correcting a few typos i made earlier in the comments

[freeglut] / src / fg_geometry.c

diff --git a/src/fg_geometry.c b/src/fg_geometry.c
index 2e0a3b3..ccbe5d7 100644 (file)
--- a/src/fg_geometry.c
+++ b/src/fg_geometry.c
@@ -60,25 +60,36 @@ static void fghDrawGeometryWire(GLfloat *vertices, GLfloat *normals, GLsizei num
     glDisableClientState(GL_VERTEX_ARRAY);
     glDisableClientState(GL_NORMAL_ARRAY);
 }
-static void fghDrawGeometrySolid(GLfloat *vertices, GLfloat *normals, GLubyte *vertIdxs, GLsizei numVertices, GLsizei numEdgePerFace)
+/**
+ * Draw the geometric shape with filled triangles
+ *
+ * - If the shape is naturally triangulated (numEdgePerFace==3), each
+ *   vertex+normal pair is used only once, so no vertex indices.
+ * 
+ * - If the shape was triangulated (DECOMPOSE_TO_TRIANGLE), some
+ *   vertex+normal pairs are reused, so use vertex indices.
+ */
+static void fghDrawGeometrySolid(GLfloat *vertices, GLfloat *normals, GLubyte *vertIdxs,
+                                GLsizei numVertices, GLsizei numVertIdxs)
 {
     glEnableClientState(GL_VERTEX_ARRAY);
     glEnableClientState(GL_NORMAL_ARRAY);
 
     glVertexPointer(3, GL_FLOAT, 0, vertices);
     glNormalPointer(GL_FLOAT, 0, normals);
-    if (numEdgePerFace==3)
+    if (vertIdxs == NULL)
         glDrawArrays(GL_TRIANGLES, 0, numVertices);
     else
-        glDrawElements(GL_TRIANGLES, numVertices, GL_UNSIGNED_BYTE, vertIdxs);
+        glDrawElements(GL_TRIANGLES, numVertIdxs, GL_UNSIGNED_BYTE, vertIdxs);
 
     glDisableClientState(GL_VERTEX_ARRAY);
     glDisableClientState(GL_NORMAL_ARRAY);
 }
 
 /* Shape decomposition to triangles
- * We'll use glDrawElements to draw all shapes that are not triangles, so
- * generate an index vector here, using the below sampling scheme.
+ * We'll use glDrawElements to draw all shapes that are not naturally
+ * composed of triangles, so generate an index vector here, using the
+ * below sampling scheme.
  * Be careful to keep winding of all triangles counter-clockwise,
  * assuming that input has correct winding...
  */
@@ -92,7 +103,7 @@ static void fghGenerateGeometryWithIndexArray(int numFaces, int numEdgePerFace,
     switch (numEdgePerFace)
     {
     case 3:
-        /* nothing to do here, we'll drawn with glDrawArrays */
+        /* nothing to do here, we'll draw with glDrawArrays */
         break;
     case 4:
         vertSamps = vert4Decomp;
@@ -145,7 +156,7 @@ static void fghGenerateGeometry(int numFaces, int numEdgePerFace, GLfloat *verti
 /* Cache of input to glDrawArrays or glDrawElements
  * In general, we build arrays with all vertices or normals.
  * We cant compress this and use glDrawElements as all combinations of
- * vertex and normals are unique.
+ * vertices and normals are unique.
  */
 #define DECLARE_SHAPE_CACHE(name,nameICaps,nameCaps)\
     static GLboolean name##Cached = FALSE;\
@@ -199,7 +210,7 @@ static GLfloat cube_n[CUBE_NUM_FACES*3] =
      0.0f, 0.0f,-1.0f
 };
 
-/* Vertex indices */
+/* Vertex indices, as quads, before triangulation */
 static GLubyte cube_vi[CUBE_VERT_PER_OBJ] =
 {
     0,1,2,3,
@@ -640,7 +651,7 @@ static void fghCircleTable(GLfloat **sint, GLfloat **cost, const int n, const GL
         else\
         {\
             fghDrawGeometrySolid(name##_verts,name##_norms,vertIdxs,\
-                                 nameCaps##_VERT_PER_OBJ_TRI,                     nameCaps##_NUM_EDGE_PER_FACE);\
+                                 nameCaps##_VERT_PER_OBJ, nameCaps##_VERT_PER_OBJ_TRI); \
         }\
     }
 #define DECLARE_INTERNAL_DRAW(name,nameICaps,nameCaps)                        _DECLARE_INTERNAL_DRAW_DO_DECLARE(name,nameICaps,nameCaps,NULL)
@@ -677,9 +688,11 @@ static void fghCube( GLfloat dSize, GLboolean useWireMode )
         vertices = cube_verts;
 
     if (useWireMode)
-        fghDrawGeometryWire (vertices,cube_norms,                                    CUBE_NUM_FACES,CUBE_NUM_EDGE_PER_FACE);
+        fghDrawGeometryWire (vertices, cube_norms,
+                            CUBE_NUM_FACES, CUBE_NUM_EDGE_PER_FACE);
     else
-        fghDrawGeometrySolid(vertices,cube_norms,cube_vertIdxs,CUBE_VERT_PER_OBJ_TRI,               CUBE_NUM_EDGE_PER_FACE);
+        fghDrawGeometrySolid(vertices, cube_norms, cube_vertIdxs,
+                            CUBE_VERT_PER_OBJ, CUBE_VERT_PER_OBJ_TRI);
 
     if (dSize!=1.f)
         /* cleanup allocated memory */
@@ -718,9 +731,9 @@ static void fghSierpinskiSponge ( int numLevels, double offset[3], GLfloat scale
 
         /* Draw and cleanup */
         if (useWireMode)
-            fghDrawGeometryWire (vertices,normals,             numFace,TETRAHEDRON_NUM_EDGE_PER_FACE);
+            fghDrawGeometryWire (vertices,normals,numFace,TETRAHEDRON_NUM_EDGE_PER_FACE);
         else
-            fghDrawGeometrySolid(vertices,normals,NULL,numVert,        TETRAHEDRON_NUM_EDGE_PER_FACE);
+            fghDrawGeometrySolid(vertices,normals,NULL,numVert,numVert);
 
         free(vertices);
         free(normals );