//
// Copyright 2015 The ANGLE Project Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
//

#include "test_utils/ANGLETest.h"
#include "test_utils/gl_raii.h"

using namespace angle;

namespace
{

GLsizei TypeStride(GLenum attribType)
{
    switch (attribType)
    {
        case GL_UNSIGNED_BYTE:
        case GL_BYTE:
            return 1;
        case GL_UNSIGNED_SHORT:
        case GL_SHORT:
            return 2;
        case GL_UNSIGNED_INT:
        case GL_INT:
        case GL_FLOAT:
            return 4;
        default:
            EXPECT_TRUE(false);
            return 0;
    }
}

template <typename T>
GLfloat Normalize(T value)
{
    static_assert(std::is_integral<T>::value, "Integer required.");
    if (std::is_signed<T>::value)
    {
        typedef typename std::make_unsigned<T>::type unsigned_type;
        return (2.0f * static_cast<GLfloat>(value) + 1.0f) /
               static_cast<GLfloat>(std::numeric_limits<unsigned_type>::max());
    }
    else
    {
        return static_cast<GLfloat>(value) / static_cast<GLfloat>(std::numeric_limits<T>::max());
    }
}

class VertexAttributeTest : public ANGLETest
{
  protected:
    VertexAttributeTest()
        : mProgram(0), mTestAttrib(-1), mExpectedAttrib(-1), mBuffer(0), mQuadBuffer(0)
    {
        setWindowWidth(128);
        setWindowHeight(128);
        setConfigRedBits(8);
        setConfigGreenBits(8);
        setConfigBlueBits(8);
        setConfigAlphaBits(8);
        setConfigDepthBits(24);
    }

    enum class Source
    {
        BUFFER,
        IMMEDIATE,
    };

    struct TestData final : private angle::NonCopyable
    {
        TestData(GLenum typeIn,
                 GLboolean normalizedIn,
                 Source sourceIn,
                 const void *inputDataIn,
                 const GLfloat *expectedDataIn)
            : type(typeIn),
              normalized(normalizedIn),
              bufferOffset(0),
              source(sourceIn),
              inputData(inputDataIn),
              expectedData(expectedDataIn)
        {
        }

        GLenum type;
        GLboolean normalized;
        size_t bufferOffset;
        Source source;

        const void *inputData;
        const GLfloat *expectedData;
    };

    void setupTest(const TestData &test, GLint typeSize)
    {
        if (mProgram == 0)
        {
            initBasicProgram();
        }

        if (test.source == Source::BUFFER)
        {
            GLsizei dataSize = kVertexCount * TypeStride(test.type);
            glBindBuffer(GL_ARRAY_BUFFER, mBuffer);
            glBufferData(GL_ARRAY_BUFFER, dataSize, test.inputData, GL_STATIC_DRAW);
            glVertexAttribPointer(mTestAttrib, typeSize, test.type, test.normalized, 0,
                                  reinterpret_cast<void *>(test.bufferOffset));
            glBindBuffer(GL_ARRAY_BUFFER, 0);
        }
        else
        {
            ASSERT_EQ(Source::IMMEDIATE, test.source);
            glBindBuffer(GL_ARRAY_BUFFER, 0);
            glVertexAttribPointer(mTestAttrib, typeSize, test.type, test.normalized, 0,
                                  test.inputData);
        }

        glVertexAttribPointer(mExpectedAttrib, typeSize, GL_FLOAT, GL_FALSE, 0, test.expectedData);

        glEnableVertexAttribArray(mTestAttrib);
        glEnableVertexAttribArray(mExpectedAttrib);
    }

    void checkPixels()
    {
        GLint viewportSize[4];
        glGetIntegerv(GL_VIEWPORT, viewportSize);

        GLint midPixelX = (viewportSize[0] + viewportSize[2]) / 2;
        GLint midPixelY = (viewportSize[1] + viewportSize[3]) / 2;

        // We need to offset our checks from triangle edges to ensure we don't fall on a single tri
        // Avoid making assumptions of drawQuad with four checks to check the four possible tri
        // regions
        EXPECT_PIXEL_EQ((midPixelX + viewportSize[0]) / 2, midPixelY, 255, 255, 255, 255);
        EXPECT_PIXEL_EQ((midPixelX + viewportSize[2]) / 2, midPixelY, 255, 255, 255, 255);
        EXPECT_PIXEL_EQ(midPixelX, (midPixelY + viewportSize[1]) / 2, 255, 255, 255, 255);
        EXPECT_PIXEL_EQ(midPixelX, (midPixelY + viewportSize[3]) / 2, 255, 255, 255, 255);
    }

    void checkPixelsUnEqual()
    {
        GLint viewportSize[4];
        glGetIntegerv(GL_VIEWPORT, viewportSize);

        GLint midPixelX = (viewportSize[0] + viewportSize[2]) / 2;
        GLint midPixelY = (viewportSize[1] + viewportSize[3]) / 2;

        // We need to offset our checks from triangle edges to ensure we don't fall on a single tri
        // Avoid making assumptions of drawQuad with four checks to check the four possible tri
        // regions
        EXPECT_PIXEL_NE((midPixelX + viewportSize[0]) / 2, midPixelY, 255, 255, 255, 255);
        EXPECT_PIXEL_NE((midPixelX + viewportSize[2]) / 2, midPixelY, 255, 255, 255, 255);
        EXPECT_PIXEL_NE(midPixelX, (midPixelY + viewportSize[1]) / 2, 255, 255, 255, 255);
        EXPECT_PIXEL_NE(midPixelX, (midPixelY + viewportSize[3]) / 2, 255, 255, 255, 255);
    }

    void runTest(const TestData &test) { runTest(test, true); }

    void runTest(const TestData &test, bool checkPixelEqual)
    {
        // TODO(geofflang): Figure out why this is broken on AMD OpenGL
        ANGLE_SKIP_TEST_IF(IsAMD() && IsOpenGL());

        for (GLint i = 0; i < 4; i++)
        {
            GLint typeSize = i + 1;
            setupTest(test, typeSize);

            drawQuad(mProgram, "position", 0.5f);

            glDisableVertexAttribArray(mTestAttrib);
            glDisableVertexAttribArray(mExpectedAttrib);

            if (checkPixelEqual)
            {
                checkPixels();
            }
            else
            {
                checkPixelsUnEqual();
            }
        }
    }

    void SetUp() override
    {
        ANGLETest::SetUp();

        glClearColor(0, 0, 0, 0);
        glClearDepthf(0.0);
        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

        glDisable(GL_DEPTH_TEST);

        glGenBuffers(1, &mBuffer);
    }

    void TearDown() override
    {
        glDeleteProgram(mProgram);
        glDeleteBuffers(1, &mBuffer);
        glDeleteBuffers(1, &mQuadBuffer);

        ANGLETest::TearDown();
    }

    GLuint compileMultiAttribProgram(GLint attribCount)
    {
        std::stringstream shaderStream;

        shaderStream << "attribute mediump vec4 position;" << std::endl;
        for (GLint attribIndex = 0; attribIndex < attribCount; ++attribIndex)
        {
            shaderStream << "attribute float a" << attribIndex << ";" << std::endl;
        }
        shaderStream << "varying mediump float color;" << std::endl
                     << "void main() {" << std::endl
                     << "  gl_Position = position;" << std::endl
                     << "  color = 0.0;" << std::endl;
        for (GLint attribIndex = 0; attribIndex < attribCount; ++attribIndex)
        {
            shaderStream << "  color += a" << attribIndex << ";" << std::endl;
        }
        shaderStream << "}" << std::endl;

        const std::string testFragmentShaderSource =
            "varying mediump float color;\n"
            "void main(void)\n"
            "{\n"
            "    gl_FragColor = vec4(color, 0.0, 0.0, 1.0);\n"
            "}\n";

        return CompileProgram(shaderStream.str(), testFragmentShaderSource);
    }

    void setupMultiAttribs(GLuint program, GLint attribCount, GLfloat value)
    {
        glUseProgram(program);
        for (GLint attribIndex = 0; attribIndex < attribCount; ++attribIndex)
        {
            std::stringstream attribStream;
            attribStream << "a" << attribIndex;
            GLint location = glGetAttribLocation(program, attribStream.str().c_str());
            ASSERT_NE(-1, location);
            glVertexAttrib1f(location, value);
            glDisableVertexAttribArray(location);
        }
    }

    void initBasicProgram()
    {
        const std::string testVertexShaderSource =
            "attribute mediump vec4 position;\n"
            "attribute mediump vec4 test;\n"
            "attribute mediump vec4 expected;\n"
            "varying mediump vec4 color;\n"
            "void main(void)\n"
            "{\n"
            "    gl_Position = position;\n"
            "    vec4 threshold = max(abs(expected) * 0.01, 1.0 / 64.0);\n"
            "    color = vec4(lessThanEqual(abs(test - expected), threshold));\n"
            "}\n";

        const std::string testFragmentShaderSource =
            "varying mediump vec4 color;\n"
            "void main(void)\n"
            "{\n"
            "    gl_FragColor = color;\n"
            "}\n";

        mProgram = CompileProgram(testVertexShaderSource, testFragmentShaderSource);
        ASSERT_NE(0u, mProgram);

        mTestAttrib = glGetAttribLocation(mProgram, "test");
        ASSERT_NE(-1, mTestAttrib);
        mExpectedAttrib = glGetAttribLocation(mProgram, "expected");
        ASSERT_NE(-1, mExpectedAttrib);

        glUseProgram(mProgram);
    }

    static constexpr size_t kVertexCount = 24;

    static void InitTestData(std::array<GLfloat, kVertexCount> &inputData,
                             std::array<GLfloat, kVertexCount> &expectedData)
    {
        for (size_t count = 0; count < kVertexCount; ++count)
        {
            inputData[count]    = static_cast<GLfloat>(count);
            expectedData[count] = inputData[count];
        }
    }

    GLuint mProgram;
    GLint mTestAttrib;
    GLint mExpectedAttrib;
    GLuint mBuffer;
    GLuint mQuadBuffer;
};

TEST_P(VertexAttributeTest, UnsignedByteUnnormalized)
{
    std::array<GLubyte, kVertexCount> inputData = {
        {0, 1, 2, 3, 4, 5, 6, 7, 125, 126, 127, 128, 129, 250, 251, 252, 253, 254, 255}};
    std::array<GLfloat, kVertexCount> expectedData;
    for (size_t i = 0; i < kVertexCount; i++)
    {
        expectedData[i] = inputData[i];
    }

    TestData data(GL_UNSIGNED_BYTE, GL_FALSE, Source::IMMEDIATE, inputData.data(),
                  expectedData.data());
    runTest(data);
}

TEST_P(VertexAttributeTest, UnsignedByteNormalized)
{
    std::array<GLubyte, kVertexCount> inputData = {
        {0, 1, 2, 3, 4, 5, 6, 7, 125, 126, 127, 128, 129, 250, 251, 252, 253, 254, 255}};
    std::array<GLfloat, kVertexCount> expectedData;
    for (size_t i = 0; i < kVertexCount; i++)
    {
        expectedData[i] = Normalize(inputData[i]);
    }

    TestData data(GL_UNSIGNED_BYTE, GL_TRUE, Source::IMMEDIATE, inputData.data(),
                  expectedData.data());
    runTest(data);
}

TEST_P(VertexAttributeTest, ByteUnnormalized)
{
    std::array<GLbyte, kVertexCount> inputData = {
        {0, 1, 2, 3, 4, -1, -2, -3, -4, 125, 126, 127, -128, -127, -126}};
    std::array<GLfloat, kVertexCount> expectedData;
    for (size_t i = 0; i < kVertexCount; i++)
    {
        expectedData[i] = inputData[i];
    }

    TestData data(GL_BYTE, GL_FALSE, Source::IMMEDIATE, inputData.data(), expectedData.data());
    runTest(data);
}

TEST_P(VertexAttributeTest, ByteNormalized)
{
    std::array<GLbyte, kVertexCount> inputData = {
        {0, 1, 2, 3, 4, -1, -2, -3, -4, 125, 126, 127, -128, -127, -126}};
    std::array<GLfloat, kVertexCount> expectedData;
    for (size_t i = 0; i < kVertexCount; i++)
    {
        expectedData[i] = Normalize(inputData[i]);
    }

    TestData data(GL_BYTE, GL_TRUE, Source::IMMEDIATE, inputData.data(), expectedData.data());
    runTest(data);
}

TEST_P(VertexAttributeTest, UnsignedShortUnnormalized)
{
    std::array<GLushort, kVertexCount> inputData = {
        {0, 1, 2, 3, 254, 255, 256, 32766, 32767, 32768, 65533, 65534, 65535}};
    std::array<GLfloat, kVertexCount> expectedData;
    for (size_t i = 0; i < kVertexCount; i++)
    {
        expectedData[i] = inputData[i];
    }

    TestData data(GL_UNSIGNED_SHORT, GL_FALSE, Source::IMMEDIATE, inputData.data(),
                  expectedData.data());
    runTest(data);
}

TEST_P(VertexAttributeTest, UnsignedShortNormalized)
{
    std::array<GLushort, kVertexCount> inputData = {
        {0, 1, 2, 3, 254, 255, 256, 32766, 32767, 32768, 65533, 65534, 65535}};
    std::array<GLfloat, kVertexCount> expectedData;
    for (size_t i = 0; i < kVertexCount; i++)
    {
        expectedData[i] = Normalize(inputData[i]);
    }

    TestData data(GL_UNSIGNED_SHORT, GL_TRUE, Source::IMMEDIATE, inputData.data(),
                  expectedData.data());
    runTest(data);
}

TEST_P(VertexAttributeTest, ShortUnnormalized)
{
    std::array<GLshort, kVertexCount> inputData = {
        {0, 1, 2, 3, -1, -2, -3, -4, 32766, 32767, -32768, -32767, -32766}};
    std::array<GLfloat, kVertexCount> expectedData;
    for (size_t i = 0; i < kVertexCount; i++)
    {
        expectedData[i] = inputData[i];
    }

    TestData data(GL_SHORT, GL_FALSE, Source::IMMEDIATE, inputData.data(), expectedData.data());
    runTest(data);
}

TEST_P(VertexAttributeTest, ShortNormalized)
{
    std::array<GLshort, kVertexCount> inputData = {
        {0, 1, 2, 3, -1, -2, -3, -4, 32766, 32767, -32768, -32767, -32766}};
    std::array<GLfloat, kVertexCount> expectedData;
    for (size_t i = 0; i < kVertexCount; i++)
    {
        expectedData[i] = Normalize(inputData[i]);
    }

    TestData data(GL_SHORT, GL_TRUE, Source::IMMEDIATE, inputData.data(), expectedData.data());
    runTest(data);
}

// Verify that using the same client memory pointer in different format won't mess up the draw.
TEST_P(VertexAttributeTest, UsingDifferentFormatAndSameClientMemoryPointer)
{
    std::array<GLshort, kVertexCount> inputData = {
        {0, 1, 2, 3, -1, -2, -3, -4, 32766, 32767, -32768, -32767, -32766}};

    std::array<GLfloat, kVertexCount> unnormalizedExpectedData;
    for (size_t i = 0; i < kVertexCount; i++)
    {
        unnormalizedExpectedData[i] = inputData[i];
    }

    TestData unnormalizedData(GL_SHORT, GL_FALSE, Source::IMMEDIATE, inputData.data(),
                              unnormalizedExpectedData.data());
    runTest(unnormalizedData);

    std::array<GLfloat, kVertexCount> normalizedExpectedData;
    for (size_t i = 0; i < kVertexCount; i++)
    {
        inputData[i]              = -inputData[i];
        normalizedExpectedData[i] = Normalize(inputData[i]);
    }

    TestData normalizedData(GL_SHORT, GL_TRUE, Source::IMMEDIATE, inputData.data(),
                            normalizedExpectedData.data());
    runTest(normalizedData);
}

// Verify that vertex format is updated correctly when the client memory pointer is same.
TEST_P(VertexAttributeTest, NegativeUsingDifferentFormatAndSameClientMemoryPointer)
{
    std::array<GLshort, kVertexCount> inputData = {
        {0, 1, 2, 3, -1, -2, -3, -4, 32766, 32767, -32768, -32767, -32766}};

    std::array<GLfloat, kVertexCount> unnormalizedExpectedData;
    for (size_t i = 0; i < kVertexCount; i++)
    {
        unnormalizedExpectedData[i] = inputData[i];
    }

    // Use unnormalized short as the format of the data in client memory pointer in the first draw.
    TestData unnormalizedData(GL_SHORT, GL_FALSE, Source::IMMEDIATE, inputData.data(),
                              unnormalizedExpectedData.data());
    runTest(unnormalizedData);

    // Use normalized short as the format of the data in client memory pointer in the second draw,
    // but mExpectedAttrib is the same as the first draw.
    TestData normalizedData(GL_SHORT, GL_TRUE, Source::IMMEDIATE, inputData.data(),
                            unnormalizedExpectedData.data());
    runTest(normalizedData, false);
}

// Verify that using different vertex format and same buffer won't mess up the draw.
TEST_P(VertexAttributeTest, UsingDifferentFormatAndSameBuffer)
{
    std::array<GLshort, kVertexCount> inputData = {
        {0, 1, 2, 3, -1, -2, -3, -4, 32766, 32767, -32768, -32767, -32766}};

    std::array<GLfloat, kVertexCount> unnormalizedExpectedData;
    std::array<GLfloat, kVertexCount> normalizedExpectedData;
    for (size_t i = 0; i < kVertexCount; i++)
    {
        unnormalizedExpectedData[i] = inputData[i];
        normalizedExpectedData[i]   = Normalize(inputData[i]);
    }

    // Use unnormalized short as the format of the data in mBuffer in the first draw.
    TestData unnormalizedData(GL_SHORT, GL_FALSE, Source::BUFFER, inputData.data(),
                              unnormalizedExpectedData.data());
    runTest(unnormalizedData);

    // Use normalized short as the format of the data in mBuffer in the second draw.
    TestData normalizedData(GL_SHORT, GL_TRUE, Source::BUFFER, inputData.data(),
                            normalizedExpectedData.data());
    runTest(normalizedData);
}

// Verify that vertex format is updated correctly when the buffer is same.
TEST_P(VertexAttributeTest, NegativeUsingDifferentFormatAndSameBuffer)
{
    std::array<GLshort, kVertexCount> inputData = {
        {0, 1, 2, 3, -1, -2, -3, -4, 32766, 32767, -32768, -32767, -32766}};

    std::array<GLfloat, kVertexCount> unnormalizedExpectedData;
    for (size_t i = 0; i < kVertexCount; i++)
    {
        unnormalizedExpectedData[i] = inputData[i];
    }

    // Use unnormalized short as the format of the data in mBuffer in the first draw.
    TestData unnormalizedData(GL_SHORT, GL_FALSE, Source::BUFFER, inputData.data(),
                              unnormalizedExpectedData.data());
    runTest(unnormalizedData);

    // Use normalized short as the format of the data in mBuffer in the second draw, but
    // mExpectedAttrib is the same as the first draw.
    TestData normalizedData(GL_SHORT, GL_TRUE, Source::BUFFER, inputData.data(),
                            unnormalizedExpectedData.data());

    // The check should fail because the test data is changed while the expected data is the same.
    runTest(normalizedData, false);
}

// Verify that mixed using buffer and client memory pointer won't mess up the draw.
TEST_P(VertexAttributeTest, MixedUsingBufferAndClientMemoryPointer)
{
    std::array<GLshort, kVertexCount> inputData = {
        {0, 1, 2, 3, -1, -2, -3, -4, 32766, 32767, -32768, -32767, -32766}};

    std::array<GLfloat, kVertexCount> unnormalizedExpectedData;
    std::array<GLfloat, kVertexCount> normalizedExpectedData;
    for (size_t i = 0; i < kVertexCount; i++)
    {
        unnormalizedExpectedData[i] = inputData[i];
        normalizedExpectedData[i]   = Normalize(inputData[i]);
    }

    TestData unnormalizedData(GL_SHORT, GL_FALSE, Source::IMMEDIATE, inputData.data(),
                              unnormalizedExpectedData.data());
    runTest(unnormalizedData);

    TestData unnormalizedBufferData(GL_SHORT, GL_FALSE, Source::BUFFER, inputData.data(),
                                    unnormalizedExpectedData.data());
    runTest(unnormalizedBufferData);

    TestData normalizedData(GL_SHORT, GL_TRUE, Source::IMMEDIATE, inputData.data(),
                            normalizedExpectedData.data());
    runTest(normalizedData);
}

class VertexAttributeTestES3 : public VertexAttributeTest
{
  protected:
    VertexAttributeTestES3() {}
};

TEST_P(VertexAttributeTestES3, IntUnnormalized)
{
    GLint lo = std::numeric_limits<GLint>::min();
    GLint hi = std::numeric_limits<GLint>::max();
    std::array<GLint, kVertexCount> inputData = {
        {0, 1, 2, 3, -1, -2, -3, -4, -1, hi, hi - 1, lo, lo + 1}};
    std::array<GLfloat, kVertexCount> expectedData;
    for (size_t i = 0; i < kVertexCount; i++)
    {
        expectedData[i] = static_cast<GLfloat>(inputData[i]);
    }

    TestData data(GL_INT, GL_FALSE, Source::BUFFER, inputData.data(), expectedData.data());
    runTest(data);
}

TEST_P(VertexAttributeTestES3, IntNormalized)
{
    GLint lo = std::numeric_limits<GLint>::min();
    GLint hi = std::numeric_limits<GLint>::max();
    std::array<GLint, kVertexCount> inputData = {
        {0, 1, 2, 3, -1, -2, -3, -4, -1, hi, hi - 1, lo, lo + 1}};
    std::array<GLfloat, kVertexCount> expectedData;
    for (size_t i = 0; i < kVertexCount; i++)
    {
        expectedData[i] = Normalize(inputData[i]);
    }

    TestData data(GL_INT, GL_TRUE, Source::BUFFER, inputData.data(), expectedData.data());
    runTest(data);
}

TEST_P(VertexAttributeTestES3, UnsignedIntUnnormalized)
{
    GLuint mid = std::numeric_limits<GLuint>::max() >> 1;
    GLuint hi  = std::numeric_limits<GLuint>::max();
    std::array<GLuint, kVertexCount> inputData = {
        {0, 1, 2, 3, 254, 255, 256, mid - 1, mid, mid + 1, hi - 2, hi - 1, hi}};
    std::array<GLfloat, kVertexCount> expectedData;
    for (size_t i = 0; i < kVertexCount; i++)
    {
        expectedData[i] = static_cast<GLfloat>(inputData[i]);
    }

    TestData data(GL_UNSIGNED_INT, GL_FALSE, Source::BUFFER, inputData.data(), expectedData.data());
    runTest(data);
}

TEST_P(VertexAttributeTestES3, UnsignedIntNormalized)
{
    GLuint mid = std::numeric_limits<GLuint>::max() >> 1;
    GLuint hi  = std::numeric_limits<GLuint>::max();
    std::array<GLuint, kVertexCount> inputData = {
        {0, 1, 2, 3, 254, 255, 256, mid - 1, mid, mid + 1, hi - 2, hi - 1, hi}};
    std::array<GLfloat, kVertexCount> expectedData;
    for (size_t i = 0; i < kVertexCount; i++)
    {
        expectedData[i] = Normalize(inputData[i]);
    }

    TestData data(GL_UNSIGNED_INT, GL_TRUE, Source::BUFFER, inputData.data(), expectedData.data());
    runTest(data);
}

void SetupColorsForUnitQuad(GLint location, const GLColor32F &color, GLenum usage, GLBuffer *vbo)
{
    glBindBuffer(GL_ARRAY_BUFFER, *vbo);
    std::vector<GLColor32F> vertices(6, color);
    glBufferData(GL_ARRAY_BUFFER, vertices.size() * sizeof(GLColor32F), vertices.data(), usage);
    glEnableVertexAttribArray(location);
    glVertexAttribPointer(location, 4, GL_FLOAT, GL_FALSE, 0, 0);
}

// Tests that rendering works as expected with VAOs.
TEST_P(VertexAttributeTestES3, VertexArrayObjectRendering)
{
    const std::string kVertexShader =
        "attribute vec4 a_position;\n"
        "attribute vec4 a_color;\n"
        "varying vec4 v_color;\n"
        "void main()\n"
        "{\n"
        "   gl_Position = a_position;\n"
        "   v_color = a_color;\n"
        "}";

    const std::string kFragmentShader =
        "precision mediump float;\n"
        "varying vec4 v_color;\n"
        "void main()\n"
        "{\n"
        "    gl_FragColor = v_color;\n"
        "}";

    ANGLE_GL_PROGRAM(program, kVertexShader, kFragmentShader);

    GLint positionLoc = glGetAttribLocation(program, "a_position");
    ASSERT_NE(-1, positionLoc);
    GLint colorLoc = glGetAttribLocation(program, "a_color");
    ASSERT_NE(-1, colorLoc);

    GLVertexArray vaos[2];
    GLBuffer positionBuffer;
    GLBuffer colorBuffers[2];

    const auto &quadVertices = GetQuadVertices();

    glBindVertexArrayOES(vaos[0]);
    glBindBuffer(GL_ARRAY_BUFFER, positionBuffer);
    glBufferData(GL_ARRAY_BUFFER, quadVertices.size() * sizeof(Vector3), quadVertices.data(),
                 GL_STATIC_DRAW);
    glEnableVertexAttribArray(positionLoc);
    glVertexAttribPointer(positionLoc, 3, GL_FLOAT, GL_FALSE, 0, 0);
    SetupColorsForUnitQuad(colorLoc, kFloatRed, GL_STREAM_DRAW, &colorBuffers[0]);

    glBindVertexArrayOES(vaos[1]);
    glBindBuffer(GL_ARRAY_BUFFER, positionBuffer);
    glEnableVertexAttribArray(positionLoc);
    glVertexAttribPointer(positionLoc, 3, GL_FLOAT, GL_FALSE, 0, 0);
    SetupColorsForUnitQuad(colorLoc, kFloatGreen, GL_STATIC_DRAW, &colorBuffers[1]);

    glUseProgram(program);
    ASSERT_GL_NO_ERROR();

    for (int ii = 0; ii < 2; ++ii)
    {
        glBindVertexArrayOES(vaos[0]);
        glDrawArrays(GL_TRIANGLES, 0, 6);
        EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::red);

        glBindVertexArrayOES(vaos[1]);
        glDrawArrays(GL_TRIANGLES, 0, 6);
        EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::green);
    }

    ASSERT_GL_NO_ERROR();
}

// Validate that we can support GL_MAX_ATTRIBS attribs
TEST_P(VertexAttributeTest, MaxAttribs)
{
    // TODO(jmadill): Figure out why we get this error on AMD/OpenGL.
    ANGLE_SKIP_TEST_IF(IsAMD() && IsOpenGL());

    GLint maxAttribs;
    glGetIntegerv(GL_MAX_VERTEX_ATTRIBS, &maxAttribs);
    ASSERT_GL_NO_ERROR();

    // Reserve one attrib for position
    GLint drawAttribs = maxAttribs - 1;

    GLuint program = compileMultiAttribProgram(drawAttribs);
    ASSERT_NE(0u, program);

    setupMultiAttribs(program, drawAttribs, 0.5f / static_cast<float>(drawAttribs));
    drawQuad(program, "position", 0.5f);

    EXPECT_GL_NO_ERROR();
    EXPECT_PIXEL_NEAR(0, 0, 128, 0, 0, 255, 1);
}

// Validate that we cannot support GL_MAX_ATTRIBS+1 attribs
TEST_P(VertexAttributeTest, MaxAttribsPlusOne)
{
    // TODO(jmadill): Figure out why we get this error on AMD/ES2/OpenGL
    ANGLE_SKIP_TEST_IF(IsAMD() && GetParam() == ES2_OPENGL());

    GLint maxAttribs;
    glGetIntegerv(GL_MAX_VERTEX_ATTRIBS, &maxAttribs);
    ASSERT_GL_NO_ERROR();

    // Exceed attrib count by one (counting position)
    GLint drawAttribs = maxAttribs;

    GLuint program = compileMultiAttribProgram(drawAttribs);
    ASSERT_EQ(0u, program);
}

// Simple test for when we use glBindAttribLocation
TEST_P(VertexAttributeTest, SimpleBindAttribLocation)
{
    // Re-use the multi-attrib program, binding attribute 0
    GLuint program = compileMultiAttribProgram(1);
    glBindAttribLocation(program, 2, "position");
    glBindAttribLocation(program, 3, "a0");
    glLinkProgram(program);

    // Setup and draw the quad
    setupMultiAttribs(program, 1, 0.5f);
    drawQuad(program, "position", 0.5f);
    EXPECT_GL_NO_ERROR();
    EXPECT_PIXEL_NEAR(0, 0, 128, 0, 0, 255, 1);
}

// Verify that drawing with a large out-of-range offset generates INVALID_OPERATION.
// Requires an ANGLE or similar implementation that checks buffer bounds.
TEST_P(VertexAttributeTest, ANGLEDrawArraysBufferTooSmall)
{
    // Test skipped due to supporting GL_KHR_robust_buffer_access_behavior
    ANGLE_SKIP_TEST_IF(extensionEnabled("GL_KHR_robust_buffer_access_behavior"));

    std::array<GLfloat, kVertexCount> inputData;
    std::array<GLfloat, kVertexCount> expectedData;
    InitTestData(inputData, expectedData);

    TestData data(GL_FLOAT, GL_FALSE, Source::BUFFER, inputData.data(), expectedData.data());
    data.bufferOffset = kVertexCount * TypeStride(GL_FLOAT);

    setupTest(data, 1);
    drawQuad(mProgram, "position", 0.5f);
    EXPECT_GL_ERROR(GL_INVALID_OPERATION);
}

// Verify that index draw with an out-of-range offset generates INVALID_OPERATION.
// Requires an ANGLE or similar implementation that checks buffer bounds.
TEST_P(VertexAttributeTest, ANGLEDrawElementsBufferTooSmall)
{
    // Test skipped due to supporting GL_KHR_robust_buffer_access_behavior
    ANGLE_SKIP_TEST_IF(extensionEnabled("GL_KHR_robust_buffer_access_behavior"));

    std::array<GLfloat, kVertexCount> inputData;
    std::array<GLfloat, kVertexCount> expectedData;
    InitTestData(inputData, expectedData);

    TestData data(GL_FLOAT, GL_FALSE, Source::BUFFER, inputData.data(), expectedData.data());
    data.bufferOffset = (kVertexCount - 3) * TypeStride(GL_FLOAT);

    setupTest(data, 1);
    drawIndexedQuad(mProgram, "position", 0.5f);
    EXPECT_GL_ERROR(GL_INVALID_OPERATION);
}

TEST_P(VertexAttributeTest, ANGLEDrawArraysOutOfBoundsCases)
{
    // Test skipped due to supporting GL_KHR_robust_buffer_access_behavior
    ANGLE_SKIP_TEST_IF(extensionEnabled("GL_KHR_robust_buffer_access_behavior"));

    initBasicProgram();

    GLfloat singleFloat = 1.0f;
    GLsizei dataSize    = TypeStride(GL_FLOAT);

    glBindBuffer(GL_ARRAY_BUFFER, mBuffer);
    glBufferData(GL_ARRAY_BUFFER, dataSize, &singleFloat, GL_STATIC_DRAW);
    glVertexAttribPointer(mTestAttrib, 2, GL_FLOAT, GL_FALSE, 8, 0);
    glEnableVertexAttribArray(mTestAttrib);
    glBindBuffer(GL_ARRAY_BUFFER, 0);

    drawIndexedQuad(mProgram, "position", 0.5f);
    EXPECT_GL_ERROR(GL_INVALID_OPERATION);
}

// Verify that using a different start vertex doesn't mess up the draw.
TEST_P(VertexAttributeTest, DrawArraysWithBufferOffset)
{
    // TODO(jmadill): Diagnose this failure.
    ANGLE_SKIP_TEST_IF(IsD3D11_FL93());

    // TODO(geofflang): Figure out why this is broken on AMD OpenGL
    ANGLE_SKIP_TEST_IF(IsAMD() && IsOpenGL());

    initBasicProgram();
    glUseProgram(mProgram);

    std::array<GLfloat, kVertexCount> inputData;
    std::array<GLfloat, kVertexCount> expectedData;
    InitTestData(inputData, expectedData);

    auto quadVertices        = GetQuadVertices();
    GLsizei quadVerticesSize = static_cast<GLsizei>(quadVertices.size() * sizeof(quadVertices[0]));

    glGenBuffers(1, &mQuadBuffer);
    glBindBuffer(GL_ARRAY_BUFFER, mQuadBuffer);
    glBufferData(GL_ARRAY_BUFFER, quadVerticesSize + sizeof(Vector3), nullptr, GL_STATIC_DRAW);
    glBufferSubData(GL_ARRAY_BUFFER, 0, quadVerticesSize, quadVertices.data());

    GLint positionLocation = glGetAttribLocation(mProgram, "position");
    ASSERT_NE(-1, positionLocation);
    glVertexAttribPointer(positionLocation, 3, GL_FLOAT, GL_FALSE, 0, nullptr);
    glEnableVertexAttribArray(positionLocation);

    GLsizei dataSize = kVertexCount * TypeStride(GL_FLOAT);
    glBindBuffer(GL_ARRAY_BUFFER, mBuffer);
    glBufferData(GL_ARRAY_BUFFER, dataSize + TypeStride(GL_FLOAT), nullptr, GL_STATIC_DRAW);
    glBufferSubData(GL_ARRAY_BUFFER, 0, dataSize, inputData.data());
    glVertexAttribPointer(mTestAttrib, 1, GL_FLOAT, GL_FALSE, 0, nullptr);
    glEnableVertexAttribArray(mTestAttrib);

    glBindBuffer(GL_ARRAY_BUFFER, 0);
    glVertexAttribPointer(mExpectedAttrib, 1, GL_FLOAT, GL_FALSE, 0, expectedData.data());
    glEnableVertexAttribArray(mExpectedAttrib);

    // Vertex draw with no start vertex offset (second argument is zero).
    glDrawArrays(GL_TRIANGLES, 0, 6);
    checkPixels();

    // Draw offset by one vertex.
    glDrawArrays(GL_TRIANGLES, 1, 6);
    checkPixels();

    EXPECT_GL_NO_ERROR();
}

// Verify that when we pass a client memory pointer to a disabled attribute the draw is still
// correct.
TEST_P(VertexAttributeTest, DrawArraysWithDisabledAttribute)
{
    initBasicProgram();

    std::array<GLfloat, kVertexCount> inputData;
    std::array<GLfloat, kVertexCount> expectedData;
    InitTestData(inputData, expectedData);

    auto quadVertices        = GetQuadVertices();
    GLsizei quadVerticesSize = static_cast<GLsizei>(quadVertices.size() * sizeof(quadVertices[0]));

    glGenBuffers(1, &mQuadBuffer);
    glBindBuffer(GL_ARRAY_BUFFER, mQuadBuffer);
    glBufferData(GL_ARRAY_BUFFER, quadVerticesSize, quadVertices.data(), GL_STATIC_DRAW);

    GLint positionLocation = glGetAttribLocation(mProgram, "position");
    ASSERT_NE(-1, positionLocation);
    glVertexAttribPointer(positionLocation, 3, GL_FLOAT, GL_FALSE, 0, nullptr);
    glEnableVertexAttribArray(positionLocation);

    glBindBuffer(GL_ARRAY_BUFFER, mBuffer);
    glBufferData(GL_ARRAY_BUFFER, sizeof(inputData), inputData.data(), GL_STATIC_DRAW);
    glVertexAttribPointer(mTestAttrib, 1, GL_FLOAT, GL_FALSE, 0, nullptr);
    glEnableVertexAttribArray(mTestAttrib);

    glBindBuffer(GL_ARRAY_BUFFER, 0);
    glVertexAttribPointer(mExpectedAttrib, 1, GL_FLOAT, GL_FALSE, 0, expectedData.data());
    glEnableVertexAttribArray(mExpectedAttrib);

    // mProgram2 adds an attribute 'disabled' on the basis of mProgram.
    const std::string testVertexShaderSource2 =
        "attribute mediump vec4 position;\n"
        "attribute mediump vec4 test;\n"
        "attribute mediump vec4 expected;\n"
        "attribute mediump vec4 disabled;\n"
        "varying mediump vec4 color;\n"
        "void main(void)\n"
        "{\n"
        "    gl_Position = position;\n"
        "    vec4 threshold = max(abs(expected + disabled) * 0.005, 1.0 / 64.0);\n"
        "    color = vec4(lessThanEqual(abs(test - expected), threshold));\n"
        "}\n";

    const std::string testFragmentShaderSource =
        "varying mediump vec4 color;\n"
        "void main(void)\n"
        "{\n"
        "    gl_FragColor = color;\n"
        "}\n";

    ANGLE_GL_PROGRAM(program, testVertexShaderSource2, testFragmentShaderSource);
    GLuint mProgram2 = program.get();

    ASSERT_EQ(positionLocation, glGetAttribLocation(mProgram2, "position"));
    ASSERT_EQ(mTestAttrib, glGetAttribLocation(mProgram2, "test"));
    ASSERT_EQ(mExpectedAttrib, glGetAttribLocation(mProgram2, "expected"));

    // Pass a client memory pointer to disabledAttribute and disable it.
    GLint disabledAttribute = glGetAttribLocation(mProgram2, "disabled");
    ASSERT_EQ(-1, glGetAttribLocation(mProgram, "disabled"));
    glVertexAttribPointer(disabledAttribute, 1, GL_FLOAT, GL_FALSE, 0, expectedData.data());
    glDisableVertexAttribArray(disabledAttribute);

    glUseProgram(mProgram);
    glDrawArrays(GL_TRIANGLES, 0, 6);
    checkPixels();

    // Now enable disabledAttribute which should be used in mProgram2.
    glEnableVertexAttribArray(disabledAttribute);
    glUseProgram(mProgram2);
    glDrawArrays(GL_TRIANGLES, 0, 6);
    checkPixels();

    EXPECT_GL_NO_ERROR();
}

// Test based on WebGL Test attribs/gl-disabled-vertex-attrib.html
TEST_P(VertexAttributeTest, DisabledAttribArrays)
{
    // Known failure on Retina MBP: http://crbug.com/635081
    ANGLE_SKIP_TEST_IF(IsOSX() && IsNVIDIA());

    const std::string vsSource =
        "attribute vec4 a_position;\n"
        "attribute vec4 a_color;\n"
        "varying vec4 v_color;\n"
        "bool isCorrectColor(vec4 v) {\n"
        "    return v.x == 0.0 && v.y == 0.0 && v.z == 0.0 && v.w == 1.0;\n"
        "}"
        "void main() {\n"
        "    gl_Position = a_position;\n"
        "    v_color = isCorrectColor(a_color) ? vec4(0, 1, 0, 1) : vec4(1, 0, 0, 1);\n"
        "}";

    const std::string fsSource =
        "varying mediump vec4 v_color;\n"
        "void main() {\n"
        "    gl_FragColor = v_color;\n"
        "}";

    GLint maxVertexAttribs = 0;
    glGetIntegerv(GL_MAX_VERTEX_ATTRIBS, &maxVertexAttribs);

    for (GLint colorIndex = 0; colorIndex < maxVertexAttribs; ++colorIndex)
    {
        GLuint vs = CompileShader(GL_VERTEX_SHADER, vsSource);
        ASSERT_NE(0u, vs);
        GLuint fs = CompileShader(GL_FRAGMENT_SHADER, fsSource);
        ASSERT_NE(0u, fs);

        GLuint program = glCreateProgram();
        glBindAttribLocation(program, colorIndex, "a_color");

        glAttachShader(program, vs);
        glDeleteShader(vs);

        glAttachShader(program, fs);
        glDeleteShader(fs);

        ASSERT_TRUE(LinkAttachedProgram(program));

        drawQuad(program, "a_position", 0.5f);
        ASSERT_GL_NO_ERROR();

        EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::green);

        glDeleteProgram(program);
    }
}

class VertexAttributeTestES31 : public VertexAttributeTestES3
{
  protected:
    VertexAttributeTestES31() {}

    void initTest()
    {
        initBasicProgram();
        glUseProgram(mProgram);

        glGenVertexArrays(1, &mVAO);
        glBindVertexArray(mVAO);

        auto quadVertices = GetQuadVertices();
        GLsizeiptr quadVerticesSize =
            static_cast<GLsizeiptr>(quadVertices.size() * sizeof(quadVertices[0]));
        glGenBuffers(1, &mQuadBuffer);
        glBindBuffer(GL_ARRAY_BUFFER, mQuadBuffer);
        glBufferData(GL_ARRAY_BUFFER, quadVerticesSize, quadVertices.data(), GL_STATIC_DRAW);

        GLint positionLocation = glGetAttribLocation(mProgram, "position");
        ASSERT_NE(-1, positionLocation);
        glVertexAttribPointer(positionLocation, 3, GL_FLOAT, GL_FALSE, 0, nullptr);
        glEnableVertexAttribArray(positionLocation);

        std::array<GLfloat, kVertexCount> expectedData;
        for (size_t count = 0; count < kVertexCount; ++count)
        {
            expectedData[count] = static_cast<GLfloat>(count);
        }

        const GLsizei kExpectedDataSize = kVertexCount * kFloatStride;
        glGenBuffers(1, &mExpectedBuffer);
        glBindBuffer(GL_ARRAY_BUFFER, mExpectedBuffer);
        glBufferData(GL_ARRAY_BUFFER, kExpectedDataSize, expectedData.data(), GL_STATIC_DRAW);
        glVertexAttribPointer(mExpectedAttrib, 1, GL_FLOAT, GL_FALSE, 0, nullptr);
        glEnableVertexAttribArray(mExpectedAttrib);
    }

    void TearDown() override
    {
        VertexAttributeTestES3::TearDown();

        glDeleteBuffers(1, &mExpectedBuffer);
        glDeleteVertexArrays(1, &mVAO);
    }

    void drawArraysWithStrideAndRelativeOffset(GLint stride, GLuint relativeOffset)
    {
        initTest();

        GLint floatStride          = std::max(stride / kFloatStride, 1);
        GLuint floatRelativeOffset = relativeOffset / kFloatStride;
        size_t floatCount = static_cast<size_t>(floatRelativeOffset) + kVertexCount * floatStride;
        GLsizeiptr inputSize   = static_cast<GLsizeiptr>(floatCount) * kFloatStride;

        std::vector<GLfloat> inputData(floatCount);
        for (size_t count = 0; count < kVertexCount; ++count)
        {
            inputData[floatRelativeOffset + count * floatStride] = static_cast<GLfloat>(count);
        }

        // Ensure inputSize, inputStride and inputOffset are multiples of TypeStride(GL_FLOAT).
        GLsizei inputStride            = floatStride * kFloatStride;
        GLsizeiptr inputRelativeOffset = floatRelativeOffset * kFloatStride;
        glBindBuffer(GL_ARRAY_BUFFER, mBuffer);
        glBufferData(GL_ARRAY_BUFFER, inputSize, nullptr, GL_STATIC_DRAW);
        glBufferSubData(GL_ARRAY_BUFFER, 0, inputSize, inputData.data());
        glVertexAttribFormat(mTestAttrib, 1, GL_FLOAT, GL_FALSE, inputRelativeOffset);
        glBindVertexBuffer(mTestAttrib, mBuffer, 0, inputStride);
        glEnableVertexAttribArray(mTestAttrib);

        glDrawArrays(GL_TRIANGLES, 0, 6);
        checkPixels();

        EXPECT_GL_NO_ERROR();
    }

    void initOnlyUpdateBindingTest(GLint bindingToUpdate)
    {
        initTest();

        constexpr GLuint kTestFloatOffset1                               = kVertexCount;
        std::array<GLfloat, kTestFloatOffset1 + kVertexCount> inputData1 = {};
        for (size_t count = 0; count < kVertexCount; ++count)
        {
            GLfloat value                         = static_cast<GLfloat>(count);
            inputData1[kTestFloatOffset1 + count] = value;
        }

        GLBuffer testBuffer1;
        glBindBuffer(GL_ARRAY_BUFFER, testBuffer1);
        glBufferData(GL_ARRAY_BUFFER, inputData1.size() * kFloatStride, inputData1.data(),
                     GL_STATIC_DRAW);

        ASSERT_NE(bindingToUpdate, mTestAttrib);
        ASSERT_NE(bindingToUpdate, mExpectedAttrib);

        // Set mTestAttrib using the binding bindingToUpdate.
        glVertexAttribFormat(mTestAttrib, 1, GL_FLOAT, GL_FALSE, 0);
        glBindVertexBuffer(bindingToUpdate, testBuffer1, kTestFloatOffset1 * kFloatStride,
                           kFloatStride);
        glVertexAttribBinding(mTestAttrib, bindingToUpdate);
        glEnableVertexAttribArray(mTestAttrib);

        // In the first draw the current VAO states are set to driver.
        glDrawArrays(GL_TRIANGLES, 0, 6);
        checkPixels();
        EXPECT_GL_NO_ERROR();

        // We need the second draw to ensure all VAO dirty bits are reset.
        // e.g. On D3D11 back-ends, Buffer11::resize is called in the first draw, where the related
        // binding is set to dirty again.
        glDrawArrays(GL_TRIANGLES, 0, 6);
        checkPixels();
        EXPECT_GL_NO_ERROR();
    }

    GLuint mVAO;
    GLuint mExpectedBuffer;

    const GLsizei kFloatStride = TypeStride(GL_FLOAT);

    // Set the maximum value for stride and relativeOffset in case they are too large.
    const GLint MAX_STRIDE_FOR_TEST          = 4095;
    const GLint MAX_RELATIVE_OFFSET_FOR_TEST = 4095;
};

// Verify that MAX_VERTEX_ATTRIB_STRIDE is no less than the minimum required value (2048) in ES3.1.
TEST_P(VertexAttributeTestES31, MaxVertexAttribStride)
{
    GLint maxStride;
    glGetIntegerv(GL_MAX_VERTEX_ATTRIB_STRIDE, &maxStride);
    ASSERT_GL_NO_ERROR();

    EXPECT_GE(maxStride, 2048);
}

// Verify that GL_MAX_VERTEX_ATTRIB_RELATIVE_OFFSET is no less than the minimum required value
// (2047) in ES3.1.
TEST_P(VertexAttributeTestES31, MaxVertexAttribRelativeOffset)
{
    GLint maxRelativeOffset;
    glGetIntegerv(GL_MAX_VERTEX_ATTRIB_RELATIVE_OFFSET, &maxRelativeOffset);
    ASSERT_GL_NO_ERROR();

    EXPECT_GE(maxRelativeOffset, 2047);
}

// Verify using MAX_VERTEX_ATTRIB_STRIDE as stride doesn't mess up the draw.
// Use default value if the value of MAX_VERTEX_ATTRIB_STRIDE is too large for this test.
TEST_P(VertexAttributeTestES31, DrawArraysWithLargeStride)
{
    GLint maxStride;
    glGetIntegerv(GL_MAX_VERTEX_ATTRIB_STRIDE, &maxStride);
    ASSERT_GL_NO_ERROR();

    GLint largeStride = std::min(maxStride, MAX_STRIDE_FOR_TEST);
    drawArraysWithStrideAndRelativeOffset(largeStride, 0);
}

// Verify using MAX_VERTEX_ATTRIB_RELATIVE_OFFSET as relativeOffset doesn't mess up the draw.
// Use default value if the value of MAX_VERTEX_ATTRIB_RELATIVE_OFFSSET is too large for this test.
TEST_P(VertexAttributeTestES31, DrawArraysWithLargeRelativeOffset)
{
    GLint maxRelativeOffset;
    glGetIntegerv(GL_MAX_VERTEX_ATTRIB_RELATIVE_OFFSET, &maxRelativeOffset);
    ASSERT_GL_NO_ERROR();

    GLint largeRelativeOffset = std::min(maxRelativeOffset, MAX_RELATIVE_OFFSET_FOR_TEST);
    drawArraysWithStrideAndRelativeOffset(0, largeRelativeOffset);
}

// Verify that using VertexAttribBinding after VertexAttribPointer won't mess up the draw.
TEST_P(VertexAttributeTestES31, ChangeAttribBindingAfterVertexAttribPointer)
{
    initTest();

    constexpr GLint kInputStride = 2;
    constexpr GLint kFloatOffset = 10;
    std::array<GLfloat, kVertexCount + kFloatOffset> inputData1;
    std::array<GLfloat, kVertexCount * kInputStride> inputData2;
    for (size_t count = 0; count < kVertexCount; ++count)
    {
        inputData1[kFloatOffset + count] = static_cast<GLfloat>(count);
        inputData2[count * kInputStride] = static_cast<GLfloat>(count);
    }

    GLBuffer mBuffer1;
    glBindBuffer(GL_ARRAY_BUFFER, mBuffer1);
    glBufferData(GL_ARRAY_BUFFER, inputData1.size() * kFloatStride, inputData1.data(),
                 GL_STATIC_DRAW);
    // Update the format indexed mTestAttrib and the binding indexed mTestAttrib by
    // VertexAttribPointer.
    const GLintptr kOffset = static_cast<GLintptr>(kFloatStride * kFloatOffset);
    glVertexAttribPointer(mTestAttrib, 1, GL_FLOAT, GL_FALSE, 0,
                          reinterpret_cast<const GLvoid *>(kOffset));
    glEnableVertexAttribArray(mTestAttrib);

    constexpr GLint kTestBinding = 10;
    ASSERT_NE(mTestAttrib, kTestBinding);

    GLBuffer mBuffer2;
    glBindBuffer(GL_ARRAY_BUFFER, mBuffer2);
    glBufferData(GL_ARRAY_BUFFER, inputData2.size() * kFloatStride, inputData2.data(),
                 GL_STATIC_DRAW);
    glBindVertexBuffer(kTestBinding, mBuffer2, 0, kFloatStride * kInputStride);

    // The attribute indexed mTestAttrib is using the binding indexed kTestBinding in the first
    // draw.
    glVertexAttribBinding(mTestAttrib, kTestBinding);
    glDrawArrays(GL_TRIANGLES, 0, 6);
    checkPixels();
    EXPECT_GL_NO_ERROR();

    // The attribute indexed mTestAttrib is using the binding indexed mTestAttrib which should be
    // set after the call VertexAttribPointer before the first draw.
    glVertexAttribBinding(mTestAttrib, mTestAttrib);
    glDrawArrays(GL_TRIANGLES, 0, 6);
    checkPixels();
    EXPECT_GL_NO_ERROR();
}

// Verify that using VertexAttribFormat after VertexAttribPointer won't mess up the draw.
TEST_P(VertexAttributeTestES31, ChangeAttribFormatAfterVertexAttribPointer)
{
    initTest();

    constexpr GLuint kFloatOffset = 10;
    std::array<GLfloat, kVertexCount + kFloatOffset> inputData;
    for (size_t count = 0; count < kVertexCount; ++count)
    {
        inputData[kFloatOffset + count] = static_cast<GLfloat>(count);
    }

    glBindBuffer(GL_ARRAY_BUFFER, mBuffer);
    glBufferData(GL_ARRAY_BUFFER, inputData.size() * kFloatStride, inputData.data(),
                 GL_STATIC_DRAW);

    // Call VertexAttribPointer on mTestAttrib. Now the relativeOffset of mTestAttrib should be 0.
    const GLuint kOffset = static_cast<GLuint>(kFloatStride * kFloatOffset);
    glVertexAttribPointer(mTestAttrib, 1, GL_FLOAT, GL_FALSE, 0, 0);
    glEnableVertexAttribArray(mTestAttrib);

    // Call VertexAttribFormat on mTestAttrib to modify the relativeOffset to kOffset.
    glVertexAttribFormat(mTestAttrib, 1, GL_FLOAT, GL_FALSE, kOffset);

    glDrawArrays(GL_TRIANGLES, 0, 6);
    checkPixels();
    EXPECT_GL_NO_ERROR();
}

// Verify that only updating a binding without updating the bound format won't mess up this draw.
TEST_P(VertexAttributeTestES31, OnlyUpdateBindingByBindVertexBuffer)
{
    // Default binding index for test
    constexpr GLint kTestBinding = 10;
    initOnlyUpdateBindingTest(kTestBinding);

    constexpr GLuint kTestFloatOffset2                               = kVertexCount * 2;
    std::array<GLfloat, kVertexCount> expectedData2                  = {};
    std::array<GLfloat, kTestFloatOffset2 + kVertexCount> inputData2 = {};
    for (size_t count = 0; count < kVertexCount; ++count)
    {
        GLfloat value2                        = static_cast<GLfloat>(count) * 2;
        expectedData2[count]                  = value2;
        inputData2[count + kTestFloatOffset2] = value2;
    }

    // Set another set of data for mExpectedAttrib.
    GLBuffer expectedBuffer2;
    glBindBuffer(GL_ARRAY_BUFFER, expectedBuffer2);
    glBufferData(GL_ARRAY_BUFFER, expectedData2.size() * kFloatStride, expectedData2.data(),
                 GL_STATIC_DRAW);
    glVertexAttribPointer(mExpectedAttrib, 1, GL_FLOAT, GL_FALSE, 0, nullptr);

    GLBuffer testBuffer2;
    glBindBuffer(GL_ARRAY_BUFFER, testBuffer2);
    glBufferData(GL_ARRAY_BUFFER, inputData2.size() * kFloatStride, inputData2.data(),
                 GL_STATIC_DRAW);

    // Only update the binding kTestBinding in the second draw by BindVertexBuffer.
    glBindVertexBuffer(kTestBinding, testBuffer2, kTestFloatOffset2 * kFloatStride, kFloatStride);

    glDrawArrays(GL_TRIANGLES, 0, 6);
    checkPixels();
    EXPECT_GL_NO_ERROR();
}

// Verify that only updating a binding without updating the bound format won't mess up this draw.
TEST_P(VertexAttributeTestES31, OnlyUpdateBindingByVertexAttribPointer)
{
    // Default binding index for test
    constexpr GLint kTestBinding = 10;
    initOnlyUpdateBindingTest(kTestBinding);

    constexpr GLuint kTestFloatOffset2                               = kVertexCount * 3;
    std::array<GLfloat, kVertexCount> expectedData2                  = {};
    std::array<GLfloat, kTestFloatOffset2 + kVertexCount> inputData2 = {};
    for (size_t count = 0; count < kVertexCount; ++count)
    {
        GLfloat value2                        = static_cast<GLfloat>(count) * 3;
        expectedData2[count]                  = value2;
        inputData2[count + kTestFloatOffset2] = value2;
    }

    // Set another set of data for mExpectedAttrib.
    GLBuffer expectedBuffer2;
    glBindBuffer(GL_ARRAY_BUFFER, expectedBuffer2);
    glBufferData(GL_ARRAY_BUFFER, expectedData2.size() * kFloatStride, expectedData2.data(),
                 GL_STATIC_DRAW);
    glVertexAttribPointer(mExpectedAttrib, 1, GL_FLOAT, GL_FALSE, 0, nullptr);

    GLBuffer testBuffer2;
    glBindBuffer(GL_ARRAY_BUFFER, testBuffer2);
    glBufferData(GL_ARRAY_BUFFER, inputData2.size() * kFloatStride, inputData2.data(),
                 GL_STATIC_DRAW);

    // Only update the binding kTestBinding in the second draw by VertexAttribPointer.
    glVertexAttribPointer(kTestBinding, 1, GL_FLOAT, GL_FALSE, 0,
                          reinterpret_cast<const void *>(kTestFloatOffset2 * kFloatStride));

    glDrawArrays(GL_TRIANGLES, 0, 6);
    checkPixels();
    EXPECT_GL_NO_ERROR();
}

class VertexAttributeCachingTest : public VertexAttributeTest
{
  protected:
    VertexAttributeCachingTest() {}

    void SetUp() override;

    template <typename DestT>
    static std::vector<GLfloat> GetExpectedData(const std::vector<GLubyte> &srcData,
                                                GLenum attribType,
                                                GLboolean normalized);

    void initDoubleAttribProgram()
    {
        const std::string testVertexShaderSource =
            "attribute mediump vec4 position;\n"
            "attribute mediump vec4 test;\n"
            "attribute mediump vec4 expected;\n"
            "attribute mediump vec4 test2;\n"
            "attribute mediump vec4 expected2;\n"
            "varying mediump vec4 color;\n"
            "void main(void)\n"
            "{\n"
            "    gl_Position = position;\n"
            "    vec4 threshold = max(abs(expected) * 0.01, 1.0 / 64.0);\n"
            "    color = vec4(lessThanEqual(abs(test - expected), threshold));\n"
            "    vec4 threshold2 = max(abs(expected2) * 0.01, 1.0 / 64.0);\n"
            "    color += vec4(lessThanEqual(abs(test2 - expected2), threshold2));\n"
            "}\n";

        const std::string testFragmentShaderSource =
            "varying mediump vec4 color;\n"
            "void main(void)\n"
            "{\n"
            "    gl_FragColor = color;\n"
            "}\n";

        mProgram = CompileProgram(testVertexShaderSource, testFragmentShaderSource);
        ASSERT_NE(0u, mProgram);

        mTestAttrib = glGetAttribLocation(mProgram, "test");
        ASSERT_NE(-1, mTestAttrib);
        mExpectedAttrib = glGetAttribLocation(mProgram, "expected");
        ASSERT_NE(-1, mExpectedAttrib);

        glUseProgram(mProgram);
    }

    struct AttribData
    {
        AttribData(GLenum typeIn, GLint sizeIn, GLboolean normalizedIn, GLsizei strideIn);

        GLenum type;
        GLint size;
        GLboolean normalized;
        GLsizei stride;
    };

    std::vector<AttribData> mTestData;
    std::map<GLenum, std::vector<GLfloat>> mExpectedData;
    std::map<GLenum, std::vector<GLfloat>> mNormExpectedData;
};

VertexAttributeCachingTest::AttribData::AttribData(GLenum typeIn,
                                                   GLint sizeIn,
                                                   GLboolean normalizedIn,
                                                   GLsizei strideIn)
    : type(typeIn), size(sizeIn), normalized(normalizedIn), stride(strideIn)
{
}

// static
template <typename DestT>
std::vector<GLfloat> VertexAttributeCachingTest::GetExpectedData(
    const std::vector<GLubyte> &srcData,
    GLenum attribType,
    GLboolean normalized)
{
    std::vector<GLfloat> expectedData;

    const DestT *typedSrcPtr = reinterpret_cast<const DestT *>(srcData.data());
    size_t iterations        = srcData.size() / TypeStride(attribType);

    if (normalized)
    {
        for (size_t index = 0; index < iterations; ++index)
        {
            expectedData.push_back(Normalize(typedSrcPtr[index]));
        }
    }
    else
    {
        for (size_t index = 0; index < iterations; ++index)
        {
            expectedData.push_back(static_cast<GLfloat>(typedSrcPtr[index]));
        }
    }

    return expectedData;
}

void VertexAttributeCachingTest::SetUp()
{
    VertexAttributeTest::SetUp();

    glBindBuffer(GL_ARRAY_BUFFER, mBuffer);

    std::vector<GLubyte> srcData;
    for (size_t count = 0; count < 4; ++count)
    {
        for (GLubyte i = 0; i < std::numeric_limits<GLubyte>::max(); ++i)
        {
            srcData.push_back(i);
        }
    }

    glBufferData(GL_ARRAY_BUFFER, srcData.size(), srcData.data(), GL_STATIC_DRAW);

    GLint viewportSize[4];
    glGetIntegerv(GL_VIEWPORT, viewportSize);

    std::vector<GLenum> attribTypes;
    attribTypes.push_back(GL_BYTE);
    attribTypes.push_back(GL_UNSIGNED_BYTE);
    attribTypes.push_back(GL_SHORT);
    attribTypes.push_back(GL_UNSIGNED_SHORT);

    if (getClientMajorVersion() >= 3)
    {
        attribTypes.push_back(GL_INT);
        attribTypes.push_back(GL_UNSIGNED_INT);
    }

    constexpr GLint kMaxSize     = 4;
    constexpr GLsizei kMaxStride = 4;

    for (GLenum attribType : attribTypes)
    {
        for (GLint attribSize = 1; attribSize <= kMaxSize; ++attribSize)
        {
            for (GLsizei stride = 1; stride <= kMaxStride; ++stride)
            {
                mTestData.push_back(AttribData(attribType, attribSize, GL_FALSE, stride));
                if (attribType != GL_FLOAT)
                {
                    mTestData.push_back(AttribData(attribType, attribSize, GL_TRUE, stride));
                }
            }
        }
    }

    mExpectedData[GL_BYTE]          = GetExpectedData<GLbyte>(srcData, GL_BYTE, GL_FALSE);
    mExpectedData[GL_UNSIGNED_BYTE] = GetExpectedData<GLubyte>(srcData, GL_UNSIGNED_BYTE, GL_FALSE);
    mExpectedData[GL_SHORT]         = GetExpectedData<GLshort>(srcData, GL_SHORT, GL_FALSE);
    mExpectedData[GL_UNSIGNED_SHORT] =
        GetExpectedData<GLushort>(srcData, GL_UNSIGNED_SHORT, GL_FALSE);
    mExpectedData[GL_INT]          = GetExpectedData<GLint>(srcData, GL_INT, GL_FALSE);
    mExpectedData[GL_UNSIGNED_INT] = GetExpectedData<GLuint>(srcData, GL_UNSIGNED_INT, GL_FALSE);

    mNormExpectedData[GL_BYTE] = GetExpectedData<GLbyte>(srcData, GL_BYTE, GL_TRUE);
    mNormExpectedData[GL_UNSIGNED_BYTE] =
        GetExpectedData<GLubyte>(srcData, GL_UNSIGNED_BYTE, GL_TRUE);
    mNormExpectedData[GL_SHORT] = GetExpectedData<GLshort>(srcData, GL_SHORT, GL_TRUE);
    mNormExpectedData[GL_UNSIGNED_SHORT] =
        GetExpectedData<GLushort>(srcData, GL_UNSIGNED_SHORT, GL_TRUE);
    mNormExpectedData[GL_INT]          = GetExpectedData<GLint>(srcData, GL_INT, GL_TRUE);
    mNormExpectedData[GL_UNSIGNED_INT] = GetExpectedData<GLuint>(srcData, GL_UNSIGNED_INT, GL_TRUE);
}

// In D3D11, we must sometimes translate buffer data into static attribute caches. We also use a
// cache management scheme which garbage collects old attributes after we start using too much
// cache data. This test tries to make as many attribute caches from a single buffer as possible
// to stress-test the caching code.
TEST_P(VertexAttributeCachingTest, BufferMulticaching)
{
    ANGLE_SKIP_TEST_IF(IsAMD() && IsDesktopOpenGL());

    initBasicProgram();

    glEnableVertexAttribArray(mTestAttrib);
    glEnableVertexAttribArray(mExpectedAttrib);

    ASSERT_GL_NO_ERROR();

    for (const auto &data : mTestData)
    {
        const auto &expected =
            (data.normalized) ? mNormExpectedData[data.type] : mExpectedData[data.type];

        GLsizei baseStride = static_cast<GLsizei>(data.size) * data.stride;
        GLsizei stride     = TypeStride(data.type) * baseStride;

        glBindBuffer(GL_ARRAY_BUFFER, mBuffer);
        glVertexAttribPointer(mTestAttrib, data.size, data.type, data.normalized, stride, nullptr);
        glBindBuffer(GL_ARRAY_BUFFER, 0);
        glVertexAttribPointer(mExpectedAttrib, data.size, GL_FLOAT, GL_FALSE,
                              sizeof(GLfloat) * baseStride, expected.data());
        drawQuad(mProgram, "position", 0.5f);
        ASSERT_GL_NO_ERROR();
        EXPECT_PIXEL_EQ(getWindowWidth() / 2, getWindowHeight() / 2, 255, 255, 255, 255);
    }
}

// With D3D11 dirty bits for VertxArray11, we can leave vertex state unchanged if there aren't any
// GL calls that affect it. This test targets leaving one vertex attribute unchanged between draw
// calls while changing another vertex attribute enough that it clears the static buffer cache
// after enough iterations. It validates the unchanged attributes don't get deleted incidentally.
TEST_P(VertexAttributeCachingTest, BufferMulticachingWithOneUnchangedAttrib)
{
    ANGLE_SKIP_TEST_IF(IsAMD() && IsDesktopOpenGL());

    initDoubleAttribProgram();

    GLint testAttrib2Location = glGetAttribLocation(mProgram, "test2");
    ASSERT_NE(-1, testAttrib2Location);
    GLint expectedAttrib2Location = glGetAttribLocation(mProgram, "expected2");
    ASSERT_NE(-1, expectedAttrib2Location);

    glEnableVertexAttribArray(mTestAttrib);
    glEnableVertexAttribArray(mExpectedAttrib);
    glEnableVertexAttribArray(testAttrib2Location);
    glEnableVertexAttribArray(expectedAttrib2Location);

    ASSERT_GL_NO_ERROR();

    // Use an attribute that we know must be converted. This is a bit sensitive.
    glBindBuffer(GL_ARRAY_BUFFER, mBuffer);
    glVertexAttribPointer(testAttrib2Location, 3, GL_UNSIGNED_SHORT, GL_FALSE, 6, nullptr);
    glBindBuffer(GL_ARRAY_BUFFER, 0);
    glVertexAttribPointer(expectedAttrib2Location, 3, GL_FLOAT, GL_FALSE, sizeof(GLfloat) * 3,
                          mExpectedData[GL_UNSIGNED_SHORT].data());

    for (const auto &data : mTestData)
    {
        const auto &expected =
            (data.normalized) ? mNormExpectedData[data.type] : mExpectedData[data.type];

        GLsizei baseStride = static_cast<GLsizei>(data.size) * data.stride;
        GLsizei stride     = TypeStride(data.type) * baseStride;

        glBindBuffer(GL_ARRAY_BUFFER, mBuffer);
        glVertexAttribPointer(mTestAttrib, data.size, data.type, data.normalized, stride, nullptr);
        glBindBuffer(GL_ARRAY_BUFFER, 0);
        glVertexAttribPointer(mExpectedAttrib, data.size, GL_FLOAT, GL_FALSE,
                              sizeof(GLfloat) * baseStride, expected.data());
        drawQuad(mProgram, "position", 0.5f);

        ASSERT_GL_NO_ERROR();
        EXPECT_PIXEL_EQ(getWindowWidth() / 2, getWindowHeight() / 2, 255, 255, 255, 255);
    }
}

// Tests that repeatedly updating a disabled vertex attribute works as expected.
// This covers an ANGLE bug where dirty bits for current values were ignoring repeated updates.
TEST_P(VertexAttributeTest, DisabledAttribUpdates)
{
    constexpr char kVertexShader[] = R"(attribute vec2 position;
attribute float actualValue;
uniform float expectedValue;
varying float result;
void main()
{
    result = (actualValue == expectedValue) ? 1.0 : 0.0;
    gl_Position = vec4(position, 0, 1);
})";

    constexpr char kFragmentShader[] = R"(varying mediump float result;
void main()
{
    gl_FragColor = result > 0.0 ? vec4(0, 1, 0, 1) : vec4(1, 0, 0, 1);
})";

    ANGLE_GL_PROGRAM(program, kVertexShader, kFragmentShader);

    glUseProgram(program);
    GLint attribLoc = glGetAttribLocation(program, "actualValue");
    ASSERT_NE(-1, attribLoc);

    GLint uniLoc = glGetUniformLocation(program, "expectedValue");
    ASSERT_NE(-1, uniLoc);

    glVertexAttribPointer(attribLoc, 1, GL_FLOAT, GL_FALSE, 0, nullptr);

    GLint positionLocation = glGetAttribLocation(program, "position");
    ASSERT_NE(-1, positionLocation);
    setupQuadVertexBuffer(0.5f, 1.0f);
    glVertexAttribPointer(positionLocation, 3, GL_FLOAT, GL_FALSE, 0, 0);
    glEnableVertexAttribArray(positionLocation);

    std::array<GLfloat, 4> testValues = {{1, 2, 3, 4}};
    for (GLfloat testValue : testValues)
    {
        glUniform1f(uniLoc, testValue);
        glVertexAttrib1f(attribLoc, testValue);
        glDrawArrays(GL_TRIANGLES, 0, 6);
        ASSERT_GL_NO_ERROR();
        EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::green);
    }
}

// Test that even inactive attributes are taken into account when checking for aliasing in case the
// shader version is >= 3.00. GLSL ES 3.00.6 section 12.46.
TEST_P(VertexAttributeTestES3, InactiveAttributeAliasing)
{
    const std::string &vertexShader =
        R"(#version 300 es
        precision mediump float;
        in vec4 input_active;
        in vec4 input_unused;
        void main()
        {
            gl_Position = input_active;
        })";

    const std::string &fragmentShader =
        R"(#version 300 es
        precision mediump float;
        out vec4 color;
        void main()
        {
            color = vec4(0.0);
        })";

    ANGLE_GL_PROGRAM(program, vertexShader, fragmentShader);
    glBindAttribLocation(program, 0, "input_active");
    glBindAttribLocation(program, 0, "input_unused");
    glLinkProgram(program);
    EXPECT_GL_NO_ERROR();
    GLint linkStatus = 0;
    glGetProgramiv(program, GL_LINK_STATUS, &linkStatus);
    EXPECT_GL_FALSE(linkStatus);
}

// Use this to select which configurations (e.g. which renderer, which GLES major version) these
// tests should be run against.
// D3D11 Feature Level 9_3 uses different D3D formats for vertex attribs compared to Feature Levels
// 10_0+, so we should test them separately.
ANGLE_INSTANTIATE_TEST(VertexAttributeTest,
                       ES2_D3D9(),
                       ES2_D3D11(),
                       ES2_D3D11_FL9_3(),
                       ES2_OPENGL(),
                       ES3_OPENGL(),
                       ES2_OPENGLES(),
                       ES3_OPENGLES());

ANGLE_INSTANTIATE_TEST(VertexAttributeTestES3, ES3_D3D11(), ES3_OPENGL(), ES3_OPENGLES());

ANGLE_INSTANTIATE_TEST(VertexAttributeTestES31, ES31_D3D11(), ES31_OPENGL(), ES31_OPENGLES());

ANGLE_INSTANTIATE_TEST(VertexAttributeCachingTest,
                       ES2_D3D9(),
                       ES2_D3D11(),
                       ES3_D3D11(),
                       ES3_OPENGL());

}  // anonymous namespace
