.0, 0.0,
	1.0, -1.0, 0.0]);
	var colors = new Uint8Array([
	255, 0, 0, 255,
	255, 0, 0, 255,
	255, 0, 0, 255,
	255, 0, 0, 255,
	255, 0, 0, 255,
	255, 0, 0, 255]);

	var buf = drawAndReadPixel(gl, vertices, colors, 0, 0);
	pixel[0] = buf[0];
	pixel[1] = buf[1];
	pixel[2] = buf[2];
	pixel[3] = buf[3];
	correctColor = (stencil ? [0, 0, 0, 255] : [255, 0, 0, 255]);
	shouldBe("pixel", "correctColor");

	if (fbHasStencil) {
	gl.bindFramebuffer(gl.FRAMEBUFFER, framebuffer);
	gl.clear(gl.COLOR_BUFFER_BIT \| gl.DEPTH_BUFFER_BIT);
	var buf = drawAndReadPixel(gl, vertices, colors, 0, 0);
	pixel[0] = buf[0];
	pixel[1] = buf[1];
	pixel[2] = buf[2];
	pixel[3] = buf[3];
	shouldBe("pixel", "[0, 0, 0, 255]");
	gl.bindFramebuffer(gl.FRAMEBUFFER, null);
	}
	}

	function testAntialias(antialias, is_default_test)
	{
	if (is_default_test) {
	debug("Testing default antialias = true");
	antialias = true;
	shouldBeNonNull("gl = getWebGL(2, 2, { depth: false, stencil: false, alpha: false }, [ 0, 0, 0, 1 ], 1, 0)");
	} else {
	debug("Testing antialias = " + antialias);
	if (antialias)
	shouldBeNonNull("gl = getWebGL(2, 2, { depth: false, stencil: false, alpha: false, antialias: true }, [ 0, 0, 0, 1 ], 1, 0)");
	else
	shouldBeNonNull("gl = getWebGL(2, 2, { depth: false, stencil: false, alpha: false, antialias: false }, [ 0, 0, 0, 1 ], 1, 0)");
	}
	shouldBeNonNull("contextAttribs = gl.getContextAttributes()");

	var vertices = new Float32Array([
	1.0, 1.0, 0.0,
	-1.0, 1.0, 0.0,
	-1.0, -1.0, 0.0]);
	var colors = new Uint8Array([
	255, 0, 0, 255,
	255, 0, 0, 255,
	255, 0, 0, 255]);
	var buf = drawAndReadPixel(gl, vertices, colors, 0, 0);
	pixel[0] = buf[0];
	shouldBe("pixel[0] != 255 && pixel[0] != 0", "contextAttribs.antialias");
	}

	function runDefaultTests(run_default_tests)
	{
	if (run_default_tests) {
	debug("Testing default values for attributes");
	testAlpha(true, run_default_tests);
	testDepth(true, run_default_tests);
	testStencilAndDepth(true, true, run_default_tests);
	testAntialias(true, run_default_tests);
	} else {
	testAlpha(true, run_default_tests);
	testAlpha(false, run_default_tests);
	testDepth(true, run_default_tests);
	testDepth(false, run_default_tests);
	testStencilAndDepth(true, false, run_default_tests);
	testStencilAndDepth(false, false, run_default_tests);
	testStencilAndDepth(true, true, run_default_tests);
	testStencilAndDepth(false, true, run_default_tests);
	testAntialias(true, run_default_tests);
	testAntialias(false, run_default_tests);
	}
	}

	function runTest()
	{
	runDefaultTests(false);
	runDefaultTests(true);
	finishTest();
	}

	</script>
	</head>
	<body onload="init()">
	<div id="description"></div>
	<div id="console"></div>
	</body>
	</html>