star-3dstl

commit 91ebd2ed889217dcf97280a4d5f66e541c2b7f47
parent f145d816b32485ddf5e6861d1c2e27d8eb0dd66c
Author: Vincent Forest <vincent.forest@meso-star.com>
Date:   Wed,  3 Feb 2016 17:26:42 +0100

Revert the STL vertex ordering

The STL and Star-3D front face vertex ordering are not the same. Switch
the vertex order in order to ensure that the front and back faces are
not inverted.

Diffstat:
M
src/s3dstl.c
 | 
7
+++++--

1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/src/s3dstl.c b/src/s3dstl.c
@@ -65,9 +65,12 @@ get_indices(const unsigned itri, unsigned ids[3], void* ctx)
   const unsigned* indices;
   ASSERT(ctx && ids && itri < desc->triangles_count);
   indices = desc->indices + itri*3;
-  ids[0] = indices[0];
+  /* Note that in the Star-STL loader, front faces are CCW ordered while in to
+   * the Star-3D library front faces are CW ordered. Flip the vertex index in
+   * order to ensure that the 3D and the STL front faces are the same */
+  ids[0] = indices[2];
   ids[1] = indices[1];
-  ids[2] = indices[2];
+  ids[2] = indices[0];
 }
 
 static void