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Bitmap Loading

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I''m trying to write a program that converts Windows 24 bit bitmaps to my own SPR file format. (I''m creating a multiplatform gaming library, so I don''t want to use the Windows loading functions to get images into my game) The thing is, I''m having troubles loading the data. it''s getting messed up somehow. I created a bitmap structure to handle it for me, and here''s the code I have. I''m open to any suggestions as to why this might be (I mean, the data is messed up in a different way then the bitmap being flipped)
class ZAPGBITMAP
{
public:
	WORD identifier; // Identifies type of bitmap, must be BM

	DWORD fileSize;  // Size of the file

	DWORD reserved1; // Reserved - not used


	DWORD dataOffset; // Offset from start of file till data
	DWORD headerSize; // Size of bitmap info header. must be 28h
	
	DWORD width; // Width of bitmap in pixels
	DWORD height; // Height of bitmap in pixels

	WORD planes; // Number of planes in bitmap

	WORD bpp; // Bits per pixel

	DWORD compression; // Type of compresssion

	DWORD bitmapDataSize; // Size of bitmap in bytes
	DWORD hResolution; // Horizontal resolution
	DWORD vResolution; // Vertical resolution

	DWORD colors; // Number of colors, EG, 256, 65536, etc
	DWORD importantColors; // Number of important colours

	DWORD strangeSenselessPacking[4];
	// We skip palette, won''t be reading in any 256 colour bm''s!

	BYTE *bitmapData;
	


	void Release()
	{
		delete []bitmapData;
	}
};



void ReadBitmap(ZAPGBITMAP *bm, FILE *fp)
{
	fread( &bm->identifier, sizeof(WORD), 1, fp);
	fread( &bm->fileSize, sizeof(DWORD), 1, fp);
	fread( &bm->reserved1, sizeof(DWORD), 1, fp);
	fread( &bm->dataOffset, sizeof(DWORD), 1, fp);
	fread( &bm->headerSize, sizeof(DWORD), 1, fp);
	fread( &bm->width, sizeof(DWORD), 1, fp);
	fread( &bm->height, sizeof(DWORD), 1, fp);
	fread( &bm->planes, sizeof(WORD), 1, fp);
	fread( &bm->bpp, sizeof(WORD), 1, fp);
	fread( &bm->compression, sizeof(DWORD), 1, fp);
	fread( &bm->bitmapDataSize, sizeof(DWORD), 1, fp);
	fread( &bm->hResolution, sizeof(DWORD), 1, fp);
	fread( &bm->vResolution, sizeof(DWORD), 1, fp);
	fread( &bm->strangeSenselessPacking, sizeof(DWORD), 4, fp);
	

	bm->bitmapData=new BYTE [bm->bitmapDataSize];
	fread( bm->bitmapData, 1, bm->bitmapDataSize, fp);
}
 

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Guest Anonymous Poster
Why are you using all those freads? Just read them all in at once.

Declare two structs:

BITMAPFILEHEADER bitmapfileheader; // ID,file size, pointer to the data
BITMAPINFOHEADER bitmapinfoheader; // image size,width,height,etc.

And read in the entire fileheader first, then the entire infoheader. The
BGR bits for a 24-bit bitmap will follow next. Allocate a buffer and read
all of this in too. Simple.

And remember that the bits are DWORD aligned per scanline if you plan to use
those bits in another format.

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