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<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>WebGL EXT_frag_depth Conformance Tests</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>
</head>
<body>
<div id="description"></div>
<canvas id="canvas" style="width: 50px; height: 50px;"> </canvas>
<div id="console"></div>
<!-- Shaders for testing fragment depth writing -->

<!-- Shader omitting the required #extension pragma -->
<script id="missingPragmaFragmentShader" type="x-shader/x-fragment">
precision mediump float;
void main() {
    gl_FragColor = vec4(1.0, 0.0, 0.0, 1.0);
    gl_FragDepthEXT = 1.0;
}
</script>

<!-- Shader to test macro definition -->
<script id="macroFragmentShader" type="x-shader/x-fragment">
precision mediump float;
void main() {
#ifdef GL_EXT_frag_depth
    gl_FragColor = vec4(1.0, 0.0, 0.0, 1.0);
#else
    // Error expected
    #error no GL_EXT_frag_depth;
#endif
}
</script>

<!-- Shader with required #extension pragma -->
<script id="testFragmentShader" type="x-shader/x-fragment">
#extension GL_EXT_frag_depth : enable
precision mediump float;
void main() {
    gl_FragColor = vec4(1.0, 0.0, 0.0, 1.0);
    gl_FragDepthEXT = 1.0;
}
</script>
<!-- Shaders to link with test fragment shaders -->
<script id="goodVertexShader" type="x-shader/x-vertex">
attribute vec4 vPosition;
void main() {
    gl_Position = vPosition;
}
</script>
<!-- Shaders to test output -->
<script id="outputVertexShader" type="x-shader/x-vertex">
attribute vec4 vPosition;
void main() {
    gl_Position = vPosition;
}
</script>
<script id="outputFragmentShader" type="x-shader/x-fragment">
#extension GL_EXT_frag_depth : enable
precision mediump float;
uniform float uDepth;
void main() {
    gl_FragColor = vec4(1.0, 0.0, 0.0, 1.0);
    gl_FragDepthEXT = uDepth;
}
</script>

<script>
"use strict";
description("This test verifies the functionality of the EXT_frag_depth extension, if it is available.");

debug("");

var wtu = WebGLTestUtils;
var canvas = document.getElementById("canvas");
var gl = wtu.create3DContext(canvas);
var ext = null;

// Run all tests once.
runAllTests();

// Run all tests against with a new context to test for any cache issues.
debug("");
debug("Testing new context to catch cache errors");
gl = wtu.create3DContext();
ext = null;
runAllTests();

function runAllTests() {
    if (!gl) {
        testFailed("WebGL context does not exist");
    } else {
        testPassed("WebGL context exists");

        runShaderTests(false);

        // Query the extension and store globally so shouldBe can access it
        ext = wtu.getExtensionWithKnownPrefixes(gl, "EXT_frag_depth");
        if (!ext) {
            testPassed("No EXT_frag_depth support -- this is legal");

            runSupportedTest(false);
        } else {
            testPassed("Successfully enabled EXT_frag_depth extension");

            runSupportedTest(true);

            runShaderTests(true);
            runOutputTests();
            runUniqueObjectTest();

            // Run deferred link tests.
            runDeferredLinkTests();
        }
    }

}

function runSupportedTest(extensionEnabled) {
    var supported = gl.getSupportedExtensions();
    if (supported.indexOf("EXT_frag_depth") >= 0) {
        if (extensionEnabled) {
            testPassed("EXT_frag_depth listed as supported and getExtension succeeded");
        } else {
            testFailed("EXT_frag_depth listed as supported but getExtension failed");
        }
    } else {
        if (extensionEnabled) {
            testFailed("EXT_frag_depth not listed as supported but getExtension succeeded");
        } else {
            testPassed("EXT_frag_depth not listed as supported and getExtension failed -- this is legal");
        }
    }
}

function runShaderTests(extensionEnabled) {
    debug("");
    debug("Testing various shader compiles with extension " + (extensionEnabled ? "enabled" : "disabled"));

    // Expect the macro shader to succeed ONLY if enabled
    var macroFragmentProgram = wtu.loadProgramFromScriptExpectError(gl, "goodVertexShader", "macroFragmentShader");
    if (extensionEnabled) {
        if (macroFragmentProgram) {
            // Expected result
            testPassed("GL_EXT_frag_depth defined in shaders when extension is enabled");
        } else {
            testFailed("GL_EXT_frag_depth not defined in shaders when extension is enabled");
        }
    } else {
        if (macroFragmentProgram) {
            testFailed("GL_EXT_frag_depth defined in shaders when extension is disabled");
        } else {
            testPassed("GL_EXT_frag_depth not defined in shaders when extension disabled");
        }
    }

    // Always expect the shader missing the #pragma to fail (whether enabled or not)
    var missingPragmaFragmentProgram = wtu.loadProgramFromScriptExpectError(gl, "goodVertexShader", "missingPragmaFragmentShader");
    if (missingPragmaFragmentProgram) {
        testFailed("Shader built-ins allowed without #extension pragma");
    } else {
        testPassed("Shader built-ins disallowed without #extension pragma");
    }

    // Try to compile a shader using the built-ins that should only succeed if enabled
    var testFragmentProgram = wtu.loadProgramFromScriptExpectError(gl, "goodVertexShader", "testFragmentShader");
    if (extensionEnabled) {
        if (testFragmentProgram) {
            testPassed("Shader built-ins compiled successfully when extension enabled");
        } else {
            testFailed("Shader built-ins failed to compile when extension enabled");
        }
    } else {
        if (testFragmentProgram) {
            testFailed("Shader built-ins compiled successfully when extension disabled");
        } else {
            testPassed("Shader built-ins failed to compile when extension disabled");
        }
    }
}

function runOutputTests() {
    var e = 2; // Amount of variance to allow in result pixels - may need to be tweaked higher

    debug("Testing various draws for valid built-in function behavior");

    canvas.width = 50; canvas.height = 50;
    gl.viewport(0, 0, canvas.width, canvas.height);

    // Enable depth testing with a clearDepth of 0.5
    // This makes it so that fragments are only rendered when
    // gl_fragDepthEXT is < 0.5
    gl.clearDepth(0.5);
    gl.enable(gl.DEPTH_TEST);

    var positionLoc = 0;
    var texcoordLoc = 1;
    var program = wtu.setupProgram(gl, ["outputVertexShader", "outputFragmentShader"], ['vPosition'], [0]);
    var quadParameters = wtu.setupUnitQuad(gl, 0, 1);
    var depthUniform = gl.getUniformLocation(program, "uDepth");

    // Draw 1: Greater than clear depth
    gl.uniform1f(depthUniform, 1.0);
    wtu.clearAndDrawUnitQuad(gl);
    wtu.checkCanvasRect(gl, 0, 0, canvas.width, canvas.height, [255, 255, 255, 255]);

    // Draw 2: Less than clear depth
    gl.uniform1f(depthUniform, 0.0);
    wtu.clearAndDrawUnitQuad(gl);
    wtu.checkCanvasRect(gl, 0, 0, canvas.width, canvas.height, [255, 0, 0, 255]);
}

function runUniqueObjectTest()
{
    debug("Testing that getExtension() returns the same object each time");
    ext = null;
    gl.getExtension("EXT_frag_depth").myProperty = 2;
    webglHarnessCollectGarbage();
    shouldBe('gl.getExtension("EXT_frag_depth").myProperty', '2');
}

function runDeferredLinkTests() {
    debug("");
    debug("Testing deferred shader compilation tests.");

    // Test for compilation failures that are caused by missing extensions
    // do not succeed if extensions are enabled during linking. This would
    // only happen for deferred shader compilations.

    // First test if link succeeds with extension enabled.
    var glEnabled = wtu.create3DContext();
    var extEnabled = glEnabled.getExtension("EXT_frag_depth");
    if (!extEnabled) {
        testFailed("Deferred link test expects the extension to be supported");
    }

    var vertexShader = wtu.loadShaderFromScript(glEnabled, "goodVertexShader");
    var fragmentShader = wtu.loadShaderFromScript(glEnabled, "macroFragmentShader");

    if (!vertexShader || !fragmentShader) {
        testFailed("Could not create good shaders.");
        return;
    }

    var program = wtu.setupProgram(glEnabled, [vertexShader, fragmentShader]);

    if (!program) {
        testFailed("Compilation with extension enabled failed.");
        return;
    }

    // Create new context to test link failure without extension enabled.
    var glDeferred = wtu.create3DContext();

    var vertexShader = wtu.loadShaderFromScript(glDeferred, "goodVertexShader", glDeferred.VERTEX_SHADER, undefined, undefined, true);
    var fragmentShader = wtu.loadShaderFromScript(glDeferred, "macroFragmentShader", glDeferred.FRAGMENT_SHADER, undefined, undefined, true);

    if (vertexShader == null || fragmentShader == null) {
        testFailed("Could not create shaders.");
        return;
    }

    // Shader compilations should have failed due to extensions not enabled.
    glDeferred.getExtension("EXT_frag_depth");
    var program = wtu.setupProgram(glDeferred, [vertexShader, fragmentShader]);
    if (program) {
        testFailed("Compilation with extension disabled then linking with extension enabled should have failed.");
        return;
    }

    testPassed("Compilation with extension disabled then linking with extension enabled.");
}

debug("");
var successfullyParsed = true;
</script>
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</body>
</html>