src/tests/gl_tests/MultisampledRenderToTextureTest.cpp

//
// Copyright 2019 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.
//

// MultisampledRenderToTextureTest: Tests of EXT_multisampled_render_to_texture extension

#include "test_utils/ANGLETest.h"
#include "test_utils/gl_raii.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);
})";

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

constexpr char kVS[] =
    "precision highp float;\n"
    "attribute vec4 position;\n"
    "varying vec2 texcoord;\n"
    "\n"
    "void main()\n"
    "{\n"
    "    gl_Position = position;\n"
    "    texcoord = (position.xy * 0.5) + 0.5;\n"
    "}\n";

constexpr char kFS[] =
    "precision highp float;\n"
    "uniform sampler2D tex;\n"
    "varying vec2 texcoord;\n"
    "\n"
    "void main()\n"
    "{\n"
    "    gl_FragColor = texture2D(tex, texcoord);\n"
    "}\n";

class MultisampledRenderToTextureTest : public ANGLETest
{
  protected:
    MultisampledRenderToTextureTest()
    {
        setWindowWidth(64);
        setWindowHeight(64);
        setConfigRedBits(8);
        setConfigGreenBits(8);
        setConfigBlueBits(8);
        setConfigAlphaBits(8);
    }

    void testSetUp() override {}

    void testTearDown() override {}

    void setupCopyTexProgram()
    {
        mCopyTextureProgram.makeRaster(kVS, kFS);
        ASSERT_GL_TRUE(mCopyTextureProgram.valid());

        mCopyTextureUniformLocation = glGetUniformLocation(mCopyTextureProgram, "tex");

        ASSERT_GL_NO_ERROR();
    }

    void verifyResults(GLuint texture,
                       GLubyte data[4],
                       GLint fboSize,
                       GLint xs,
                       GLint ys,
                       GLint xe,
                       GLint ye)
    {
        glViewport(0, 0, fboSize, fboSize);

        glBindFramebuffer(GL_FRAMEBUFFER, 0);

        // Draw a quad with the target texture
        glUseProgram(mCopyTextureProgram);
        glBindTexture(GL_TEXTURE_2D, texture);
        glUniform1i(mCopyTextureUniformLocation, 0);

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

        // Expect that the rendered quad has the same color as the source texture
        EXPECT_PIXEL_NEAR(xs, ys, data[0], data[1], data[2], data[3], 1.0);
        EXPECT_PIXEL_NEAR(xs, ye - 1, data[0], data[1], data[2], data[3], 1.0);
        EXPECT_PIXEL_NEAR(xe - 1, ys, data[0], data[1], data[2], data[3], 1.0);
        EXPECT_PIXEL_NEAR(xe - 1, ye - 1, data[0], data[1], data[2], data[3], 1.0);
        EXPECT_PIXEL_NEAR((xs + xe) / 2, (ys + ye) / 2, data[0], data[1], data[2], data[3], 1.0);
    }

    void clearAndDrawQuad(GLuint program, GLsizei viewportWidth, GLsizei viewportHeight)
    {
        glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
        glClear(GL_COLOR_BUFFER_BIT);
        glViewport(0, 0, viewportWidth, viewportHeight);
        ASSERT_GL_NO_ERROR();

        drawQuad(program, "position", 0.0f);
    }

    GLProgram mCopyTextureProgram;
    GLint mCopyTextureUniformLocation = -1;
};

class MultisampledRenderToTextureES3Test : public MultisampledRenderToTextureTest
{};

// Checking against invalid parameters for RenderbufferStorageMultisampleEXT.
TEST_P(MultisampledRenderToTextureTest, RenderbufferParameterCheck)
{
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));

    GLRenderbuffer renderbuffer;
    glBindRenderbuffer(GL_RENDERBUFFER, renderbuffer);

    // Positive test case
    glRenderbufferStorageMultisampleEXT(GL_RENDERBUFFER, 4, GL_DEPTH_COMPONENT16, 64, 64);
    ASSERT_GL_NO_ERROR();

    GLint samples;
    glGetIntegerv(GL_MAX_SAMPLES_EXT, &samples);
    ASSERT_GL_NO_ERROR();
    EXPECT_GE(samples, 1);

    // Samples too large
    glRenderbufferStorageMultisampleEXT(GL_RENDERBUFFER, samples + 1, GL_DEPTH_COMPONENT16, 64, 64);
    ASSERT_GL_ERROR(GL_INVALID_VALUE);

    // Renderbuffer size too large
    GLint maxSize;
    glGetIntegerv(GL_MAX_RENDERBUFFER_SIZE, &maxSize);
    glRenderbufferStorageMultisampleEXT(GL_RENDERBUFFER, 2, GL_DEPTH_COMPONENT16, maxSize + 1,
                                        maxSize);
    ASSERT_GL_ERROR(GL_INVALID_VALUE);
    glRenderbufferStorageMultisampleEXT(GL_RENDERBUFFER, 2, GL_DEPTH_COMPONENT16, maxSize,
                                        maxSize + 1);
    ASSERT_GL_ERROR(GL_INVALID_VALUE);

    // Retrieving samples
    glRenderbufferStorageMultisampleEXT(GL_RENDERBUFFER, 4, GL_DEPTH_COMPONENT16, 64, 64);
    GLint param = 0;
    glGetRenderbufferParameteriv(GL_RENDERBUFFER, GL_RENDERBUFFER_SAMPLES_EXT, &param);
    // GE because samples may vary base on implementation. Spec says "the resulting value for
    // RENDERBUFFER_SAMPLES_EXT is guaranteed to be greater than or equal to samples and no more
    // than the next larger sample count supported by the implementation"
    EXPECT_GE(param, 4);
}

// Checking against invalid parameters for FramebufferTexture2DMultisampleEXT.
TEST_P(MultisampledRenderToTextureTest, Texture2DParameterCheck)
{
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));

    GLTexture texture;
    glBindTexture(GL_TEXTURE_2D, texture);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 64, 64, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);
    ASSERT_GL_NO_ERROR();

    GLFramebuffer fbo;
    glBindFramebuffer(GL_FRAMEBUFFER, fbo);
    // Positive test case
    glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D,
                                         texture, 0, 4);
    ASSERT_GL_NO_ERROR();

    // Attachment not COLOR_ATTACHMENT0
    glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT1, GL_TEXTURE_2D,
                                         texture, 0, 4);
    ASSERT_GL_ERROR(GL_INVALID_ENUM);

    // Target not framebuffer
    glFramebufferTexture2DMultisampleEXT(GL_RENDERBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D,
                                         texture, 0, 4);
    ASSERT_GL_ERROR(GL_INVALID_ENUM);

    GLint samples;
    glGetIntegerv(GL_MAX_SAMPLES_EXT, &samples);
    ASSERT_GL_NO_ERROR();
    EXPECT_GE(samples, 1);

    // Samples too large
    glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D,
                                         texture, 0, samples + 1);
    ASSERT_GL_ERROR(GL_INVALID_VALUE);

    // Retrieving samples
    glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D,
                                         texture, 0, 4);
    GLint param = 0;
    glGetFramebufferAttachmentParameteriv(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,
                                          GL_FRAMEBUFFER_ATTACHMENT_TEXTURE_SAMPLES_EXT, &param);
    // GE because samples may vary base on implementation. Spec says "the resulting value for
    // TEXTURE_SAMPLES_EXT is guaranteed to be greater than or equal to samples and no more than the
    // next larger sample count supported by the implementation"
    EXPECT_GE(param, 4);
}

// Checking against invalid parameters for FramebufferTexture2DMultisampleEXT (cubemap).
TEST_P(MultisampledRenderToTextureTest, TextureCubeMapParameterCheck)
{
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));

    GLTexture texture;
    glBindTexture(GL_TEXTURE_CUBE_MAP, texture);
    for (GLenum face = 0; face < 6; face++)
    {
        glTexImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_X + face, 0, GL_RGBA, 64, 64, 0, GL_RGBA,
                     GL_UNSIGNED_BYTE, nullptr);
        ASSERT_GL_NO_ERROR();
    }

    GLint samples;
    glGetIntegerv(GL_MAX_SAMPLES_EXT, &samples);
    ASSERT_GL_NO_ERROR();
    EXPECT_GE(samples, 1);

    GLFramebuffer FBO;
    glBindFramebuffer(GL_FRAMEBUFFER, FBO);
    for (GLenum face = 0; face < 6; face++)
    {
        // Positive test case
        glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,
                                             GL_TEXTURE_CUBE_MAP_POSITIVE_X + face, texture, 0, 4);
        ASSERT_GL_NO_ERROR();

        // Attachment not COLOR_ATTACHMENT0
        glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT1,
                                             GL_TEXTURE_CUBE_MAP_POSITIVE_X + face, texture, 0, 4);
        ASSERT_GL_ERROR(GL_INVALID_ENUM);

        // Target not framebuffer
        glFramebufferTexture2DMultisampleEXT(GL_RENDERBUFFER, GL_COLOR_ATTACHMENT0,
                                             GL_TEXTURE_CUBE_MAP_POSITIVE_X + face, texture, 0, 4);
        ASSERT_GL_ERROR(GL_INVALID_ENUM);

        // Samples too large
        glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,
                                             GL_TEXTURE_CUBE_MAP_POSITIVE_X + face, texture, 0,
                                             samples + 1);
        ASSERT_GL_ERROR(GL_INVALID_VALUE);

        // Retrieving samples
        glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,
                                             GL_TEXTURE_CUBE_MAP_POSITIVE_X + face, texture, 0, 4);
        GLint param = 0;
        glGetFramebufferAttachmentParameteriv(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,
                                              GL_FRAMEBUFFER_ATTACHMENT_TEXTURE_SAMPLES_EXT,
                                              &param);
        // GE because samples may vary base on implementation. Spec says "the resulting value for
        // TEXTURE_SAMPLES_EXT is guaranteed to be greater than or equal to samples and no more than
        // the next larger sample count supported by the implementation"
        EXPECT_GE(param, 4);
    }
}

// Checking for framebuffer completeness using extension methods.
TEST_P(MultisampledRenderToTextureTest, FramebufferCompleteness)
{
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));

    // Checking that Renderbuffer and texture2d having different number of samples results
    // in a FRAMEBUFFER_INCOMPLETE_MULTISAMPLE
    GLTexture texture;
    glBindTexture(GL_TEXTURE_2D, texture);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 64, 64, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);
    ASSERT_GL_NO_ERROR();

    GLFramebuffer FBO;
    glBindFramebuffer(GL_FRAMEBUFFER, FBO);
    glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D,
                                         texture, 0, 4);
    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);

    GLRenderbuffer renderbuffer;
    glBindRenderbuffer(GL_RENDERBUFFER, renderbuffer);
    glRenderbufferStorageMultisampleEXT(GL_RENDERBUFFER, 8, GL_DEPTH_COMPONENT16, 64, 64);
    ASSERT_GL_NO_ERROR();
    glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, renderbuffer);
    EXPECT_GLENUM_EQ(GL_FRAMEBUFFER_INCOMPLETE_MULTISAMPLE,
                     glCheckFramebufferStatus(GL_FRAMEBUFFER));
}

// Draw test with color attachment only.
TEST_P(MultisampledRenderToTextureTest, 2DColorAttachmentMultisampleDrawTest)
{
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));
    // Set up texture and bind to FBO
    GLsizei size = 6;
    GLTexture texture;
    glBindTexture(GL_TEXTURE_2D, texture);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, size, size, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);
    ASSERT_GL_NO_ERROR();

    GLFramebuffer FBO;
    glBindFramebuffer(GL_FRAMEBUFFER, FBO);
    glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D,
                                         texture, 0, 4);
    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);

    // Set viewport and clear to black
    glViewport(0, 0, size, size);
    glClearColor(0.0, 0.0, 0.0, 1.0);
    glClear(GL_COLOR_BUFFER_BIT);

    // Set up Green square program
    ANGLE_GL_PROGRAM(program, kBasicVertexShader, kGreenFragmentShader);
    glUseProgram(program);
    GLint positionLocation = glGetAttribLocation(program, "position");
    ASSERT_NE(-1, positionLocation);

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

    // Draw green square
    glDrawArrays(GL_TRIANGLES, 0, 6);
    ASSERT_GL_NO_ERROR();

    EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::black);
    EXPECT_PIXEL_COLOR_EQ(size / 2, size / 2, GLColor::green);

    // Set up Red square program
    ANGLE_GL_PROGRAM(program2, kBasicVertexShader, kRedFragmentShader);
    glUseProgram(program2);
    GLint positionLocation2 = glGetAttribLocation(program2, "position");
    ASSERT_NE(-1, positionLocation2);

    setupQuadVertexBuffer(0.5f, 0.75f);
    glVertexAttribPointer(positionLocation2, 3, GL_FLOAT, GL_FALSE, 0, 0);

    // Draw red square
    glDrawArrays(GL_TRIANGLES, 0, 6);
    ASSERT_GL_NO_ERROR();

    EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::black);
    EXPECT_PIXEL_COLOR_EQ(size / 2, size / 2, GLColor::red);

    glDisableVertexAttribArray(0);
    glBindBuffer(GL_ARRAY_BUFFER, 0);
}

// Draw test using both color and depth attachments.
TEST_P(MultisampledRenderToTextureTest, 2DColorDepthMultisampleDrawTest)
{
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));
    GLsizei size = 6;
    // create complete framebuffer with depth buffer
    GLTexture texture;
    glBindTexture(GL_TEXTURE_2D, texture);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, size, size, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);
    ASSERT_GL_NO_ERROR();

    GLFramebuffer FBO;
    glBindFramebuffer(GL_FRAMEBUFFER, FBO);
    glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D,
                                         texture, 0, 4);

    GLRenderbuffer renderbuffer;
    glBindRenderbuffer(GL_RENDERBUFFER, renderbuffer);
    glRenderbufferStorageMultisampleEXT(GL_RENDERBUFFER, 4, GL_DEPTH_COMPONENT16, size, size);
    ASSERT_GL_NO_ERROR();
    glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, renderbuffer);
    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);

    // Set viewport and clear framebuffer
    glViewport(0, 0, size, size);
    glClearColor(0.0, 0.0, 0.0, 1.0);
    glClearDepthf(0.5f);
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    // Draw first green square
    ANGLE_GL_PROGRAM(program, kBasicVertexShader, kGreenFragmentShader);
    glEnable(GL_DEPTH_TEST);
    glDepthFunc(GL_GREATER);
    glUseProgram(program);
    GLint positionLocation = glGetAttribLocation(program, "position");
    ASSERT_NE(-1, positionLocation);

    setupQuadVertexBuffer(0.8f, 0.5f);
    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::black);
    EXPECT_PIXEL_COLOR_EQ(size / 2, size / 2, GLColor::green);

    // Draw red square behind green square
    ANGLE_GL_PROGRAM(program2, kBasicVertexShader, kRedFragmentShader);
    glUseProgram(program2);
    GLint positionLocation2 = glGetAttribLocation(program2, "position");
    ASSERT_NE(-1, positionLocation2);

    setupQuadVertexBuffer(0.7f, 1.0f);
    glVertexAttribPointer(positionLocation2, 3, GL_FLOAT, GL_FALSE, 0, 0);

    glDrawArrays(GL_TRIANGLES, 0, 6);
    ASSERT_GL_NO_ERROR();
    glDisable(GL_DEPTH_TEST);

    EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::red);
    EXPECT_PIXEL_COLOR_EQ(size / 2, size / 2, GLColor::green);

    glDisableVertexAttribArray(0);
    glBindBuffer(GL_ARRAY_BUFFER, 0);
}

// Read pixels with pack buffer. ES3+.
TEST_P(MultisampledRenderToTextureES3Test, MultisampleReadPixelsTest)
{
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));

    // PBO only available ES3 and above
    ANGLE_SKIP_TEST_IF(getClientMajorVersion() < 3);
    GLsizei size = 6;
    GLTexture texture;
    glBindTexture(GL_TEXTURE_2D, texture);
    glTexStorage2D(GL_TEXTURE_2D, 1, GL_RGBA8, size, size);
    ASSERT_GL_NO_ERROR();

    GLFramebuffer FBO;
    glBindFramebuffer(GL_FRAMEBUFFER, FBO);
    glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D,
                                         texture, 0, 4);
    EXPECT_GL_FRAMEBUFFER_COMPLETE(GL_FRAMEBUFFER);

    // Set viewport and clear to red
    glViewport(0, 0, size, size);
    glClearColor(1.0f, 0.0f, 0.0f, 1.0f);
    glClear(GL_COLOR_BUFFER_BIT);
    ASSERT_GL_NO_ERROR();

    // Bind Pack Pixel Buffer and read to it
    GLBuffer PBO;
    glBindBuffer(GL_PIXEL_PACK_BUFFER, PBO);
    glBufferData(GL_PIXEL_PACK_BUFFER, 4 * size * size, nullptr, GL_STATIC_DRAW);
    glReadPixels(0, 0, size, size, GL_RGBA, GL_UNSIGNED_BYTE, 0);
    ASSERT_GL_NO_ERROR();

    // Retrieving pixel color
    void *mappedPtr    = glMapBufferRange(GL_PIXEL_PACK_BUFFER, 0, 32, GL_MAP_READ_BIT);
    GLColor *dataColor = static_cast<GLColor *>(mappedPtr);
    EXPECT_GL_NO_ERROR();

    EXPECT_EQ(GLColor::red, dataColor[0]);

    glUnmapBuffer(GL_PIXEL_PACK_BUFFER);
    EXPECT_GL_NO_ERROR();
}

// CopyTexImage from a multisampled texture functionality test.
TEST_P(MultisampledRenderToTextureTest, MultisampleCopyTexImageTest)
{
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));
    GLsizei size = 16;

    setupCopyTexProgram();
    GLTexture texture;
    glBindTexture(GL_TEXTURE_2D, texture);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, size, size, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);

    // Disable mipmapping
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);

    GLFramebuffer FBO;
    glBindFramebuffer(GL_FRAMEBUFFER, FBO);
    glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D,
                                         texture, 0, 4);

    // Set color for framebuffer
    glClearColor(0.25f, 1.0f, 0.75f, 0.5f);
    glClear(GL_COLOR_BUFFER_BIT);
    ASSERT_GL_NO_ERROR();

    GLTexture copyToTex;
    glBindTexture(GL_TEXTURE_2D, copyToTex);

    // Disable mipmapping
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);

    glCopyTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, 0, 0, size, size, 0);
    ASSERT_GL_NO_ERROR();

    GLubyte expected[4] = {64, 255, 191, 255};
    verifyResults(copyToTex, expected, size, 0, 0, size, size);
}

// CopyTexSubImage from a multisampled texture functionality test.
TEST_P(MultisampledRenderToTextureTest, MultisampleCopyTexSubImageTest)
{
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));
    GLsizei size = 16;

    setupCopyTexProgram();

    GLTexture texture;
    // Create texture in copyFBO0 with color (.25, 1, .75, .5)
    glBindTexture(GL_TEXTURE_2D, texture);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, size, size, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);

    // Disable mipmapping
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);

    GLFramebuffer copyFBO0;
    glBindFramebuffer(GL_FRAMEBUFFER, copyFBO0);
    glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D,
                                         texture, 0, 4);

    // Set color for
    glClearColor(0.25f, 1.0f, 0.75f, 0.5f);
    glClear(GL_COLOR_BUFFER_BIT);
    ASSERT_GL_NO_ERROR();

    // Create texture in copyFBO[1] with color (1, .75, .5, .25)
    GLTexture texture1;
    glBindTexture(GL_TEXTURE_2D, texture1);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, size, size, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);

    // Disable mipmapping
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);

    GLFramebuffer copyFBO1;
    glBindFramebuffer(GL_FRAMEBUFFER, copyFBO1);
    glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D,
                                         texture1, 0, 4);

    // Set color for
    glClearColor(1.0f, 0.75f, 0.5f, 0.25f);
    glClear(GL_COLOR_BUFFER_BIT);
    ASSERT_GL_NO_ERROR();

    GLTexture copyToTex;
    glBindTexture(GL_TEXTURE_2D, copyToTex);

    // Disable mipmapping
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);

    // copyFBO0 -> copyToTex
    // copyToTex should hold what was originally in copyFBO0 : (.25, 1, .75, .5)
    glBindFramebuffer(GL_FRAMEBUFFER, copyFBO0);
    glCopyTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, 0, 0, size, size, 0);
    ASSERT_GL_NO_ERROR();

    GLubyte expected0[4] = {64, 255, 191, 255};
    verifyResults(copyToTex, expected0, size, 0, 0, size, size);

    // copyFBO[1] - copySubImage -> copyToTex
    // copyToTex should have subportion what was in copyFBO[1] : (1, .75, .5, .25)
    // The rest should still be untouched: (.25, 1, .75, .5)
    GLint half = size / 2;
    glBindFramebuffer(GL_FRAMEBUFFER, copyFBO1);
    glCopyTexSubImage2D(GL_TEXTURE_2D, 0, half, half, half, half, half, half);
    ASSERT_GL_NO_ERROR();

    GLubyte expected1[4] = {255, 191, 127, 255};
    verifyResults(copyToTex, expected1, size, half, half, size, size);

    // Verify rest is untouched
    verifyResults(copyToTex, expected0, size, 0, 0, half, half);
    verifyResults(copyToTex, expected0, size, 0, half, half, size);
    verifyResults(copyToTex, expected0, size, half, 0, size, half);
}

// BlitFramebuffer functionality test. ES3+.
TEST_P(MultisampledRenderToTextureES3Test, MultisampleBlitFramebufferTest)
{
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));
    // blitFramebuffer only available ES3 and above
    ANGLE_SKIP_TEST_IF(getClientMajorVersion() < 3);

    GLsizei size = 16;

    // Create multisampled framebuffer to use as source.
    GLRenderbuffer depthMS;
    glBindRenderbuffer(GL_RENDERBUFFER, depthMS.get());
    glRenderbufferStorageMultisampleEXT(GL_RENDERBUFFER, 4, GL_DEPTH_COMPONENT24, size, size);

    GLTexture colorMS;
    glBindTexture(GL_TEXTURE_2D, colorMS);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, size, size, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);

    GLFramebuffer fboMS;
    glBindFramebuffer(GL_FRAMEBUFFER, fboMS);
    glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, depthMS.get());
    glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D,
                                         colorMS, 0, 4);
    ASSERT_GL_NO_ERROR();

    // Clear depth to 0.5 and color to green.
    glClearDepthf(0.5f);
    glClearColor(0.0f, 1.0f, 0.0f, 1.0f);
    glClear(GL_DEPTH_BUFFER_BIT | GL_COLOR_BUFFER_BIT);
    glFlush();
    ASSERT_GL_NO_ERROR();

    // Draw red into the multisampled color buffer.
    ANGLE_GL_PROGRAM(drawRed, essl1_shaders::vs::Simple(), essl1_shaders::fs::Red());
    glEnable(GL_DEPTH_TEST);
    glDepthFunc(GL_EQUAL);
    drawQuad(drawRed.get(), essl1_shaders::PositionAttrib(), 0.0f);
    ASSERT_GL_NO_ERROR();

    // Create single sampled framebuffer to use as dest.
    GLFramebuffer fboSS;
    glBindFramebuffer(GL_FRAMEBUFFER, fboSS);
    GLTexture colorSS;
    glBindTexture(GL_TEXTURE_2D, colorSS);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, size, size, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);
    glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, colorSS, 0);
    ASSERT_GL_NO_ERROR();

    // Bind MS to READ as SS is already bound to DRAW.
    glBindFramebuffer(GL_READ_FRAMEBUFFER, fboMS.get());
    glBlitFramebuffer(0, 0, size, size, 0, 0, size, size, GL_COLOR_BUFFER_BIT, GL_NEAREST);
    ASSERT_GL_NO_ERROR();

    // Bind SS to READ so we can readPixels from it
    glBindFramebuffer(GL_FRAMEBUFFER, fboSS.get());

    EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::red);
    EXPECT_PIXEL_COLOR_EQ(size - 1, 0, GLColor::red);
    EXPECT_PIXEL_COLOR_EQ(0, size - 1, GLColor::red);
    EXPECT_PIXEL_COLOR_EQ(size - 1, size - 1, GLColor::red);
    EXPECT_PIXEL_COLOR_EQ(size / 2, size / 2, GLColor::red);
    ASSERT_GL_NO_ERROR();
}

// GenerateMipmap functionality test
TEST_P(MultisampledRenderToTextureTest, MultisampleGenerateMipmapTest)
{
    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_EXT_multisampled_render_to_texture"));
    GLsizei size = 64;
    // Vertex Shader source
    constexpr char kVS[] = R"(attribute vec4 position;
varying vec2 vTexCoord;

void main()
{
    gl_Position = position;
    vTexCoord   = (position.xy * 0.5) + 0.5;
})";

    // Fragment Shader source
    constexpr char kFS[] = R"(precision mediump float;
uniform sampler2D uTexture;
varying vec2 vTexCoord;

void main()
{
    gl_FragColor = texture2D(uTexture, vTexCoord);
})";

    GLProgram m2DProgram;
    m2DProgram.makeRaster(kVS, kFS);
    ASSERT_GL_TRUE(m2DProgram.valid());

    ASSERT_GL_NO_ERROR();

    // Initialize texture with blue
    GLTexture texture;
    glBindTexture(GL_TEXTURE_2D, texture);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, size, size, 0, GL_RGB, GL_UNSIGNED_BYTE, nullptr);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);

    GLFramebuffer FBO;
    glBindFramebuffer(GL_FRAMEBUFFER, FBO);
    glFramebufferTexture2DMultisampleEXT(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D,
                                         texture, 0, 4);
    ASSERT_GLENUM_EQ(GL_FRAMEBUFFER_COMPLETE, glCheckFramebufferStatus(GL_FRAMEBUFFER));
    glClearColor(0.0f, 0.0f, 1.0f, 1.0f);
    glClear(GL_COLOR_BUFFER_BIT);
    glViewport(0, 0, size, size);
    glBindFramebuffer(GL_FRAMEBUFFER, 0);
    ASSERT_GL_NO_ERROR();

    // Generate mipmap
    glGenerateMipmap(GL_TEXTURE_2D);
    ASSERT_GL_NO_ERROR();

    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_NEAREST);

    // Now draw the texture to various different sized areas.
    clearAndDrawQuad(m2DProgram, size, size);
    EXPECT_PIXEL_COLOR_EQ(size / 2, size / 2, GLColor::blue);

    // Use mip level 1
    clearAndDrawQuad(m2DProgram, size / 2, size / 2);
    EXPECT_PIXEL_COLOR_EQ(size / 4, size / 4, GLColor::blue);

    // Use mip level 2
    clearAndDrawQuad(m2DProgram, size / 4, size / 4);
    EXPECT_PIXEL_COLOR_EQ(size / 8, size / 8, GLColor::blue);

    ASSERT_GL_NO_ERROR();
}
ANGLE_INSTANTIATE_TEST(MultisampledRenderToTextureTest,
                       ES2_D3D9(),
                       ES2_D3D11(),
                       ES3_D3D11(),
                       ES2_OPENGL(),
                       ES3_OPENGL(),
                       ES2_OPENGLES(),
                       ES3_OPENGLES(),
                       ES2_VULKAN(),
                       ES3_VULKAN());
ANGLE_INSTANTIATE_TEST(MultisampledRenderToTextureES3Test,
                       ES3_D3D11(),
                       ES3_OPENGL(),
                       ES3_OPENGLES(),
                       ES3_VULKAN());
}  // namespace