tests/gl_tests/SimpleOperationTest.cpp

//
// 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.
//
// SimpleOperationTest:
//   Basic GL commands such as linking a program, initializing a buffer, etc.

#include "test_utils/ANGLETest.h"

#include <vector>

#include "test_utils/gl_raii.h"
#include "util/EGLWindow.h"
#include "util/random_utils.h"

using namespace angle;

namespace
{
constexpr char kBasicVertexShader[] =
    R"(attribute vec3 position;
void main()
{
    gl_Position = vec4(position, 1);
})";

constexpr char kGreenFragmentShader[] =
    R"(void main()
{
    gl_FragColor = vec4(0, 1, 0, 1);
})";

class SimpleOperationTest : public ANGLETest
{
  protected:
    SimpleOperationTest()
    {
        setWindowWidth(128);
        setWindowHeight(128);
        setConfigRedBits(8);
        setConfigGreenBits(8);
        setConfigBlueBits(8);
        setConfigAlphaBits(8);
    }

    void verifyBuffer(const std::vector<uint8_t> &data, GLenum binding);

    template <typename T>
    void testDrawElementsLineLoopUsingClientSideMemory(GLenum indexType,
                                                       int windowWidth,
                                                       int windowHeight);
};

class SimpleOperationTest31 : public SimpleOperationTest
{};

void SimpleOperationTest::verifyBuffer(const std::vector<uint8_t> &data, GLenum binding)
{
    if (!IsGLExtensionEnabled("GL_EXT_map_buffer_range"))
    {
        return;
    }

    uint8_t *mapPointer =
        static_cast<uint8_t *>(glMapBufferRangeEXT(GL_ARRAY_BUFFER, 0, 1024, GL_MAP_READ_BIT));
    ASSERT_GL_NO_ERROR();

    std::vector<uint8_t> readbackData(data.size());
    memcpy(readbackData.data(), mapPointer, data.size());
    glUnmapBufferOES(GL_ARRAY_BUFFER);

    EXPECT_EQ(data, readbackData);
}

// Validates if culling rasterization states work. Simply draws a quad with
// cull face enabled and make sure we still render correctly.
TEST_P(SimpleOperationTest, CullFaceEnabledState)
{
    ANGLE_GL_PROGRAM(program, kBasicVertexShader, kGreenFragmentShader);
    glUseProgram(program);

    glClear(GL_COLOR_BUFFER_BIT);
    glEnable(GL_CULL_FACE);

    drawQuad(program.get(), "position", 0.0f, 1.0f, true);

    ASSERT_GL_NO_ERROR();

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

// Validates if culling rasterization states work. Simply draws a quad with
// cull face enabled with cullface front and make sure the face have not been rendered.
TEST_P(SimpleOperationTest, CullFaceFrontEnabledState)
{
    ANGLE_GL_PROGRAM(program, kBasicVertexShader, kGreenFragmentShader);
    glUseProgram(program);

    glClear(GL_COLOR_BUFFER_BIT);
    glEnable(GL_CULL_FACE);

    // Should make the quad disappear since we draw it front facing.
    glCullFace(GL_FRONT);

    drawQuad(program.get(), "position", 0.0f, 1.0f, true);

    ASSERT_GL_NO_ERROR();

    EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::transparentBlack);
}

// Validates if blending render states work. Simply draws twice and verify the color have been
// added in the final output.
TEST_P(SimpleOperationTest, BlendingRenderState)
{
    // The precision when blending isn't perfect and some tests fail with a color of 254 instead
    // of 255 on the green component. This is why we need 0.51 green instead of .5
    constexpr char halfGreenFragmentShader[] =
        R"(void main()
{
    gl_FragColor = vec4(0, 0.51, 0, 1);
})";

    ANGLE_GL_PROGRAM(program, kBasicVertexShader, halfGreenFragmentShader);
    glUseProgram(program);

    glClear(GL_COLOR_BUFFER_BIT);
    glEnable(GL_BLEND);
    glBlendFunc(GL_ONE, GL_ONE);
    glBlendEquation(GL_FUNC_ADD);

    auto vertices = GetQuadVertices();

    const GLint positionLocation = glGetAttribLocation(program, "position");
    ASSERT_NE(-1, positionLocation);

    GLBuffer vertexBuffer;
    glBindBuffer(GL_ARRAY_BUFFER, vertexBuffer.get());
    glBufferData(GL_ARRAY_BUFFER, sizeof(vertices[0]) * vertices.size(), vertices.data(),
                 GL_STATIC_DRAW);
    glVertexAttribPointer(positionLocation, 3, GL_FLOAT, GL_FALSE, 0, 0);

    glEnableVertexAttribArray(positionLocation);

    // Drawing a quad once will give 0.51 green, but if we enable blending
    // with additive function we should end up with full green of 1.0 with
    // a clamping func of 1.0.
    glDrawArrays(GL_TRIANGLES, 0, static_cast<GLsizei>(vertices.size()));
    glDrawArrays(GL_TRIANGLES, 0, static_cast<GLsizei>(vertices.size()));

    ASSERT_GL_NO_ERROR();

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

TEST_P(SimpleOperationTest, CompileVertexShader)
{
    GLuint shader = CompileShader(GL_VERTEX_SHADER, kBasicVertexShader);
    EXPECT_NE(shader, 0u);
    glDeleteShader(shader);

    ASSERT_GL_NO_ERROR();
}

TEST_P(SimpleOperationTest, CompileFragmentShaderSingleVaryingInput)
{
    constexpr char kFS[] = R"(precision mediump float;
varying vec4 v_input;
void main()
{
    gl_FragColor = v_input;
})";

    GLuint shader = CompileShader(GL_FRAGMENT_SHADER, kFS);
    EXPECT_NE(shader, 0u);
    glDeleteShader(shader);

    ASSERT_GL_NO_ERROR();
}

// Covers a simple bug in Vulkan to do with dependencies between the Surface and the default
// Framebuffer.
TEST_P(SimpleOperationTest, ClearAndSwap)
{
    glClearColor(1.0, 0.0, 0.0, 1.0);
    glClear(GL_COLOR_BUFFER_BIT);
    swapBuffers();

    // Can't check the pixel result after the swap, and checking the pixel result affects the
    // behaviour of the test on the Vulkan back-end, so don't bother checking correctness.
    ASSERT_GL_NO_ERROR();
    ASSERT_FALSE(getGLWindow()->hasError());
}

// Simple case of setting a scissor, enabled or disabled.
TEST_P(SimpleOperationTest, ScissorTest)
{
    ANGLE_GL_PROGRAM(program, kBasicVertexShader, kGreenFragmentShader);

    glClear(GL_COLOR_BUFFER_BIT);
    glEnable(GL_SCISSOR_TEST);
    glScissor(getWindowWidth() / 4, getWindowHeight() / 4, getWindowWidth() / 2,
              getWindowHeight() / 2);

    // Fill the whole screen with a quad.
    drawQuad(program.get(), "position", 0.0f, 1.0f, true);

    ASSERT_GL_NO_ERROR();

    // Test outside the scissor test, pitch black.
    EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::transparentBlack);

    // Test inside, green of the fragment shader.
    EXPECT_PIXEL_COLOR_EQ(getWindowWidth() / 2, getWindowHeight() / 2, GLColor::green);
}

TEST_P(SimpleOperationTest, LinkProgramShadersNoInputs)
{
    constexpr char kVS[] = "void main() { gl_Position = vec4(1.0, 1.0, 1.0, 1.0); }";
    constexpr char kFS[] = "void main() { gl_FragColor = vec4(1.0, 1.0, 1.0, 1.0); }";

    ANGLE_GL_PROGRAM(program, kVS, kFS);
    ASSERT_GL_NO_ERROR();
}

TEST_P(SimpleOperationTest, LinkProgramWithUniforms)
{
    constexpr char kVS[] = R"(void main()
{
    gl_Position = vec4(1.0, 1.0, 1.0, 1.0);
})";
    constexpr char kFS[] = R"(precision mediump float;
uniform vec4 u_input;
void main()
{
    gl_FragColor = u_input;
})";

    ANGLE_GL_PROGRAM(program, kVS, kFS);

    const GLint uniformLoc = glGetUniformLocation(program, "u_input");
    EXPECT_NE(-1, uniformLoc);

    ASSERT_GL_NO_ERROR();
}

TEST_P(SimpleOperationTest, LinkProgramWithAttributes)
{
    constexpr char kVS[] = R"(attribute vec4 a_input;
void main()
{
    gl_Position = a_input;
})";

    ANGLE_GL_PROGRAM(program, kVS, kGreenFragmentShader);

    const GLint attribLoc = glGetAttribLocation(program, "a_input");
    EXPECT_NE(-1, attribLoc);

    ASSERT_GL_NO_ERROR();
}

TEST_P(SimpleOperationTest, BufferDataWithData)
{
    GLBuffer buffer;
    glBindBuffer(GL_ARRAY_BUFFER, buffer.get());

    std::vector<uint8_t> data(1024);
    FillVectorWithRandomUBytes(&data);
    glBufferData(GL_ARRAY_BUFFER, data.size(), &data[0], GL_STATIC_DRAW);

    verifyBuffer(data, GL_ARRAY_BUFFER);

    ASSERT_GL_NO_ERROR();
}

TEST_P(SimpleOperationTest, BufferDataWithNoData)
{
    GLBuffer buffer;
    glBindBuffer(GL_ARRAY_BUFFER, buffer.get());
    glBufferData(GL_ARRAY_BUFFER, 1024, nullptr, GL_STATIC_DRAW);

    ASSERT_GL_NO_ERROR();
}

TEST_P(SimpleOperationTest, BufferSubData)
{
    GLBuffer buffer;
    glBindBuffer(GL_ARRAY_BUFFER, buffer.get());

    constexpr size_t bufferSize = 1024;
    std::vector<uint8_t> data(bufferSize);
    FillVectorWithRandomUBytes(&data);

    glBufferData(GL_ARRAY_BUFFER, bufferSize, nullptr, GL_STATIC_DRAW);

    constexpr size_t subDataCount = 16;
    constexpr size_t sliceSize    = bufferSize / subDataCount;
    for (size_t i = 0; i < subDataCount; i++)
    {
        size_t offset = i * sliceSize;
        glBufferSubData(GL_ARRAY_BUFFER, offset, sliceSize, &data[offset]);
    }

    verifyBuffer(data, GL_ARRAY_BUFFER);

    ASSERT_GL_NO_ERROR();
}

// Simple quad test.
TEST_P(SimpleOperationTest, DrawQuad)
{
    ANGLE_GL_PROGRAM(program, kBasicVertexShader, kGreenFragmentShader);

    drawQuad(program.get(), "position", 0.5f, 1.0f, true);

    ASSERT_GL_NO_ERROR();

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

// Simple quad test with data in client memory, not vertex buffer.
TEST_P(SimpleOperationTest, DrawQuadFromClientMemory)
{
    ANGLE_GL_PROGRAM(program, kBasicVertexShader, kGreenFragmentShader);

    drawQuad(program.get(), "position", 0.5f, 1.0f, false);

    ASSERT_GL_NO_ERROR();

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

// Simple double quad test.
TEST_P(SimpleOperationTest, DrawQuadTwice)
{
    ANGLE_GL_PROGRAM(program, kBasicVertexShader, kGreenFragmentShader);

    drawQuad(program.get(), "position", 0.5f, 1.0f, true);
    drawQuad(program.get(), "position", 0.5f, 1.0f, true);

    ASSERT_GL_NO_ERROR();

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

// Simple line test.
TEST_P(SimpleOperationTest, DrawLine)
{
    // We assume in the test the width and height are equal and we are tracing
    // the line from bottom left to top right. Verify that all pixels along that line
    // have been traced with green.
    ASSERT_EQ(getWindowWidth(), getWindowHeight());

    ANGLE_GL_PROGRAM(program, kBasicVertexShader, kGreenFragmentShader);
    glUseProgram(program);

    std::vector<Vector3> vertices = {{-1.0f, -1.0f, 0.0f}, {1.0f, 1.0f, 0.0f}};

    const GLint positionLocation = glGetAttribLocation(program, "position");
    ASSERT_NE(-1, positionLocation);

    GLBuffer vertexBuffer;
    glBindBuffer(GL_ARRAY_BUFFER, vertexBuffer);
    glBufferData(GL_ARRAY_BUFFER, sizeof(vertices[0]) * vertices.size(), vertices.data(),
                 GL_STATIC_DRAW);
    glVertexAttribPointer(positionLocation, 3, GL_FLOAT, GL_FALSE, 0, nullptr);
    glEnableVertexAttribArray(positionLocation);

    glClear(GL_COLOR_BUFFER_BIT);
    glDrawArrays(GL_LINES, 0, static_cast<GLsizei>(vertices.size()));

    glDisableVertexAttribArray(positionLocation);

    ASSERT_GL_NO_ERROR();

    for (int x = 0; x < getWindowWidth(); x++)
    {
        EXPECT_PIXEL_COLOR_EQ(x, x, GLColor::green);
    }
}

// Simple line test that will use a very large offset in the vertex attributes.
TEST_P(SimpleOperationTest, DrawLineWithLargeAttribPointerOffset)
{
    // We assume in the test the width and height are equal and we are tracing
    // the line from bottom left to top right. Verify that all pixels along that line
    // have been traced with green.
    ASSERT_EQ(getWindowWidth(), getWindowHeight());

    ANGLE_GL_PROGRAM(program, kBasicVertexShader, kGreenFragmentShader);
    glUseProgram(program);

    int kOffset = 3315;
    std::vector<Vector3> vertices(kOffset);
    Vector3 vector1{-1.0f, -1.0f, 0.0f};
    Vector3 vector2{1.0f, 1.0f, 0.0f};
    vertices.emplace_back(vector1);
    vertices.emplace_back(vector2);

    const GLint positionLocation = glGetAttribLocation(program, "position");
    ASSERT_NE(-1, positionLocation);

    GLBuffer vertexBuffer;
    glBindBuffer(GL_ARRAY_BUFFER, vertexBuffer);
    glBufferData(GL_ARRAY_BUFFER, sizeof(vertices[0]) * vertices.size(), vertices.data(),
                 GL_STATIC_DRAW);
    glVertexAttribPointer(positionLocation, 3, GL_FLOAT, GL_FALSE, 0,
                          reinterpret_cast<const void *>(kOffset * sizeof(vertices[0])));
    glEnableVertexAttribArray(positionLocation);

    glClear(GL_COLOR_BUFFER_BIT);
    glDrawArrays(GL_LINES, 0, 2);

    glDisableVertexAttribArray(positionLocation);

    ASSERT_GL_NO_ERROR();

    for (auto x = 0; x < getWindowWidth(); x++)
    {
        EXPECT_PIXEL_COLOR_EQ(x, x, GLColor::green);
    }
}

// Simple line strip test.
TEST_P(SimpleOperationTest, DrawLineStrip)
{
    // We assume in the test the width and height are equal and we are tracing
    // the line from bottom left to center, then from center to bottom right.
    // Verify that all pixels along these lines have been traced with green.
    ASSERT_EQ(getWindowWidth(), getWindowHeight());

    ANGLE_GL_PROGRAM(program, kBasicVertexShader, kGreenFragmentShader);
    glUseProgram(program);

    auto vertices =
        std::vector<Vector3>{{-1.0f, -1.0f, 0.0f}, {0.0f, 0.0f, 0.0f}, {1.0f, -1.0f, 0.0f}};

    const GLint positionLocation = glGetAttribLocation(program, "position");
    ASSERT_NE(-1, positionLocation);

    GLBuffer vertexBuffer;
    glBindBuffer(GL_ARRAY_BUFFER, vertexBuffer.get());
    glBufferData(GL_ARRAY_BUFFER, sizeof(vertices[0]) * vertices.size(), vertices.data(),
                 GL_STATIC_DRAW);
    glVertexAttribPointer(positionLocation, 3, GL_FLOAT, GL_FALSE, 0, 0);

    glEnableVertexAttribArray(positionLocation);

    glClear(GL_COLOR_BUFFER_BIT);
    glDrawArrays(GL_LINE_STRIP, 0, static_cast<GLsizei>(vertices.size()));

    ASSERT_GL_NO_ERROR();

    const auto centerX = getWindowWidth() / 2;
    const auto centerY = getWindowHeight() / 2;

    for (auto x = 0; x < centerX; x++)
    {
        EXPECT_PIXEL_COLOR_EQ(x, x, GLColor::green);
    }

    for (auto x = centerX, y = centerY - 1; x < getWindowWidth() && y >= 0; x++, y--)
    {
        EXPECT_PIXEL_COLOR_EQ(x, y, GLColor::green);
    }
}

class TriangleFanDrawTest : public SimpleOperationTest
{
  protected:
    void testSetUp() override
    {
        // We assume in the test the width and height are equal and we are tracing
        // 2 triangles to cover half the surface like this:
        ASSERT_EQ(getWindowWidth(), getWindowHeight());

        mProgram.makeRaster(kBasicVertexShader, kGreenFragmentShader);
        ASSERT_TRUE(mProgram.valid());
        glUseProgram(mProgram);

        const GLint positionLocation = glGetAttribLocation(mProgram, "position");
        ASSERT_NE(-1, positionLocation);

        glBindBuffer(GL_ARRAY_BUFFER, mVertexBuffer.get());
        glBufferData(GL_ARRAY_BUFFER, sizeof(mVertices[0]) * mVertices.size(), mVertices.data(),
                     GL_STATIC_DRAW);
        glVertexAttribPointer(positionLocation, 3, GL_FLOAT, GL_FALSE, 0, 0);
        glEnableVertexAttribArray(positionLocation);

        glClearColor(1, 0, 0, 1);
        glClear(GL_COLOR_BUFFER_BIT);
    }

    void readPixels()
    {
        if (mReadPixels.empty())
        {
            mReadPixels.resize(getWindowWidth() * getWindowWidth());
        }

        glReadPixels(0, 0, getWindowWidth(), getWindowHeight(), GL_RGBA, GL_UNSIGNED_BYTE,
                     mReadPixels.data());
        EXPECT_GL_NO_ERROR();
    }

    void verifyPixelAt(int x, int y, const GLColor &expected)
    {
        EXPECT_EQ(mReadPixels[y * getWindowWidth() + x], expected);
    }

    void verifyTriangles()
    {
        readPixels();

        // Check 4 lines accross de triangles to make sure we filled it.
        // Don't check every pixel as it would slow down our tests.
        for (auto x = 0; x < getWindowWidth(); x++)
        {
            verifyPixelAt(x, x, GLColor::green);
        }

        for (auto x = getWindowWidth() / 3, y = 0; x < getWindowWidth(); x++, y++)
        {
            verifyPixelAt(x, y, GLColor::green);
        }

        for (auto x = getWindowWidth() / 2, y = 0; x < getWindowWidth(); x++, y++)
        {
            verifyPixelAt(x, y, GLColor::green);
        }

        for (auto x = (getWindowWidth() / 4) * 3, y = 0; x < getWindowWidth(); x++, y++)
        {
            verifyPixelAt(x, y, GLColor::green);
        }

        // Area outside triangles
        for (auto x = 0; x < getWindowWidth() - 2; x++)
        {
            verifyPixelAt(x, x + 2, GLColor::red);
        }
    }

    const std::vector<Vector3> mVertices = {{0.0f, 0.0f, 0.0f},
                                            {-1.0f, -1.0f, 0.0f},
                                            {0.0f, -1.0f, 0.0f},
                                            {1.0f, -1.0f, 0.0f},
                                            {1.0f, 1.0f, 0.0f}};

    GLBuffer mVertexBuffer;
    GLProgram mProgram;

    std::vector<GLColor> mReadPixels;
};

// Simple triangle fans test.
TEST_P(TriangleFanDrawTest, DrawTriangleFan)
{
    glClear(GL_COLOR_BUFFER_BIT);
    glDrawArrays(GL_TRIANGLE_FAN, 0, static_cast<GLsizei>(mVertices.size()));

    EXPECT_GL_NO_ERROR();

    verifyTriangles();
}

// Triangle fans test with index buffer.
TEST_P(TriangleFanDrawTest, DrawTriangleFanElements)
{
    std::vector<GLubyte> indices = {0, 1, 2, 3, 4};

    GLBuffer indexBuffer;
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, indexBuffer.get());
    glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices[0]) * indices.size(), indices.data(),
                 GL_STATIC_DRAW);

    glClear(GL_COLOR_BUFFER_BIT);
    glDrawElements(GL_TRIANGLE_FAN, static_cast<GLsizei>(indices.size()), GL_UNSIGNED_BYTE, 0);

    EXPECT_GL_NO_ERROR();

    verifyTriangles();
}

// Triangle fans test with primitive restart index at the middle.
TEST_P(TriangleFanDrawTest, DrawTriangleFanPrimitiveRestartAtMiddle)
{
    ANGLE_SKIP_TEST_IF(getClientMajorVersion() < 3);

    std::vector<GLubyte> indices = {0, 1, 2, 3, 0xff, 0, 4, 3};

    GLBuffer indexBuffer;
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, indexBuffer.get());
    glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices[0]) * indices.size(), indices.data(),
                 GL_STATIC_DRAW);
    glEnable(GL_PRIMITIVE_RESTART_FIXED_INDEX);

    glDrawElements(GL_TRIANGLE_FAN, static_cast<GLsizei>(indices.size()), GL_UNSIGNED_BYTE, 0);

    EXPECT_GL_NO_ERROR();

    verifyTriangles();
}

// Triangle fans test with primitive restart at begin.
TEST_P(TriangleFanDrawTest, DrawTriangleFanPrimitiveRestartAtBegin)
{
    ANGLE_SKIP_TEST_IF(getClientMajorVersion() < 3);

    // Primitive restart index is at middle, but we will use draw call which index offset=4.
    std::vector<GLubyte> indices = {0, 1, 2, 3, 0xff, 0, 4, 3};

    GLBuffer indexBuffer;
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, indexBuffer.get());
    glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices[0]) * indices.size(), indices.data(),
                 GL_STATIC_DRAW);
    glEnable(GL_PRIMITIVE_RESTART_FIXED_INDEX);

    glDrawElements(GL_TRIANGLE_FAN, 4, GL_UNSIGNED_BYTE, 0);
    glDrawElements(GL_TRIANGLE_FAN, 4, GL_UNSIGNED_BYTE,
                   reinterpret_cast<void *>(sizeof(indices[0]) * 4));

    EXPECT_GL_NO_ERROR();

    verifyTriangles();
}

// Triangle fans test with primitive restart at end.
TEST_P(TriangleFanDrawTest, DrawTriangleFanPrimitiveRestartAtEnd)
{
    ANGLE_SKIP_TEST_IF(getClientMajorVersion() < 3);

    std::vector<GLubyte> indices = {0, 1, 2, 3, 4, 0xff};

    GLBuffer indexBuffer;
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, indexBuffer.get());
    glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices[0]) * indices.size(), indices.data(),
                 GL_STATIC_DRAW);
    glEnable(GL_PRIMITIVE_RESTART_FIXED_INDEX);

    glDrawElements(GL_TRIANGLE_FAN, static_cast<GLsizei>(indices.size()), GL_UNSIGNED_BYTE, 0);

    EXPECT_GL_NO_ERROR();

    verifyTriangles();
}

// Simple repeated draw and swap test.
TEST_P(SimpleOperationTest, DrawQuadAndSwap)
{
    ANGLE_GL_PROGRAM(program, kBasicVertexShader, kGreenFragmentShader);

    for (int i = 0; i < 8; ++i)
    {
        drawQuad(program.get(), "position", 0.5f, 1.0f, true);
        ASSERT_GL_NO_ERROR();
        EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::green);
        swapBuffers();
    }

    ASSERT_GL_NO_ERROR();
}

// Simple indexed quad test.
TEST_P(SimpleOperationTest, DrawIndexedQuad)
{
    ANGLE_GL_PROGRAM(program, kBasicVertexShader, kGreenFragmentShader);

    drawIndexedQuad(program.get(), "position", 0.5f, 1.0f, true);

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

// Simple repeated indexed draw and swap test.
TEST_P(SimpleOperationTest, DrawIndexedQuadAndSwap)
{
    ANGLE_GL_PROGRAM(program, kBasicVertexShader, kGreenFragmentShader);

    // 32 iterations is an arbitrary number. The more iterations, the more flaky syncronization
    // issues will reproduce consistently.
    for (int i = 0; i < 32; ++i)
    {
        drawIndexedQuad(program.get(), "position", 0.5f, 1.0f, true);
        ASSERT_GL_NO_ERROR();
        EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::green);
        swapBuffers();
    }

    ASSERT_GL_NO_ERROR();
}

// Draw with a fragment uniform.
TEST_P(SimpleOperationTest, DrawQuadWithFragmentUniform)
{
    constexpr char kFS[] =
        "uniform mediump vec4 color;\n"
        "void main()\n"
        "{\n"
        "    gl_FragColor = color;\n"
        "}";
    ANGLE_GL_PROGRAM(program, kBasicVertexShader, kFS);

    GLint location = glGetUniformLocation(program, "color");
    ASSERT_NE(-1, location);

    glUseProgram(program);
    glUniform4f(location, 0.0f, 1.0f, 0.0f, 1.0f);

    drawQuad(program.get(), "position", 0.5f, 1.0f, true);

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

// Draw with a vertex uniform.
TEST_P(SimpleOperationTest, DrawQuadWithVertexUniform)
{
    constexpr char kVS[] =
        "attribute vec3 position;\n"
        "uniform vec4 color;\n"
        "varying vec4 vcolor;\n"
        "void main()\n"
        "{\n"
        "    gl_Position = vec4(position, 1);\n"
        "    vcolor = color;\n"
        "}";
    constexpr char kFS[] =
        "varying mediump vec4 vcolor;\n"
        "void main()\n"
        "{\n"
        "    gl_FragColor = vcolor;\n"
        "}";
    ANGLE_GL_PROGRAM(program, kVS, kFS);

    const GLint location = glGetUniformLocation(program, "color");
    ASSERT_NE(-1, location);

    glUseProgram(program);
    glUniform4f(location, 0.0f, 1.0f, 0.0f, 1.0f);

    drawQuad(program.get(), "position", 0.5f, 1.0f, true);

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

// Draw with two uniforms.
TEST_P(SimpleOperationTest, DrawQuadWithTwoUniforms)
{
    constexpr char kVS[] =
        "attribute vec3 position;\n"
        "uniform vec4 color1;\n"
        "varying vec4 vcolor1;\n"
        "void main()\n"
        "{\n"
        "    gl_Position = vec4(position, 1);\n"
        "    vcolor1 = color1;\n"
        "}";
    constexpr char kFS[] =
        "uniform mediump vec4 color2;\n"
        "varying mediump vec4 vcolor1;\n"
        "void main()\n"
        "{\n"
        "    gl_FragColor = vcolor1 + color2;\n"
        "}";
    ANGLE_GL_PROGRAM(program, kVS, kFS);

    const GLint location1 = glGetUniformLocation(program, "color1");
    ASSERT_NE(-1, location1);

    const GLint location2 = glGetUniformLocation(program, "color2");
    ASSERT_NE(-1, location2);

    glUseProgram(program);
    glUniform4f(location1, 0.0f, 1.0f, 0.0f, 1.0f);
    glUniform4f(location2, 1.0f, 0.0f, 0.0f, 1.0f);

    drawQuad(program.get(), "position", 0.5f, 1.0f, true);

    ASSERT_GL_NO_ERROR();
    EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::yellow);
}

// Tests a shader program with more than one vertex attribute, with vertex buffers.
TEST_P(SimpleOperationTest, ThreeVertexAttributes)
{
    constexpr char kVS[] = R"(attribute vec2 position;
attribute vec4 color1;
attribute vec4 color2;
varying vec4 color;
void main()
{
    gl_Position = vec4(position, 0, 1);
    color = color1 + color2;
})";

    constexpr char kFS[] = R"(precision mediump float;
varying vec4 color;
void main()
{
    gl_FragColor = color;
}
)";

    ANGLE_GL_PROGRAM(program, kVS, kFS);

    glUseProgram(program);

    const GLint color1Loc = glGetAttribLocation(program, "color1");
    const GLint color2Loc = glGetAttribLocation(program, "color2");
    ASSERT_NE(-1, color1Loc);
    ASSERT_NE(-1, color2Loc);

    const auto &indices = GetQuadIndices();

    // Make colored corners with red == x or 1 -x , and green = y or 1 - y.

    std::array<GLColor, 4> baseColors1 = {
        {GLColor::black, GLColor::red, GLColor::green, GLColor::yellow}};
    std::array<GLColor, 4> baseColors2 = {
        {GLColor::yellow, GLColor::green, GLColor::red, GLColor::black}};

    std::vector<GLColor> colors1;
    std::vector<GLColor> colors2;

    for (GLushort index : indices)
    {
        colors1.push_back(baseColors1[index]);
        colors2.push_back(baseColors2[index]);
    }

    GLBuffer color1Buffer;
    glBindBuffer(GL_ARRAY_BUFFER, color1Buffer);
    glBufferData(GL_ARRAY_BUFFER, colors1.size() * sizeof(GLColor), colors1.data(), GL_STATIC_DRAW);
    glVertexAttribPointer(color1Loc, 4, GL_UNSIGNED_BYTE, GL_TRUE, 0, nullptr);
    glEnableVertexAttribArray(color1Loc);

    GLBuffer color2Buffer;
    glBindBuffer(GL_ARRAY_BUFFER, color2Buffer);
    glBufferData(GL_ARRAY_BUFFER, colors2.size() * sizeof(GLColor), colors2.data(), GL_STATIC_DRAW);
    glVertexAttribPointer(color2Loc, 4, GL_UNSIGNED_BYTE, GL_TRUE, 0, nullptr);
    glEnableVertexAttribArray(color2Loc);

    // Draw a non-indexed quad with all vertex buffers. Should draw yellow to the entire window.
    drawQuad(program, "position", 0.5f, 1.0f, true);
    ASSERT_GL_NO_ERROR();
    EXPECT_PIXEL_RECT_EQ(0, 0, getWindowWidth(), getWindowHeight(), GLColor::yellow);
}

// Creates a 2D texture, no other operations.
TEST_P(SimpleOperationTest, CreateTexture2DNoData)
{
    GLTexture texture;
    glBindTexture(GL_TEXTURE_2D, texture);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 16, 16, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);
    ASSERT_GL_NO_ERROR();
}

// Creates a 2D texture, no other operations.
TEST_P(SimpleOperationTest, CreateTexture2DWithData)
{
    std::vector<GLColor> colors(16 * 16, GLColor::red);

    GLTexture texture;
    glBindTexture(GL_TEXTURE_2D, texture);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 16, 16, 0, GL_RGBA, GL_UNSIGNED_BYTE, colors.data());
    ASSERT_GL_NO_ERROR();
}

// Creates a cube texture, no other operations.
TEST_P(SimpleOperationTest, CreateTextureCubeNoData)
{
    GLTexture texture;
    glBindTexture(GL_TEXTURE_CUBE_MAP, texture);
    for (GLenum cubeFace : kCubeFaces)
    {
        glTexImage2D(cubeFace, 0, GL_RGBA, 16, 16, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);
    }
    ASSERT_GL_NO_ERROR();
}

// Creates a cube texture, no other operations.
TEST_P(SimpleOperationTest, CreateTextureCubeWithData)
{
    std::vector<GLColor> colors(16 * 16, GLColor::red);

    GLTexture texture;
    glBindTexture(GL_TEXTURE_CUBE_MAP, texture);
    for (GLenum cubeFace : kCubeFaces)
    {
        glTexImage2D(cubeFace, 0, GL_RGBA, 16, 16, 0, GL_RGBA, GL_UNSIGNED_BYTE, colors.data());
    }
    ASSERT_GL_NO_ERROR();
}

// Creates a program with a texture.
TEST_P(SimpleOperationTest, LinkProgramWithTexture)
{
    ASSERT_NE(0u, get2DTexturedQuadProgram());
    ASSERT_GL_NO_ERROR();
}

// Creates a program with a 2D texture and renders with it.
TEST_P(SimpleOperationTest, DrawWith2DTexture)
{
    std::array<GLColor, 4> colors = {
        {GLColor::red, GLColor::green, GLColor::blue, GLColor::yellow}};

    GLTexture tex;
    glBindTexture(GL_TEXTURE_2D, tex);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 2, 2, 0, GL_RGBA, GL_UNSIGNED_BYTE, colors.data());
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);

    draw2DTexturedQuad(0.5f, 1.0f, true);
    ASSERT_GL_NO_ERROR();

    int w = getWindowWidth() - 2;
    int h = getWindowHeight() - 2;

    EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::red);
    EXPECT_PIXEL_COLOR_EQ(w, 0, GLColor::green);
    EXPECT_PIXEL_COLOR_EQ(0, h, GLColor::blue);
    EXPECT_PIXEL_COLOR_EQ(w, h, GLColor::yellow);
}

template <typename T>
void SimpleOperationTest::testDrawElementsLineLoopUsingClientSideMemory(GLenum indexType,
                                                                        int windowWidth,
                                                                        int windowHeight)
{
    ANGLE_GL_PROGRAM(program, kBasicVertexShader, kGreenFragmentShader);
    glUseProgram(program);

    // We expect to draw a square with these 4 vertices with a drawArray call.
    std::vector<Vector3> vertices;
    CreatePixelCenterWindowCoords({{32, 96}, {32, 32}, {96, 32}, {96, 96}}, windowWidth,
                                  windowHeight, &vertices);

    // If we use these indices to draw however, we should be drawing an hourglass.
    std::vector<T> indices{3, 2, 1, 0};

    GLint positionLocation = glGetAttribLocation(program, "position");
    ASSERT_NE(-1, positionLocation);

    GLBuffer vertexBuffer;
    glBindBuffer(GL_ARRAY_BUFFER, vertexBuffer);
    glBufferData(GL_ARRAY_BUFFER, sizeof(vertices[0]) * vertices.size(), vertices.data(),
                 GL_STATIC_DRAW);

    glVertexAttribPointer(positionLocation, 3, GL_FLOAT, GL_FALSE, 0, nullptr);
    glEnableVertexAttribArray(positionLocation);
    glClear(GL_COLOR_BUFFER_BIT);
    glDrawElements(GL_LINE_LOOP, 4, indexType, indices.data());
    glDisableVertexAttribArray(positionLocation);

    ASSERT_GL_NO_ERROR();

    int quarterWidth  = windowWidth / 4;
    int quarterHeight = windowHeight / 4;

    // Bottom left
    EXPECT_PIXEL_COLOR_EQ(quarterWidth, quarterHeight, GLColor::green);

    // Top left
    EXPECT_PIXEL_COLOR_EQ(quarterWidth, (quarterHeight * 3), GLColor::green);

    // Top right
    EXPECT_PIXEL_COLOR_EQ((quarterWidth * 3), (quarterHeight * 3) - 1, GLColor::green);

    // Verify line is closed between the 2 last vertices
    EXPECT_PIXEL_COLOR_EQ((quarterWidth * 2), quarterHeight, GLColor::green);
}

// Draw a line loop using a drawElement call and client side memory.
TEST_P(SimpleOperationTest, DrawElementsLineLoopUsingUShortClientSideMemory)
{
    testDrawElementsLineLoopUsingClientSideMemory<GLushort>(GL_UNSIGNED_SHORT, getWindowWidth(),
                                                            getWindowHeight());
}

// Draw a line loop using a drawElement call and client side memory.
TEST_P(SimpleOperationTest, DrawElementsLineLoopUsingUByteClientSideMemory)
{
    testDrawElementsLineLoopUsingClientSideMemory<GLubyte>(GL_UNSIGNED_BYTE, getWindowWidth(),
                                                           getWindowHeight());
}

// Creates a program with a cube texture and renders with it.
TEST_P(SimpleOperationTest, DrawWithCubeTexture)
{
    std::array<Vector2, 6 * 4> positions = {{
        {0, 1}, {1, 1}, {1, 2}, {0, 2} /* first face */,
        {1, 0}, {2, 0}, {2, 1}, {1, 1} /* second face */,
        {1, 1}, {2, 1}, {2, 2}, {1, 2} /* third face */,
        {1, 2}, {2, 2}, {2, 3}, {1, 3} /* fourth face */,
        {2, 1}, {3, 1}, {3, 2}, {2, 2} /* fifth face */,
        {3, 1}, {4, 1}, {4, 2}, {3, 2} /* sixth face */,
    }};

    const float w4 = 1.0f / 4.0f;
    const float h3 = 1.0f / 3.0f;

    // This draws a "T" shape based on the four faces of the cube. The window is divided into four
    // tiles horizontally and three tiles vertically (hence the w4 and h3 variable naming).
    for (Vector2 &pos : positions)
    {
        pos.data()[0] = pos.data()[0] * w4 * 2.0f - 1.0f;
        pos.data()[1] = pos.data()[1] * h3 * 2.0f - 1.0f;
    }

    const Vector3 posX(1, 0, 0);
    const Vector3 negX(-1, 0, 0);
    const Vector3 posY(0, 1, 0);
    const Vector3 negY(0, -1, 0);
    const Vector3 posZ(0, 0, 1);
    const Vector3 negZ(0, 0, -1);

    std::array<Vector3, 6 * 4> coords = {{
        posX, posX, posX, posX /* first face */, negX, negX, negX, negX /* second face */,
        posY, posY, posY, posY /* third face */, negY, negY, negY, negY /* fourth face */,
        posZ, posZ, posZ, posZ /* fifth face */, negZ, negZ, negZ, negZ /* sixth face */,
    }};

    const std::array<std::array<GLColor, 4>, 6> colors = {{
        {GLColor::red, GLColor::red, GLColor::red, GLColor::red},
        {GLColor::green, GLColor::green, GLColor::green, GLColor::green},
        {GLColor::blue, GLColor::blue, GLColor::blue, GLColor::blue},
        {GLColor::yellow, GLColor::yellow, GLColor::yellow, GLColor::yellow},
        {GLColor::cyan, GLColor::cyan, GLColor::cyan, GLColor::cyan},
        {GLColor::magenta, GLColor::magenta, GLColor::magenta, GLColor::magenta},
    }};

    GLTexture texture;
    glBindTexture(GL_TEXTURE_CUBE_MAP, texture);

    for (size_t faceIndex = 0; faceIndex < kCubeFaces.size(); ++faceIndex)
    {
        glTexImage2D(kCubeFaces[faceIndex], 0, GL_RGBA, 2, 2, 0, GL_RGBA, GL_UNSIGNED_BYTE,
                     colors[faceIndex].data());
    }
    glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
    glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MAG_FILTER, GL_NEAREST);

    constexpr char kVertexShader[] = R"(attribute vec2 pos;
attribute vec3 coord;
varying vec3 texCoord;
void main()
{
    gl_Position = vec4(pos, 0, 1);
    texCoord = coord;
})";

    constexpr char kFragmentShader[] = R"(precision mediump float;
varying vec3 texCoord;
uniform samplerCube tex;
void main()
{
    gl_FragColor = textureCube(tex, texCoord);
})";

    ANGLE_GL_PROGRAM(program, kVertexShader, kFragmentShader);
    GLint samplerLoc = glGetUniformLocation(program, "tex");
    ASSERT_EQ(samplerLoc, 0);

    glUseProgram(program);

    GLint posLoc = glGetAttribLocation(program, "pos");
    ASSERT_NE(-1, posLoc);

    GLint coordLoc = glGetAttribLocation(program, "coord");
    ASSERT_NE(-1, coordLoc);

    GLBuffer posBuffer;
    glBindBuffer(GL_ARRAY_BUFFER, posBuffer);
    glBufferData(GL_ARRAY_BUFFER, positions.size() * sizeof(Vector2), positions.data(),
                 GL_STATIC_DRAW);
    glVertexAttribPointer(posLoc, 2, GL_FLOAT, GL_FALSE, 0, nullptr);
    glEnableVertexAttribArray(posLoc);

    GLBuffer coordBuffer;
    glBindBuffer(GL_ARRAY_BUFFER, coordBuffer);
    glBufferData(GL_ARRAY_BUFFER, coords.size() * sizeof(Vector3), coords.data(), GL_STATIC_DRAW);
    glVertexAttribPointer(coordLoc, 3, GL_FLOAT, GL_FALSE, 0, nullptr);
    glEnableVertexAttribArray(coordLoc);

    auto quadIndices = GetQuadIndices();
    std::array<GLushort, 6 * 6> kElementsData;
    for (GLushort quadIndex = 0; quadIndex < 6; ++quadIndex)
    {
        for (GLushort elementIndex = 0; elementIndex < 6; ++elementIndex)
        {
            kElementsData[quadIndex * 6 + elementIndex] = quadIndices[elementIndex] + 4 * quadIndex;
        }
    }

    glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
    glClear(GL_COLOR_BUFFER_BIT);

    GLBuffer elementBuffer;
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, elementBuffer);
    glBufferData(GL_ELEMENT_ARRAY_BUFFER, kElementsData.size() * sizeof(GLushort),
                 kElementsData.data(), GL_STATIC_DRAW);
    glDrawElements(GL_TRIANGLES, static_cast<GLsizei>(kElementsData.size()), GL_UNSIGNED_SHORT,
                   nullptr);
    ASSERT_GL_NO_ERROR();

    for (int faceIndex = 0; faceIndex < 6; ++faceIndex)
    {
        int index      = faceIndex * 4;
        Vector2 center = (positions[index] + positions[index + 1] + positions[index + 2] +
                          positions[index + 3]) /
                         4.0f;
        center *= 0.5f;
        center += Vector2(0.5f);
        center *= Vector2(getWindowWidth(), getWindowHeight());
        EXPECT_PIXEL_COLOR_EQ(static_cast<GLint>(center.x()), static_cast<GLint>(center.y()),
                              colors[faceIndex][0]);
    }
}

// Tests rendering to a user framebuffer.
TEST_P(SimpleOperationTest, RenderToTexture)
{
    constexpr int kSize = 16;

    GLTexture texture;
    glBindTexture(GL_TEXTURE_2D, texture);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, kSize, kSize, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);
    ASSERT_GL_NO_ERROR();

    GLFramebuffer framebuffer;
    glBindFramebuffer(GL_FRAMEBUFFER, framebuffer);
    glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, texture, 0);
    ASSERT_GL_NO_ERROR();
    ASSERT_GLENUM_EQ(GL_FRAMEBUFFER_COMPLETE, glCheckFramebufferStatus(GL_FRAMEBUFFER));

    glViewport(0, 0, kSize, kSize);

    ANGLE_GL_PROGRAM(program, kBasicVertexShader, kGreenFragmentShader);
    drawQuad(program, "position", 0.5f, 1.0f, true);
    ASSERT_GL_NO_ERROR();
    EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::green);
}

// Create a simple basic Renderbuffer.
TEST_P(SimpleOperationTest, CreateRenderbuffer)
{
    GLRenderbuffer renderbuffer;
    glBindRenderbuffer(GL_RENDERBUFFER, renderbuffer);
    glRenderbufferStorage(GL_RENDERBUFFER, GL_RGBA8, 16, 16);
    ASSERT_GL_NO_ERROR();
}

// Render to a simple color Renderbuffer.
TEST_P(SimpleOperationTest, RenderbufferAttachment)
{
    constexpr int kSize = 16;

    GLRenderbuffer renderbuffer;
    glBindRenderbuffer(GL_RENDERBUFFER, renderbuffer);
    glRenderbufferStorage(GL_RENDERBUFFER, GL_RGBA8, kSize, kSize);

    GLFramebuffer framebuffer;
    glBindFramebuffer(GL_FRAMEBUFFER, framebuffer);
    glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_RENDERBUFFER, renderbuffer);
    ASSERT_GL_NO_ERROR();
    ASSERT_GLENUM_EQ(GL_FRAMEBUFFER_COMPLETE, glCheckFramebufferStatus(GL_FRAMEBUFFER));

    glViewport(0, 0, kSize, kSize);

    ANGLE_GL_PROGRAM(program, kBasicVertexShader, kGreenFragmentShader);
    drawQuad(program, "position", 0.5f, 1.0f, true);
    ASSERT_GL_NO_ERROR();
    EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::green);
}

// Tests that using desktop GL_QUADS/GL_POLYGONS enums generate the correct error.
TEST_P(SimpleOperationTest, PrimitiveModeNegativeTest)
{
    // Draw a correct quad.
    ANGLE_GL_PROGRAM(program, kBasicVertexShader, kGreenFragmentShader);
    glUseProgram(program);

    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);

    // Tests that TRIANGLES works.
    glDrawArrays(GL_TRIANGLES, 0, 6);
    ASSERT_GL_NO_ERROR();
    EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::green);

    // Tests that specific invalid enums don't work.
    glDrawArrays(static_cast<GLenum>(7), 0, 6);
    EXPECT_GL_ERROR(GL_INVALID_ENUM);

    glDrawArrays(static_cast<GLenum>(8), 0, 6);
    EXPECT_GL_ERROR(GL_INVALID_ENUM);

    glDrawArrays(static_cast<GLenum>(9), 0, 6);
    EXPECT_GL_ERROR(GL_INVALID_ENUM);
}

// Verify we don't crash when attempting to draw using GL_TRIANGLES without a program bound.
TEST_P(SimpleOperationTest31, DrawTrianglesWithoutProgramBound)
{
    glDrawArrays(GL_TRIANGLES, 0, 6);
}

// Verify we don't crash when attempting to draw using GL_LINE_STRIP_ADJACENCY without a program
// bound.
TEST_P(SimpleOperationTest31, DrawLineStripAdjacencyWithoutProgramBound)
{
    ANGLE_SKIP_TEST_IF(!IsGLExtensionEnabled("GL_EXT_geometry_shader"));

    glDrawArrays(GL_LINE_STRIP_ADJACENCY, 0, 10);
}

// Verify instanceCount == 0 is no-op
TEST_P(SimpleOperationTest, DrawArraysZeroInstanceCountIsNoOp)
{
    ANGLE_SKIP_TEST_IF(!IsGLExtensionEnabled("GL_ANGLE_instanced_arrays"));

    // Draw a correct green quad.
    ANGLE_GL_PROGRAM(program, kBasicVertexShader, kGreenFragmentShader);
    glUseProgram(program);

    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);

    // If nothing is drawn it should be red
    glClearColor(1.0, 0.0, 0.0, 1.0);

    {
        // Non-instanced draw should draw
        glClear(GL_COLOR_BUFFER_BIT);
        glDrawArrays(GL_TRIANGLES, 0, 6);
        ASSERT_GL_NO_ERROR();
        EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::green);
    }
    {
        // instanceCount == 0 should be no-op
        glClear(GL_COLOR_BUFFER_BIT);
        glDrawArraysInstancedANGLE(GL_TRIANGLES, 0, 6, 0);
        ASSERT_GL_NO_ERROR();
        EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::red);
    }
    {
        // instanceCount > 0 should draw
        glClear(GL_COLOR_BUFFER_BIT);
        glDrawArraysInstancedANGLE(GL_TRIANGLES, 0, 6, 1);
        ASSERT_GL_NO_ERROR();
        EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::green);
    }
}

// Verify instanceCount == 0 is no-op
TEST_P(SimpleOperationTest, DrawElementsZeroInstanceCountIsNoOp)
{
    ANGLE_SKIP_TEST_IF(!IsGLExtensionEnabled("GL_ANGLE_instanced_arrays"));

    // Draw a correct green quad.
    ANGLE_GL_PROGRAM(program, kBasicVertexShader, kGreenFragmentShader);
    glUseProgram(program);

    GLint positionLocation = glGetAttribLocation(program, "position");
    ASSERT_NE(-1, positionLocation);

    setupIndexedQuadVertexBuffer(0.5f, 1.0f);
    glVertexAttribPointer(positionLocation, 3, GL_FLOAT, GL_FALSE, 0, 0);
    glEnableVertexAttribArray(positionLocation);

    setupIndexedQuadIndexBuffer();

    // If nothing is drawn it should be red
    glClearColor(1.0, 0.0, 0.0, 1.0);

    {
        // Non-instanced draw should draw
        glClear(GL_COLOR_BUFFER_BIT);
        glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_SHORT, nullptr);
        ASSERT_GL_NO_ERROR();
        EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::green);
    }
    {
        // instanceCount == 0 should be no-op
        glClear(GL_COLOR_BUFFER_BIT);
        glDrawElementsInstancedANGLE(GL_TRIANGLES, 6, GL_UNSIGNED_SHORT, nullptr, 0);
        ASSERT_GL_NO_ERROR();
        EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::red);
    }
    {
        // instanceCount > 0 should draw
        glClear(GL_COLOR_BUFFER_BIT);
        glDrawElementsInstancedANGLE(GL_TRIANGLES, 6, GL_UNSIGNED_SHORT, nullptr, 1);
        ASSERT_GL_NO_ERROR();
        EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::green);
    }
}

// Use this to select which configurations (e.g. which renderer, which GLES major version) these
// tests should be run against.
ANGLE_INSTANTIATE_TEST_ES2_AND_ES3_AND(
    SimpleOperationTest,
    WithMetalForcedBufferGPUStorage(ES3_METAL()),
    WithMetalMemoryBarrierAndCheapRenderPass(ES3_METAL(),
                                             /* hasBarrier */ false,
                                             /* cheapRenderPass */ false),
    WithNoVulkanViewportFlip(ES2_VULKAN()));

ANGLE_INSTANTIATE_TEST_ES2_AND_ES3_AND(
    TriangleFanDrawTest,
    WithMetalForcedBufferGPUStorage(ES3_METAL()),
    WithMetalMemoryBarrierAndCheapRenderPass(ES3_METAL(),
                                             /* hasBarrier */ false,
                                             /* cheapRenderPass */ false),
    WithNoVulkanViewportFlip(ES2_VULKAN()));

ANGLE_INSTANTIATE_TEST_ES2_AND_ES3_AND_ES31(SimpleOperationTest31);

}  // namespace