Help wanted in Bitmap loading

The code to extract the bitmap from the file is as below:

bool BitmapSurface::LoadBmpData()
{
HANDLE fileHandle;
DWORD bytesRead;
DDSURFACEDESC2 ddsd;
LPDIRECTDRAWPALETTE lpddpal = NULL;
UCHAR* bmpData;

// Open the file
fileHandle = CreateFile (bmpfile, GENERIC_READ, 0, NULL,
OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL / FILE_FLAG_SEQUENTIAL_SCAN,
NULL);

if (fileHandle == NULL)
return 0;

// Set the cursor to start of the data
SetFilePointer (fileHandle,-(int)(byteSize), NULL, FILE_END);

// Read the image the data into the buffer
if (!surface7)
return FALSE;

// Lock the surface to get the image data
if (!(Lock(&ddsd, NULL)))
{
TraceToFile ("Lock of the bmpsurface failed");
return FALSE;
}

ZeroMemory (ddsd.lpSurface, byteSize);

// Allocate memory for the memory pointer
bmpData = (UCHAR*) malloc(byteSize);

// Read the image data from the file
// if (!(ReadFile(fileHandle, (void*) ddsd.lpSurface, byteSize, &bytesRead, NULL)))
if (!(ReadFile(fileHandle, (void*) bmpData, byteSize, &bytesRead, NULL)))
{
TraceToFile ("ReadFile failed", GetLastError ());
return FALSE;

}

// Load the bmpData into the surface
// memory is non-linear, copy line by line
UCHAR* surfacePtr = (UCHAR*) ddsd.lpSurface;
for (int y=0; y < height; y++)
{
// copy line
memcpy((void *)surfacePtr, (void *)bmpData, width);

// advance pointers to next line
surfacePtr += ddsd.lPitch;
bmpData += width;
} // end for

// Unlock the surface
UnLock (NULL);

// Close the file
CloseHandle (fileHandle);

return 1;

} /* BitmapSurface::LoadBmpData */

If you want I have written my own blit routine which will blit from any sized locked surface to any other sized locked surface using the following passed in variables.

Source,Dest,SourcePitch,DestPitch,SourceRect,DestX,DestY,bpp

Where Source is the returned address after locking the source surface and dest is the address of the locked destination surface, SourcePitch is the Pitch of the source surface and DestPitch is the Pitch of the destination surface, Source Rect is a RECT filled in with the source rectangle you want to copy. DestX & Y are the destination co-ordinats (Warning this does no out of bounds testing, so you have to make sure the blit is within the surface) and bpp is bits per pixel.
Now there''s two things about this, it''s only been tested at 16bpp, and it copies by DWORD for speed so 16bpp bitmaps had to be multiples of 2 pixels wide, for an 8 bit picture I''d guess it has to be multiples of 4 pixels. Last but not least I wrote it in assembler as my game will have to do several hundred blits per frame. So the idea is that you locked your TileSet or source surface, and the dest (usually backbuffer) and then blit everything before unlocking. This is even faster than using BltFast w/ DirectDraw.
So you may want a small bit of understanding of assembler.
So if you want me to send it to you email me. (Click my profile icon to get it, I don''t like including for i-bots)
See ya,
Ben

After each line the bitmap has a couple of extra bytes. You can get how many these bytes are by taking:

WidthInBytes % 4;

You should change this line:
bmpData += width;

to
bmpData += (width + (width % 4));

Here I suppose that the resolution on screen is the smae as in the bitmap.