solstice-solver

commit 2f6c35655c5d8de6a2512525694715228f039f94
parent ab82f0f545354343be646009d0ff81ad53af4e16
Author: Vincent Forest <vincent.forest@meso-star.com>
Date:   Wed, 14 Dec 2016 17:37:25 +0100

Fix the shading normal orientation

Ensure that the shading normal of a surface fragment look forward the
incoming direction.

Diffstat:
M
src/ssol_material.c
 | 
9
++++++++-
M
src/ssol_solver.c
 | 
4
++--

2 files changed, 10 insertions(+), 3 deletions(-)
diff --git a/src/ssol_material.c b/src/ssol_material.c
@@ -304,6 +304,9 @@ surface_fragment_setup
   char has_texcoord, has_normal;
   ASSERT(fragment && pos && dir && primitive && uv);
 
+  /* Assume that the submitted normal look forward the incoming dir */
+  ASSERT(d3_dot(normal, dir) <= 0);
+
   /* Setup the incoming direction */
   d3_set(fragment->dir, dir);
 
@@ -349,7 +352,11 @@ surface_fragment_setup
     }
     d3_set_f3(fragment->Ns, attr.value);
     d3_normalize(fragment->Ns, fragment->Ns);
-    /* FIXME: flip normal if backface??? */
+
+    /* Ensure that the fetched shading normal look forward the incoming dir */
+    if(d3_dot(dir, fragment->Ns) > 0) {
+      d3_minus(fragment->Ns, fragment->Ns);
+    }
   }
 }
 
diff --git a/src/ssol_solver.c b/src/ssol_solver.c
@@ -119,7 +119,7 @@ point_init
     pt->side = SSOL_FRONT;
   } else {
     pt->side = SSOL_BACK;
-    d3_minus(pt->N, pt->N);
+    d3_minus(pt->N, pt->N); /* Force the normal to look forward dir */
   }
 
   /* Initialise the ray data to avoid self intersection */
@@ -185,7 +185,7 @@ point_update_from_hit
     pt->side = SSOL_FRONT;
   } else {
     pt->side = SSOL_BACK;
-    d3_minus(pt->N, pt->N);
+    d3_minus(pt->N, pt->N); /* Force the normal to look forward dir */
   }
 }