//
// Copyright 2018 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.
//
// MultiviewTest:
//   Implementation of helpers for multiview testing.
//

#include "test_utils/MultiviewTest.h"
#include "platform/autogen/FeaturesD3D_autogen.h"
#include "test_utils/gl_raii.h"

namespace angle
{

GLuint CreateSimplePassthroughProgram(int numViews, ExtensionName multiviewExtension)
{
    std::string ext;
    switch (multiviewExtension)
    {
        case multiview:
            ext = "GL_OVR_multiview";
            break;
        case multiview2:
            ext = "GL_OVR_multiview2";
            break;
        default:
            // Unknown extension.
            break;
    }

    const std::string vsSource =
        "#version 300 es\n"
        "#extension " +
        ext +
        " : require\n"
        "layout(num_views = " +
        ToString(numViews) +
        ") in;\n"
        "layout(location=0) in vec2 vPosition;\n"
        "void main()\n"
        "{\n"
        "   gl_PointSize = 1.;\n"
        "   gl_Position = vec4(vPosition.xy, 0.0, 1.0);\n"
        "}\n";

    const std::string fsSource =
        "#version 300 es\n"
        "#extension " +
        ext +
        " : require\n"
        "precision mediump float;\n"
        "out vec4 col;\n"
        "void main()\n"
        "{\n"
        "   col = vec4(0,1,0,1);\n"
        "}\n";
    return CompileProgram(vsSource.c_str(), fsSource.c_str());
}

void CreateMultiviewBackingTextures(int samples,
                                    int viewWidth,
                                    int height,
                                    int numLayers,
                                    std::vector<GLuint> colorTextures,
                                    GLuint depthTexture,
                                    GLuint depthStencilTexture)
{
    // The same zero data is used to initialize both color and depth/stencil textures.
    std::vector<GLubyte> textureData;
    textureData.resize(viewWidth * height * numLayers * 4, 0u);

    // We can't upload data to multisample textures, so we clear them using a temporary framebuffer
    // instead. The current framebuffer binding is stored so we can restore it once we're done with
    // using the temporary framebuffers.
    GLint restoreDrawFramebuffer;
    glGetIntegerv(GL_DRAW_FRAMEBUFFER_BINDING, &restoreDrawFramebuffer);

    // Create color and depth textures.
    GLenum texTarget = (samples > 0) ? GL_TEXTURE_2D_MULTISAMPLE_ARRAY_OES : GL_TEXTURE_2D_ARRAY;
    for (auto colorTexture : colorTextures)
    {
        glBindTexture(texTarget, colorTexture);
        if (samples > 0)
        {
            glTexStorage3DMultisampleOES(texTarget, samples, GL_RGBA8, viewWidth, height, numLayers,
                                         false);

            GLFramebuffer tempFbo;
            glBindFramebuffer(GL_DRAW_FRAMEBUFFER, tempFbo);
            glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
            for (int layerIndex = 0; layerIndex < numLayers; ++layerIndex)
            {
                glFramebufferTextureLayer(GL_DRAW_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, colorTexture,
                                          0, layerIndex);
                glClear(GL_COLOR_BUFFER_BIT);
            }
        }
        else
        {
            glTexImage3D(texTarget, 0, GL_RGBA8, viewWidth, height, numLayers, 0, GL_RGBA,
                         GL_UNSIGNED_BYTE, textureData.data());
            glTexParameteri(texTarget, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
            glTexParameteri(texTarget, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
        }
    }

    if (depthTexture != 0)
    {
        glBindTexture(texTarget, depthTexture);
        if (samples > 0)
        {
            glTexStorage3DMultisampleOES(texTarget, samples, GL_DEPTH_COMPONENT32F, viewWidth,
                                         height, numLayers, false);

            GLFramebuffer tempFbo;
            glBindFramebuffer(GL_DRAW_FRAMEBUFFER, tempFbo);
            glClearDepthf(0.0f);
            for (int layerIndex = 0; layerIndex < numLayers; ++layerIndex)
            {
                glFramebufferTextureLayer(GL_DRAW_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, depthTexture, 0,
                                          layerIndex);
                glClear(GL_DEPTH_BUFFER_BIT);
            }
        }
        else
        {
            glTexImage3D(texTarget, 0, GL_DEPTH_COMPONENT32F, viewWidth, height, numLayers, 0,
                         GL_DEPTH_COMPONENT, GL_FLOAT, textureData.data());
        }
    }
    if (depthStencilTexture != 0)
    {
        glBindTexture(texTarget, depthStencilTexture);
        if (samples > 0)
        {
            glTexStorage3DMultisampleOES(texTarget, samples, GL_DEPTH24_STENCIL8, viewWidth, height,
                                         numLayers, false);

            GLFramebuffer tempFbo;
            glBindFramebuffer(GL_DRAW_FRAMEBUFFER, tempFbo);
            glClearDepthf(0.0f);
            glClearStencil(0);
            for (int layerIndex = 0; layerIndex < numLayers; ++layerIndex)
            {
                glFramebufferTextureLayer(GL_DRAW_FRAMEBUFFER, GL_DEPTH_STENCIL_ATTACHMENT,
                                          depthTexture, 0, layerIndex);
                glClear(GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);
            }
        }
        else
        {
            glTexImage3D(texTarget, 0, GL_DEPTH24_STENCIL8, viewWidth, height, numLayers, 0,
                         GL_DEPTH_STENCIL, GL_UNSIGNED_INT_24_8, textureData.data());
        }
    }
    glBindTexture(texTarget, 0);
    ASSERT_GL_NO_ERROR();

    glBindFramebuffer(GL_DRAW_FRAMEBUFFER, restoreDrawFramebuffer);
}

void CreateMultiviewBackingTextures(int samples,
                                    int viewWidth,
                                    int height,
                                    int numLayers,
                                    GLuint colorTexture,
                                    GLuint depthTexture,
                                    GLuint depthStencilTexture)
{
    ASSERT_TRUE(colorTexture != 0u);
    std::vector<GLuint> colorTextures(1, colorTexture);
    CreateMultiviewBackingTextures(samples, viewWidth, height, numLayers, colorTextures,
                                   depthTexture, depthStencilTexture);
}

void AttachMultiviewTextures(GLenum target,
                             int viewWidth,
                             int numViews,
                             int baseViewIndex,
                             std::vector<GLuint> colorTextures,
                             GLuint depthTexture,
                             GLuint depthStencilTexture)
{
    ASSERT_TRUE(depthTexture == 0u || depthStencilTexture == 0u);
    for (size_t i = 0; i < colorTextures.size(); ++i)
    {
        GLenum attachment = static_cast<GLenum>(GL_COLOR_ATTACHMENT0 + i);
        glFramebufferTextureMultiviewOVR(target, attachment, colorTextures[i], 0, baseViewIndex,
                                         numViews);
    }
    if (depthTexture)
    {
        glFramebufferTextureMultiviewOVR(target, GL_DEPTH_ATTACHMENT, depthTexture, 0,
                                         baseViewIndex, numViews);
    }
    if (depthStencilTexture)
    {
        glFramebufferTextureMultiviewOVR(target, GL_DEPTH_STENCIL_ATTACHMENT, depthStencilTexture,
                                         0, baseViewIndex, numViews);
    }
}

void AttachMultiviewTextures(GLenum target,
                             int viewWidth,
                             int numViews,
                             int baseViewIndex,
                             GLuint colorTexture,
                             GLuint depthTexture,
                             GLuint depthStencilTexture)
{
    ASSERT_TRUE(colorTexture != 0u);
    std::vector<GLuint> colorTextures(1, colorTexture);
    AttachMultiviewTextures(target, viewWidth, numViews, baseViewIndex, colorTextures, depthTexture,
                            depthStencilTexture);
}

std::ostream &operator<<(std::ostream &os, const MultiviewImplementationParams &params)
{
    const PlatformParameters &base = static_cast<const PlatformParameters &>(params);
    os << base << "_";
    if (params.mMultiviewExtension == angle::multiview)
    {
        os << "_multiview";
    }
    else
    {
        os << "_multiview2";
    }
    return os;
}

MultiviewImplementationParams VertexShaderOpenGL(GLint majorVersion,
                                                 GLint minorVersion,
                                                 ExtensionName multiviewExtension)
{
    return MultiviewImplementationParams(majorVersion, minorVersion, egl_platform::OPENGL(),
                                         multiviewExtension);
}

MultiviewImplementationParams VertexShaderVulkan(GLint majorVersion,
                                                 GLint minorVersion,
                                                 ExtensionName multiviewExtension)
{
    return MultiviewImplementationParams(majorVersion, minorVersion, egl_platform::VULKAN(),
                                         multiviewExtension);
}

MultiviewImplementationParams VertexShaderD3D11(GLint majorVersion,
                                                GLint minorVersion,
                                                ExtensionName multiviewExtension)
{
    return MultiviewImplementationParams(majorVersion, minorVersion, egl_platform::D3D11(),
                                         multiviewExtension);
}

MultiviewImplementationParams GeomShaderD3D11(GLint majorVersion,
                                              GLint minorVersion,
                                              ExtensionName multiviewExtension)
{
    return MultiviewImplementationParams(
        majorVersion, minorVersion,
        egl_platform::D3D11().enable(Feature::SelectViewInGeometryShader), multiviewExtension);
}

}  // namespace angle
