star-sf

commit 5d6ed65f64f2cd87d92abb8953dc307606b3e349
parent a4e69f379e5389abcea746f2ed54a1f7184769e8
Author: Christophe Coustet <christophe.coustet@meso-star.com>
Date:   Thu, 24 Aug 2017 17:56:02 +0200

Small performance improvement.

Diffstat:
M
src/ssf_bsdf.c
 | 
12
++++--------

1 file changed, 4 insertions(+), 8 deletions(-)
diff --git a/src/ssf_bsdf.c b/src/ssf_bsdf.c
@@ -151,7 +151,7 @@ ssf_bsdf_sample
    int* type,
    double* out_pdf)
 {
-  double cumul[MAX_BxDFs];
+  double cumul;
   double R;
   double r;
   double pdf;
@@ -170,16 +170,12 @@ ssf_bsdf_sample
 
   bsdf_normalize_weights(bsdf);
 
-  /* Compute the cumulative from the normalized weights of the BxDFs */
-  cumul[0] = bsdf->weights[0];
-  FOR_EACH(i, 1, bsdf->nbxdfs) {
-    cumul[i] = bsdf->weights[i] + cumul[i-1];
-  }
-
   /* Sample a component */
   r = ssp_rng_canonical(rng);
+  cumul = bsdf->weights[0];
   FOR_EACH(i, 0, bsdf->nbxdfs-1) {
-    if(r <= cumul[i]) break;
+    if(r <= cumul) break;
+    cumul += bsdf->weights[i];
   }
 
   /* Sample a direction from the selected component */