[Racer-svn] SF.net SVN: racer:[346] trunk/libtrack/Mesh/MeshFaces.cpp

[<jl...@us...>]

Revision: 346
          http://racer.svn.sourceforge.net/racer/?rev=346&view=rev
Author:   jlegg
Date:     2010-09-25 02:28:09 +0000 (Sat, 25 Sep 2010)

Log Message:
-----------
Smooth shade track edge pieces. Some themes need adjusting.

Modified Paths:
--------------
    trunk/libtrack/Mesh/MeshFaces.cpp

Modified: trunk/libtrack/Mesh/MeshFaces.cpp
===================================================================
--- trunk/libtrack/Mesh/MeshFaces.cpp	2010-09-19 14:48:19 UTC (rev 345)
+++ trunk/libtrack/Mesh/MeshFaces.cpp	2010-09-25 02:28:09 UTC (rev 346)
@@ -361,21 +361,62 @@
 void MeshFaces::copy_faces(const MeshFaces & other)
 {
     faces = other.faces;
-    // Set normals for each face vertex.
-    for (std::vector<Face>::iterator it = faces.begin(); it != faces.end(); it++)
+    // Smooth shading: calculate vertex normals for curved objects.
+    // For each vertex, find the average face normal of all faces using it, and renormalize.
+    for (unsigned int i = 0; i < vertices_position.size(); i++)
     {
-        // solid shading: face normals are consistant across a face
-        assert(it->fv1.vertex_index < vertices_position.size());
-        assert(it->fv2.vertex_index < vertices_position.size());
-        assert(it->fv3.vertex_index < vertices_position.size());
-        btVector3 & v1 = vertices_position[it->fv1.vertex_index];
-        btVector3 & v2 = vertices_position[it->fv2.vertex_index];
-        btVector3 & v3 = vertices_position[it->fv3.vertex_index];
-        btVector3 n = (v2-v1).cross(v3-v1).normalize();
-        it->fv1.normal = n;
-        it->fv2.normal = n;
-        it->fv3.normal = n;
-        /// @todo smooth shading: calculate and use vertex normals for curved objects.
+        // find where the normal is used
+        std::vector<btVector3 *> normal_uses;
+        std::vector<btVector3> face_normals;
+        for (std::vector<Face>::iterator it = faces.begin(); it != faces.end(); it++)
+        {
+            bool use_this_face = false;
+            if (it->fv1.vertex_index == i)
+            {
+                normal_uses.push_back(&(it->fv1.normal));
+                use_this_face = true;
+            }
+            if (it->fv2.vertex_index == i)
+            {
+                normal_uses.push_back(&(it->fv2.normal));
+                use_this_face = true;
+            }
+            if (it->fv3.vertex_index == i)
+            {
+                normal_uses.push_back(&(it->fv3.normal));
+                use_this_face = true;
+            }
+            if (use_this_face)
+            {
+                // calculate face normal.
+                btVector3 & v1 = vertices_position[it->fv1.vertex_index];
+                btVector3 & v2 = vertices_position[it->fv2.vertex_index];
+                btVector3 & v3 = vertices_position[it->fv3.vertex_index];
+                // not normalised, so we get a weighted average by face area.
+                btVector3 n = (v2-v1).cross(v3-v1);
+                face_normals.push_back(n);
+            }
+        }
+        // find average face normal
+        btVector3 smooth_normal(0, 0, 0);
+        for (std::vector<btVector3>::iterator it = face_normals.begin();
+             it != face_normals.end();
+             it++)
+        {
+            smooth_normal += *it;
+        }
+        smooth_normal.normalize();
+        // eh hum
+        /*btScalar ox = smooth_normal.x();
+        smooth_normal.setX(smooth_normal.z());
+        smooth_normal.setZ(ox);*/
+        // now update all the faces that use this.
+        for (std::vector<btVector3 *>::iterator it = normal_uses.begin();
+             it != normal_uses.end();
+             it++)
+        {
+            **it = smooth_normal;
+        }
     }
 }
 


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