src/tests/gl_tests/FramebufferMultiviewTest.cpp

//
// Copyright 2017 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.
//
// Framebuffer multiview tests:
// The tests modify and examine the multiview state.
//

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

using namespace angle;

namespace
{
std::vector<GLenum> GetDrawBufferRange(size_t numColorAttachments)
{
    std::vector<GLenum> drawBuffers(numColorAttachments);
    const size_t kBase = static_cast<size_t>(GL_COLOR_ATTACHMENT0);
    for (size_t i = 0u; i < drawBuffers.size(); ++i)
    {
        drawBuffers[i] = static_cast<GLenum>(kBase + i);
    }
    return drawBuffers;
}
}  // namespace

// Base class for tests that care mostly about draw call validity and not rendering results.
class FramebufferMultiviewTest : public MultiviewTest
{
  protected:
    FramebufferMultiviewTest() : MultiviewTest() {}
};

class FramebufferMultiviewLayeredClearTest : public FramebufferMultiviewTest
{
  protected:
    FramebufferMultiviewLayeredClearTest() : mMultiviewFBO(0), mDepthTex(0), mDepthStencilTex(0) {}

    void testTearDown() override
    {
        if (mMultiviewFBO != 0)
        {
            glDeleteFramebuffers(1, &mMultiviewFBO);
            mMultiviewFBO = 0u;
        }
        if (!mNonMultiviewFBO.empty())
        {
            GLsizei textureCount = static_cast<GLsizei>(mNonMultiviewFBO.size());
            glDeleteTextures(textureCount, mNonMultiviewFBO.data());
            mNonMultiviewFBO.clear();
        }
        if (!mColorTex.empty())
        {
            GLsizei textureCount = static_cast<GLsizei>(mColorTex.size());
            glDeleteTextures(textureCount, mColorTex.data());
            mColorTex.clear();
        }
        if (mDepthStencilTex != 0u)
        {
            glDeleteTextures(1, &mDepthStencilTex);
            mDepthStencilTex = 0u;
        }
        if (mDepthTex != 0u)
        {
            glDeleteTextures(1, &mDepthTex);
            mDepthTex = 0u;
        }
        MultiviewTest::testTearDown();
    }

    void initializeFBOs(int width,
                        int height,
                        int numLayers,
                        int baseViewIndex,
                        int numViews,
                        int numColorAttachments,
                        bool stencil,
                        bool depth)
    {
        ASSERT_TRUE(mColorTex.empty());
        ASSERT_EQ(0u, mDepthStencilTex);
        ASSERT_EQ(0u, mDepthTex);
        ASSERT_LE(baseViewIndex + numViews, numLayers);

        // Generate textures.
        mColorTex.resize(numColorAttachments);
        GLsizei textureCount = static_cast<GLsizei>(mColorTex.size());
        glGenTextures(textureCount, mColorTex.data());
        if (stencil)
        {
            glGenTextures(1, &mDepthStencilTex);
        }
        else if (depth)
        {
            glGenTextures(1, &mDepthTex);
        }

        CreateMultiviewBackingTextures(0, width, height, numLayers, mColorTex, mDepthTex,
                                       mDepthStencilTex);

        glGenFramebuffers(1, &mMultiviewFBO);

        // Generate multiview FBO and attach textures.
        glBindFramebuffer(GL_FRAMEBUFFER, mMultiviewFBO);
        AttachMultiviewTextures(GL_FRAMEBUFFER, width, numViews, baseViewIndex, mColorTex,
                                mDepthTex, mDepthStencilTex);

        const auto &drawBuffers = GetDrawBufferRange(numColorAttachments);
        glDrawBuffers(numColorAttachments, drawBuffers.data());

        // Generate non-multiview FBOs and attach textures.
        mNonMultiviewFBO.resize(numLayers);
        GLsizei framebufferCount = static_cast<GLsizei>(mNonMultiviewFBO.size());
        glGenFramebuffers(framebufferCount, mNonMultiviewFBO.data());
        for (int i = 0; i < numLayers; ++i)
        {
            glBindFramebuffer(GL_FRAMEBUFFER, mNonMultiviewFBO[i]);
            for (int j = 0; j < numColorAttachments; ++j)
            {
                glFramebufferTextureLayer(GL_FRAMEBUFFER,
                                          static_cast<GLenum>(GL_COLOR_ATTACHMENT0 + j),
                                          mColorTex[j], 0, i);
            }
            if (stencil)
            {
                glFramebufferTextureLayer(GL_FRAMEBUFFER, GL_DEPTH_STENCIL_ATTACHMENT,
                                          mDepthStencilTex, 0, i);
            }
            else if (depth)
            {
                glFramebufferTextureLayer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, mDepthTex, 0, i);
            }
            glDrawBuffers(numColorAttachments, drawBuffers.data());
        }

        ASSERT_GL_NO_ERROR();
    }

    GLColor getLayerColor(size_t layer, GLenum attachment, GLint x, GLint y)
    {
        EXPECT_LT(layer, mNonMultiviewFBO.size());
        glBindFramebuffer(GL_FRAMEBUFFER, mNonMultiviewFBO[layer]);
        glReadBuffer(attachment);
        return angle::ReadColor(x, y);
    }

    GLColor getLayerColor(size_t layer, GLenum attachment)
    {
        return getLayerColor(layer, attachment, 0, 0);
    }

    GLuint mMultiviewFBO;
    std::vector<GLuint> mNonMultiviewFBO;

  private:
    std::vector<GLuint> mColorTex;
    GLuint mDepthTex;
    GLuint mDepthStencilTex;
};

// Test that the framebuffer tokens introduced by OVR_multiview2 can be used to query the
// framebuffer state and that their corresponding default values are correctly set.
TEST_P(FramebufferMultiviewTest, DefaultState)
{
    ANGLE_SKIP_TEST_IF(!requestMultiviewExtension());

    GLFramebuffer fbo;
    glBindFramebuffer(GL_FRAMEBUFFER, fbo);

    GLTexture tex;
    glBindTexture(GL_TEXTURE_2D, tex);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, 1, 1, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);
    glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, tex, 0);

    GLint numViews = -1;
    glGetFramebufferAttachmentParameteriv(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,
                                          GL_FRAMEBUFFER_ATTACHMENT_TEXTURE_NUM_VIEWS_OVR,
                                          &numViews);
    ASSERT_GL_NO_ERROR();
    EXPECT_EQ(1, numViews);

    GLint baseViewIndex = -1;
    glGetFramebufferAttachmentParameteriv(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,
                                          GL_FRAMEBUFFER_ATTACHMENT_TEXTURE_BASE_VIEW_INDEX_OVR,
                                          &baseViewIndex);
    ASSERT_GL_NO_ERROR();
    EXPECT_EQ(0, baseViewIndex);
}

// Test that without having the OVR_multiview2 extension, querying for the framebuffer state using
// the OVR_multiview2 tokens results in an INVALID_ENUM error.
TEST_P(FramebufferMultiviewTest, NegativeFramebufferStateQueries)
{
    GLFramebuffer fbo;
    glBindFramebuffer(GL_FRAMEBUFFER, fbo);

    GLTexture tex;
    glBindTexture(GL_TEXTURE_2D, tex);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, 1, 1, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);
    glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, tex, 0);

    GLint numViews = -1;
    glGetFramebufferAttachmentParameteriv(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,
                                          GL_FRAMEBUFFER_ATTACHMENT_TEXTURE_NUM_VIEWS_OVR,
                                          &numViews);
    EXPECT_GL_ERROR(GL_INVALID_ENUM);

    GLint baseViewIndex = -1;
    glGetFramebufferAttachmentParameteriv(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,
                                          GL_FRAMEBUFFER_ATTACHMENT_TEXTURE_BASE_VIEW_INDEX_OVR,
                                          &baseViewIndex);
    EXPECT_GL_ERROR(GL_INVALID_ENUM);
}

// Test that the correct errors are generated whenever glFramebufferTextureMultiviewOVR is
// called with invalid arguments.
TEST_P(FramebufferMultiviewTest, InvalidMultiviewLayeredArguments)
{
    ANGLE_SKIP_TEST_IF(!requestMultiviewExtension());

    GLFramebuffer fbo;
    glBindFramebuffer(GL_FRAMEBUFFER, fbo);

    GLTexture tex;
    glBindTexture(GL_TEXTURE_2D_ARRAY, tex);
    glTexImage3D(GL_TEXTURE_2D_ARRAY, 0, GL_RGBA8, 1, 1, 2, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);
    ASSERT_GL_NO_ERROR();

    // Negative base view index.
    glFramebufferTextureMultiviewOVR(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, tex, 0, -1, 1);
    EXPECT_GL_ERROR(GL_INVALID_VALUE);

    // baseViewIndex + numViews is greater than MAX_TEXTURE_LAYERS.
    GLint maxTextureLayers = 0;
    glGetIntegerv(GL_MAX_ARRAY_TEXTURE_LAYERS, &maxTextureLayers);
    glFramebufferTextureMultiviewOVR(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, tex, 0, maxTextureLayers,
                                     1);
    EXPECT_GL_ERROR(GL_INVALID_VALUE);
}

// Test that an INVALID_OPERATION error is generated whenever the OVR_multiview2 extension is not
// available.
TEST_P(FramebufferMultiviewTest, ExtensionNotAvailableCheck)
{
    GLFramebuffer fbo;
    glBindFramebuffer(GL_FRAMEBUFFER, fbo);

    GLTexture tex;
    glBindTexture(GL_TEXTURE_2D, tex);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, 1, 1, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);

    ASSERT_GL_NO_ERROR();
    glFramebufferTextureMultiviewOVR(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, tex, 0, 1, 1);
    EXPECT_GL_ERROR(GL_INVALID_OPERATION);
}

// Test that the active read framebuffer can be read with glCopyTex* if it only has one layered
// view.
TEST_P(FramebufferMultiviewTest, CopyTex)
{
    ANGLE_SKIP_TEST_IF(!requestMultiviewExtension());

    GLFramebuffer fbo;
    glBindFramebuffer(GL_FRAMEBUFFER, fbo);

    GLTexture tex;
    glBindTexture(GL_TEXTURE_2D_ARRAY, tex);
    glTexImage3D(GL_TEXTURE_2D_ARRAY, 0, GL_RGBA8, 1, 1, 2, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);

    glFramebufferTextureMultiviewOVR(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, tex, 0, 0, 1);
    ASSERT_GLENUM_EQ(GL_FRAMEBUFFER_COMPLETE, glCheckFramebufferStatus(GL_FRAMEBUFFER));
    ASSERT_GL_NO_ERROR();

    // Test glCopyTexImage2D and glCopyTexSubImage2D.
    {
        GLTexture tex2;
        glBindTexture(GL_TEXTURE_2D, tex2);
        glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, 1, 1, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);

        glBindFramebuffer(GL_FRAMEBUFFER, fbo);
        glClearColor(0.0f, 1.0f, 0.0f, 1.0f);
        glClear(GL_COLOR_BUFFER_BIT);

        glCopyTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, 0, 0, 1, 1, 0);
        ASSERT_GL_NO_ERROR();

        // Test texture contents.
        glBindFramebuffer(GL_FRAMEBUFFER, 0);
        draw2DTexturedQuad(0.0f, 1.0f, true);
        EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::green);

        glBindFramebuffer(GL_FRAMEBUFFER, fbo);
        glClearColor(0.0f, 1.0f, 1.0f, 1.0f);
        glClear(GL_COLOR_BUFFER_BIT);

        glCopyTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, 0, 0, 1, 1);
        ASSERT_GL_NO_ERROR();

        glBindFramebuffer(GL_FRAMEBUFFER, 0);
        draw2DTexturedQuad(0.0f, 1.0f, true);
        EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::cyan);
    }

    // Test glCopyTexSubImage3D.
    {
        GLTexture tex2;
        glBindTexture(GL_TEXTURE_3D, tex2);
        glTexImage3D(GL_TEXTURE_3D, 0, GL_RGBA8, 1, 1, 1, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);

        glBindFramebuffer(GL_FRAMEBUFFER, fbo);
        glClearColor(1.0f, 1.0f, 0.0f, 1.0f);
        glClear(GL_COLOR_BUFFER_BIT);
        glCopyTexSubImage3D(GL_TEXTURE_3D, 0, 0, 0, 0, 0, 0, 1, 1);
        ASSERT_GL_NO_ERROR();

        glBindFramebuffer(GL_FRAMEBUFFER, 0);
        draw3DTexturedQuad(0.0f, 1.0f, true, 0.0f);
        EXPECT_PIXEL_COLOR_EQ(0, 0, GLColor::yellow);
    }
}

// Test that glBlitFramebuffer succeeds if the current read framebuffer has just one layered view.
TEST_P(FramebufferMultiviewTest, Blit)
{
    ANGLE_SKIP_TEST_IF(!requestMultiviewExtension());

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

    GLFramebuffer fbo;
    glBindFramebuffer(GL_FRAMEBUFFER, fbo);

    GLTexture tex;
    glBindTexture(GL_TEXTURE_2D_ARRAY, tex);
    glTexImage3D(GL_TEXTURE_2D_ARRAY, 0, GL_RGBA8, 1, 1, 2, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);

    glFramebufferTextureMultiviewOVR(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, tex, 0, 0, 1);
    ASSERT_GLENUM_EQ(GL_FRAMEBUFFER_COMPLETE, glCheckFramebufferStatus(GL_FRAMEBUFFER));
    ASSERT_GL_NO_ERROR();

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

    glBindFramebuffer(GL_READ_FRAMEBUFFER, fbo);
    glBindFramebuffer(GL_DRAW_FRAMEBUFFER, 0);
    glBlitFramebuffer(0, 0, 1, 1, 0, 0, 1, 1, GL_COLOR_BUFFER_BIT, GL_NEAREST);
    ASSERT_GL_NO_ERROR();

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

// Test that glReadPixels succeeds from a layered multiview framebuffer with just one view.
TEST_P(FramebufferMultiviewTest, ReadPixels)
{
    ANGLE_SKIP_TEST_IF(!requestMultiviewExtension());

    GLFramebuffer fbo;
    glBindFramebuffer(GL_FRAMEBUFFER, fbo);

    GLTexture tex;
    glBindTexture(GL_TEXTURE_2D_ARRAY, tex);
    glTexImage3D(GL_TEXTURE_2D_ARRAY, 0, GL_RGBA8, 1, 1, 2, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);

    glFramebufferTextureMultiviewOVR(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, tex, 0, 0, 1);
    ASSERT_GLENUM_EQ(GL_FRAMEBUFFER_COMPLETE, glCheckFramebufferStatus(GL_FRAMEBUFFER));
    ASSERT_GL_NO_ERROR();

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

    GLColor pixelColor;
    glReadPixels(0, 0, 1, 1, GL_RGBA, GL_UNSIGNED_BYTE, &pixelColor.R);
    ASSERT_GL_NO_ERROR();
    EXPECT_COLOR_NEAR(GLColor::green, pixelColor, 2);
}

// Test that glFramebufferTextureMultiviewOVR modifies the internal multiview state.
TEST_P(FramebufferMultiviewTest, ModifyLayeredState)
{
    ANGLE_SKIP_TEST_IF(!requestMultiviewExtension());

    GLFramebuffer multiviewFBO;
    glBindFramebuffer(GL_FRAMEBUFFER, multiviewFBO);

    GLTexture tex;
    glBindTexture(GL_TEXTURE_2D_ARRAY, tex);
    glTexImage3D(GL_TEXTURE_2D_ARRAY, 0, GL_RGBA8, 1, 1, 4, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);
    ASSERT_GL_NO_ERROR();

    glFramebufferTextureMultiviewOVR(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, tex, 0, 1, 2);
    ASSERT_GL_NO_ERROR();

    GLint numViews = -1;
    glGetFramebufferAttachmentParameteriv(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,
                                          GL_FRAMEBUFFER_ATTACHMENT_TEXTURE_NUM_VIEWS_OVR,
                                          &numViews);
    ASSERT_GL_NO_ERROR();
    EXPECT_EQ(2, numViews);

    GLint baseViewIndex = -1;
    glGetFramebufferAttachmentParameteriv(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0,
                                          GL_FRAMEBUFFER_ATTACHMENT_TEXTURE_BASE_VIEW_INDEX_OVR,
                                          &baseViewIndex);
    ASSERT_GL_NO_ERROR();
    EXPECT_EQ(1, baseViewIndex);
}

// Test framebuffer completeness status of a layered framebuffer with color attachments.
TEST_P(FramebufferMultiviewTest, IncompleteViewTargetsLayered)
{
    ANGLE_SKIP_TEST_IF(!requestMultiviewExtension());

    GLFramebuffer fbo;
    glBindFramebuffer(GL_FRAMEBUFFER, fbo);

    GLTexture tex;
    glBindTexture(GL_TEXTURE_2D_ARRAY, tex);
    glTexImage3D(GL_TEXTURE_2D_ARRAY, 0, GL_RGBA8, 1, 1, 4, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);

    // Set the 0th attachment and keep it as it is till the end of the test. The 1st color
    // attachment will be modified to change the framebuffer's status.
    glFramebufferTextureMultiviewOVR(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, tex, 0, 0, 2);
    ASSERT_GL_NO_ERROR();

    GLTexture otherTexLayered;
    glBindTexture(GL_TEXTURE_2D_ARRAY, otherTexLayered);
    glTexImage3D(GL_TEXTURE_2D_ARRAY, 0, GL_RGBA8, 1, 1, 4, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);

    // Test framebuffer completeness when the base view index differs.
    glFramebufferTextureMultiviewOVR(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT1, otherTexLayered, 0, 1,
                                     2);
    ASSERT_GL_NO_ERROR();
    EXPECT_GLENUM_EQ(GL_FRAMEBUFFER_INCOMPLETE_VIEW_TARGETS_OVR,
                     glCheckFramebufferStatus(GL_FRAMEBUFFER));

    // Test framebuffer completeness when the 1st attachment has a non-multiview layout.
    glFramebufferTextureLayer(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT1, otherTexLayered, 0, 0);
    ASSERT_GL_NO_ERROR();
    EXPECT_GLENUM_EQ(GL_FRAMEBUFFER_INCOMPLETE_VIEW_TARGETS_OVR,
                     glCheckFramebufferStatus(GL_FRAMEBUFFER));

    // Test that framebuffer is complete when the number of views, base view index and layouts are
    // the same.
    glFramebufferTextureMultiviewOVR(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT1, otherTexLayered, 0, 0,
                                     2);
    ASSERT_GL_NO_ERROR();
    EXPECT_GLENUM_EQ(GL_FRAMEBUFFER_COMPLETE, glCheckFramebufferStatus(GL_FRAMEBUFFER));
}

// Test that glClear clears the contents of the color buffer for only the attached layers to a
// layered FBO.
TEST_P(FramebufferMultiviewLayeredClearTest, ColorBufferClear)
{
    ANGLE_SKIP_TEST_IF(!requestMultiviewExtension());

    initializeFBOs(1, 1, 4, 1, 2, 1, false, false);

    // Bind and specify viewport/scissor dimensions for each view.
    glBindFramebuffer(GL_FRAMEBUFFER, mMultiviewFBO);

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

    EXPECT_EQ(GLColor::transparentBlack, getLayerColor(0, GL_COLOR_ATTACHMENT0));
    EXPECT_EQ(GLColor::green, getLayerColor(1, GL_COLOR_ATTACHMENT0));
    EXPECT_EQ(GLColor::green, getLayerColor(2, GL_COLOR_ATTACHMENT0));
    EXPECT_EQ(GLColor::transparentBlack, getLayerColor(3, GL_COLOR_ATTACHMENT0));
}

// Test that glClearBufferfv can be used to clear individual color buffers of a layered FBO.
TEST_P(FramebufferMultiviewLayeredClearTest, ClearIndividualColorBuffer)
{
    ANGLE_SKIP_TEST_IF(!requestMultiviewExtension());

    initializeFBOs(1, 1, 4, 1, 2, 2, false, false);

    for (int i = 0; i < 2; ++i)
    {
        for (int layer = 0; layer < 4; ++layer)
        {
            GLenum colorAttachment = static_cast<GLenum>(GL_COLOR_ATTACHMENT0 + i);
            EXPECT_EQ(GLColor::transparentBlack, getLayerColor(layer, colorAttachment));
        }
    }

    glBindFramebuffer(GL_FRAMEBUFFER, mMultiviewFBO);

    float clearValues0[4] = {0.f, 0.f, 1.f, 1.f};
    glClearBufferfv(GL_COLOR, 0, clearValues0);

    float clearValues1[4] = {0.f, 1.f, 0.f, 1.f};
    glClearBufferfv(GL_COLOR, 1, clearValues1);

    EXPECT_EQ(GLColor::transparentBlack, getLayerColor(0, GL_COLOR_ATTACHMENT0));
    EXPECT_EQ(GLColor::blue, getLayerColor(1, GL_COLOR_ATTACHMENT0));
    EXPECT_EQ(GLColor::blue, getLayerColor(2, GL_COLOR_ATTACHMENT0));
    EXPECT_EQ(GLColor::transparentBlack, getLayerColor(3, GL_COLOR_ATTACHMENT0));

    EXPECT_EQ(GLColor::transparentBlack, getLayerColor(0, GL_COLOR_ATTACHMENT1));
    EXPECT_EQ(GLColor::green, getLayerColor(1, GL_COLOR_ATTACHMENT1));
    EXPECT_EQ(GLColor::green, getLayerColor(2, GL_COLOR_ATTACHMENT1));
    EXPECT_EQ(GLColor::transparentBlack, getLayerColor(3, GL_COLOR_ATTACHMENT1));
}

// Test that glClearBufferfi clears the contents of the stencil buffer for only the attached layers
// to a layered FBO.
TEST_P(FramebufferMultiviewLayeredClearTest, ClearBufferfi)
{
    ANGLE_SKIP_TEST_IF(!requestMultiviewExtension());

    // Create program to draw a quad.
    constexpr char kVS[] =
        "#version 300 es\n"
        "in vec3 vPos;\n"
        "void main(){\n"
        "   gl_Position = vec4(vPos, 1.);\n"
        "}\n";
    constexpr char kFS[] =
        "#version 300 es\n"
        "precision mediump float;\n"
        "uniform vec3 uCol;\n"
        "out vec4 col;\n"
        "void main(){\n"
        "   col = vec4(uCol,1.);\n"
        "}\n";
    ANGLE_GL_PROGRAM(program, kVS, kFS);
    glUseProgram(program);
    GLuint mColorUniformLoc = glGetUniformLocation(program, "uCol");

    initializeFBOs(1, 1, 4, 1, 2, 1, true, false);
    glEnable(GL_STENCIL_TEST);
    glDisable(GL_DEPTH_TEST);

    // Set clear values.
    glClearColor(1, 0, 0, 1);
    glClearStencil(0xFF);

    // Clear the color and stencil buffers of each layer.
    for (size_t i = 0u; i < mNonMultiviewFBO.size(); ++i)
    {
        glBindFramebuffer(GL_FRAMEBUFFER, mNonMultiviewFBO[i]);
        glClear(GL_COLOR_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);
    }

    // Switch to multiview framebuffer and clear portions of the texture.
    glBindFramebuffer(GL_FRAMEBUFFER, mMultiviewFBO);
    glClearBufferfi(GL_DEPTH_STENCIL, 0, 0.0f, 0);

    // Draw a fullscreen quad, but adjust the stencil function so that only the cleared regions pass
    // the test.
    glStencilOp(GL_KEEP, GL_KEEP, GL_REPLACE);
    glStencilFunc(GL_EQUAL, 0x00, 0xFF);
    for (size_t i = 0u; i < mNonMultiviewFBO.size(); ++i)
    {
        glBindFramebuffer(GL_FRAMEBUFFER, mNonMultiviewFBO[i]);
        glUniform3f(mColorUniformLoc, 0.0f, 1.0f, 0.0f);
        drawQuad(program, "vPos", 0.0f, 1.0f, true);
    }
    EXPECT_EQ(GLColor::red, getLayerColor(0, GL_COLOR_ATTACHMENT0));
    EXPECT_EQ(GLColor::green, getLayerColor(1, GL_COLOR_ATTACHMENT0));
    EXPECT_EQ(GLColor::green, getLayerColor(2, GL_COLOR_ATTACHMENT0));
    EXPECT_EQ(GLColor::red, getLayerColor(3, GL_COLOR_ATTACHMENT0));
}

// Test that glClear does not clear the content of a detached texture.
TEST_P(FramebufferMultiviewLayeredClearTest, UnmodifiedDetachedTexture)
{
    ANGLE_SKIP_TEST_IF(!requestMultiviewExtension());

    initializeFBOs(1, 1, 4, 1, 2, 2, false, false);

    // Clear all attachments.
    glBindFramebuffer(GL_FRAMEBUFFER, mMultiviewFBO);
    glClearColor(0, 1, 0, 1);
    glClear(GL_COLOR_BUFFER_BIT);

    for (int i = 0; i < 2; ++i)
    {
        GLenum colorAttachment = static_cast<GLenum>(GL_COLOR_ATTACHMENT0 + i);
        EXPECT_EQ(GLColor::transparentBlack, getLayerColor(0, colorAttachment));
        EXPECT_EQ(GLColor::green, getLayerColor(1, colorAttachment));
        EXPECT_EQ(GLColor::green, getLayerColor(2, colorAttachment));
        EXPECT_EQ(GLColor::transparentBlack, getLayerColor(3, colorAttachment));
    }

    // Detach and clear again.
    glBindFramebuffer(GL_FRAMEBUFFER, mMultiviewFBO);
    glFramebufferTextureMultiviewOVR(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT1, 0, 0, 1, 2);
    glClearColor(1, 1, 0, 1);
    glClear(GL_COLOR_BUFFER_BIT);

    // Check that color attachment 0 is modified.
    EXPECT_EQ(GLColor::transparentBlack, getLayerColor(0, GL_COLOR_ATTACHMENT0));
    EXPECT_EQ(GLColor::yellow, getLayerColor(1, GL_COLOR_ATTACHMENT0));
    EXPECT_EQ(GLColor::yellow, getLayerColor(2, GL_COLOR_ATTACHMENT0));
    EXPECT_EQ(GLColor::transparentBlack, getLayerColor(3, GL_COLOR_ATTACHMENT0));

    // Check that color attachment 1 is unmodified.
    EXPECT_EQ(GLColor::transparentBlack, getLayerColor(0, GL_COLOR_ATTACHMENT1));
    EXPECT_EQ(GLColor::green, getLayerColor(1, GL_COLOR_ATTACHMENT1));
    EXPECT_EQ(GLColor::green, getLayerColor(2, GL_COLOR_ATTACHMENT1));
    EXPECT_EQ(GLColor::transparentBlack, getLayerColor(3, GL_COLOR_ATTACHMENT1));
}

// Test that glClear clears only the contents within the scissor rectangle of the attached layers.
TEST_P(FramebufferMultiviewLayeredClearTest, ScissoredClear)
{
    ANGLE_SKIP_TEST_IF(!requestMultiviewExtension());

    initializeFBOs(2, 1, 4, 1, 2, 1, false, false);

    // Bind and specify viewport/scissor dimensions for each view.
    glBindFramebuffer(GL_FRAMEBUFFER, mMultiviewFBO);

    glEnable(GL_SCISSOR_TEST);
    glScissor(1, 0, 1, 1);
    glClearColor(0, 1, 0, 1);
    glClear(GL_COLOR_BUFFER_BIT);

    EXPECT_EQ(GLColor::transparentBlack, getLayerColor(0, GL_COLOR_ATTACHMENT0, 0, 0));
    EXPECT_EQ(GLColor::transparentBlack, getLayerColor(0, GL_COLOR_ATTACHMENT0, 1, 0));

    EXPECT_EQ(GLColor::transparentBlack, getLayerColor(1, GL_COLOR_ATTACHMENT0, 0, 0));
    EXPECT_EQ(GLColor::green, getLayerColor(1, GL_COLOR_ATTACHMENT0, 1, 0));

    EXPECT_EQ(GLColor::transparentBlack, getLayerColor(2, GL_COLOR_ATTACHMENT0, 0, 0));
    EXPECT_EQ(GLColor::green, getLayerColor(2, GL_COLOR_ATTACHMENT0, 1, 0));

    EXPECT_EQ(GLColor::transparentBlack, getLayerColor(3, GL_COLOR_ATTACHMENT0, 0, 0));
    EXPECT_EQ(GLColor::transparentBlack, getLayerColor(3, GL_COLOR_ATTACHMENT0, 1, 0));
}

// Test that glClearBufferfi clears the contents of the stencil buffer for only the attached layers
// to a layered FBO.
TEST_P(FramebufferMultiviewLayeredClearTest, ScissoredClearBufferfi)
{
    ANGLE_SKIP_TEST_IF(!requestMultiviewExtension());

    // Create program to draw a quad.
    constexpr char kVS[] =
        "#version 300 es\n"
        "in vec3 vPos;\n"
        "void main(){\n"
        "   gl_Position = vec4(vPos, 1.);\n"
        "}\n";
    constexpr char kFS[] =
        "#version 300 es\n"
        "precision mediump float;\n"
        "uniform vec3 uCol;\n"
        "out vec4 col;\n"
        "void main(){\n"
        "   col = vec4(uCol,1.);\n"
        "}\n";
    ANGLE_GL_PROGRAM(program, kVS, kFS);
    glUseProgram(program);
    GLuint mColorUniformLoc = glGetUniformLocation(program, "uCol");

    initializeFBOs(1, 2, 4, 1, 2, 1, true, false);
    glEnable(GL_STENCIL_TEST);
    glDisable(GL_DEPTH_TEST);

    // Set clear values.
    glClearColor(1, 0, 0, 1);
    glClearStencil(0xFF);

    // Clear the color and stencil buffers of each layer.
    for (size_t i = 0u; i < mNonMultiviewFBO.size(); ++i)
    {
        glBindFramebuffer(GL_FRAMEBUFFER, mNonMultiviewFBO[i]);
        glClear(GL_COLOR_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);
    }

    // Switch to multiview framebuffer and clear portions of the texture.
    glBindFramebuffer(GL_FRAMEBUFFER, mMultiviewFBO);
    glEnable(GL_SCISSOR_TEST);
    glScissor(0, 0, 1, 1);
    glClearBufferfi(GL_DEPTH_STENCIL, 0, 0.0f, 0);
    glDisable(GL_SCISSOR_TEST);

    // Draw a fullscreen quad, but adjust the stencil function so that only the cleared regions pass
    // the test.
    glStencilOp(GL_KEEP, GL_KEEP, GL_REPLACE);
    glStencilFunc(GL_EQUAL, 0x00, 0xFF);
    glUniform3f(mColorUniformLoc, 0.0f, 1.0f, 0.0f);
    for (size_t i = 0u; i < mNonMultiviewFBO.size(); ++i)
    {
        glBindFramebuffer(GL_FRAMEBUFFER, mNonMultiviewFBO[i]);
        drawQuad(program, "vPos", 0.0f, 1.0f, true);
    }
    EXPECT_EQ(GLColor::red, getLayerColor(0, GL_COLOR_ATTACHMENT0, 0, 0));
    EXPECT_EQ(GLColor::red, getLayerColor(0, GL_COLOR_ATTACHMENT0, 0, 1));
    EXPECT_EQ(GLColor::green, getLayerColor(1, GL_COLOR_ATTACHMENT0, 0, 0));
    EXPECT_EQ(GLColor::red, getLayerColor(1, GL_COLOR_ATTACHMENT0, 0, 1));
    EXPECT_EQ(GLColor::green, getLayerColor(2, GL_COLOR_ATTACHMENT0, 0, 0));
    EXPECT_EQ(GLColor::red, getLayerColor(2, GL_COLOR_ATTACHMENT0, 0, 1));
    EXPECT_EQ(GLColor::red, getLayerColor(3, GL_COLOR_ATTACHMENT0, 0, 0));
    EXPECT_EQ(GLColor::red, getLayerColor(3, GL_COLOR_ATTACHMENT0, 0, 1));
}

// Test that detaching an attachment does not generate an error whenever the multi-view related
// arguments are invalid.
TEST_P(FramebufferMultiviewTest, InvalidMultiviewArgumentsOnDetach)
{
    ANGLE_SKIP_TEST_IF(!requestMultiviewExtension());

    GLFramebuffer fbo;
    glBindFramebuffer(GL_FRAMEBUFFER, fbo);

    // Invalid base view index.
    glFramebufferTextureMultiviewOVR(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, 0, 0, -1, 1);
    EXPECT_GL_NO_ERROR();

    // Invalid number of views.
    glFramebufferTextureMultiviewOVR(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, 0, 0, 0, 0);
    EXPECT_GL_NO_ERROR();
}

// Test that glClear clears the contents of the color buffer whenever all layers of a 2D texture
// array are attached. The test is added because a special fast code path is used for this case.
TEST_P(FramebufferMultiviewLayeredClearTest, ColorBufferClearAllLayersAttached)
{
    ANGLE_SKIP_TEST_IF(!requestMultiviewExtension());

    initializeFBOs(1, 1, 2, 0, 2, 1, false, false);

    glBindFramebuffer(GL_FRAMEBUFFER, mMultiviewFBO);
    glClearColor(0, 1, 0, 1);
    glClear(GL_COLOR_BUFFER_BIT);

    EXPECT_EQ(GLColor::green, getLayerColor(0, GL_COLOR_ATTACHMENT0));
    EXPECT_EQ(GLColor::green, getLayerColor(1, GL_COLOR_ATTACHMENT0));
}

// Test that attaching a multisampled texture array is not possible if all the required extensions
// are not enabled.
TEST_P(FramebufferMultiviewTest, NegativeMultisampledFramebufferTest)
{
    ANGLE_SKIP_TEST_IF(!requestMultiviewExtension());

    ANGLE_SKIP_TEST_IF(!EnsureGLExtensionEnabled("GL_OES_texture_storage_multisample_2d_array"));

    // We don't enable OVR_multiview2_multisample

    GLTexture multisampleTexture;
    glBindTexture(GL_TEXTURE_2D_MULTISAMPLE_ARRAY_OES, multisampleTexture);

    GLFramebuffer fbo;
    glBindFramebuffer(GL_FRAMEBUFFER, fbo);
    glFramebufferTextureMultiviewOVR(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, multisampleTexture, 0, 0,
                                     2);
    // From the extension spec: "An INVALID_OPERATION error is generated if texture is not zero, and
    // does not name an existing texture object of type TEXTURE_2D_ARRAY."
    EXPECT_GL_ERROR(GL_INVALID_OPERATION);
}

ANGLE_INSTANTIATE_TEST(FramebufferMultiviewTest,
                       VertexShaderOpenGL(3, 0, ExtensionName::multiview),
                       GeomShaderD3D11(3, 0, ExtensionName::multiview),
                       VertexShaderOpenGL(3, 0, ExtensionName::multiview2),
                       GeomShaderD3D11(3, 0, ExtensionName::multiview2));
ANGLE_INSTANTIATE_TEST(FramebufferMultiviewLayeredClearTest,
                       VertexShaderOpenGL(3, 0, ExtensionName::multiview),
                       GeomShaderD3D11(3, 0, ExtensionName::multiview),
                       VertexShaderOpenGL(3, 0, ExtensionName::multiview2),
                       GeomShaderD3D11(3, 0, ExtensionName::multiview2));