// 
//---------------------------------------------------------------------------
//
// 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/
//
//--------------------------------------------------------------------------
//
/*
** gltexture.cpp
** Low level OpenGL texture handling. These classes are also
** containers for the various translations a texture can have.
**
*/

#include "gl_load/gl_system.h"
#include "templates.h"
#include "c_cvars.h"
#include "r_data/colormaps.h"
#include "hwrenderer/textures/hw_material.h"

#include "gl_load/gl_interface.h"
#include "hwrenderer/utility/hw_cvars.h"
#include "gl/system/gl_debug.h"
#include "gl/renderer/gl_renderer.h"
#include "gl/renderer/gl_renderstate.h"
#include "gl/textures/gl_samplers.h"

namespace OpenGLRenderer
{


TexFilter_s TexFilter[]={
	{GL_NEAREST,					GL_NEAREST,		false},
	{GL_NEAREST_MIPMAP_NEAREST,		GL_NEAREST,		true},
	{GL_LINEAR,						GL_LINEAR,		false},
	{GL_LINEAR_MIPMAP_NEAREST,		GL_LINEAR,		true},
	{GL_LINEAR_MIPMAP_LINEAR,		GL_LINEAR,		true},
	{GL_NEAREST_MIPMAP_LINEAR,		GL_NEAREST,		true},
	{GL_LINEAR_MIPMAP_LINEAR,		GL_NEAREST,		true},
};

int TexFormat[]={
	GL_RGBA8,
	GL_RGB5_A1,
	GL_RGBA4,
	GL_RGBA2,
	// [BB] Added compressed texture formats.
	GL_COMPRESSED_RGBA_ARB,
	GL_COMPRESSED_RGBA_S3TC_DXT1_EXT,
	GL_COMPRESSED_RGBA_S3TC_DXT3_EXT,
	GL_COMPRESSED_RGBA_S3TC_DXT5_EXT,
};



//===========================================================================
// 
//	Static texture data
//
//===========================================================================
unsigned int FHardwareTexture::lastbound[FHardwareTexture::MAX_TEXTURES];

//===========================================================================
// 
//	Loads the texture image into the hardware
//
// NOTE: For some strange reason I was unable to find the source buffer
// should be one line higher than the actual texture. I got extremely
// strange crashes deep inside the GL driver when I didn't do it!
//
//===========================================================================

unsigned int FHardwareTexture::CreateTexture(unsigned char * buffer, int w, int h, int texunit, bool mipmap, int translation, const char *name)
{
	int rh,rw;
	int texformat = GL_RGBA8;// TexFormat[gl_texture_format];
	bool deletebuffer=false;

	/*
	if (forcenocompression)
	{
		texformat = GL_RGBA8;
	}
	*/
	bool firstCall = glTexID == 0;
	if (firstCall)
	{
		glGenTextures(1, &glTexID);
	}

	int textureBinding = UINT_MAX;
	if (texunit == -1)	glGetIntegerv(GL_TEXTURE_BINDING_2D, &textureBinding);
	if (texunit > 0) glActiveTexture(GL_TEXTURE0+texunit);
	if (texunit >= 0) lastbound[texunit] = glTexID;
	glBindTexture(GL_TEXTURE_2D, glTexID);

	FGLDebug::LabelObject(GL_TEXTURE, glTexID, name);

	rw = GetTexDimension(w);
	rh = GetTexDimension(h);
	if (glBufferID > 0)
	{
		glUnmapBuffer(GL_PIXEL_UNPACK_BUFFER);
		buffer = nullptr;
	}
	else if (!buffer)
	{
		// The texture must at least be initialized if no data is present.
		mipmapped = false;
		buffer=(unsigned char *)calloc(4,rw * (rh+1));
		deletebuffer=true;
		//texheight=-h;	
	}
	else
	{
		if (rw < w || rh < h)
		{
			// The texture is larger than what the hardware can handle so scale it down.
			unsigned char * scaledbuffer=(unsigned char *)calloc(4,rw * (rh+1));
			if (scaledbuffer)
			{
				Resize(w, h, rw, rh, buffer, scaledbuffer);
				deletebuffer=true;
				buffer=scaledbuffer;
			}
		}
	}
	// store the physical size.

	int sourcetype;
	if (glTextureBytes > 0)
	{
		if (glTextureBytes < 4) glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
		static const int ITypes[] = { GL_R8, GL_RG8, GL_RGB8, GL_RGBA8 };
		static const int STypes[] = { GL_RED, GL_RG, GL_BGR, GL_BGRA };

		texformat = ITypes[glTextureBytes - 1];
		sourcetype = STypes[glTextureBytes - 1];
	}
	else
	{
		sourcetype = GL_BGRA;
	}
	
	if (!firstCall && glBufferID > 0)
		glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, rw, rh, sourcetype, GL_UNSIGNED_BYTE, buffer);
	else
		glTexImage2D(GL_TEXTURE_2D, 0, texformat, rw, rh, 0, sourcetype, GL_UNSIGNED_BYTE, buffer);

	if (deletebuffer && buffer) free(buffer);
	else if (glBufferID)
	{
		glPixelStorei(GL_UNPACK_ALIGNMENT, 4);
		glBindBuffer(GL_PIXEL_UNPACK_BUFFER, 0);
	}

	if (mipmap && TexFilter[gl_texture_filter].mipmapping)
	{
		glGenerateMipmap(GL_TEXTURE_2D);
		mipmapped = true;
	}

	if (texunit > 0) glActiveTexture(GL_TEXTURE0);
	else if (texunit == -1) glBindTexture(GL_TEXTURE_2D, textureBinding);
	return glTexID;
}


//===========================================================================
// 
//
//
//===========================================================================
void FHardwareTexture::AllocateBuffer(int w, int h, int texelsize)
{
	int rw = GetTexDimension(w);
	int rh = GetTexDimension(h);
	if (texelsize < 1 || texelsize > 4) texelsize = 4;
	glTextureBytes = texelsize;
	if (rw == w || rh == h)
	{
		glGenBuffers(1, &glBufferID);
		glBindBuffer(GL_PIXEL_UNPACK_BUFFER, glBufferID);
		glBufferData(GL_PIXEL_UNPACK_BUFFER, w*h*texelsize, nullptr, GL_STREAM_DRAW);
		glBindBuffer(GL_PIXEL_UNPACK_BUFFER, 0);
	}
}


uint8_t *FHardwareTexture::MapBuffer()
{
	glBindBuffer(GL_PIXEL_UNPACK_BUFFER, glBufferID);
	return (uint8_t*)glMapBuffer(GL_PIXEL_UNPACK_BUFFER, GL_WRITE_ONLY);
}

//===========================================================================
// 
//	Destroys the texture
//
//===========================================================================
FHardwareTexture::~FHardwareTexture() 
{ 
	if (glTexID != 0) glDeleteTextures(1, &glTexID);
	if (glBufferID != 0) glDeleteBuffers(1, &glBufferID);
}


//===========================================================================
// 
//	Binds this patch
//
//===========================================================================
unsigned int FHardwareTexture::Bind(int texunit, bool needmipmap)
{
	if (glTexID != 0)
	{
		if (lastbound[texunit] == glTexID) return glTexID;
		lastbound[texunit] = glTexID;
		if (texunit != 0) glActiveTexture(GL_TEXTURE0 + texunit);
		glBindTexture(GL_TEXTURE_2D, glTexID);
		// Check if we need mipmaps on a texture that was creted without them.
		if (needmipmap && !mipmapped && TexFilter[gl_texture_filter].mipmapping)
		{
			glGenerateMipmap(GL_TEXTURE_2D);
			mipmapped = true;
		}
		if (texunit != 0) glActiveTexture(GL_TEXTURE0);
		return glTexID;
	}
	return 0;
}

unsigned int FHardwareTexture::GetTextureHandle(int translation)
{
	return glTexID;
}

void FHardwareTexture::Unbind(int texunit)
{
	if (lastbound[texunit] != 0)
	{
		if (texunit != 0) glActiveTexture(GL_TEXTURE0+texunit);
		glBindTexture(GL_TEXTURE_2D, 0);
		if (texunit != 0) glActiveTexture(GL_TEXTURE0);
		lastbound[texunit] = 0;
	}
}

void FHardwareTexture::UnbindAll()
{
	for(int texunit = 0; texunit < 16; texunit++)
	{
		Unbind(texunit);
	}
	gl_RenderState.ClearLastMaterial();
}

//===========================================================================
// 
//	Creates a depth buffer for this texture
//
//===========================================================================

int FHardwareTexture::GetDepthBuffer(int width, int height)
{
	if (glDepthID == 0)
	{
		glGenRenderbuffers(1, &glDepthID);
		glBindRenderbuffer(GL_RENDERBUFFER, glDepthID);
		glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH24_STENCIL8, 
			GetTexDimension(width), GetTexDimension(height));
		glBindRenderbuffer(GL_RENDERBUFFER, 0);
	}
	return glDepthID;
}


//===========================================================================
// 
//	Binds this texture's surfaces to the current framrbuffer
//
//===========================================================================

void FHardwareTexture::BindToFrameBuffer(int width, int height)
{
	width = GetTexDimension(width);
	height = GetTexDimension(height);
	glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, glTexID, 0);
	glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, GetDepthBuffer(width, height));
	glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_STENCIL_ATTACHMENT, GL_RENDERBUFFER, GetDepthBuffer(width, height));
}


//===========================================================================
// 
//	Binds a texture to the renderer
//
//===========================================================================

bool FHardwareTexture::BindOrCreate(FTexture *tex, int texunit, int clampmode, int translation, int flags)
{
	int usebright = false;

	if (translation <= 0)
	{
		translation = -translation;
	}
	else
	{
		auto remap = TranslationToTable(translation);
		translation = remap == nullptr ? 0 : remap->GetUniqueIndex();
	}

	bool needmipmap = (clampmode <= CLAMP_XY);

	// Bind it to the system.
	if (!Bind(texunit, needmipmap))
	{

		int w = 0, h = 0;

		// Create this texture
		
		FTextureBuffer texbuffer;

		if (!tex->isHardwareCanvas())
		{
			texbuffer = tex->CreateTexBuffer(translation, flags | CTF_ProcessData);
			w = texbuffer.mWidth;
			h = texbuffer.mHeight;
		}
		else
		{
			w = tex->GetWidth();
			h = tex->GetHeight();
		}
		if (!CreateTexture(texbuffer.mBuffer, w, h, texunit, needmipmap, translation, "FHardwareTexture.BindOrCreate"))
		{
			// could not create texture
			return false;
		}
	}
	if (tex->isHardwareCanvas()) static_cast<FCanvasTexture*>(tex)->NeedUpdate();
	GLRenderer->mSamplerManager->Bind(texunit, clampmode, 255);
	return true;
}

}
