1 files changed, 22 insertions, 10 deletions

diff --git a/Smoke/fluids.c b/Smoke/fluids.c
index 01ca443..a6c0a03 100644
--- a/Smoke/fluids.c
+++ b/Smoke/fluids.c
@@ -247,6 +247,11 @@ struct point vector_normal(struct point vert1, struct point vert2, struct point
   return_value.y /= length;
   return_value.z /= length;
 
+  if (return_value.x == return_value.y == return_value.z == 0.0f)
+  {
+    return_value.z = 1.0f;
+  }
+
   return return_value;
 }
 
@@ -263,7 +268,7 @@ void calculate_normal_vectors(void)
 	for (j = 0; j < DIM; j++)
 	{
     for (i = 0; i < DIM; i++)
-	  {
+    {
       idx = (j * DIM) + i;
       px = wn + (fftw_real)i * wn;
 		  py = hn + (fftw_real)(j + 1) * hn;
@@ -281,33 +286,39 @@ void calculate_normal_vectors(void)
       p3.z = height_array[idx + 1];
 
       normal_array[idx] = vector_normal(p2, p1, p3);
+      normal_array[idx + 1] = vector_normal(p2, p1, p3);
     }
   }
 }
 
 struct point calculate_normal_vector(fftw_real *height, int index, int i, int j)
 {
-  struct point p1, p2, p3;
+  int idx;
+  float px, py;
+  struct point p1, p2, p3, rv;
 
   fftw_real wn = (fftw_real)winWidth  / (fftw_real)(DIM + 1); // Grid cell width
 	fftw_real hn = (fftw_real)winHeight / (fftw_real)(DIM + 1); // Grid cell height
-  float px = wn + (fftw_real)i * wn;
-	float py = hn + (fftw_real)(j + 1) * hn;
+
+  px = wn + (fftw_real)i * wn;
+  py = hn + (fftw_real)(j + 1) * hn;
 
   p1.x = px;
-  p1.y = py + hn;
-  p1.z = height[index + DIM];
+  p1.y = py;
+  p1.z = height[index];
 
   p2.x = px;
-  p2.y = py;
-  p2.z = height[index];
+  p2.y = py + hn;
+  p2.z = height[index + DIM];
 
   p3.x = px + wn;
   p3.y = py;
   p3.z = height[index + 1];
 
+  normal_array[index] = vector_normal(p2, p1, p3);
+  rv = vector_normal(p2, p1, p3);
 
-  return vector_normal(p1, p2, p3);
+  return rv;
 }
 
 void calculate_height_plots(void)
@@ -486,7 +497,8 @@ void fluids_calculate_one_simulation_step(struct vis_data_arrays *vis_data)
   int dataset;
   fftw_real *frame;
 
-  if (fluids_calculate) {
+  if (fluids_calculate)
+  {
       set_forces();
       solve(DIM, vx, vy, vx0, vy0, visc, dt);
       diffuse_matter(DIM, vx, vy, rho, rho0, dt);