star-sf

commit c773354e904af2919f9077c712cdd12c1d8af395
parent cf7feb20bbfb4a197903a12f2db79dadad650d89
Author: Vincent Forest <vincent.forest@meso-star.com>
Date:   Thu, 15 Sep 2016 15:40:35 +0200

Fix the ssf_bsdf_view_sample function

Ensure that the random numbers used to sample a component are in [0, 1[

Diffstat:
M
src/ssf_bsdf_view.c
 | 
9
+++++++--

1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/src/ssf_bsdf_view.c b/src/ssf_bsdf_view.c
@@ -13,11 +13,16 @@
  * You should have received a copy of the GNU General Public License
  * along with this program. If not, see <http://www.gnu.org/licenses/>. */
 
+#define _POSIX_C_SOURCE 200112L /* nextafter */
+
 #include "ssf.h"
 #include "ssf_bsdf_view_c.h"
 
 #include <rsys/mem_allocator.h>
 
+#include <float.h>
+#include <math.h>
+
 /*******************************************************************************
  * Helper functions
  ******************************************************************************/
@@ -145,8 +150,8 @@ ssf_bsdf_view_sample
   }
 
   /* Rescale the random number to reuse it (NOTE why?) */
-  w = (u - view->cumulative[icomponent] )
-    / (view->cumulative[icomponent+1] - view->cumulative[icomponent]);
+  w = (u - view->cumulative[icomponent] )/ nextafter
+    (view->cumulative[icomponent+1] - view->cumulative[icomponent], DBL_MAX);
 
   /* Sample the component */
   reflectivity = ssf_bxdf_sample(view->components[icomponent], w, v, wi, N, wo);