// Purpose: Loads a file from disk. returns pointer to file in memory or NULL if it failed// In: sFilename	: string with filename to load// Out: pointer to buffer.//// Note: I included this routine to make it complete. This is not the DemoGL fileloader <img src="wink.gif" width=15 height=15 align=middle>//byte*FLoadFile(const char *sFilename){	FILE	*fpFile;	byte	*pBuffer;	long	lFileLength;	fpFile=fopen(sFilename,"rb");	if(!fpFile)	{		return NULL;	}	fseek(fpFile,0,SEEK_END);	lFileLength=ftell(fpFile);	fseek(fpFile,0,SEEK_SET);	pBuffer=(byte *)malloc(lFileLength * sizeof(byte));	fread(pBuffer,lFileLength,1,fpFile);	fclose(fpFile);	return pBuffer;}// Purpose: loads a tga file into the passed texture object txTexture.// In: pTexture     : pointer to pointervariable wherein the address of the buffer which contains the texturedata should be stored//     sFilename    : tga file to load//     iMaxWidth    : maxwidth in pixels of destination texture.//     iMaxHeight   : maxheight in pixels of destination texture//     bCreateAlphaFromColor: if true, the greyvalue of RGB is used to create the A(lpha) value// Out: SYS_OK   : txTexture is filled.//      Errorcode: if something went wrong.// Additional Info: - Will clear texture in txTexture first, if present//                  - Converts all bitmap data to 24bit RGB triplets (because OpenGL wants that)//                  - Uses integers for width and height in pixels. Because hardware can''t use textures//                    larger than 2048x2048 (which is large), an integer can hold up to 32768x32768 (which is insane)//                    If updates are needed, we can swap to longs. Now this is not needed.//					- Only true color (24 bit/32 bit) are supported. (type 2) TGA is added for alphareading purposes.//                  - When bCreateAlphaFromColor is true, the eventually available alphabyte is ignored.//					- XYorigin is ignored. (0,0) is left lower corner) //// Uses ConvertTGAtoRGBA() for dataconversion.intDoImportTGA(byte **pTexture, const char *sFilename, int iMaxWidth, int iMaxHeight, bool bCreateAlphaFromColor){	int					iHeight, iWidth, iResult;	byte				*pTextureBuffer, *pTGAFile;	// load file.	pTGAFile = FLoadFile(sFilename);	if(!pTGAFile)	{		// open didn''t succeed		return SYS_TGA_LOAD_FAILED;	}	// Check if we have the right type of file.	if(pTGAFile[2] !=2)	{		// invalid format		free(pTGAFile);		return SYS_TGA_INVALID_FORMAT;	}	// SHITMACINTELCRAP. An integer is 4 bytes. lo-hi shit is reversed due to intel weirdness.	iWidth = int(pTGAFile[12] | ((int)pTGAFile[13] << 8));	iHeight = int(pTGAFile[14] | ((int)pTGAFile[15] << 8));	if((iMaxWidth < iWidth)||(iMaxHeight < iHeight))	{		// too large.		free(pTGAFile);		return SYS_TGA_INVALID_SIZE;	}	pTextureBuffer = (byte *)malloc(sizeof(byte) * iWidth * iHeight * 4);	// check if creation did go well...	if(!pTextureBuffer)	{		free(pTGAFile);		return SYS_MEM_ALLOC_FAIL;	}	iResult=ConvertTGAtoRGBA(pTGAFile, pTextureBuffer,iWidth, iHeight, bCreateAlphaFromColor);	*pTexture=NULL;	if(iResult==SYS_OK)	{		*pTexture=pTextureBuffer;	}	// clean up	free(pTGAFile);	return iResult;}// Purpose: converts a buffer that contains a TGA file to RGBA data.// Gets: pTGAFile, bytepointer, pointer to the TGAfile in memory// Gets: pRGBABuffer, bytepointer, pointer to pre-allocated RGBAbuffer. Should be of the size iWidth*iHeight*4//                    No boundary checks are made!// Gets: iWidth, iHeight, ints, with and height of picture// Gets: bCreateAlphaFromColor, bool, if true the color of the pixel will be used to create the alphabyte, otherwise// the alphabyte in the pixelitself is used, if present, otherwise 0xFF is used.// Returns: SYS_OK if all went well, SYS_NOK otherwiseintConvertTGAtoRGBA(byte *pTGAFile, byte *pRGBABuffer, int iWidth, int iHeight, bool bCreateAlphaFromColor){	int					i,j,ibytesPerPixel;	bool				bAlpha;	byte				*pPixelData;	byte				byR, byG, byB, byAlpha;	if(!pRGBABuffer)	{		return SYS_NOK;	}	if(!pTGAFile)	{		return SYS_NOK;	}	ibytesPerPixel = pTGAFile[16] / 8;	bAlpha = ((pTGAFile[17] & 0x0F) == 8);	// now we have to skip the colormap and identification IF present.	pPixelData = pTGAFile;	if(pTGAFile[1]!=0)	{		// there is a colormap. Ignore it. Get the length and add this to pPixelData		pPixelData += (int)(pTGAFile[3] | ((int)pTGAFile[4] << 8)) + ((int)(pTGAFile[5] | ((int)pTGAFile[6] << 8)) * pTGAFile[7]);	}	else	{		// there is no colormap. perhaps an identification. skip it.		pPixelData = pTGAFile + pTGAFile[0] + 18;	}		// reverse the order of the data by copying the data reverse to the texturememory reserved in the	// texture object. Copy pixel for pixel the data towards the texture space in the texture object	// because we don''t support 1 and 4 color tga files, we don''t have to worry about alignbits.	for(i=0; i<iHeight;i++)	{		for(j=0;j<iWidth;j++)		{			// is stored as BGRA			byR = pPixelData[(i * iWidth*ibytesPerPixel) + (j * ibytesPerPixel)+2];	// R			byG = pPixelData[(i * iWidth*ibytesPerPixel) + (j * ibytesPerPixel)+1];	// G			byB = pPixelData[(i * iWidth*ibytesPerPixel) + (j * ibytesPerPixel)];	// B			pRGBABuffer[(i * iWidth * 4) + (j * 4)] = byR;	// R			pRGBABuffer[(i * iWidth * 4) + (j * 4)+1] = byG;	// G			pRGBABuffer[(i * iWidth * 4) + (j * 4)+2] = byB;	// B			if(bCreateAlphaFromColor)			{				byAlpha = (byte)((0.35f * byR) + (0.45f * byG) + (0.20 * byB));			}			else			{				if(bAlpha)				{					byAlpha = pPixelData[(i * iWidth * ibytesPerPixel) + (j * ibytesPerPixel)+3];				}				else				{					byAlpha = 0xFF;				}			}			pRGBABuffer[(i * iWidth * 4) + (j * 4)+3] = byAlpha;		}	}	return SYS_OK;}  

      ///////////////////////////////////////////////////////                  TYPEDEFS/////////////////////////////////////////////////////#ifndef bytetypedef unsigned char byte;#endif///////////////////////////////////////////////////////					DEFINES/////////////////////////////////////////////////////// DoImportTGA specific:#define SYS_TGA_LOAD_FAILED	11#define	SYS_TGA_EMPTY_FILE	12#define SYS_TGA_INVALID_FORMAT	13#define	SYS_TGA_INVALID_SIZE	14#define SYS_OK			0#define SYS_NOK			1#define SYS_MEM_ALLOC_FAIL	2///////////////////////////////////////////////////////					EXTERNS/////////////////////////////////////////////////////extern	int	DoImportTGA(byte *pTexture, const char *sFilename, int iMaxWidth, int iMaxHeight, bool bCreateAlphaFromColor);///////////////////////////////////////////////////////					other functiondefs/////////////////////////////////////////////////////int	ConvertTGAtoRGBA(byte *pTGAFile, byte *pRGBABuffer, int iWidth, int iHeight, bool bCreateAlphaFromColor);