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Copyright (c) 2019 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.
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<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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"use strict";
var wtu = WebGLTestUtils;
var canvas;
var gl;
var shouldGenerateGLError;
var WEBGL_lose_context;
var new_WEBGL_lose_context;
var bufferObjects;
var program;
var texture;
var texColor = [255, 10, 20, 255];
var allowRestore;
var contextLostEventFired;
var contextRestoredEventFired;
var OES_vertex_array_object;
var old_OES_vertex_array_object;
var vertexArrayObject;
var OES_texture_float;
var newExtension;

function init()
{
    enableJSTestPreVerboseLogging();
    description("Tests behavior under a restored context.");

    shouldGenerateGLError = wtu.shouldGenerateGLError;
    testLosingContext();
}

function setupTest()
{
    canvas = document.createElement("canvas");
    canvas.width = 1;
    canvas.height = 1;
    gl = wtu.create3DContext(canvas);
    WEBGL_lose_context = getExtensionAndAddProperty(gl, "WEBGL_lose_context");
    if (!WEBGL_lose_context) {
        debug("Could not find WEBGL_lose_context extension");
        return false;
    }

    // Try to get a few extensions
    OES_vertex_array_object = getExtensionAndAddProperty(gl, "OES_vertex_array_object");
    OES_texture_float = getExtensionAndAddProperty(gl, "OES_texture_float");

    return true;
}

function getExtensionAndAddProperty(gl, name) {
  var ext = wtu.getExtensionWithKnownPrefixes(gl, name);
  if (ext) {
    ext.webglTestProperty = true;
  }
  return ext;
}

function reGetExtensionAndTestForProperty(gl, name, expectProperty) {
  newExtension = wtu.getExtensionWithKnownPrefixes(gl, name);
  // NOTE: while getting a extension after context lost/restored is allowed to fail
  // for the purpose the conformance tests it is not.
  //
  // Hypothetically the user can switch GPUs live. For example on Windows, install 2 GPUs,
  // then in the control panen enable 1, disable the others and visa versa. Since the GPUs
  // have different capabilities one or the other may not support a particlar extension.
  //
  // But, for the purpose of the conformance tests the context is expected to restore
  // on the same GPU and therefore the extensions that succeeded previously should
  // succeed on restore.
  shouldBeTrue("newExtension != null");
  if (expectProperty) {
    shouldBeTrue("newExtension.webglTestProperty === true");
  } else {
    shouldBeTrue("newExtension.webglTestProperty === undefined");
  }
  return newExtension;
}

function testLosingContext()
{
    if (!setupTest()) {
        finishTest();
        return;
    }

    debug("Test losing a context and inability to restore it.");

    canvas.addEventListener("webglcontextlost", function(e) {
       testLostContext(e);
       // restore the context after this event has exited.
       setTimeout(function() {
         // we didn't call prevent default so we should not be able to restore the context
         shouldGenerateGLError(gl, gl.INVALID_OPERATION, "WEBGL_lose_context.restoreContext()");
         testLosingAndRestoringContext();
       }, 0);
    });
    canvas.addEventListener("webglcontextrestored", testShouldNotRestoreContext);
    allowRestore = false;
    contextLostEventFired = false;
    contextRestoredEventFired = false;

    testOriginalContext();
    WEBGL_lose_context.loseContext();
    // The context should be lost immediately.
    shouldBeTrue("gl.isContextLost()");
    shouldBe("gl.getError()", "gl.CONTEXT_LOST_WEBGL");
    shouldBe("gl.getError()", "gl.NO_ERROR");
    // gl methods should be no-ops
    shouldGenerateGLError(gl, gl.NO_ERROR, "gl.blendFunc(gl.TEXTURE_2D, gl.TEXTURE_CUBE_MAP)");
    // but the event should not have been fired.
    shouldBeFalse("contextLostEventFired");
}

function testLosingAndRestoringContext()
{
    if (!setupTest())
        finishTest();

    debug("");
    debug("Test losing and restoring a context.");

    canvas.addEventListener("webglcontextlost", function(e) {
      testLostContext(e);
      // restore the context after this event has exited.
      setTimeout(function() {
        shouldGenerateGLError(gl, gl.NO_ERROR, "WEBGL_lose_context.restoreContext()");
        // Calling restoreContext() twice should not cause error or crash
        shouldGenerateGLError(gl, gl.NO_ERROR, "WEBGL_lose_context.restoreContext()");
        // The context should still be lost. It will not get restored until the
        // webglrestorecontext event is fired.
        shouldBeTrue("gl.isContextLost()");
        shouldBe("gl.getError()", "gl.NO_ERROR");
        // gl methods should still be no-ops
        shouldGenerateGLError(gl, gl.NO_ERROR, "gl.blendFunc(gl.TEXTURE_2D, gl.TEXTURE_CUBE_MAP)");
      }, 0);
    });
    canvas.addEventListener("webglcontextrestored", function() {
      testRestoredContext();
      finishTest();
    });
    allowRestore = true;
    contextLostEventFired = false;
    contextRestoredEventFired = false;

    testOriginalContext();
    WEBGL_lose_context.loseContext();
    // The context should be lost immediately.
    shouldBeTrue("gl.isContextLost()");
    shouldBe("gl.getError()", "gl.CONTEXT_LOST_WEBGL");
    shouldBe("gl.getError()", "gl.NO_ERROR");
    // gl methods should be no-ops
    shouldGenerateGLError(gl, gl.NO_ERROR, "gl.blendFunc(gl.TEXTURE_2D, gl.TEXTURE_CUBE_MAP)");
    // but the event should not have been fired.
    shouldBeFalse("contextLostEventFired");
}

function testRendering()
{
    gl.clearColor(0, 0, 0, 255);
    gl.colorMask(1, 1, 1, 0);
    gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);

    program = wtu.setupSimpleTextureProgram(gl);
    bufferObjects = wtu.setupUnitQuad(gl);
    texture = wtu.createColoredTexture(gl, canvas.width, canvas.height, texColor);

    gl.uniform1i(gl.getUniformLocation(program, "tex"), 0);
    wtu.clearAndDrawUnitQuad(gl, [0, 0, 0, 255]);

    var compare = texColor.slice(0, 3);
    wtu.checkCanvasRect(gl, 0, 0, canvas.width, canvas.height, compare, "shouldBe " + compare);

    shouldBe("gl.getError()", "gl.NO_ERROR");
}

function testOriginalContext()
{
    debug("Test valid context");
    shouldBeFalse("gl.isContextLost()");
    shouldBe("gl.getError()", "gl.NO_ERROR");
    testRendering();
    debug("");
}

function testLostContext(e)
{
    debug("Test lost context");
    shouldBeFalse("contextLostEventFired");
    contextLostEventFired = true;
    shouldBeTrue("gl.isContextLost()");
    shouldBe("gl.getError()", "gl.NO_ERROR");
    debug("");
    if (allowRestore)
      e.preventDefault();
}

function testShouldNotRestoreContext(e)
{
    testFailed("Should not restore the context unless preventDefault is called on the context lost event");
    debug("");
}

function testResources(expected)
{
    var tests = [
        "gl.bindTexture(gl.TEXTURE_2D, texture)",
        "gl.useProgram(program)",
        "gl.bindBuffer(gl.ARRAY_BUFFER, bufferObjects[0])",
    ];

    for (var i = 0; i < tests.length; ++i)
        shouldGenerateGLError(gl, expected, tests[i]);
}

function testOESTextureFloat() {
  if (OES_texture_float) {
    // Extension must still be lost.
    var tex = gl.createTexture();
    gl.bindTexture(gl.TEXTURE_2D, tex);
    shouldGenerateGLError(gl, gl.INVALID_ENUM, "gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, 1, 1, 0, gl.RGBA, gl.FLOAT, null)");
    // Try re-enabling extension
    OES_texture_float = reGetExtensionAndTestForProperty(gl, "OES_texture_float", false);
    shouldGenerateGLError(gl, gl.NO_ERROR, "gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, 1, 1, 0, gl.RGBA, gl.FLOAT, null)");
  }
}

function testOESVertexArrayObject() {
  if (OES_vertex_array_object) {
    // Extension must still be lost.
    shouldBeNull("OES_vertex_array_object.createVertexArrayOES()");
    // Try re-enabling extension

    old_OES_vertex_array_object = OES_vertex_array_object;
    OES_vertex_array_object = reGetExtensionAndTestForProperty(gl, "OES_vertex_array_object", false);
    shouldBeTrue("OES_vertex_array_object.createVertexArrayOES() != null");
    shouldBeTrue("old_OES_vertex_array_object.createVertexArrayOES() == null");
  }
}

function testExtensions() {
  testOESTextureFloat();
  testOESVertexArrayObject();
  // Only the WEBGL_lose_context extension should be the same object after context lost.
  new_WEBGL_lose_context = reGetExtensionAndTestForProperty(gl, "WEBGL_lose_context", true);
}

function testRestoredContext()
{
    debug("Test restored context");
    shouldBeFalse("contextRestoredEventFired");
    contextRestoredEventFired = true;
    shouldBeFalse("gl.isContextLost()");
    shouldBe("gl.getError()", "gl.NO_ERROR");

    // Validate that using old resources fails.
    testResources(gl.INVALID_OPERATION);

    testRendering();

    // Validate new resources created in testRendering().
    testResources(gl.NO_ERROR);

    testExtensions();

    debug("");
}


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