//
// Copyright (c) 2014 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.
//

// Compiler.cpp: implements the gl::Compiler class.

#include "libANGLE/Compiler.h"

#include "common/debug.h"
#include "libANGLE/ContextState.h"
#include "libANGLE/renderer/CompilerImpl.h"
#include "libANGLE/renderer/GLImplFactory.h"

namespace gl
{

namespace
{

// Global count of active shader compiler handles. Needed to know when to call sh::Initialize and
// sh::Finalize.
size_t activeCompilerHandles = 0;

ShShaderSpec SelectShaderSpec(GLint majorVersion, GLint minorVersion, bool isWebGL)
{
    if (majorVersion >= 3)
    {
        if (minorVersion == 1)
        {
            return isWebGL ? SH_WEBGL3_SPEC : SH_GLES3_1_SPEC;
        }
        else
        {
            return isWebGL ? SH_WEBGL2_SPEC : SH_GLES3_SPEC;
        }
    }

    // GLES1 emulation: Use GLES3 shader spec.
    if (!isWebGL && majorVersion == 1)
    {
        return SH_GLES3_SPEC;
    }

    return isWebGL ? SH_WEBGL_SPEC : SH_GLES2_SPEC;
}

}  // anonymous namespace

Compiler::Compiler(rx::GLImplFactory *implFactory, const ContextState &state)
    : mImplementation(implFactory->createCompiler()),
      mSpec(SelectShaderSpec(state.getClientMajorVersion(),
                             state.getClientMinorVersion(),
                             state.getExtensions().webglCompatibility)),
      mOutputType(mImplementation->getTranslatorOutputType()),
      mResources(),
      mShaderCompilers({})
{
    ASSERT(state.getClientMajorVersion() == 1 || state.getClientMajorVersion() == 2 ||
           state.getClientMajorVersion() == 3);

    const gl::Caps &caps             = state.getCaps();
    const gl::Extensions &extensions = state.getExtensions();

    sh::InitBuiltInResources(&mResources);
    mResources.MaxVertexAttribs             = caps.maxVertexAttributes;
    mResources.MaxVertexUniformVectors      = caps.maxVertexUniformVectors;
    mResources.MaxVaryingVectors            = caps.maxVaryingVectors;
    mResources.MaxVertexTextureImageUnits   = caps.maxShaderTextureImageUnits[ShaderType::Vertex];
    mResources.MaxCombinedTextureImageUnits = caps.maxCombinedTextureImageUnits;
    mResources.MaxTextureImageUnits         = caps.maxShaderTextureImageUnits[ShaderType::Fragment];
    mResources.MaxFragmentUniformVectors    = caps.maxFragmentUniformVectors;
    mResources.MaxDrawBuffers               = caps.maxDrawBuffers;
    mResources.OES_standard_derivatives     = extensions.standardDerivatives;
    mResources.EXT_draw_buffers             = extensions.drawBuffers;
    mResources.EXT_shader_texture_lod       = extensions.shaderTextureLOD;
    mResources.OES_EGL_image_external       = extensions.eglImageExternal;
    mResources.OES_EGL_image_external_essl3 = extensions.eglImageExternalEssl3;
    mResources.NV_EGL_stream_consumer_external = extensions.eglStreamConsumerExternal;
    mResources.ARB_texture_rectangle           = extensions.textureRectangle;
    // TODO: use shader precision caps to determine if high precision is supported?
    mResources.FragmentPrecisionHigh = 1;
    mResources.EXT_frag_depth        = extensions.fragDepth;

    // OVR_multiview state
    mResources.OVR_multiview = extensions.multiview;
    mResources.MaxViewsOVR   = extensions.maxViews;

    // GLSL ES 3.0 constants
    mResources.MaxVertexOutputVectors  = caps.maxVertexOutputComponents / 4;
    mResources.MaxFragmentInputVectors = caps.maxFragmentInputComponents / 4;
    mResources.MinProgramTexelOffset   = caps.minProgramTexelOffset;
    mResources.MaxProgramTexelOffset   = caps.maxProgramTexelOffset;

    // GLSL ES 3.1 constants
    mResources.MaxProgramTextureGatherOffset    = caps.maxProgramTextureGatherOffset;
    mResources.MinProgramTextureGatherOffset    = caps.minProgramTextureGatherOffset;
    mResources.MaxImageUnits                    = caps.maxImageUnits;
    mResources.MaxVertexImageUniforms           = caps.maxVertexImageUniforms;
    mResources.MaxFragmentImageUniforms         = caps.maxFragmentImageUniforms;
    mResources.MaxComputeImageUniforms          = caps.maxComputeImageUniforms;
    mResources.MaxCombinedImageUniforms         = caps.maxCombinedImageUniforms;
    mResources.MaxCombinedShaderOutputResources = caps.maxCombinedShaderOutputResources;
    mResources.MaxUniformLocations              = caps.maxUniformLocations;

    for (size_t index = 0u; index < 3u; ++index)
    {
        mResources.MaxComputeWorkGroupCount[index] = caps.maxComputeWorkGroupCount[index];
        mResources.MaxComputeWorkGroupSize[index]  = caps.maxComputeWorkGroupSize[index];
    }

    mResources.MaxComputeUniformComponents = caps.maxComputeUniformComponents;
    mResources.MaxComputeTextureImageUnits = caps.maxShaderTextureImageUnits[ShaderType::Compute];

    mResources.MaxComputeAtomicCounters       = caps.maxComputeAtomicCounters;
    mResources.MaxComputeAtomicCounterBuffers = caps.maxComputeAtomicCounterBuffers;

    mResources.MaxVertexAtomicCounters         = caps.maxVertexAtomicCounters;
    mResources.MaxFragmentAtomicCounters       = caps.maxFragmentAtomicCounters;
    mResources.MaxCombinedAtomicCounters       = caps.maxCombinedAtomicCounters;
    mResources.MaxAtomicCounterBindings        = caps.maxAtomicCounterBufferBindings;
    mResources.MaxVertexAtomicCounterBuffers   = caps.maxVertexAtomicCounterBuffers;
    mResources.MaxFragmentAtomicCounterBuffers = caps.maxFragmentAtomicCounterBuffers;
    mResources.MaxCombinedAtomicCounterBuffers = caps.maxCombinedAtomicCounterBuffers;
    mResources.MaxAtomicCounterBufferSize      = caps.maxAtomicCounterBufferSize;

    mResources.MaxUniformBufferBindings       = caps.maxUniformBufferBindings;
    mResources.MaxShaderStorageBufferBindings = caps.maxShaderStorageBufferBindings;

    // Needed by point size clamping workaround
    mResources.MaxPointSize = caps.maxAliasedPointSize;

    if (state.getClientMajorVersion() == 2 && !extensions.drawBuffers)
    {
        mResources.MaxDrawBuffers = 1;
    }

    // Geometry Shader constants
    mResources.EXT_geometry_shader              = extensions.geometryShader;
    mResources.MaxGeometryUniformComponents     = caps.maxGeometryUniformComponents;
    mResources.MaxGeometryUniformBlocks         = caps.maxShaderUniformBlocks[ShaderType::Geometry];
    mResources.MaxGeometryInputComponents       = caps.maxGeometryInputComponents;
    mResources.MaxGeometryOutputComponents      = caps.maxGeometryOutputComponents;
    mResources.MaxGeometryOutputVertices        = caps.maxGeometryOutputVertices;
    mResources.MaxGeometryTotalOutputComponents = caps.maxGeometryTotalOutputComponents;
    mResources.MaxGeometryTextureImageUnits = caps.maxShaderTextureImageUnits[ShaderType::Geometry];
    mResources.MaxGeometryAtomicCounterBuffers = caps.maxGeometryAtomicCounterBuffers;
    mResources.MaxGeometryAtomicCounters       = caps.maxGeometryAtomicCounters;
    mResources.MaxGeometryShaderStorageBlocks  = caps.maxShaderStorageBlocks[ShaderType::Geometry];
    mResources.MaxGeometryShaderInvocations    = caps.maxGeometryShaderInvocations;
    mResources.MaxGeometryImageUniforms        = caps.maxGeometryImageUniforms;
}

Compiler::~Compiler()
{
    for (ShaderType shaderType : AllShaderTypes())
    {
        ShHandle compilerHandle = mShaderCompilers[shaderType];
        if (compilerHandle)
        {
            sh::Destruct(compilerHandle);
            mShaderCompilers[shaderType] = nullptr;

            ASSERT(activeCompilerHandles > 0);
            activeCompilerHandles--;
        }
    }

    if (activeCompilerHandles == 0)
    {
        sh::Finalize();
    }

    ANGLE_SWALLOW_ERR(mImplementation->release());
}

ShHandle Compiler::getCompilerHandle(ShaderType type)
{
    ASSERT(type != ShaderType::InvalidEnum);
    ShHandle *compiler = &mShaderCompilers[type];

    if (!(*compiler))
    {
        if (activeCompilerHandles == 0)
        {
            sh::Initialize();
        }

        *compiler = sh::ConstructCompiler(ToGLenum(type), mSpec, mOutputType, &mResources);
        ASSERT(*compiler);
        activeCompilerHandles++;
    }

    return *compiler;
}

const std::string &Compiler::getBuiltinResourcesString(ShaderType type)
{
    return sh::GetBuiltInResourcesString(getCompilerHandle(type));
}

}  // namespace gl