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

#include <vector>

#include "Core/HW/Memmap.h"
#include "VideoBackends/D3D/D3DBase.h"
#include "VideoBackends/D3D/D3DShader.h"
#include "VideoBackends/D3D/D3DState.h"
#include "VideoBackends/D3D/D3DUtil.h"
#include "VideoBackends/D3D/Television.h"
#include "VideoBackends/D3D/VertexShaderCache.h"
#include "VideoCommon/VideoConfig.h"

namespace DX11
{
static const char YUYV_DECODER_PS[] =
    "// dolphin-emu YUYV decoder pixel shader\n"

    "Texture2D Tex0 : register(t0);\n"
    "sampler Samp0 : register(s0);\n"

    "static const float3x3 YCBCR_TO_RGB = float3x3(\n"
    "1.164, 0.000, 1.596,\n"
    "1.164, -0.392, -0.813,\n"
    "1.164, 2.017, 0.000\n"
    ");\n"

    "void main(out float4 ocol0 : SV_Target, in float4 pos : SV_Position, in float2 uv0 : "
    "TEXCOORD0)\n"
    "{\n"
    "float3 sample = Tex0.Sample(Samp0, uv0).rgb;\n"

    // GameCube/Wii XFB data is in YUYV format with ITU-R Rec. BT.601 color
    // primaries, compressed to the range Y in 16..235, U and V in 16..240.
    // We want to convert it to RGB format with sRGB color primaries, with
    // range 0..255.

    // Recover RGB components
    "float3 yuv_601_sub = sample.grb - float3(16.0/255.0, 128.0/255.0, 128.0/255.0);\n"
    "float3 rgb_601 = mul(YCBCR_TO_RGB, yuv_601_sub);\n"

    // If we were really obsessed with accuracy, we would correct for the
    // differing color primaries between BT.601 and sRGB. However, this may not
    // be worth the trouble because:
    // - BT.601 defines two sets of primaries: one for NTSC and one for PAL.
    // - sRGB's color primaries are actually an intermediate between BT.601's
    //   NTSC and PAL primaries.
    // - If users even noticed any difference at all, they would be confused by
    //   the slightly-different colors in the NTSC and PAL versions of the same
    //   game.
    // - Even the game designers probably don't pay close attention to this
    //   stuff.
    // Still, instructions on how to do it can be found at
    // <http://www.poynton.com/notes/colour_and_gamma/ColorFAQ.html#RTFToC20>

    "ocol0 = float4(rgb_601, 1);\n"
    "}\n";

Television::Television() : m_yuyvTexture(nullptr), m_yuyvTextureSRV(nullptr), m_pShader(nullptr)
{
}

void Television::Init()
{
  HRESULT hr;

  // Create YUYV texture for real XFB mode

  // Initialize the texture with YCbCr black
  //
  // Some games use narrower XFB widths (Nintendo titles are fond of 608),
  // so the sampler's BorderColor won't cover the right side
  // (see sampler state below)
  const unsigned int MAX_XFB_SIZE = 2 * (MAX_XFB_WIDTH)*MAX_XFB_HEIGHT;
  std::vector<u8> fill(MAX_XFB_SIZE);
  for (size_t i = 0; i < MAX_XFB_SIZE / sizeof(u32); ++i)
    reinterpret_cast<u32*>(fill.data())[i] = 0x80108010;
  D3D11_SUBRESOURCE_DATA srd = {fill.data(), 2 * (MAX_XFB_WIDTH), 0};

  // This texture format is designed for YUYV data.
  D3D11_TEXTURE2D_DESC t2dd =
      CD3D11_TEXTURE2D_DESC(DXGI_FORMAT_G8R8_G8B8_UNORM, MAX_XFB_WIDTH, MAX_XFB_HEIGHT, 1, 1);
  hr = D3D::device->CreateTexture2D(&t2dd, &srd, &m_yuyvTexture);
  CHECK(SUCCEEDED(hr), "create tv yuyv texture");
  D3D::SetDebugObjectName(m_yuyvTexture, "tv yuyv texture");

  // Create shader resource view for YUYV texture

  D3D11_SHADER_RESOURCE_VIEW_DESC srvd = CD3D11_SHADER_RESOURCE_VIEW_DESC(
      m_yuyvTexture, D3D11_SRV_DIMENSION_TEXTURE2D, DXGI_FORMAT_G8R8_G8B8_UNORM);
  hr = D3D::device->CreateShaderResourceView(m_yuyvTexture, &srvd, &m_yuyvTextureSRV);
  CHECK(SUCCEEDED(hr), "create tv yuyv texture srv");
  D3D::SetDebugObjectName(m_yuyvTextureSRV, "tv yuyv texture srv");

  // Create YUYV-decoding pixel shader

  m_pShader = D3D::CompileAndCreatePixelShader(YUYV_DECODER_PS);
  CHECK(m_pShader != nullptr, "compile and create yuyv decoder pixel shader");
  D3D::SetDebugObjectName(m_pShader, "yuyv decoder pixel shader");

  // Create sampler state and set border color
  //
  // The default sampler border color of { 0.f, 0.f, 0.f, 0.f }
  // creates a green border around the image - see issue 6483
  // (remember, the XFB is being interpreted as YUYV, and 0,0,0,0
  // is actually two green pixels in YUYV - black should be 16,128,16,128,
  // but we reverse the order to match DXGI_FORMAT_G8R8_G8B8_UNORM's ordering)
  float border[4] = {128.0f / 255.0f, 16.0f / 255.0f, 128.0f / 255.0f, 16.0f / 255.0f};
  D3D11_SAMPLER_DESC samDesc = CD3D11_SAMPLER_DESC(
      D3D11_FILTER_MIN_MAG_MIP_LINEAR, D3D11_TEXTURE_ADDRESS_BORDER, D3D11_TEXTURE_ADDRESS_BORDER,
      D3D11_TEXTURE_ADDRESS_BORDER, 0.f, 1, D3D11_COMPARISON_ALWAYS, border, 0.f, 0.f);
  hr = D3D::device->CreateSamplerState(&samDesc, &m_samplerState);
  CHECK(SUCCEEDED(hr), "create yuyv decoder sampler state");
  D3D::SetDebugObjectName(m_samplerState, "yuyv decoder sampler state");
}

void Television::Shutdown()
{
  SAFE_RELEASE(m_pShader);
  SAFE_RELEASE(m_yuyvTextureSRV);
  SAFE_RELEASE(m_yuyvTexture);
  SAFE_RELEASE(m_samplerState);
}

void Television::Submit(u32 xfbAddr, u32 stride, u32 width, u32 height)
{
  m_curAddr = xfbAddr;
  m_curWidth = width;
  m_curHeight = height;

  // Load data from GameCube RAM to YUYV texture
  u8* yuyvSrc = Memory::GetPointer(xfbAddr);
  D3D11_BOX box = CD3D11_BOX(0, 0, 0, stride, height, 1);
  D3D::context->UpdateSubresource(m_yuyvTexture, 0, &box, yuyvSrc, 2 * stride, 2 * stride * height);
}

void Television::Render()
{
  if (g_ActiveConfig.bUseRealXFB && g_ActiveConfig.bUseXFB)
  {
    // Use real XFB mode
    // TODO: If this is the lower field, render at a vertical offset of 1
    // line down. We could even consider implementing a deinterlacing
    // algorithm.

    D3D11_RECT sourceRc = CD3D11_RECT(0, 0, int(m_curWidth), int(m_curHeight));

    D3D::stateman->SetSampler(0, m_samplerState);

    D3D::drawShadedTexQuad(m_yuyvTextureSRV, &sourceRc, MAX_XFB_WIDTH, MAX_XFB_HEIGHT, m_pShader,
                           VertexShaderCache::GetSimpleVertexShader(),
                           VertexShaderCache::GetSimpleInputLayout());
  }
  else if (g_ActiveConfig.bUseXFB)
  {
    // Use virtual XFB mode

    // TODO: Eventually, Television should render the Virtual XFB mode
    // display as well.
  }
}
}
