diff options
Diffstat (limited to 'src/gallium')
| -rw-r--r-- | src/gallium/auxiliary/draw/draw_pipe_clip.c | 11 |
1 files changed, 8 insertions, 3 deletions
diff --git a/src/gallium/auxiliary/draw/draw_pipe_clip.c b/src/gallium/auxiliary/draw/draw_pipe_clip.c index 7b879c4cd50..3110809ce0e 100644 --- a/src/gallium/auxiliary/draw/draw_pipe_clip.c +++ b/src/gallium/auxiliary/draw/draw_pipe_clip.c @@ -167,12 +167,17 @@ static void interp( const struct clip_stage *clip, { int k; t_nopersp = t; - for (k = 0; k < 2; k++) + /* find either in.x != out.x or in.y != out.y */ + for (k = 0; k < 2; k++) { if (in->clip[k] != out->clip[k]) { - t_nopersp = (dst->clip[k] - out->clip[k]) / - (in->clip[k] - out->clip[k]); + /* do divide by W, then compute linear interpolation factor */ + float in_coord = in->clip[k] / in->clip[3]; + float out_coord = out->clip[k] / out->clip[3]; + float dst_coord = dst->clip[k] / dst->clip[3]; + t_nopersp = (dst_coord - out_coord) / (in_coord - out_coord); break; } + } } /* Other attributes |