diff options
| author | Vito Caputo <vcaputo@pengaru.com> | 2022-05-02 09:52:55 -0700 |
|---|---|---|
| committer | Vito Caputo <vcaputo@pengaru.com> | 2022-05-02 09:57:48 -0700 |
| commit | 51e38e69f075d99bbab13d52e3c70840bf341cc4 (patch) | |
| tree | db4f45c35a575f9c5db30e0de6be196e82cf66e3 | |
| parent | 8292d95533801b41ee4b05edc0bf296394085528 (diff) | |
modules/submit: fix bilerp mode out-of-bounds access
Found via -fsanitize=address, this is a quick and dirty way to
prevent the OOB access without adding more conditionals, just
prevent scaling the fragment dimensions to the full grid
dimensions.
This could be done better by reworking things a bit and putting
zero at the center of the grid with a -1..+1 mapping, so rounding
towards zero would land in the middle as opposed to off the
start, with the existing .5f offset.
But for now just fix the bug, nobody will notice the slight LCD
overscan-style difference of bilerp=on vs. off due to this way.
| -rw-r--r-- | src/modules/submit/submit.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/src/modules/submit/submit.c b/src/modules/submit/submit.c index 1f3a2ae..af2d044 100644 --- a/src/modules/submit/submit.c +++ b/src/modules/submit/submit.c @@ -208,15 +208,15 @@ static void draw_grid(submit_context_t *ctxt, til_fb_fragment_t *fragment) static void draw_grid_bilerp(submit_context_t *ctxt, til_fb_fragment_t *fragment) { - float xscale = ((float)GRID_SIZE - 1.f) / (float)fragment->frame_width; - float yscale = ((float)GRID_SIZE - 1.f) / (float)fragment->frame_height; + float xscale = ((float)GRID_SIZE - 2.f) / (float)fragment->frame_width; + float yscale = ((float)GRID_SIZE - 2.f) / (float)fragment->frame_height; for (int y = 0; y < fragment->height; y++) { for (int x = 0; x < fragment->width; x++) { uint32_t color; /* TODO: this could be optimized a bit! i.e. don't recompute the y for every x etc. */ - color = sample_grid_bilerp(ctxt, .5f + ((float)(fragment->x + x)) * xscale, .5f + ((float)(fragment->y + y)) * yscale); + color = sample_grid_bilerp(ctxt, 1.f + ((float)(fragment->x + x)) * xscale, 1.f + ((float)(fragment->y + y)) * yscale); til_fb_fragment_put_pixel_unchecked(fragment, 0, fragment->x + x, fragment->y + y, color); } } |