- let start_x = (xpos as isize) - (EDGE_PRE as isize) * xstep;
- let end_x = (xpos as isize) + ((size + EDGE_POST) as isize) * xstep;
- let start_y = (ypos as isize) - (EDGE_PRE as isize) * ymul;
- let end_y = (ypos as isize) + ((size + EDGE_POST) as isize) * ymul;
+ let mut start_x = (xpos as isize) + ((mvx >> 3) as isize) - (EDGE_PRE as isize);
+ let mut end_x = (xpos as isize) + ((mvx >> 3) as isize) + ((size + EDGE_POST) as isize);
+ if xstep < 0 {
+ start_x -= (size + EDGE_POST) as isize;
+ } else if xstep > 0 {
+ end_x += (size as isize) * xstep;
+ }
+ let mut start_y = (ypos as isize) + ((mvy >> 3) as isize) - (EDGE_PRE as isize) * ymul;
+ let mut end_y = (ypos as isize) + ((mvy >> 3) as isize) + ((size + EDGE_POST) as isize) * ymul;
+ if ymul == 0 {
+ start_y -= EDGE_PRE as isize;
+ end_y += (EDGE_POST + 1) as isize;
+ }