star-sp

commit 424ed34658422dc46808cbfdc8b36d4e309609ab
parent 96738f21aef83519e46dab47a5166c039b8b54d8
Author: Vincent Forest <vincent.forest@meso-star.com>
Date:   Thu, 23 Jul 2015 14:40:14 +0200

Fix a strong issue in the uniform sampling of a triangle

Diffstat:
M
cmake/CMakeLists.txt
 | 
2
+-
M
src/ssp.h
 | 
8
++++----

2 files changed, 5 insertions(+), 5 deletions(-)
diff --git a/cmake/CMakeLists.txt b/cmake/CMakeLists.txt
@@ -67,7 +67,7 @@ rcmake_append_runtime_dirs(_runtime_dirs RSys ${Boost_LIBRARY_DIRS})
 ################################################################################
 set(VERSION_MAJOR 0)
 set(VERSION_MINOR 2)
-set(VERSION_PATCH 0)
+set(VERSION_PATCH 1)
 set(VERSION ${VERSION_MAJOR}.${VERSION_MINOR}.${VERSION_PATCH})
 
 set(SSP_FILES_SRC ssp_rng.c ssp_rng_proxy.c)
diff --git a/src/ssp.h b/src/ssp.h
@@ -251,17 +251,17 @@ ssp_ran_triangle_uniform
    const float v0[3], const float v1[3],  const float v2[3],/*triangle vertices*/
    float sample[3]) /* Sampled position */
 {
-  double u, v, one_minus_u;
+  double sqrt_u, v, one_minus_u;
   int i;
   ASSERT(rng && v0 && v1 && v2 && sample);
 
-  u = ssp_rng_canonical(rng);
+  sqrt_u = sqrt(ssp_rng_canonical(rng));
   v = ssp_rng_canonical(rng);
-  one_minus_u = 1.0 - u;
+  one_minus_u = 1.0 - sqrt_u;
 
   FOR_EACH(i, 0, 3) {
     sample[i] = (float)
-      (v2[i] + one_minus_u * (v0[i] - v2[i]) + (v*u) * (v1[i] - v2[i]));
+      (v2[i] + one_minus_u * (v0[i] - v2[i]) + (v*sqrt_u) * (v1[i] - v2[i]));
   }
   return sample;
 }