// Copyright 2011 Dolphin Emulator Project
// Licensed under GPLv2+
// Refer to the license.txt file included.

#include "VideoBackends/D3D/XFBEncoder.h"
#include "Common/CommonTypes.h"
#include "Common/Logging/Log.h"
#include "Common/MsgHandler.h"
#include "VideoBackends/D3D/D3DBase.h"
#include "VideoBackends/D3D/D3DBlob.h"
#include "VideoBackends/D3D/D3DShader.h"
#include "VideoBackends/D3D/D3DState.h"
#include "VideoBackends/D3D/FramebufferManager.h"
#include "VideoBackends/D3D/Render.h"

namespace DX11
{
union XFBEncodeParams {
  struct
  {
    FLOAT Width;  // Width and height of encoded XFB in luma pixels
    FLOAT Height;
    FLOAT TexLeft;  // Normalized tex coordinates of XFB source area in EFB texture
    FLOAT TexTop;
    FLOAT TexRight;
    FLOAT TexBottom;
    FLOAT Gamma;
  };
  // Constant buffers must be a multiple of 16 bytes in size
  u8 pad[32];  // Pad to the next multiple of 16
};

static const char XFB_ENCODE_VS[] =
    "// dolphin-emu XFB encoder vertex shader\n"

    "cbuffer cbParams : register(b0)\n"
    "{\n"
    "struct\n"  // Should match XFBEncodeParams above
    "{\n"
    "float Width;\n"
    "float Height;\n"
    "float TexLeft;\n"
    "float TexTop;\n"
    "float TexRight;\n"
    "float TexBottom;\n"
    "float Gamma;\n"
    "} Params;\n"
    "}\n"

    "struct Output\n"
    "{\n"
    "float4 Pos : SV_Position;\n"
    "float2 Coord : ENCODECOORD;\n"
    "};\n"

    "Output main(in float2 Pos : POSITION)\n"
    "{\n"
    "Output result;\n"
    "result.Pos = float4(2*Pos.x-1, -2*Pos.y+1, 0, 1);\n"
    "result.Coord = Pos * float2(floor(Params.Width/2), Params.Height);\n"
    "return result;\n"
    "}\n";

static const char XFB_ENCODE_PS[] =
    "// dolphin-emu XFB encoder pixel shader\n"

    "cbuffer cbParams : register(b0)\n"
    "{\n"
    "struct\n"  // Should match XFBEncodeParams above
    "{\n"
    "float Width;\n"
    "float Height;\n"
    "float TexLeft;\n"
    "float TexTop;\n"
    "float TexRight;\n"
    "float TexBottom;\n"
    "float Gamma;\n"
    "} Params;\n"
    "}\n"

    "Texture2DArray EFBTexture : register(t0);\n"
    "sampler EFBSampler : register(s0);\n"

    // GameCube/Wii uses the BT.601 standard algorithm for converting to YCbCr; see
    // <http://www.equasys.de/colorconversion.html#YCbCr-RGBColorFormatConversion>
    "static const float3x4 RGB_TO_YCBCR = float3x4(\n"
    "0.257, 0.504, 0.098, 16.0/255.0,\n"
    "-0.148, -0.291, 0.439, 128.0/255.0,\n"
    "0.439, -0.368, -0.071, 128.0/255.0\n"
    ");\n"

    "float3 SampleEFB(float2 coord)\n"
    "{\n"
    "float2 texCoord = lerp(float2(Params.TexLeft,Params.TexTop), "
    "float2(Params.TexRight,Params.TexBottom), coord / float2(Params.Width,Params.Height));\n"
    "return EFBTexture.Sample(EFBSampler, float3(texCoord, 0.0)).rgb;\n"
    "}\n"

    "void main(out float4 ocol0 : SV_Target, in float4 Pos : SV_Position, in float2 Coord : "
    "ENCODECOORD)\n"
    "{\n"
    // Multiplying X by 2, moves pixel centers from (x+0.5) to (2x+1) instead of (2x+0.5), so
    // subtract 0.5 to compensate
    "float2 baseCoord = Coord * float2(2,1) - float2(0.5,0);\n"
    // FIXME: Shall we apply gamma here, or apply it below to the Y components?
    // Be careful if you apply it to Y! The Y components are in the range (16..235) / 255.
    "float3 sampleL = pow(abs(SampleEFB(baseCoord+float2(-1,0))), Params.Gamma);\n"  // Left
    "float3 sampleM = pow(abs(SampleEFB(baseCoord)), Params.Gamma);\n"               // Middle
    "float3 sampleR = pow(abs(SampleEFB(baseCoord+float2(1,0))), Params.Gamma);\n"   // Right

    "float3 yuvL = mul(RGB_TO_YCBCR, float4(sampleL,1));\n"
    "float3 yuvM = mul(RGB_TO_YCBCR, float4(sampleM,1));\n"
    "float3 yuvR = mul(RGB_TO_YCBCR, float4(sampleR,1));\n"

    // The Y components correspond to two EFB pixels, while the U and V are
    // made from a blend of three EFB pixels.
    "float y0 = yuvM.r;\n"
    "float y1 = yuvR.r;\n"
    "float u0 = 0.25*yuvL.g + 0.5*yuvM.g + 0.25*yuvR.g;\n"
    "float v0 = 0.25*yuvL.b + 0.5*yuvM.b + 0.25*yuvR.b;\n"

    "ocol0 = float4(y0, u0, y1, v0);\n"
    "}\n";

static const D3D11_INPUT_ELEMENT_DESC QUAD_LAYOUT_DESC[] = {
    {"POSITION", 0, DXGI_FORMAT_R32G32_FLOAT, 0, 0, D3D11_INPUT_PER_VERTEX_DATA, 0}};

static const struct QuadVertex
{
  float posX;
  float posY;
} QUAD_VERTS[4] = {{0, 0}, {1, 0}, {0, 1}, {1, 1}};

XFBEncoder::XFBEncoder()
    : m_out(nullptr), m_outRTV(nullptr), m_outStage(nullptr), m_encodeParams(nullptr),
      m_quad(nullptr), m_vShader(nullptr), m_quadLayout(nullptr), m_pShader(nullptr),
      m_xfbEncodeBlendState(nullptr), m_xfbEncodeDepthState(nullptr), m_xfbEncodeRastState(nullptr),
      m_efbSampler(nullptr)
{
}

void XFBEncoder::Init()
{
  HRESULT hr;

  // Create output texture

  // The pixel shader can generate one YUYV entry per pixel. One YUYV entry
  // is created for every two EFB pixels.
  D3D11_TEXTURE2D_DESC t2dd = CD3D11_TEXTURE2D_DESC(DXGI_FORMAT_R8G8B8A8_UNORM, MAX_XFB_WIDTH / 2,
                                                    MAX_XFB_HEIGHT, 1, 1, D3D11_BIND_RENDER_TARGET);
  hr = D3D::device->CreateTexture2D(&t2dd, nullptr, &m_out);
  CHECK(SUCCEEDED(hr), "create xfb encoder output texture");
  D3D::SetDebugObjectName(m_out, "xfb encoder output texture");

  // Create output render target view

  D3D11_RENDER_TARGET_VIEW_DESC rtvd = CD3D11_RENDER_TARGET_VIEW_DESC(
      m_out, D3D11_RTV_DIMENSION_TEXTURE2D, DXGI_FORMAT_R8G8B8A8_UNORM);
  hr = D3D::device->CreateRenderTargetView(m_out, &rtvd, &m_outRTV);
  CHECK(SUCCEEDED(hr), "create xfb encoder output texture rtv");
  D3D::SetDebugObjectName(m_outRTV, "xfb encoder output rtv");

  // Create output staging buffer

  t2dd.Usage = D3D11_USAGE_STAGING;
  t2dd.BindFlags = 0;
  t2dd.CPUAccessFlags = D3D11_CPU_ACCESS_READ;
  hr = D3D::device->CreateTexture2D(&t2dd, nullptr, &m_outStage);
  CHECK(SUCCEEDED(hr), "create xfb encoder output staging buffer");
  D3D::SetDebugObjectName(m_outStage, "xfb encoder output staging buffer");

  // Create constant buffer for uploading params to shaders

  D3D11_BUFFER_DESC bd = CD3D11_BUFFER_DESC(sizeof(XFBEncodeParams), D3D11_BIND_CONSTANT_BUFFER);
  hr = D3D::device->CreateBuffer(&bd, nullptr, &m_encodeParams);
  CHECK(SUCCEEDED(hr), "create xfb encode params buffer");
  D3D::SetDebugObjectName(m_encodeParams, "xfb encoder params buffer");

  // Create vertex quad

  bd = CD3D11_BUFFER_DESC(sizeof(QUAD_VERTS), D3D11_BIND_VERTEX_BUFFER, D3D11_USAGE_IMMUTABLE);
  D3D11_SUBRESOURCE_DATA srd = {QUAD_VERTS, 0, 0};

  hr = D3D::device->CreateBuffer(&bd, &srd, &m_quad);
  CHECK(SUCCEEDED(hr), "create xfb encode quad vertex buffer");
  D3D::SetDebugObjectName(m_quad, "xfb encoder quad vertex buffer");

  // Create vertex shader

  D3DBlob* bytecode = nullptr;
  if (!D3D::CompileVertexShader(XFB_ENCODE_VS, &bytecode))
  {
    ERROR_LOG(VIDEO, "XFB encode vertex shader failed to compile");
    return;
  }

  hr = D3D::device->CreateVertexShader(bytecode->Data(), bytecode->Size(), nullptr, &m_vShader);
  CHECK(SUCCEEDED(hr), "create xfb encode vertex shader");
  D3D::SetDebugObjectName(m_vShader, "xfb encoder vertex shader");

  // Create input layout for vertex quad using bytecode from vertex shader

  hr = D3D::device->CreateInputLayout(QUAD_LAYOUT_DESC,
                                      sizeof(QUAD_LAYOUT_DESC) / sizeof(D3D11_INPUT_ELEMENT_DESC),
                                      bytecode->Data(), bytecode->Size(), &m_quadLayout);
  CHECK(SUCCEEDED(hr), "create xfb encode quad vertex layout");
  D3D::SetDebugObjectName(m_quadLayout, "xfb encoder quad layout");

  bytecode->Release();

  // Create pixel shader

  m_pShader = D3D::CompileAndCreatePixelShader(XFB_ENCODE_PS);
  if (!m_pShader)
  {
    ERROR_LOG(VIDEO, "XFB encode pixel shader failed to compile");
    return;
  }
  D3D::SetDebugObjectName(m_pShader, "xfb encoder pixel shader");

  // Create blend state

  D3D11_BLEND_DESC bld = CD3D11_BLEND_DESC(CD3D11_DEFAULT());
  hr = D3D::device->CreateBlendState(&bld, &m_xfbEncodeBlendState);
  CHECK(SUCCEEDED(hr), "create xfb encode blend state");
  D3D::SetDebugObjectName(m_xfbEncodeBlendState, "xfb encoder blend state");

  // Create depth state

  D3D11_DEPTH_STENCIL_DESC dsd = CD3D11_DEPTH_STENCIL_DESC(CD3D11_DEFAULT());
  dsd.DepthEnable = FALSE;
  hr = D3D::device->CreateDepthStencilState(&dsd, &m_xfbEncodeDepthState);
  CHECK(SUCCEEDED(hr), "create xfb encode depth state");
  D3D::SetDebugObjectName(m_xfbEncodeDepthState, "xfb encoder depth state");

  // Create rasterizer state

  D3D11_RASTERIZER_DESC rd = CD3D11_RASTERIZER_DESC(CD3D11_DEFAULT());
  rd.CullMode = D3D11_CULL_NONE;
  rd.DepthClipEnable = FALSE;
  hr = D3D::device->CreateRasterizerState(&rd, &m_xfbEncodeRastState);
  CHECK(SUCCEEDED(hr), "create xfb encode rasterizer state");
  D3D::SetDebugObjectName(m_xfbEncodeRastState, "xfb encoder rast state");

  // Create EFB texture sampler

  D3D11_SAMPLER_DESC sd = CD3D11_SAMPLER_DESC(CD3D11_DEFAULT());
  sd.Filter = D3D11_FILTER_MIN_MAG_LINEAR_MIP_POINT;
  hr = D3D::device->CreateSamplerState(&sd, &m_efbSampler);
  CHECK(SUCCEEDED(hr), "create xfb encode texture sampler");
  D3D::SetDebugObjectName(m_efbSampler, "xfb encoder texture sampler");
}

void XFBEncoder::Shutdown()
{
  SAFE_RELEASE(m_efbSampler);
  SAFE_RELEASE(m_xfbEncodeRastState);
  SAFE_RELEASE(m_xfbEncodeDepthState);
  SAFE_RELEASE(m_xfbEncodeBlendState);
  SAFE_RELEASE(m_pShader);
  SAFE_RELEASE(m_quadLayout);
  SAFE_RELEASE(m_vShader);
  SAFE_RELEASE(m_quad);
  SAFE_RELEASE(m_encodeParams);
  SAFE_RELEASE(m_outStage);
  SAFE_RELEASE(m_outRTV);
  SAFE_RELEASE(m_out);
}

void XFBEncoder::Encode(u8* dst, u32 width, u32 height, const EFBRectangle& srcRect, float gamma)
{
  HRESULT hr;

  // Reset API

  g_renderer->ResetAPIState();

  // Set up all the state for XFB encoding

  D3D::stateman->SetPixelShader(m_pShader);
  D3D::stateman->SetVertexShader(m_vShader);
  D3D::stateman->SetGeometryShader(nullptr);

  D3D::stateman->PushBlendState(m_xfbEncodeBlendState);
  D3D::stateman->PushDepthState(m_xfbEncodeDepthState);
  D3D::stateman->PushRasterizerState(m_xfbEncodeRastState);

  D3D11_VIEWPORT vp = CD3D11_VIEWPORT(0.f, 0.f, FLOAT(width / 2), FLOAT(height));
  D3D::context->RSSetViewports(1, &vp);

  D3D::stateman->SetInputLayout(m_quadLayout);
  D3D::stateman->SetPrimitiveTopology(D3D11_PRIMITIVE_TOPOLOGY_TRIANGLESTRIP);
  UINT stride = sizeof(QuadVertex);
  UINT offset = 0;
  D3D::stateman->SetVertexBuffer(m_quad, stride, offset);

  TargetRectangle targetRect = g_renderer->ConvertEFBRectangle(srcRect);

  XFBEncodeParams params = {0};
  params.Width = FLOAT(width);
  params.Height = FLOAT(height);
  params.TexLeft = FLOAT(targetRect.left) / g_renderer->GetTargetWidth();
  params.TexTop = FLOAT(targetRect.top) / g_renderer->GetTargetHeight();
  params.TexRight = FLOAT(targetRect.right) / g_renderer->GetTargetWidth();
  params.TexBottom = FLOAT(targetRect.bottom) / g_renderer->GetTargetHeight();
  params.Gamma = gamma;
  D3D::context->UpdateSubresource(m_encodeParams, 0, nullptr, &params, 0, 0);

  D3D::context->OMSetRenderTargets(1, &m_outRTV, nullptr);

  ID3D11ShaderResourceView* pEFB = FramebufferManager::GetResolvedEFBColorTexture()->GetSRV();

  D3D::stateman->SetVertexConstants(m_encodeParams);
  D3D::stateman->SetPixelConstants(m_encodeParams);
  D3D::stateman->SetTexture(0, pEFB);
  D3D::stateman->SetSampler(0, m_efbSampler);

  // Encode!

  D3D::stateman->Apply();
  D3D::context->Draw(4, 0);

  // Copy to staging buffer

  D3D11_BOX srcBox = CD3D11_BOX(0, 0, 0, width / 2, height, 1);
  D3D::context->CopySubresourceRegion(m_outStage, 0, 0, 0, 0, m_out, 0, &srcBox);

  // Clean up state

  D3D::context->OMSetRenderTargets(0, nullptr, nullptr);

  D3D::stateman->SetSampler(0, nullptr);
  D3D::stateman->SetTexture(0, nullptr);
  D3D::stateman->SetPixelConstants(nullptr);
  D3D::stateman->SetVertexConstants(nullptr);

  D3D::stateman->SetPixelShader(nullptr);
  D3D::stateman->SetVertexShader(nullptr);

  D3D::stateman->PopRasterizerState();
  D3D::stateman->PopDepthState();
  D3D::stateman->PopBlendState();

  // Transfer staging buffer to GameCube/Wii RAM

  D3D11_MAPPED_SUBRESOURCE map = {0};
  hr = D3D::context->Map(m_outStage, 0, D3D11_MAP_READ, 0, &map);
  CHECK(SUCCEEDED(hr), "map staging buffer");

  u8* src = (u8*)map.pData;
  for (unsigned int y = 0; y < height; ++y)
  {
    memcpy(dst, src, 2 * width);
    dst += bpmem.copyMipMapStrideChannels * 32;
    src += map.RowPitch;
  }

  D3D::context->Unmap(m_outStage, 0);

  // Restore API
  g_renderer->RestoreAPIState();
  D3D::stateman->Apply();  // force unbind efb texture as shader resource
  D3D::context->OMSetRenderTargets(1, &FramebufferManager::GetEFBColorTexture()->GetRTV(),
                                   FramebufferManager::GetEFBDepthTexture()->GetDSV());
}
}
