/* listing 4: Example of how to generate mip-maps

Generates a half size version of a monochrome 8 bit image in "src", of dimensions
src_width, src_height with pitch src_pitch. outputs to image dst with pitch
dst_pitch */

void GenerateOneMipMap(UBYTE *src, int src_width, int src_height, int src_pitch,
					   UBYTE *dst, int dst_pitch)
{
	int w=src_width>>1; // compute size of output mipmap
	int h=src_height>>1;
	dst_pitch-=w;	// adjust pitches to account for loops
	int src_pitch2=src_pitch*2-w*2;
	for (int y=0;y<h;y++)
	{
		for (int x=0;x<w;x++)
		{
			// average four source pixels into one
			*dst++=(src[0]+src[1]+src[src_pitch]+src[src_pitch+1])>>2;
			src+=2;
		}
		dst+=dst_pitch;
		src+=src_pitch2;
	}
}