allow option for backfaces in ray_triangle

diff --git a/vg_m.h b/vg_m.h
index 68e2304a339c13013eae62c3dd3644a62ae6118e..2de095eb544c3508af92b147dddafdbdc2c5eae6 100644 (file)
--- a/vg_m.h
+++ b/vg_m.h
@@ -2017,7 +2017,7 @@ int ray_aabb1( boxf box, v3f co, v3f dir_inv, f32 dist )
 
 /* Time of intersection with ray vs triangle */
 static int ray_tri( v3f tri[3], v3f co, 
-                    v3f dir, f32 *dist )
+                    v3f dir, f32 *dist, int backfaces )
 {
    f32 const kEpsilon = 0.00001f;
 
@@ -2033,7 +2033,7 @@ static int ray_tri( v3f tri[3], v3f co,
    v3_cross( dir, v1, h );
    v3_cross( v0, v1, n );
 
-   if( v3_dot( n, dir ) > 0.0f ) /* Backface culling */
+   if( (v3_dot( n, dir ) > 0.0f) && !backfaces ) /* Backface culling */
       return 0;
    
    /* Parralel */
@@ -2171,7 +2171,7 @@ static int spherecast_triangle( v3f tri[3],
    f32 t_min = INFINITY,
          t1;
 
-   if( ray_tri( sum, co, dir, &t1 ) ){
+   if( ray_tri( sum, co, dir, &t1, 0 ) ){
       t_min = vg_minf( t_min, t1 );
       hit = 1;
    }