tweak laplace stuff

This commit is contained in:
Connor Olding 2017-04-02 00:48:46 +00:00
parent 7f8b65ac36
commit 81c86dcc3f
1 changed files with 11 additions and 1 deletions

View File

@ -225,7 +225,7 @@ static void make_offset_list(Resynth_state *s) {
}
INLINE int weight_at(const Coord point) {
if (point.x == 0 && point.y == 0) return 0;
if (point.x == 0 && point.y == 0) return 360;
// this is stable and accurate up to -N 37 (-R 9)
// 520 might work in place of 360 and provide more accuracy w/o overflows.
return 360 / (point.x * point.x + point.y * point.y);
@ -241,6 +241,7 @@ INLINE void try_point(Resynth_state *s, const Coord point, bool weighted) {
int diff = 0;
if (off_point.x < 0 || off_point.y < 0 ||
off_point.x >= s->corpus.width || off_point.y >= s->corpus.height) {
// penalize edges, assuming the corpus image doesn't wrap cleanly.
diff = s->diff_table[0] * s->input_bytes;
} else if (i) {
const Pixel *corpus_pixel = image_atc(s->corpus, off_point);
@ -251,7 +252,16 @@ INLINE void try_point(Resynth_state *s, const Coord point, bool weighted) {
}
if (weighted) diff *= weight_at(s->neighbors[i]);
#ifdef NDEBUG
sum += diff;
#else
if (__builtin_add_overflow(sum, diff, &sum)) {
fprintf(stderr, "integer overflow at (%i,%i) + (%i,%i)\n",
point.x, point.y, s->neighbors[i].x, s->neighbors[i].y);
fprintf(stderr, "diff: %i\n", diff);
exit(1);
}
#endif
if (sum >= s->best) return;
}