Can anyone find anything wrong with this bitmap drawing function? Sometimes it works, like if the bitmap is 64 by 64, but if i change it to 50 by 50, it doesn''t. It draws the map all sideways. I can''t figure it out. Here it is: // DrawBitmap int DrawBitmap(int x, int y, int width, int height, LPDIRECTDRAWSURFACE7 lpdds, char *filename, int cx, int cy) { // clean the surface Fill_Surface(lpdds,0); // load the 8-bit image if (!Load_Bitmap_File(&bitmap,filename)) return(0); // clear ddsd and set size DDRAW_INIT_STRUCT(ddsd2); // copy the bitmap image to the primary buffer line by line // lock the primary surface lpdds->Lock(NULL,&ddsd2, DDLOCK_SURFACEMEMORYPTR | DDLOCK_WAIT,NULL); // get video pointer to primary surfce USHORT *primary_buffer = (USHORT *)ddsd2.lpSurface; // compute starting location on surface //primary_buffer += (x+y*(ddsd2.lPitch/2)); if(SCREEN_BPP == 16 && bitmap.bitmapinfoheader.biBitCount == 24) { // process each line and copy it into the primary buffer for (int index_y = 0; index_y < height; index_y++) { for (int index_x = 0; index_x < width; index_x++) { // rip out the UCHAR boundried 8-bit color segments for passing to the 16-bit color word macro int pos = (index_y)*(bitmap.bitmapinfoheader.biWidth)*3 + (index_x)*3; // compute position UCHAR blue = (bitmap.buffer[pos]>>3), // 5 bits for blue green = (bitmap.buffer[pos+1]>>2), // 6 bits for green red = (bitmap.buffer[pos+2]>>3); // 5 bits for red // this builds a 32 bit color value in A.8.8.8 format USHORT pixel = _RGB16BIT565(red,green,blue); // write the pixel primary_buffer[index_x + (index_y*ddsd2.lPitch/2)] = pixel; } // end for index_x } // end for index_y } // now unlock the primary surface if (FAILED(lpdds->Unlock(NULL))) return(0); // unload the bitmap file, we no longer need it if(!Unload_Bitmap_File(&bitmap)) return(0); return(1); // return success }// end DrawBitmap

Does it work if the Bitmap is 32 * 32 ?
Or 16*16 ?

If so, there have been a few threads recently, try searching the archive. It is to do with bitmaps being packed up to a word boundary IIRC.

If it doesn''t work then I apologise

I beleive the bitmap width has to be divisible by 4 (or was it 8) otherwise it adds padding.. so you''d have to do something like this...




*Note This is untested, but should work. By your description I think this was the problem (makes each line look off a bit since it''s adding padding to each line). Also, it may just be easier to simply make sure you''re Bitmap widths are divisible by 4 (or was it 8?)... then you don''t have to worry about it :D

Billy - BillyB@mrsnj.com