First, I have never been too fond of GDI.

But more importantly, the bitmap data itself is going to be in memory, and not necessarily from a file. I see no way of using GDI's LoadImage() function to grab the bitmap data from memory, only from a resource or a file.

So, I need a way to convert from 24-bit RGB source images - because I like true color - to a 16-bit format (presumable the primary display adaptor's 16-bit mode) in order to allow 16-bit display modes to be used with my game.

- Splat

quote:Also, is it possible to just drop the source bitmap into a temporary surface at 24-bits, then Blit it to a 16-bit surface, and let DirectDraw handle the conversion?

I have written such a thing down a couple of times, and oh well. Here it comes again.

code:

BOOL CopyBMPDataTo1555Surface (BITMAPINFOHEADER *BMPh, unsigned char *pdata, LPDIRECTDRAWSURFACE surface){    DDSURFACEDESC   ddsd;		//Get a valid pointer to the texture surface.	memset (&ddsd, 0, sizeof (ddsd));	ddsd.dwSize = sizeof (ddsd);		if (surface->Lock(NULL, &(ddsd), DDLOCK_WAIT, NULL) == DD_OK)	{		//Copy 888 .BMP image to 1555 DirectDraw texture surface in video 		//memory, converting as we go. BMP data is stored bottom to top 		//(i.e., from left to right along a row, but the rows are		//stored bottom to top in memory). For applications that support 		//multiple texture formats, this code fragment can be broken 		//out into a separate function, and then copied and modified 		//for each supported texture format. 		unsigned char r,g,b;		unsigned char *oldpdata;		unsigned short color1555;		unsigned short *texSurfBase;		int x, y;		int skip;			//actual vs. asked for surface width			int imageWidthInBytes;				oldpdata = pdata;		texSurfBase = (unsigned short *)ddsd.lpSurface;		imageWidthInBytes = BMPh->biWidth*IMAGEDEPTH_IN_BYTES;		skip = ddsd.lPitch - BMPh->biWidth*COLORDEPTH_IN_BYTES;				//start at beginning of last row of image		pdata += BMPh->biHeight*imageWidthInBytes - imageWidthInBytes;				for (y=0; ybiHeight; y++)		{			for (x=0; xbiWidth; x++)			{				b = *pdata++;				g = *pdata++;				r = *pdata++;								color1555 = (unsigned short)( ((r >> 3) << 10) |					((g >> 3) << 5)  |					(b >> 3) );				*texSurfBase++ = color1555;			}						//go to next row of texture surface			texSurfBase += skip;						//go to start of previous row (i.e., go back			//two rows worth of bytes, the one just completed,			//and the one we want to get to the start of...			pdata -= imageWidthInBytes*2;		}				pdata = oldpdata;		//reset pdata's original address				surface->Unlock (ddsd.lpSurface);				return TRUE;	}	else	{		MessageBox(hWnd, "Surface Lock failed", "yeah whatnow?", MB_OK);		return FALSE;	}	}

of course you need a pointer to the place where the bgr stuff begins.....then this'll do the rest

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Dance with me......

Maybe I should rephrase my question. I guess the question now is: if I had unlimited processing time, how can I convert a 24-bit bitmap to 16-bit bitmap that looks as good as 16-bit can get?

- Splat

Anyway, that's for all of your help guys.

- Splat

Also, is it possible to just drop the source bitmap into a temporary surface at 24-bits, then Blit it to a 16-bit surface, and let DirectDraw handle the conversion?

- Splat

- Splat