[Bf-blender-cvs] [fe08aa4e2cb] blender-v2.83-release: Fix T80604: BLI_polyfill_calc exceeds stack size allocating points
Campbell Barton
noreply at git.blender.org
Wed Sep 16 14:39:18 CEST 2020
Commit: fe08aa4e2cb9b7e58cefc062afdb886961a4cf9a
Author: Campbell Barton
Date: Wed Sep 9 12:48:29 2020 +1000
Branches: blender-v2.83-release
https://developer.blender.org/rBfe08aa4e2cb9b7e58cefc062afdb886961a4cf9a
Fix T80604: BLI_polyfill_calc exceeds stack size allocating points
On systems with 512kb stack this happened at around 13k points.
This happened at times with grease-pencil, although callers that
frequently use complex polygons should be using BLI_polyfill_calc_arena.
===================================================================
M source/blender/blenlib/intern/polyfill_2d.c
===================================================================
diff --git a/source/blender/blenlib/intern/polyfill_2d.c b/source/blender/blenlib/intern/polyfill_2d.c
index 90a4a4f4c2d..99bc7db64eb 100644
--- a/source/blender/blenlib/intern/polyfill_2d.c
+++ b/source/blender/blenlib/intern/polyfill_2d.c
@@ -909,6 +909,19 @@ void BLI_polyfill_calc(const float (*coords)[2],
const int coords_sign,
uint (*r_tris)[3])
{
+ /* Fallback to heap memory for large allocations.
+ * Avoid running out of stack memory on systems with 512kb stack (macOS).
+ * This happens at around 13,000 points, use a much lower value to be safe. */
+ if (UNLIKELY(coords_tot > 8192)) {
+ /* The buffer size only accounts for the index allocation,
+ * worst case we do two allocations when concave, while we should try to be efficient,
+ * any caller that relies on this frequently should use #BLI_polyfill_calc_arena directly. */
+ MemArena *arena = BLI_memarena_new(sizeof(PolyIndex) * coords_tot, __func__);
+ BLI_polyfill_calc_arena(coords, coords_tot, coords_sign, r_tris, arena);
+ BLI_memarena_free(arena);
+ return;
+ }
+
PolyFill pf;
PolyIndex *indices = BLI_array_alloca(indices, coords_tot);
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