htrdr

commit c1e0c6fc21e575d1a024e1fbfed06651bcecff0b
parent ee741359dc23ec048e0335a3f70ac8f6502c0428
Author: Vincent Forest <vincent.forest@meso-star.com>
Date:   Mon,  8 Jun 2020 18:10:16 +0200

Fix a possible infinite loop in the compute_radiance_sw

A traced ray must be explicitly stopped whenever the traversal distance
without any scattering event is too high. This occurs when the maximum
scattering coefficient has a very small value in a voxel whose length is
[quasi] infinite along the propagation direction.

Diffstat:
M
src/htrdr_compute_radiance_sw.c
 | 
7
+++++++

1 file changed, 7 insertions(+), 0 deletions(-)
diff --git a/src/htrdr_compute_radiance_sw.c b/src/htrdr_compute_radiance_sw.c
@@ -109,6 +109,13 @@ scattering_hit_filter
       ASSERT(ctx->traversal_dst >= hit->distance[0]);
       ASSERT(ctx->traversal_dst <= hit->distance[1]);
 
+      /* Stop the ray whenever the traversal distance without any scattering
+       * event is too high. It means the maximum scattering coefficient has a
+       * very small value, and the returned radiance is null. This can only
+       * happen when the voxel has a [quasi] infinite length in the propagation
+       * direction. */
+      if(ctx->traversal_dst > 1e9) break;
+
       /* Compute the world space position where a collision may occur */
       pos[0] = org[0] + ctx->traversal_dst * dir[0];
       pos[1] = org[1] + ctx->traversal_dst * dir[1];