// Copyright (C) 2003 Dolphin Project.

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, version 2.0.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License 2.0 for more details.

// A copy of the GPL 2.0 should have been included with the program.
// If not, see http://www.gnu.org/licenses/

// Official SVN repository and contact information can be found at
// http://code.google.com/p/dolphin-emu/

#include "PointGeometryShader.h"

#include <sstream>
#include "D3DBase.h"
#include "D3DShader.h"
#include "VertexShaderGen.h"

namespace DX11
{

union PointGSParams
{
	struct
	{
		FLOAT PointSize; // In units of 1/6 of an EFB pixel
		FLOAT TexOffset;
		FLOAT VpWidth; // Width and height of viewport in EFB pixels
		FLOAT VpHeight;
	};
	// Constant buffers must be a multiple of 16 bytes in size.
	u8 pad[16]; // Pad to the next multiple of 16 bytes
};

static const char POINT_GS_COMMON[] =
// The struct VS_OUTPUT used by the vertex shader goes here.
"// dolphin-emu point geometry shader common part\n"

"cbuffer cbParams : register(b0)\n"
"{\n"
	"struct\n" // Should match PointGSParams above
	"{\n"
		"float PointSize;\n"
		"float TexOffset;\n"
		"float VpWidth;\n"
		"float VpHeight;\n"
	"} Params;\n"
"}\n"

"[maxvertexcount(4)]\n"
"void main(point VS_OUTPUT input[1], inout TriangleStream<VS_OUTPUT> outStream)\n"
"{\n"
	"VS_OUTPUT ptLL = input[0];\n"
	"VS_OUTPUT ptLR = ptLL;\n"
	"VS_OUTPUT ptUL = ptLL;\n"
	"VS_OUTPUT ptUR = ptLL;\n"

	// Offset from center to upper right vertex
	// Lerp Params.PointSize/2 from [0,0..VpWidth,VpHeight] to [-1,1..1,-1]
	"float2 offset = float2(Params.PointSize/Params.VpWidth, -Params.PointSize/Params.VpHeight) * input[0].pos.w;\n"

	"ptLL.pos.xy += float2(-1,-1) * offset;\n"
	"ptLR.pos.xy += float2(1,-1) * offset;\n"
	"ptUL.pos.xy += float2(-1,1) * offset;\n"
	"ptUR.pos.xy += offset;\n"

	"float2 texOffset = float2(Params.TexOffset, Params.TexOffset);\n"

"#ifndef NUM_TEXCOORDS\n"
"#error NUM_TEXCOORDS not defined\n"
"#endif\n"

	// Apply TexOffset to all tex coordinates in the vertex
	// FIXME: The game may be able to enable TexOffset for some coords and
	// disable for others, but where is that information stored?
"#if NUM_TEXCOORDS >= 1\n"
	"ptLL.tex0.xy += float2(0,1) * texOffset;\n"
	"ptLR.tex0.xy += texOffset;\n"
	"ptUR.tex0.xy += float2(1,0) * texOffset;\n"
"#endif\n"
"#if NUM_TEXCOORDS >= 2\n"
	"ptLL.tex1.xy += float2(0,1) * texOffset;\n"
	"ptLR.tex1.xy += texOffset;\n"
	"ptUR.tex1.xy += float2(1,0) * texOffset;\n"
"#endif\n"
"#if NUM_TEXCOORDS >= 3\n"
	"ptLL.tex2.xy += float2(0,1) * texOffset;\n"
	"ptLR.tex2.xy += texOffset;\n"
	"ptUR.tex2.xy += float2(1,0) * texOffset;\n"
"#endif\n"
"#if NUM_TEXCOORDS >= 4\n"
	"ptLL.tex3.xy += float2(0,1) * texOffset;\n"
	"ptLR.tex3.xy += texOffset;\n"
	"ptUR.tex3.xy += float2(1,0) * texOffset;\n"
"#endif\n"
"#if NUM_TEXCOORDS >= 5\n"
	"ptLL.tex4.xy += float2(0,1) * texOffset;\n"
	"ptLR.tex4.xy += texOffset;\n"
	"ptUR.tex4.xy += float2(1,0) * texOffset;\n"
"#endif\n"
"#if NUM_TEXCOORDS >= 6\n"
	"ptLL.tex5.xy += float2(0,1) * texOffset;\n"
	"ptLR.tex5.xy += texOffset;\n"
	"ptUR.tex5.xy += float2(1,0) * texOffset;\n"
"#endif\n"
"#if NUM_TEXCOORDS >= 7\n"
	"ptLL.tex6.xy += float2(0,1) * texOffset;\n"
	"ptLR.tex6.xy += texOffset;\n"
	"ptUR.tex6.xy += float2(1,0) * texOffset;\n"
"#endif\n"
"#if NUM_TEXCOORDS >= 8\n"
	"ptLL.tex7.xy += float2(0,1) * texOffset;\n"
	"ptLR.tex7.xy += texOffset;\n"
	"ptUR.tex7.xy += float2(1,0) * texOffset;\n"
"#endif\n"

	"outStream.Append(ptLL);\n"
	"outStream.Append(ptLR);\n"
	"outStream.Append(ptUL);\n"
	"outStream.Append(ptUR);\n"
"}\n"
;

PointGeometryShader::PointGeometryShader()
	: m_ready(false)
{
	// Create constant buffer for uploading data to geometry shader

	D3D11_BUFFER_DESC bd = CD3D11_BUFFER_DESC(sizeof(PointGSParams),
		D3D11_BIND_CONSTANT_BUFFER);
	m_paramsBuffer = CreateBufferShared(&bd, NULL);
	CHECK(m_paramsBuffer, "create point geometry shader params buffer");
	D3D::SetDebugObjectName(m_paramsBuffer, "point geometry shader params buffer");

	m_ready = true;
}

bool PointGeometryShader::SetShader(u32 components, float pointSize,
	float texOffset, float vpWidth, float vpHeight)
{
	if (!m_ready)
		return false;

	// Make sure geometry shader for "components" is available
	ComboMap::iterator shaderIt = m_shaders.find(components);
	if (shaderIt == m_shaders.end())
	{
		// Generate new shader. Warning: not thread-safe.
		static char code[16384];
		char* p = code;
		p = GenerateVSOutputStruct(p, components, API_D3D11);
		p += sprintf(p, "\n%s", POINT_GS_COMMON);
		
		std::stringstream numTexCoordsStr;
		numTexCoordsStr << xfregs.numTexGen.numTexGens;

		INFO_LOG(VIDEO, "Compiling point geometry shader for components 0x%.08X (num texcoords %d)",
			components, xfregs.numTexGen.numTexGens);

		D3D_SHADER_MACRO macros[] = {
			{ "NUM_TEXCOORDS", numTexCoordsStr.str().c_str() },
			{ NULL, NULL }
		};
		
		auto const newShader = D3D::CompileAndCreateGeometryShader(code, unsigned int(strlen(code)), macros);
		if (!newShader)
		{
			WARN_LOG(VIDEO, "Point geometry shader for components 0x%.08X failed to compile", components);
			// Add dummy shader to prevent trying to compile again
			m_shaders[components].reset();
			return false;
		}

		shaderIt = m_shaders.insert(std::make_pair(components, newShader)).first;
	}

	if (shaderIt != m_shaders.end())
	{
		if (shaderIt->second)
		{
			PointGSParams params = {};
			params.PointSize = pointSize;
			params.TexOffset = texOffset;
			params.VpWidth = vpWidth;
			params.VpHeight = vpHeight;
			D3D::g_context->UpdateSubresource(m_paramsBuffer, 0, NULL, &params, 0, 0);
			
			DEBUG_LOG(VIDEO, "Point params: size %f, texOffset %f, vpWidth %f, vpHeight %f",
				pointSize, texOffset, vpWidth, vpHeight);

			D3D::g_context->GSSetShader(shaderIt->second, NULL, 0);
			D3D::g_context->GSSetConstantBuffers(0, 1, &m_paramsBuffer);

			return true;
		}
		else
			return false;
	}
	else
		return false;
}

}