// 
//---------------------------------------------------------------------------
//
// Copyright(C) 2004-2016 Christoph Oelckers
// All rights reserved.
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// 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 Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with this program.  If not, see http://www.gnu.org/licenses/
//
//--------------------------------------------------------------------------
//

#ifndef __GL_SHADERS_H__
#define __GL_SHADERS_H__

#include "gl_renderstate.h"
#include "name.h"

extern bool gl_shaderactive;

struct HWViewpointUniforms;

namespace OpenGLRenderer
{
	class FShaderCollection;

//==========================================================================
//
//
//==========================================================================

class FUniform1i
{
	int mIndex;

public:
	void Init(GLuint hShader, const GLchar *name)
	{
		mIndex = glGetUniformLocation(hShader, name);
	}

	void Set(int newvalue)
	{
		glUniform1i(mIndex, newvalue);
	}
};

class FBufferedUniform1i
{
	int mBuffer;
	int mIndex;

public:
	void Init(GLuint hShader, const GLchar *name)
	{
		mIndex = glGetUniformLocation(hShader, name);
		mBuffer = 0;
	}

	void Set(int newvalue)
	{
		if (newvalue != mBuffer)
		{
			mBuffer = newvalue;
			glUniform1i(mIndex, newvalue);
		}
	}
};

class FBufferedUniform4i
{
	int mBuffer[4];
	int mIndex;

public:
	void Init(GLuint hShader, const GLchar *name)
	{
		mIndex = glGetUniformLocation(hShader, name);
		memset(mBuffer, 0, sizeof(mBuffer));
	}

	void Set(const int *newvalue)
	{
		if (memcmp(newvalue, mBuffer, sizeof(mBuffer)))
		{
			memcpy(mBuffer, newvalue, sizeof(mBuffer));
			glUniform4iv(mIndex, 1, newvalue);
		}
	}
};

class FBufferedUniform1f
{
	float mBuffer;
	int mIndex;

public:
	void Init(GLuint hShader, const GLchar *name)
	{
		mIndex = glGetUniformLocation(hShader, name);
		mBuffer = 0;
	}

	void Set(float newvalue)
	{
		if (newvalue != mBuffer)
		{
			mBuffer = newvalue;
			glUniform1f(mIndex, newvalue);
		}
	}
};

class FBufferedUniform2f
{
	float mBuffer[2];
	int mIndex;

public:
	void Init(GLuint hShader, const GLchar *name)
	{
		mIndex = glGetUniformLocation(hShader, name);
		memset(mBuffer, 0, sizeof(mBuffer));
	}

	void Set(const float *newvalue)
	{
		if (memcmp(newvalue, mBuffer, sizeof(mBuffer)))
		{
			memcpy(mBuffer, newvalue, sizeof(mBuffer));
			glUniform2fv(mIndex, 1, newvalue);
		}
	}

	void Set(float f1, float f2)
	{
		if (mBuffer[0] != f1 || mBuffer[1] != f2)
		{
			mBuffer[0] = f1;
			mBuffer[1] = f2;
			glUniform2fv(mIndex, 1, mBuffer);
		}
	}

};

class FBufferedUniform4f
{
	float mBuffer[4];
	int mIndex;

public:
	void Init(GLuint hShader, const GLchar *name)
	{
		mIndex = glGetUniformLocation(hShader, name);
		memset(mBuffer, 0, sizeof(mBuffer));
	}

	void Set(const float *newvalue)
	{
		if (memcmp(newvalue, mBuffer, sizeof(mBuffer)))
		{
			memcpy(mBuffer, newvalue, sizeof(mBuffer));
			glUniform4fv(mIndex, 1, newvalue);
		}
	}
};

class FUniform4f
{
	int mIndex;

public:
	void Init(GLuint hShader, const GLchar *name)
	{
		mIndex = glGetUniformLocation(hShader, name);
	}

	void Set(const float *newvalue)
	{
		glUniform4fv(mIndex, 1, newvalue);
	}

	void Set(float a, float b, float c, float d)
	{
		glUniform4f(mIndex, a, b, c, d);
	}

	void Set(PalEntry newvalue)
	{
		glUniform4f(mIndex, newvalue.r / 255.f, newvalue.g / 255.f, newvalue.b / 255.f, newvalue.a / 255.f);
	}

};

class FBufferedUniformPE
{
	FVector4PalEntry mBuffer;
	int mIndex;

public:
	void Init(GLuint hShader, const GLchar *name)
	{
		mIndex = glGetUniformLocation(hShader, name);
		mBuffer = 0;
	}

	void Set(const FVector4PalEntry &newvalue)
	{
		if (newvalue != mBuffer)
		{
			mBuffer = newvalue;
			glUniform4f(mIndex, newvalue.r, newvalue.g, newvalue.b, newvalue.a);
		}
	}
};

class FShader
{
	friend class FShaderCollection;
	friend class FGLRenderState;

	unsigned int hShader;
	unsigned int hVertProg;
	unsigned int hFragProg;
	FName mName;

	FBufferedUniform1f muDesaturation;
	FBufferedUniform1i muFogEnabled;
	FBufferedUniform1i muTextureMode;
	FBufferedUniform4f muLightParms;
	FBufferedUniform2f muClipSplit;
	FBufferedUniform1i muLightIndex;
	FBufferedUniformPE muFogColor;
	FBufferedUniform4f muDynLightColor;
	FBufferedUniformPE muObjectColor;
	FBufferedUniformPE muObjectColor2;
	FBufferedUniformPE muAddColor;
	FBufferedUniformPE muTextureBlendColor;
	FBufferedUniformPE muTextureModulateColor;
	FBufferedUniformPE muTextureAddColor;
	FUniform4f muGlowBottomColor;
	FUniform4f muGlowTopColor;
	FUniform4f muGlowBottomPlane;
	FUniform4f muGlowTopPlane;
	FUniform4f muGradientBottomPlane;
	FUniform4f muGradientTopPlane;
	FUniform4f muSplitBottomPlane;
	FUniform4f muSplitTopPlane;
	FUniform4f muDetailParms;
	FBufferedUniform1f muInterpolationFactor;
	FBufferedUniform1f muAlphaThreshold;
	FBufferedUniform2f muSpecularMaterial;
	FBufferedUniform1f muTimer;
#ifdef NPOT_EMULATION
	FBufferedUniform2f muNpotEmulation;
#endif

	int lights_index;
	int modelmatrix_index;
	int normalmodelmatrix_index;
	int texturematrix_index;

	int currentglowstate = 0;
	int currentgradientstate = 0;
	int currentsplitstate = 0;
	int currentcliplinestate = 0;
	int currentfixedcolormap = 0;
	bool currentTextureMatrixState = true;// by setting the matrix state to 'true' it is guaranteed to be set the first time the render state gets applied.
	bool currentModelMatrixState = true;

public:
	FShader(const char *name)
		: mName(name)
	{
		hShader = hVertProg = hFragProg = 0;
	}

	~FShader();

	bool Load(const char * name, const char * vert_prog_lump, const char * fragprog, const char * fragprog2, const char * light_fragprog, const char *defines);

	bool Bind();
	unsigned int GetHandle() const { return hShader; }
};

//==========================================================================
//
// The global shader manager
//
//==========================================================================
class FShaderManager
{
public:
	FShaderManager();
	~FShaderManager();

	FShader *BindEffect(int effect, EPassType passType);
	FShader *Get(unsigned int eff, bool alphateston, EPassType passType);

	void SetActiveShader(FShader *sh);
	bool CompileNextShader();
private:

	FShader *mActiveShader = nullptr;
	TArray<FShaderCollection*> mPassShaders;
	int mCompilePass = 0;

	friend class FShader;
};

class FShaderCollection
{
	TArray<FShader*> mMaterialShaders;
	TArray<FShader*> mMaterialShadersNAT;
	FShader *mEffectShaders[MAX_EFFECTS];
	int mCompileState = 0, mCompileIndex = 0;
	EPassType mPassType;

	void Clean();

public:
	FShaderCollection(EPassType passType);
	~FShaderCollection();
	FShader *Compile(const char *ShaderName, const char *ShaderPath, const char *LightModePath, const char *shaderdefines, bool usediscard, EPassType passType);
	int Find(const char *mame);
	bool CompileNextShader();
	FShader *BindEffect(int effect);

	FShader *Get(unsigned int eff, bool alphateston)
	{
		// indices 0-2 match the warping modes, 3 no texture, the following are custom
		if (!alphateston && eff < SHADER_NoTexture && mCompileState == -1)
		{
			return mMaterialShadersNAT[eff];	// Non-alphatest shaders are only created for default, warp1+2 and brightmap. The rest won't get used anyway
		}
		if (eff < mMaterialShaders.Size())
		{
			return mMaterialShaders[eff];
		}
		return NULL;
	}
};

}
#endif