/*
 * OpenClonk, http://www.openclonk.org
 *
 * Copyright (c) 2002, 2005-2006, 2010  Sven Eberhardt
 * Copyright (c) 2005-2012  Günther Brammer
 * Copyright (c) 2007  Julian Raschke
 * Copyright (c) 2008  Matthes Bender
 * Copyright (c) 2009  Carl-Philip Hänsch
 * Copyright (c) 2009-2012  Armin Burgmeier
 * Copyright (c) 2009-2010  Nicolas Hake
 * Copyright (c) 2010  Benjamin Herr
 * Copyright (c) 2012  Julius Michaelis
 * Copyright (c) 2012  Bernhard Bonigl
 * Copyright (c) 2001-2009, RedWolf Design GmbH, http://www.clonk.de
 *
 * Portions might be copyrighted by other authors who have contributed
 * to OpenClonk.
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 * See isc_license.txt for full license and disclaimer.
 *
 * "Clonk" is a registered trademark of Matthes Bender.
 * See clonk_trademark_license.txt for full license.
 */

/* OpenGL implementation of NewGfx */

#include "C4Include.h"
#include <C4DrawGL.h>

#include <C4Surface.h>
#include <C4Window.h>
#include "C4Rect.h"
#include "C4Config.h"
#include "C4Application.h"

#ifdef USE_GL

// MSVC doesn't define M_PI in math.h unless requested
#ifdef  _MSC_VER
#define _USE_MATH_DEFINES
#endif  /* _MSC_VER */

#include <stdio.h>
#include <math.h>
#include <limits.h>

static void glColorDw(DWORD dwClr)
{
	glColor4ub(GLubyte(dwClr>>16), GLubyte(dwClr>>8), GLubyte(dwClr), GLubyte(dwClr>>24));
}

// GLubyte (&r)[4] is a reference to an array of four bytes named r.
static void DwTo4UB(DWORD dwClr, GLubyte (&r)[4])
{
	//unsigned char r[4];
	r[0] = GLubyte(dwClr>>16);
	r[1] = GLubyte(dwClr>>8);
	r[2] = GLubyte(dwClr);
	r[3] = GLubyte(dwClr>>24);
}

CStdGL::CStdGL():
		pMainCtx(0)
{
	Default();
	byByteCnt=4;
	// global ptr
	pGL = this;
	shaders[0] = 0;
	vbo = 0;
	lines_tex = 0;
}

CStdGL::~CStdGL()
{
	Clear();
	pGL=NULL;
}

void CStdGL::Clear()
{
	NoPrimaryClipper();
	//if (pTexMgr) pTexMgr->IntUnlock(); // cannot do this here or we can't preserve textures across GL reinitialization as required when changing multisampling
	InvalidateDeviceObjects();
	NoPrimaryClipper();
	RenderTarget = NULL;
	// clear context
	if (pCurrCtx) pCurrCtx->Deselect();
	pMainCtx=0;
	C4Draw::Clear();
}

void CStdGL::FillBG(DWORD dwClr)
{
	if (!pCurrCtx) return;
	glClearColor((float)GetRedValue(dwClr)/255.0f, (float)GetGreenValue(dwClr)/255.0f, (float)GetBlueValue(dwClr)/255.0f, 0.0f);
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
}

bool CStdGL::UpdateClipper()
{
	// no render target? do nothing
	if (!RenderTarget || !Active) return true;
	// negative/zero?
	int iWdt=Min(iClipX2, RenderTarget->Wdt-1)-iClipX1+1;
	int iHgt=Min(iClipY2, RenderTarget->Hgt-1)-iClipY1+1;
	int iX=iClipX1; if (iX<0) { iWdt+=iX; iX=0; }
	int iY=iClipY1; if (iY<0) { iHgt+=iY; iY=0; }

	if (iWdt<=0 || iHgt<=0)
	{
		ClipAll=true;
		return true;
	}
	ClipAll=false;
	// set it
	glViewport(iX, RenderTarget->Hgt-iY-iHgt, iWdt, iHgt);
	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();

	// Set clipping plane to -1000 and 1000 so that large meshes are not
	// clipped away.
	//glOrtho((GLdouble) iX, (GLdouble) (iX+iWdt), (GLdouble) (iY+iHgt), (GLdouble) iY, -1000.0f, 1000.0f);
	gluOrtho2D((GLdouble) iX, (GLdouble) (iX+iWdt), (GLdouble) (iY+iHgt), (GLdouble) iY);
	//gluOrtho2D((GLdouble) 0, (GLdouble) xRes, (GLdouble) yRes, (GLdouble) yRes-iHgt);
	return true;
}

bool CStdGL::PrepareRendering(C4Surface * sfcToSurface)
{
	// call from gfx thread only!
	if (!pApp || !pApp->AssertMainThread()) return false;
	// not ready?
	if (!Active)
		//if (!RestoreDeviceObjects())
		return false;
	// target?
	if (!sfcToSurface) return false;
	// target locked?
	if (sfcToSurface->Locked) return false;
	// target is already set as render target?
	if (sfcToSurface != RenderTarget)
	{
		// target is a render-target?
		if (!sfcToSurface->IsRenderTarget()) return false;
		// context
		if (sfcToSurface->pCtx && sfcToSurface->pCtx != pCurrCtx)
			if (!sfcToSurface->pCtx->Select()) return false;
		// set target
		RenderTarget=sfcToSurface;
		// new target has different size; needs other clipping rect
		UpdateClipper();
	}
	// done
	return true;
}

void CStdGL::SetupTextureEnv(bool fMod2, bool landscape)
{
	if (shaders[0])
	{
		GLuint s = landscape ? 2 : (fMod2 ? 1 : 0);
		if (Saturation < 255)
		{
			s += 3;
		}
		if (fUseClrModMap)
		{
			s += 6;
		}
		glBindProgramARB(GL_FRAGMENT_PROGRAM_ARB, shaders[s]);
		if (Saturation < 255)
		{
			GLfloat bla[4] = { Saturation / 255.0f, Saturation / 255.0f, Saturation / 255.0f, 1.0f };
			glProgramLocalParameter4fvARB(GL_FRAGMENT_PROGRAM_ARB, 0, bla);
		}
	}
	// texture environment
	else
	{
		glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_COMBINE);
		glTexEnvi(GL_TEXTURE_ENV, GL_COMBINE_RGB, fMod2 ? GL_ADD_SIGNED : GL_MODULATE);
		glTexEnvf(GL_TEXTURE_ENV, GL_RGB_SCALE, fMod2 ? 2.0f : 1.0f);
		glTexEnvi(GL_TEXTURE_ENV, GL_COMBINE_ALPHA, GL_MODULATE);
		glTexEnvi(GL_TEXTURE_ENV, GL_SOURCE0_RGB, GL_TEXTURE);
		glTexEnvi(GL_TEXTURE_ENV, GL_SOURCE1_RGB, GL_PRIMARY_COLOR);
		glTexEnvi(GL_TEXTURE_ENV, GL_SOURCE0_ALPHA, GL_TEXTURE);
		glTexEnvi(GL_TEXTURE_ENV, GL_SOURCE1_ALPHA, GL_PRIMARY_COLOR);
		glTexEnvi(GL_TEXTURE_ENV, GL_OPERAND0_RGB, GL_SRC_COLOR);
		glTexEnvi(GL_TEXTURE_ENV, GL_OPERAND1_RGB, GL_SRC_COLOR);
		glTexEnvi(GL_TEXTURE_ENV, GL_OPERAND0_ALPHA, GL_SRC_ALPHA);
		glTexEnvi(GL_TEXTURE_ENV, GL_OPERAND1_ALPHA, GL_SRC_ALPHA);
	}
	// set modes
	glShadeModel((fUseClrModMap && !shaders[0]) ? GL_SMOOTH : GL_FLAT);
}

void CStdGL::PerformBlt(C4BltData &rBltData, C4TexRef *pTex, DWORD dwModClr, bool fMod2, bool fExact)
{
	// global modulation map
	int i;
	bool fAnyModNotBlack = (dwModClr != 0xff000000);
	if (!shaders[0] && fUseClrModMap && dwModClr != 0xff000000)
	{
		fAnyModNotBlack = false;
		for (i=0; i<rBltData.byNumVertices; ++i)
		{
			float x = rBltData.vtVtx[i].ftx;
			float y = rBltData.vtVtx[i].fty;
			if (rBltData.pTransform)
			{
				rBltData.pTransform->TransformPoint(x,y);
			}
			DWORD c = pClrModMap->GetModAt(int(x), int(y));
			ModulateClr(c, dwModClr);
			if (c != 0xff000000) fAnyModNotBlack = true;
			DwTo4UB(c, rBltData.vtVtx[i].color);
		}
	}
	else
	{
		for (i=0; i<rBltData.byNumVertices; ++i)
			DwTo4UB(dwModClr, rBltData.vtVtx[i].color);
	}
	// reset MOD2 for completely black modulations
	fMod2 = fMod2 && fAnyModNotBlack;
	SetupTextureEnv(fMod2, false);
	glBindTexture(GL_TEXTURE_2D, pTex->texName);
	if (!fExact)
	{
		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
	}

	glMatrixMode(GL_TEXTURE);
	/*float matrix[16];
	matrix[0]=rBltData.TexPos.mat[0];  matrix[1]=rBltData.TexPos.mat[3];  matrix[2]=0;  matrix[3]=rBltData.TexPos.mat[6];
	matrix[4]=rBltData.TexPos.mat[1];  matrix[5]=rBltData.TexPos.mat[4];  matrix[6]=0;  matrix[7]=rBltData.TexPos.mat[7];
	matrix[8]=0;                       matrix[9]=0;                       matrix[10]=1; matrix[11]=0;
	matrix[12]=rBltData.TexPos.mat[2]; matrix[13]=rBltData.TexPos.mat[5]; matrix[14]=0; matrix[15]=rBltData.TexPos.mat[8];
	glLoadMatrixf(matrix);*/
	glLoadIdentity();

	if (shaders[0] && fUseClrModMap)
	{
		glActiveTexture(GL_TEXTURE3);
		glLoadIdentity();
		C4Surface * pSurface = pClrModMap->GetSurface();
		glScalef(1.0f/(pClrModMap->GetResolutionX()*(*pSurface->ppTex)->iSizeX), 1.0f/(pClrModMap->GetResolutionY()*(*pSurface->ppTex)->iSizeY), 1.0f);
		glTranslatef(float(-pClrModMap->OffX), float(-pClrModMap->OffY), 0.0f);
	}
	if (rBltData.pTransform)
	{
		const float * mat = rBltData.pTransform->mat;
		float matrix[16];
		matrix[0]=mat[0];  matrix[1]=mat[3];  matrix[2]=0;  matrix[3]=mat[6];
		matrix[4]=mat[1];  matrix[5]=mat[4];  matrix[6]=0;  matrix[7]=mat[7];
		matrix[8]=0;       matrix[9]=0;       matrix[10]=1; matrix[11]=0;
		matrix[12]=mat[2]; matrix[13]=mat[5]; matrix[14]=0; matrix[15]=mat[8];
		if (shaders[0] && fUseClrModMap)
		{
			glMultMatrixf(matrix);
		}
		glActiveTexture(GL_TEXTURE0);
		glMatrixMode(GL_MODELVIEW);
		glLoadMatrixf(matrix);
	}
	else
	{
		glActiveTexture(GL_TEXTURE0);
		glMatrixMode(GL_MODELVIEW);
		glLoadIdentity();
	}

	// draw polygon
	for (i=0; i<rBltData.byNumVertices; ++i)
	{
		//rBltData.vtVtx[i].tx = rBltData.vtVtx[i].ftx;
		//rBltData.vtVtx[i].ty = rBltData.vtVtx[i].fty;
		//if (rBltData.pTransform) rBltData.pTransform->TransformPoint(rBltData.vtVtx[i].ftx, rBltData.vtVtx[i].fty);
		rBltData.vtVtx[i].ftz = 0;
	}
	if (vbo)
	{
		glBufferDataARB(GL_ARRAY_BUFFER_ARB, rBltData.byNumVertices*sizeof(C4BltVertex), rBltData.vtVtx, GL_STREAM_DRAW_ARB);
		glInterleavedArrays(GL_T2F_C4UB_V3F, sizeof(C4BltVertex), 0);
	}
	else
	{
		glInterleavedArrays(GL_T2F_C4UB_V3F, sizeof(C4BltVertex), rBltData.vtVtx);
	}
	if (shaders[0] && fUseClrModMap)
	{
		glClientActiveTexture(GL_TEXTURE3);
		glEnableClientState(GL_TEXTURE_COORD_ARRAY);
		glTexCoordPointer(2, GL_FLOAT, sizeof(C4BltVertex), &rBltData.vtVtx[0].ftx);
		glClientActiveTexture(GL_TEXTURE0);
	}
	glDrawArrays(GL_POLYGON, 0, rBltData.byNumVertices);
	if(shaders[0] && fUseClrModMap)
	{
		glClientActiveTexture(GL_TEXTURE3);
		glDisableClientState(GL_TEXTURE_COORD_ARRAY);
		glClientActiveTexture(GL_TEXTURE0);
	}
	glLoadIdentity();
	if (!fExact)
	{
		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
	}
}

void CStdGL::BlitLandscape(C4Surface * sfcSource, float fx, float fy,
                           C4Surface * sfcTarget, float tx, float ty, float wdt, float hgt, const C4Surface * mattextures[])
{
	//Blit(sfcSource, fx, fy, wdt, hgt, sfcTarget, tx, ty, wdt, hgt);return;
	// safety
	if (!sfcSource || !sfcTarget || !wdt || !hgt) return;
	assert(sfcTarget->IsRenderTarget());
	assert(!(dwBlitMode & C4GFXBLIT_MOD2));
	// Apply Zoom
	float twdt = wdt;
	float thgt = hgt;
	tx = (tx - ZoomX) * Zoom + ZoomX;
	ty = (ty - ZoomY) * Zoom + ZoomY;
	twdt *= Zoom;
	thgt *= Zoom;
	// bound
	if (ClipAll) return;
	// manual clipping? (primary surface only)
	if (Config.Graphics.ClipManuallyE)
	{
		int iOver;
		// Left
		iOver=int(tx)-iClipX1;
		if (iOver<0)
		{
			wdt+=iOver;
			twdt+=iOver*Zoom;
			fx-=iOver;
			tx=float(iClipX1);
		}
		// Top
		iOver=int(ty)-iClipY1;
		if (iOver<0)
		{
			hgt+=iOver;
			thgt+=iOver*Zoom;
			fy-=iOver;
			ty=float(iClipY1);
		}
		// Right
		iOver=iClipX2+1-int(tx+twdt);
		if (iOver<0)
		{
			wdt+=iOver/Zoom;
			twdt+=iOver;
		}
		// Bottom
		iOver=iClipY2+1-int(ty+thgt);
		if (iOver<0)
		{
			hgt+=iOver/Zoom;
			thgt+=iOver;
		}
	}
	// inside screen?
	if (wdt<=0 || hgt<=0) return;
	// prepare rendering to surface
	if (!PrepareRendering(sfcTarget)) return;
	// texture present?
	if (!sfcSource->ppTex)
	{
		return;
	}
	// get involved texture offsets
	int iTexSizeX=sfcSource->iTexSize;
	int iTexSizeY=sfcSource->iTexSize;
	int iTexX=Max(int(fx/iTexSizeX), 0);
	int iTexY=Max(int(fy/iTexSizeY), 0);
	int iTexX2=Min((int)(fx+wdt-1)/iTexSizeX +1, sfcSource->iTexX);
	int iTexY2=Min((int)(fy+hgt-1)/iTexSizeY +1, sfcSource->iTexY);
	// blit from all these textures
	SetTexture();
	if (mattextures)
	{
		glActiveTexture(GL_TEXTURE1);
		glEnable(GL_TEXTURE_2D);
		glActiveTexture(GL_TEXTURE0);
	}
	DWORD dwModMask = 0;
	SetupTextureEnv(false, !!mattextures);
	glMatrixMode(GL_MODELVIEW);
	glLoadIdentity();
	glMatrixMode(GL_TEXTURE);
	glLoadIdentity();
	for (int iY=iTexY; iY<iTexY2; ++iY)
	{
		for (int iX=iTexX; iX<iTexX2; ++iX)
		{
			// blit
			DWORD dwModClr = BlitModulated ? BlitModulateClr : 0xffffffff;

			glActiveTexture(GL_TEXTURE0);
			C4TexRef *pTex = *(sfcSource->ppTex + iY * sfcSource->iTexX + iX);
			glBindTexture(GL_TEXTURE_2D, pTex->texName);
			if (!mattextures && Zoom != 1.0)
			{
				glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
				glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
			}
			else
			{
				glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
				glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
			}

			// get current blitting offset in texture
			int iBlitX=sfcSource->iTexSize*iX;
			int iBlitY=sfcSource->iTexSize*iY;
			// size changed? recalc dependant, relevant (!) values
			if (iTexSizeX != pTex->iSizeX)
				iTexSizeX = pTex->iSizeX;
			if (iTexSizeY != pTex->iSizeY)
				iTexSizeY = pTex->iSizeY;
			// get new texture source bounds
			FLOAT_RECT fTexBlt;
			// get new dest bounds
			FLOAT_RECT tTexBlt;
			// set up blit data as rect
			fTexBlt.left  = Max<float>((float)(fx - iBlitX), 0.0f);
			tTexBlt.left  = (fTexBlt.left  + iBlitX - fx) * Zoom + tx;
			fTexBlt.top   = Max<float>((float)(fy - iBlitY), 0.0f);
			tTexBlt.top   = (fTexBlt.top   + iBlitY - fy) * Zoom + ty;
			fTexBlt.right = Min<float>((float)(fx + wdt - iBlitX), (float)iTexSizeX);
			tTexBlt.right = (fTexBlt.right + iBlitX - fx) * Zoom + tx;
			fTexBlt.bottom= Min<float>((float)(fy + hgt - iBlitY), (float)iTexSizeY);
			tTexBlt.bottom= (fTexBlt.bottom+ iBlitY - fy) * Zoom + ty;
			C4BltVertex Vtx[4];
			// blit positions
			Vtx[0].ftx = tTexBlt.left;  Vtx[0].fty = tTexBlt.top;
			Vtx[1].ftx = tTexBlt.right; Vtx[1].fty = tTexBlt.top;
			Vtx[2].ftx = tTexBlt.right; Vtx[2].fty = tTexBlt.bottom;
			Vtx[3].ftx = tTexBlt.left;  Vtx[3].fty = tTexBlt.bottom;
			// blit positions
			Vtx[0].tx = fTexBlt.left;  Vtx[0].ty = fTexBlt.top;
			Vtx[1].tx = fTexBlt.right; Vtx[1].ty = fTexBlt.top;
			Vtx[2].tx = fTexBlt.right; Vtx[2].ty = fTexBlt.bottom;
			Vtx[3].tx = fTexBlt.left;  Vtx[3].ty = fTexBlt.bottom;

			// color modulation
			// global modulation map
			if (shaders[0] && fUseClrModMap)
			{
				glActiveTexture(GL_TEXTURE3);
				glLoadIdentity();
				C4Surface * pSurface = pClrModMap->GetSurface();
				glScalef(1.0f/(pClrModMap->GetResolutionX()*(*pSurface->ppTex)->iSizeX), 1.0f/(pClrModMap->GetResolutionY()*(*pSurface->ppTex)->iSizeY), 1.0f);
				glTranslatef(float(-pClrModMap->OffX), float(-pClrModMap->OffY), 0.0f);

				glClientActiveTexture(GL_TEXTURE3);
				glEnableClientState(GL_TEXTURE_COORD_ARRAY);
				glTexCoordPointer(2, GL_FLOAT, sizeof(C4BltVertex), &Vtx[0].ftx);
				glClientActiveTexture(GL_TEXTURE0);
			}
			if (!shaders[0] && fUseClrModMap && dwModClr)
			{
				for (int i=0; i<4; ++i)
				{
					DWORD c = pClrModMap->GetModAt(int(Vtx[i].ftx), int(Vtx[i].fty));
					ModulateClr(c, dwModClr);
					DwTo4UB(c | dwModMask, Vtx[i].color);
				}
			}
			else
			{
				for (int i=0; i<4; ++i)
					DwTo4UB(dwModClr | dwModMask, Vtx[i].color);
			}
			for (int i=0; i<4; ++i)
			{
				Vtx[i].tx /= iTexSizeX;
				Vtx[i].ty /= iTexSizeY;
				Vtx[i].ftz = 0;
			}
			if (mattextures)
			{
				GLfloat shaderparam[4];
				for (int cnt=1; cnt<127; cnt++)
				{
					if (mattextures[cnt])
					{
						shaderparam[0]=static_cast<GLfloat>(cnt)/255.0f;
						glProgramLocalParameter4fvARB(GL_FRAGMENT_PROGRAM_ARB, 1, shaderparam);
						//Bind Mat Texture
						glActiveTexture(GL_TEXTURE1);
						glBindTexture(GL_TEXTURE_2D, (*(mattextures[cnt]->ppTex))->texName);
						glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
						glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
						glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
						glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
						glActiveTexture(GL_TEXTURE0);

						glInterleavedArrays(GL_T2F_C4UB_V3F, sizeof(C4BltVertex), Vtx);
						glDrawArrays(GL_QUADS, 0, 4);
					}
				}
			}
			else
			{
				glInterleavedArrays(GL_T2F_C4UB_V3F, sizeof(C4BltVertex), Vtx);
				glDrawArrays(GL_QUADS, 0, 4);
			}

			if(shaders[0] && fUseClrModMap)
			{
				glClientActiveTexture(GL_TEXTURE3);
				glDisableClientState(GL_TEXTURE_COORD_ARRAY);
				glClientActiveTexture(GL_TEXTURE0);
			}

		}
	}
	if (mattextures)
	{
		glActiveTexture(GL_TEXTURE1);
		glDisable(GL_TEXTURE_2D);
		glActiveTexture(GL_TEXTURE0);
	}
	// reset texture
	ResetTexture();
}

CStdGLCtx *CStdGL::CreateContext(C4Window * pWindow, C4AbstractApp *pApp)
{
	DebugLog("  gl: Create Context...");
	// safety
	if (!pWindow) return NULL;
	// create it
	CStdGLCtx *pCtx = new CStdGLCtx();
	if (!pMainCtx) pMainCtx = pCtx;
	if (!pCtx->Init(pWindow, pApp))
	{
		delete pCtx; Error("  gl: Error creating secondary context!"); return NULL;
	}
	// creation selected the new context - switch back to previous context
	RenderTarget = NULL;
	pCurrCtx = NULL;
	// done
	return pCtx;
}

#ifdef USE_WIN32_WINDOWS
CStdGLCtx *CStdGL::CreateContext(HWND hWindow, C4AbstractApp *pApp)
{
	// safety
	if (!hWindow) return NULL;
	// create it
	CStdGLCtx *pCtx = new CStdGLCtx();
	if (!pCtx->Init(NULL, pApp, hWindow))
	{
		delete pCtx; Error("  gl: Error creating secondary context!"); return NULL;
	}
	if (!pMainCtx)
	{
		pMainCtx = pCtx;
	}
	else
	{
		// creation selected the new context - switch back to previous context
		RenderTarget = NULL;
		pCurrCtx = NULL;
	}
	// done
	return pCtx;
}
#endif

bool CStdGL::CreatePrimarySurfaces(bool, unsigned int, unsigned int, int iColorDepth, unsigned int)
{
	// store options

	return RestoreDeviceObjects();
}

void CStdGL::DrawQuadDw(C4Surface * sfcTarget, float *ipVtx, DWORD dwClr1, DWORD dwClr2, DWORD dwClr3, DWORD dwClr4)
{
	// prepare rendering to target
	if (!PrepareRendering(sfcTarget)) return;
	// apply global modulation
	ClrByCurrentBlitMod(dwClr1);
	ClrByCurrentBlitMod(dwClr2);
	ClrByCurrentBlitMod(dwClr3);
	ClrByCurrentBlitMod(dwClr4);
	// apply modulation map
	if (fUseClrModMap)
	{
		ModulateClr(dwClr1, pClrModMap->GetModAt(int(ipVtx[0]), int(ipVtx[1])));
		ModulateClr(dwClr2, pClrModMap->GetModAt(int(ipVtx[2]), int(ipVtx[3])));
		ModulateClr(dwClr3, pClrModMap->GetModAt(int(ipVtx[4]), int(ipVtx[5])));
		ModulateClr(dwClr4, pClrModMap->GetModAt(int(ipVtx[6]), int(ipVtx[7])));
	}
	glShadeModel((dwClr1 == dwClr2 && dwClr1 == dwClr3 && dwClr1 == dwClr4) ? GL_FLAT : GL_SMOOTH);
	// set blitting state
	int iAdditive = dwBlitMode & C4GFXBLIT_ADDITIVE;
	glBlendFunc(GL_SRC_ALPHA, iAdditive ? GL_ONE : GL_ONE_MINUS_SRC_ALPHA);
	// draw two triangles
	glInterleavedArrays(GL_V2F, sizeof(float)*2, ipVtx);
	GLubyte colors[4][4];
	DwTo4UB(dwClr1,colors[0]);
	DwTo4UB(dwClr2,colors[1]);
	DwTo4UB(dwClr3,colors[2]);
	DwTo4UB(dwClr4,colors[3]);
	glColorPointer(4,GL_UNSIGNED_BYTE,0,colors);
	glEnableClientState(GL_COLOR_ARRAY);
	glDrawArrays(GL_POLYGON, 0, 4);
	glDisableClientState(GL_COLOR_ARRAY);
	glShadeModel(GL_FLAT);
}

#ifdef _MSC_VER
#ifdef _M_X64
# include <emmintrin.h>
#endif
static inline long int lrintf(float f)
{
#ifdef _M_X64
	return _mm_cvtt_ss2si(_mm_load_ps1(&f));
#else
	long int i;
	__asm
	{
		fld f
		fistp i
	};
	return i;
#endif
}
#endif

void CStdGL::PerformLine(C4Surface * sfcTarget, float x1, float y1, float x2, float y2, DWORD dwClr, float width)
{
	// render target?
	if (sfcTarget->IsRenderTarget())
	{
		// prepare rendering to target
		if (!PrepareRendering(sfcTarget)) return;
		SetTexture();
		SetupTextureEnv(false, false);
		float offx = y1 - y2;
		float offy = x2 - x1;
		float l = sqrtf(offx * offx + offy * offy);
		// avoid division by zero
		l += 0.000000005f;
		offx /= l; offx *= Zoom * width;
		offy /= l; offy *= Zoom * width;
		C4BltVertex vtx[4];
		vtx[0].ftx = x1 + offx; vtx[0].fty = y1 + offy; vtx[0].ftz = 0;
		vtx[1].ftx = x1 - offx; vtx[1].fty = y1 - offy; vtx[1].ftz = 0;
		vtx[2].ftx = x2 - offx; vtx[2].fty = y2 - offy; vtx[2].ftz = 0;
		vtx[3].ftx = x2 + offx; vtx[3].fty = y2 + offy; vtx[3].ftz = 0;
		// global clr modulation map
		DWORD dwClr1 = dwClr;
		glMatrixMode(GL_TEXTURE);
		glLoadIdentity();
		if (fUseClrModMap)
		{
			if (shaders[0])
			{
				glActiveTexture(GL_TEXTURE3);
				glLoadIdentity();
				C4Surface * pSurface = pClrModMap->GetSurface();
				glScalef(1.0f/(pClrModMap->GetResolutionX()*(*pSurface->ppTex)->iSizeX), 1.0f/(pClrModMap->GetResolutionY()*(*pSurface->ppTex)->iSizeY), 1.0f);
				glTranslatef(float(-pClrModMap->OffX), float(-pClrModMap->OffY), 0.0f);

				glClientActiveTexture(GL_TEXTURE3);
				glEnableClientState(GL_TEXTURE_COORD_ARRAY);
				glTexCoordPointer(2, GL_FLOAT, sizeof(C4BltVertex), &vtx[0].ftx);
				glClientActiveTexture(GL_TEXTURE0);
			}
			else
			{
				ModulateClr(dwClr1, pClrModMap->GetModAt(lrintf(x1), lrintf(y1)));
				ModulateClr(dwClr, pClrModMap->GetModAt(lrintf(x2), lrintf(y2)));
			}
		}
		glMatrixMode(GL_MODELVIEW);
		glLoadIdentity();
		DwTo4UB(dwClr1,vtx[0].color);
		DwTo4UB(dwClr1,vtx[1].color);
		DwTo4UB(dwClr,vtx[2].color);
		DwTo4UB(dwClr,vtx[3].color);
		vtx[0].tx = 0; vtx[0].ty = 0;
		vtx[1].tx = 0; vtx[1].ty = 2;
		vtx[2].tx = 1; vtx[2].ty = 2;
		vtx[3].tx = 1; vtx[3].ty = 0;
		// draw two triangles
		glActiveTexture(GL_TEXTURE0);
		glBindTexture(GL_TEXTURE_2D, lines_tex);
		glInterleavedArrays(GL_T2F_C4UB_V3F, sizeof(C4BltVertex), vtx);
		glDrawArrays(GL_POLYGON, 0, 4);
		glClientActiveTexture(GL_TEXTURE3);
		glDisableClientState(GL_TEXTURE_COORD_ARRAY);
		glClientActiveTexture(GL_TEXTURE0);
		ResetTexture();
	}
	else
	{
		// emulate
		if (!LockSurfaceGlobal(sfcTarget)) return;
		ForLine((int32_t)x1,(int32_t)y1,(int32_t)x2,(int32_t)y2,&DLineSPixDw,(int) dwClr);
		UnLockSurfaceGlobal(sfcTarget);
	}
}

void CStdGL::PerformPix(C4Surface * sfcTarget, float tx, float ty, DWORD dwClr)
{
	// render target?
	if (sfcTarget->IsRenderTarget())
	{
		if (!PrepareRendering(sfcTarget)) return;
		int iAdditive = dwBlitMode & C4GFXBLIT_ADDITIVE;
		// use a different blendfunc here because of GL_POINT_SMOOTH
		glBlendFunc(GL_SRC_ALPHA, iAdditive ? GL_ONE : GL_ONE_MINUS_SRC_ALPHA);
		// convert the alpha value for that blendfunc
		glBegin(GL_POINTS);
		glColorDw(dwClr);
		glVertex2f(tx + 0.5f, ty + 0.5f);
		glEnd();
	}
	else
	{
		// emulate
		sfcTarget->SetPixDw((int)tx, (int)ty, dwClr);
	}
}

static void DefineShaderARB(const char * p, GLuint & s)
{
	glBindProgramARB (GL_FRAGMENT_PROGRAM_ARB, s);
	glProgramStringARB (GL_FRAGMENT_PROGRAM_ARB, GL_PROGRAM_FORMAT_ASCII_ARB, strlen(p), p);
	if (GL_INVALID_OPERATION == glGetError())
	{
		GLint errPos; glGetIntegerv (GL_PROGRAM_ERROR_POSITION_ARB, &errPos);
		fprintf (stderr, "ARB program%d:%d: Error: %s\n", s, errPos, glGetString (GL_PROGRAM_ERROR_STRING_ARB));
		s = 0;
	}
}

bool CStdGL::RestoreDeviceObjects()
{
	assert(pMainCtx);
	// delete any previous objects
	InvalidateDeviceObjects();

	// set states
	Active = pMainCtx->Select();
	RenderTarget = pApp->pWindow->pSurface;

	// BGRA Pixel Formats, Multitexturing, Texture Combine Environment Modes
	// Check for GL 1.2 and two functions from 1.3 we need.
	if( !GLEW_VERSION_1_2 ||
		glActiveTexture == NULL ||
		glClientActiveTexture == NULL
	) {
		return Error("  gl: OpenGL Version 1.3 or higher required. A better graphics driver will probably help.");
	}

	// lines texture
	glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
	glGenTextures(1, &lines_tex);
	glBindTexture(GL_TEXTURE_2D, lines_tex);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_MIRRORED_REPEAT);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_MIRRORED_REPEAT);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
	const char * linedata = byByteCnt == 2 ? "\xff\xf0\xff\xff" : "\xff\xff\xff\x00\xff\xff\xff\xff";
	glTexImage2D(GL_TEXTURE_2D, 0, 4, 1, 2, 0, GL_BGRA, byByteCnt == 2 ? GL_UNSIGNED_SHORT_4_4_4_4_REV : GL_UNSIGNED_INT_8_8_8_8_REV, linedata);


	MaxTexSize = 64;
	GLint s = 0;
	glGetIntegerv(GL_MAX_TEXTURE_SIZE, &s);
	if (s>0) MaxTexSize = s;

	// restore gamma if active
	if (Active)
		EnableGamma();
	// reset blit states
	dwBlitMode = 0;

	// Vertex Buffer Objects crash some versions of the free radeon driver. TODO: provide an option for them
	if (0 && GLEW_ARB_vertex_buffer_object)
	{
		glGenBuffersARB(1, &vbo);
		glBindBufferARB(GL_ARRAY_BUFFER_ARB, vbo);
		glBufferDataARB(GL_ARRAY_BUFFER_ARB, 8 * sizeof(C4BltVertex), 0, GL_STREAM_DRAW_ARB);
	}

	if (!Config.Graphics.EnableShaders)
	{
	}
	else if (!shaders[0] && GLEW_ARB_fragment_program)
	{
		glGenProgramsARB (sizeof(shaders)/sizeof(*shaders), shaders);
		const char * preface =
		  "!!ARBfp1.0\n"
		  "TEMP tmp;\n"
		  // sample the texture
		  "TXP tmp, fragment.texcoord[0], texture, 2D;\n";
		const char * alpha_mod =
		  // perform the modulation
		  "MUL tmp.rgba, tmp, fragment.color.primary;\n";
		const char * funny_add =
		  // perform the modulation
		  "ADD tmp.rgb, tmp, fragment.color.primary;\n"
		  "MUL tmp.a, tmp, fragment.color.primary;\n"
		  "MAD_SAT tmp, tmp, { 2.0, 2.0, 2.0, 1.0 }, { -1.0, -1.0, -1.0, 0.0 };\n";
		const char * grey =
		  "TEMP grey;\n"
		  "DP3 grey, tmp, { 0.299, 0.587, 0.114, 1.0 };\n"
		  "LRP tmp.rgb, program.local[0], tmp, grey;\n";
		const char * landscape =
		  "TEMP col;\n"
		  "MOV col.x, program.local[1].x;\n" //Load color to indentify
		  "ADD col.y, col.x, 0.001;\n"
		  "SUB col.z, col.x, 0.001;\n"  //epsilon-range
		  "SGE tmp.r, tmp.b, 0.5015;\n" //Tunnel?
		  "MAD tmp.r, tmp.r, -0.5019, tmp.b;\n"
		  "SGE col.z, tmp.r, col.z;\n" //mat identified?
		  "SLT col.y, tmp.r, col.y;\n"
		  "TEMP coo;\n"
		  "MOV coo, fragment.texcoord;\n"
		  "MUL coo.xy, coo, 3.0;\n"
		  "TXP tmp, coo, texture[1], 2D;\n"
		  "MUL tmp.a, col.y, col.z;\n";
		const char * fow =
		  "TEMP fow;\n"
		  // sample the texture
		  "TXP fow, fragment.texcoord[3], texture[3], 2D;\n"
		  "LRP tmp.rgb, fow.aaaa, tmp, fow;\n";
		const char * end =
		  "MOV result.color, tmp;\n"
		  "END\n";
		DefineShaderARB(FormatString("%s%s%s",       preface,            alpha_mod,            end).getData(), shaders[0]);
		DefineShaderARB(FormatString("%s%s%s",       preface,            funny_add,            end).getData(), shaders[1]);
		DefineShaderARB(FormatString("%s%s%s%s",     preface, landscape, alpha_mod,            end).getData(), shaders[2]);
		DefineShaderARB(FormatString("%s%s%s%s",     preface,            alpha_mod, grey,      end).getData(), shaders[3]);
		DefineShaderARB(FormatString("%s%s%s%s",     preface,            funny_add, grey,      end).getData(), shaders[4]);
		DefineShaderARB(FormatString("%s%s%s%s%s",   preface, landscape, alpha_mod, grey,      end).getData(), shaders[5]);
		DefineShaderARB(FormatString("%s%s%s%s",     preface,            alpha_mod,       fow, end).getData(), shaders[6]);
		DefineShaderARB(FormatString("%s%s%s%s",     preface,            funny_add,       fow, end).getData(), shaders[7]);
		DefineShaderARB(FormatString("%s%s%s%s%s",   preface, landscape, alpha_mod,       fow, end).getData(), shaders[8]);
		DefineShaderARB(FormatString("%s%s%s%s%s",   preface,            alpha_mod, grey, fow, end).getData(), shaders[9]);
		DefineShaderARB(FormatString("%s%s%s%s%s",   preface,            funny_add, grey, fow, end).getData(), shaders[10]);
		DefineShaderARB(FormatString("%s%s%s%s%s%s", preface, landscape, alpha_mod, grey, fow, end).getData(), shaders[11]);
	}
	// done
	return Active;
}

bool CStdGL::InvalidateDeviceObjects()
{
	bool fSuccess=true;
	// clear gamma
#ifndef USE_SDL_MAINLOOP
	DisableGamma();
#endif
	// deactivate
	Active=false;
	// invalidate font objects
	// invalidate primary surfaces
	if (lines_tex)
	{
		glDeleteTextures(1, &lines_tex);
		lines_tex = 0;
	}
	if (shaders[0])
	{
		glDeleteProgramsARB(sizeof(shaders)/sizeof(*shaders), shaders);
		shaders[0] = 0;
	}
	if (vbo)
	{
		glDeleteBuffersARB(1, &vbo);
		vbo = 0;
	}
	return fSuccess;
}

void CStdGL::SetTexture()
{
	glBlendFunc(GL_SRC_ALPHA, (dwBlitMode & C4GFXBLIT_ADDITIVE) ? GL_ONE : GL_ONE_MINUS_SRC_ALPHA);
	if (shaders[0])
	{
		glEnable(GL_FRAGMENT_PROGRAM_ARB);
		if (fUseClrModMap)
		{
			glActiveTexture(GL_TEXTURE3);
			glEnable(GL_TEXTURE_2D);
			glBindTexture(GL_TEXTURE_2D, (*pClrModMap->GetSurface()->ppTex)->texName);
			glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
			glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
			glActiveTexture(GL_TEXTURE0);
		}
	}
	glEnable(GL_TEXTURE_2D);
}

void CStdGL::ResetTexture()
{
	// disable texturing
	if (shaders[0])
	{
		glDisable(GL_FRAGMENT_PROGRAM_ARB);
		glActiveTexture(GL_TEXTURE3);
		glDisable(GL_TEXTURE_2D);
		glActiveTexture(GL_TEXTURE0);
	}
	glDisable(GL_TEXTURE_2D);
}

bool CStdGL::Error(const char *szMsg)
{
#ifdef USE_WIN32_WINDOWS
	DWORD err = GetLastError();
#endif
	bool r = C4Draw::Error(szMsg);
#ifdef USE_WIN32_WINDOWS
	wchar_t * lpMsgBuf;
	FormatMessage(
		FORMAT_MESSAGE_ALLOCATE_BUFFER |
		FORMAT_MESSAGE_FROM_SYSTEM |
		FORMAT_MESSAGE_IGNORE_INSERTS,
		NULL,
		err,
		MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
		(LPTSTR) &lpMsgBuf,
		0, NULL );
	LogF("  gl: GetLastError() = %d - %s", err, StdStrBuf(lpMsgBuf).getData());
	LocalFree(lpMsgBuf);
#endif
	LogF("  gl: %s", glGetString(GL_VENDOR));
	LogF("  gl: %s", glGetString(GL_RENDERER));
	LogF("  gl: %s", glGetString(GL_VERSION));
	LogF("  gl: %s", glGetString(GL_EXTENSIONS));
	return r;
}

bool CStdGL::CheckGLError(const char *szAtOp)
{
	GLenum err = glGetError();
	if (!err) return true;
	Log(szAtOp);
	switch (err)
	{
	case GL_INVALID_ENUM:       Log("GL_INVALID_ENUM"); break;
	case GL_INVALID_VALUE:      Log("GL_INVALID_VALUE"); break;
	case GL_INVALID_OPERATION:  Log("GL_INVALID_OPERATION"); break;
	case GL_STACK_OVERFLOW:     Log("GL_STACK_OVERFLOW"); break;
	case GL_STACK_UNDERFLOW:    Log("GL_STACK_UNDERFLOW"); break;
	case GL_OUT_OF_MEMORY:      Log("GL_OUT_OF_MEMORY"); break;
	default: Log("unknown error"); break;
	}
	return false;
}

CStdGL *pGL=NULL;

#ifdef USE_WIN32_WINDOWS
void CStdGL::TaskOut()
{
	if (pCurrCtx) pCurrCtx->Deselect();
}
#endif

bool CStdGL::OnResolutionChanged(unsigned int iXRes, unsigned int iYRes)
{
	// Re-create primary clipper to adapt to new size.
	CreatePrimaryClipper(iXRes, iYRes);
	RestoreDeviceObjects();
	return true;
}

void CStdGL::Default()
{
	C4Draw::Default();
	pCurrCtx = NULL;
	iPixelFormat=0;
	sfcFmt=0;
	iClrDpt=0;
}

#endif // USE_GL
