// Copyright 2013 Dolphin Emulator Project
// Licensed under GPLv2
// Refer to the license.txt file included.

#include "Television.h"

#include "VideoConfig.h"
#include "D3DBase.h"
#include "D3DShader.h"
#include "D3DUtil.h"
#include "VertexShaderCache.h"
#include "HW/Memmap.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(NULL), m_yuyvTextureSRV(NULL), m_pShader(NULL)
{ }

void Television::Init()
{
	HRESULT hr;

	// Create YUYV texture for real XFB mode

	// 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, NULL, &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, sizeof(YUYV_DECODER_PS));
	CHECK(m_pShader != NULL, "compile and create yuyv decoder pixel shader");
	D3D::SetDebugObjectName(m_pShader, "yuyv decoder pixel shader");
}

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

void Television::Submit(u32 xfbAddr, 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, width, height, 1);
	D3D::context->UpdateSubresource(m_yuyvTexture, 0, &box, yuyvSrc, 2*width, 2*width*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.

		MathUtil::Rectangle<float> sourceRc(0.f, 0.f, float(m_curWidth), float(m_curHeight));
		MathUtil::Rectangle<float> destRc(-1.f, 1.f, 1.f, -1.f);

		D3D::drawShadedTexSubQuad(
			m_yuyvTextureSRV, &sourceRc,
			MAX_XFB_WIDTH, MAX_XFB_HEIGHT,
			&destRc,
			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.
	}
}

}