/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "MLGDevice.h"
#include "mozilla/layers/TextureHost.h"
#include "BufferCache.h"
#include "ClearRegionHelper.h"
#include "gfxConfig.h"
#include "mozilla/StaticPrefs_layers.h"
#include "gfxUtils.h"
#include "ShaderDefinitionsMLGPU.h"
#include "SharedBufferMLGPU.h"
#include "UtilityMLGPU.h"

namespace mozilla {
namespace layers {

using namespace gfx;
using namespace mlg;

MLGRenderTarget::MLGRenderTarget(MLGRenderTargetFlags aFlags)
    : mFlags(aFlags), mLastDepthStart(-1) {}

MLGSwapChain::MLGSwapChain() : mIsDoubleBuffered(false) {}

bool MLGSwapChain::ApplyNewInvalidRegion(
    nsIntRegion&& aRegion, const Maybe<gfx::IntRect>& aExtraRect) {
  // We clamp the invalid region to the backbuffer size, otherwise the present
  // can fail.
  IntRect bounds(IntPoint(0, 0), GetSize());
  nsIntRegion invalid = std::move(aRegion);
  invalid.AndWith(bounds);
  if (invalid.IsEmpty()) {
    return false;
  }

  if (aExtraRect) {
    IntRect rect = aExtraRect.value().Intersect(bounds);
    if (!rect.IsEmpty()) {
      invalid.OrWith(rect);
    }
  }

  // This area is now invalid in the back and front buffers. Note that the front
  // buffer is either totally valid or totally invalid, since either the last
  // paint succeeded or was thrown out due to a buffer resize. Effectively, it
  // will now contain the invalid region specific to this frame.
  mBackBufferInvalid.OrWith(invalid);
  AL_LOG("Backbuffer invalid region: %s\n",
         Stringify(mBackBufferInvalid).c_str());

  if (mIsDoubleBuffered) {
    mFrontBufferInvalid.OrWith(invalid);
    AL_LOG("Frontbuffer invalid region: %s\n",
           Stringify(mFrontBufferInvalid).c_str());
  }
  return true;
}

MLGDevice::MLGDevice()
    : mTopology(MLGPrimitiveTopology::Unknown),
      mInitialized(false),
      mIsValid(false),
      mCanUseClearView(false),
      mCanUseConstantBufferOffsetBinding(false),
      mMaxConstantBufferBindSize(0) {}

MLGDevice::~MLGDevice() = default;

bool MLGDevice::Initialize() {
  if (!mMaxConstantBufferBindSize) {
    return Fail("FEATURE_FAILURE_NO_MAX_CB_BIND_SIZE",
                "Failed to set a max constant buffer bind size");
  }
  if (mMaxConstantBufferBindSize < mlg::kMaxConstantBufferSize) {
    // StagingBuffer depends on this value being accurate, so for now we just
    // double-check it here.
    return Fail("FEATURE_FAILURE_MIN_MAX_CB_BIND_SIZE",
                "Minimum constant buffer bind size not met");
  }

  // We allow this to be pref'd off for testing. Switching it off enables
  // Direct3D 11.0/Windows 7/OpenGL-style buffer code paths.
  if (!StaticPrefs::layers_mlgpu_enable_buffer_sharing_AtStartup()) {
    gfxConfig::EnableFallback(Fallback::NO_CONSTANT_BUFFER_OFFSETTING,
                              "Disabled by pref");
    mCanUseConstantBufferOffsetBinding = false;
  }
  if (mCanUseConstantBufferOffsetBinding && !VerifyConstantBufferOffsetting()) {
    gfxConfig::EnableFallback(Fallback::NO_CONSTANT_BUFFER_OFFSETTING,
                              "Constant buffer offset binding does not work");
    mCanUseConstantBufferOffsetBinding = false;
  }

  // We allow this to be pref'd off for testing. Disabling it turns on
  // ID3D11DeviceContext1::ClearView support, which is present on
  // newer Windows 8+ drivers.
  if (!StaticPrefs::layers_mlgpu_enable_clear_view_AtStartup()) {
    mCanUseClearView = false;
  }

  // When compositing normal sized layer trees, we typically have small vertex
  // buffers. Empirically the vertex and pixel constant buffer sizes are
  // generally under 1KB and the vertex constant buffer size is under 8KB.
  static const size_t kDefaultVertexBufferSize = 4096;
  static const size_t kDefaultVSConstantBufferSize =
      512 * kConstantBufferElementSize;
  static const size_t kDefaultPSConstantBufferSize =
      256 * kConstantBufferElementSize;

  // Note: we create these after we've verified all the device-specific
  // properties above.
  mSharedVertexBuffer =
      MakeUnique<SharedVertexBuffer>(this, kDefaultVertexBufferSize);
  mSharedVSBuffer =
      MakeUnique<SharedConstantBuffer>(this, kDefaultVSConstantBufferSize);
  mSharedPSBuffer =
      MakeUnique<SharedConstantBuffer>(this, kDefaultPSConstantBufferSize);

  if (!mSharedVertexBuffer->Init() || !mSharedVSBuffer->Init() ||
      !mSharedPSBuffer->Init()) {
    return Fail("FEATURE_FAILURE_ALLOC_SHARED_BUFFER",
                "Failed to allocate a shared shader buffer");
  }

  if (StaticPrefs::layers_mlgpu_enable_buffer_cache_AtStartup()) {
    mConstantBufferCache = MakeUnique<BufferCache>(this);
  }

  mInitialized = true;
  mIsValid = true;
  return true;
}

void MLGDevice::BeginFrame() {
  mSharedVertexBuffer->Reset();
  mSharedPSBuffer->Reset();
  mSharedVSBuffer->Reset();
}

void MLGDevice::EndFrame() {
  if (mConstantBufferCache) {
    mConstantBufferCache->EndFrame();
  }
}

void MLGDevice::FinishSharedBufferUse() {
  mSharedVertexBuffer->PrepareForUsage();
  mSharedPSBuffer->PrepareForUsage();
  mSharedVSBuffer->PrepareForUsage();
}

void MLGDevice::SetTopology(MLGPrimitiveTopology aTopology) {
  if (mTopology == aTopology) {
    return;
  }
  SetPrimitiveTopology(aTopology);
  mTopology = aTopology;
}

void MLGDevice::SetVertexBuffer(uint32_t aSlot,
                                const VertexBufferSection* aSection) {
  if (!aSection->IsValid()) {
    return;
  }
  SetVertexBuffer(aSlot, aSection->GetBuffer(), aSection->Stride(),
                  aSection->Offset());
}

void MLGDevice::SetPSConstantBuffer(uint32_t aSlot,
                                    const ConstantBufferSection* aSection) {
  if (!aSection->IsValid()) {
    return;
  }

  MLGBuffer* buffer = aSection->GetBuffer();

  if (aSection->HasOffset()) {
    uint32_t first = aSection->Offset();
    uint32_t numConstants = aSection->NumConstants();
    SetPSConstantBuffer(aSlot, buffer, first, numConstants);
  } else {
    SetPSConstantBuffer(aSlot, buffer);
  }
}

void MLGDevice::SetVSConstantBuffer(uint32_t aSlot,
                                    const ConstantBufferSection* aSection) {
  if (!aSection->IsValid()) {
    return;
  }

  MLGBuffer* buffer = aSection->GetBuffer();

  if (aSection->HasOffset()) {
    uint32_t first = aSection->Offset();
    uint32_t numConstants = aSection->NumConstants();
    SetVSConstantBuffer(aSlot, buffer, first, numConstants);
  } else {
    SetVSConstantBuffer(aSlot, buffer);
  }
}

void MLGDevice::SetPSTexturesYUV(uint32_t aSlot, TextureSource* aTexture) {
  // Note, we don't support tiled YCbCr textures.
  const int Y = 0, Cb = 1, Cr = 2;
  TextureSource* textures[3] = {aTexture->GetSubSource(Y),
                                aTexture->GetSubSource(Cb),
                                aTexture->GetSubSource(Cr)};
  MOZ_ASSERT(textures[0]);
  MOZ_ASSERT(textures[1]);
  MOZ_ASSERT(textures[2]);

  SetPSTextures(0, 3, textures);
}

void MLGDevice::SetPSTexture(uint32_t aSlot, TextureSource* aSource) {
  SetPSTextures(aSlot, 1, &aSource);
}

void MLGDevice::SetSamplerMode(uint32_t aIndex, gfx::SamplingFilter aFilter) {
  SetSamplerMode(aIndex, FilterToSamplerMode(aFilter));
}

bool MLGDevice::Fail(const nsCString& aFailureId, const nsCString* aMessage) {
  const char* message =
      aMessage ? aMessage->get() : "Failed initializing MLGDeviceD3D11";
  gfxWarning() << "Failure initializing MLGDeviceD3D11: " << message;
  mFailureId = aFailureId;
  mFailureMessage = message;
  return false;
}

void MLGDevice::UnmapSharedBuffers() {
  mSharedVertexBuffer->Reset();
  mSharedPSBuffer->Reset();
  mSharedVSBuffer->Reset();
}

RefPtr<MLGBuffer> MLGDevice::GetBufferForColorSpace(YUVColorSpace aColorSpace) {
  if (mColorSpaceBuffers[aColorSpace]) {
    return mColorSpaceBuffers[aColorSpace];
  }

  YCbCrShaderConstants buffer;
  memcpy(&buffer.yuvColorMatrix,
         gfxUtils::YuvToRgbMatrix4x3RowMajor(aColorSpace),
         sizeof(buffer.yuvColorMatrix));

  RefPtr<MLGBuffer> resource = CreateBuffer(
      MLGBufferType::Constant, sizeof(buffer), MLGUsage::Immutable, &buffer);
  if (!resource) {
    return nullptr;
  }

  mColorSpaceBuffers[aColorSpace] = resource;
  return resource;
}

RefPtr<MLGBuffer> MLGDevice::GetBufferForColorDepthCoefficient(
    ColorDepth aColorDepth) {
  if (mColorDepthBuffers[aColorDepth]) {
    return mColorDepthBuffers[aColorDepth];
  }

  YCbCrColorDepthConstants buffer;
  buffer.coefficient = gfx::RescalingFactorForColorDepth(aColorDepth);

  RefPtr<MLGBuffer> resource = CreateBuffer(
      MLGBufferType::Constant, sizeof(buffer), MLGUsage::Immutable, &buffer);
  if (!resource) {
    return nullptr;
  }

  mColorDepthBuffers[aColorDepth] = resource;
  return resource;
}

bool MLGDevice::Synchronize() { return true; }

void MLGDevice::PrepareClearRegion(ClearRegionHelper* aOut,
                                   nsTArray<gfx::IntRect>&& aRects,
                                   const Maybe<int32_t>& aSortIndex) {
  if (CanUseClearView() && !aSortIndex) {
    aOut->mRects = std::move(aRects);
    return;
  }

  mSharedVertexBuffer->Allocate(&aOut->mInput, aRects.Length(), sizeof(IntRect),
                                aRects.Elements());

  ClearConstants consts(aSortIndex ? aSortIndex.value() : 1);
  mSharedVSBuffer->Allocate(&aOut->mVSBuffer, consts);
}

void MLGDevice::DrawClearRegion(const ClearRegionHelper& aHelper) {
  // If we've set up vertices for a shader-based clear, execute that now.
  if (aHelper.mInput.IsValid()) {
    SetTopology(MLGPrimitiveTopology::UnitQuad);
    SetVertexShader(VertexShaderID::Clear);
    SetVertexBuffer(1, &aHelper.mInput);
    SetVSConstantBuffer(kClearConstantBufferSlot, &aHelper.mVSBuffer);
    SetBlendState(MLGBlendState::Copy);
    SetPixelShader(PixelShaderID::Clear);
    DrawInstanced(4, aHelper.mInput.NumVertices(), 0, 0);
    return;
  }

  // Otherwise, if we have a normal rect list, we wanted to use the faster
  // ClearView.
  if (!aHelper.mRects.IsEmpty()) {
    DeviceColor color(0.0, 0.0, 0.0, 0.0);
    ClearView(mCurrentRT, color, aHelper.mRects.Elements(),
              aHelper.mRects.Length());
  }
}

void MLGDevice::WriteAsPNG(MLGTexture* aTexture, const char* aPath) {
  MLGMappedResource map;
  if (!Map(aTexture, MLGMapType::READ, &map)) {
    return;
  }

  RefPtr<DataSourceSurface> surface = Factory::CreateWrappingDataSourceSurface(
      map.mData, map.mStride, aTexture->GetSize(), SurfaceFormat::B8G8R8A8);
  gfxUtils::WriteAsPNG(surface, aPath);

  Unmap(aTexture);
}

RefPtr<MLGTexture> MLGDevice::CopyAndCreateReadbackTexture(
    MLGTexture* aTexture) {
  RefPtr<MLGTexture> copy =
      CreateTexture(aTexture->GetSize(), SurfaceFormat::B8G8R8A8,
                    MLGUsage::Staging, MLGTextureFlags::None);
  if (!copy) {
    return nullptr;
  }
  CopyTexture(copy, IntPoint(0, 0), aTexture,
              IntRect(IntPoint(0, 0), aTexture->GetSize()));
  return copy;
}

}  // namespace layers
}  // namespace mozilla