egg2pg: fix CollisionBox generation for transformed objects

Rather than xforming after the fact, which does not work properly for boxes, we need to apply the transform to the vertices around which the box is generated.

Fixes #506

panda/src/egg2pg/eggLoader.cxx

@@ -1814,10 +1814,11 @@ make_node(EggGroup *egg_group, PandaNode *parent) {
     // A collision group: create collision geometry.
     node = new CollisionNode(egg_group->get_name());
 
+    // Piggy-back the desired transform to apply onto the node, since we can't
+    // break the ABI in 1.10.
+    node->set_transform(TransformState::make_mat(LCAST(PN_stdfloat, egg_group->get_vertex_to_node())));
     make_collision_solids(egg_group, egg_group, (CollisionNode *)node.p());
-
-    // Transform all of the collision solids into local space.
-    node->xform(LCAST(PN_stdfloat, egg_group->get_vertex_to_node()));
+    node->clear_transform();
 
     if ((egg_group->get_collide_flags() & EggGroup::CF_keep) != 0) {
       // If we also specified to keep the geometry, continue the traversal.
@@ -2773,7 +2774,7 @@ make_sphere(EggGroup *egg_group, EggGroup::CollideFlags flags,
  */
 bool EggLoader::
 make_box(EggGroup *egg_group, EggGroup::CollideFlags flags,
-         LPoint3 &min_p, LPoint3 &max_p, LColor &color) {
+         const LMatrix4 &xform, LPoint3 &min_p, LPoint3 &max_p) {
   EggGroup *geom_group = find_collision_geometry(egg_group, flags);
   if (geom_group != nullptr) {
     // Collect all of the vertices.
@@ -2802,13 +2803,12 @@ make_box(EggGroup *egg_group, EggGroup::CollideFlags flags,
     }
 
     EggVertex *vertex = (*vi);
-    LVertexd min_pd = vertex->get_pos3();
-    LVertexd max_pd = min_pd;
-    color = vertex->get_color();
+    LPoint3 min_pd = LCAST(PN_stdfloat, vertex->get_pos3()) * xform;
+    LPoint3 max_pd = min_pd;
 
     for (++vi; vi != vertices.end(); ++vi) {
       vertex = (*vi);
-      const LVertexd &pos = vertex->get_pos3();
+      LPoint3 pos = LCAST(PN_stdfloat, vertex->get_pos3()) * xform;
       min_pd.set(min(min_pd[0], pos[0]),
                  min(min_pd[1], pos[1]),
                  min(min_pd[2], pos[2]));
@@ -2817,13 +2817,25 @@ make_box(EggGroup *egg_group, EggGroup::CollideFlags flags,
                  max(max_pd[2], pos[2]));
     }
 
-    min_p = LCAST(PN_stdfloat, min_pd);
-    max_p = LCAST(PN_stdfloat, max_pd);
+    min_p = min_pd;
+    max_p = max_pd;
     return (min_pd != max_pd);
   }
   return false;
 }
 
+/**
+ * Creates a single generic Box corresponding to the polygons associated with
+ * this group.  This box is used by make_collision_box.
+ */
+bool EggLoader::
+make_box(EggGroup *egg_group, EggGroup::CollideFlags flags,
+         LPoint3 &min_p, LPoint3 &max_p, LColor &color) {
+
+  color.set(1.0, 1.0, 1.0, 1.0);
+  return make_box(egg_group, flags, LMatrix4::ident_mat(), min_p, max_p);
+}
+
 /**
  * Creates CollisionSolids corresponding to the collision geometry indicated
  * at the given node and below.
@@ -2904,6 +2916,7 @@ make_collision_plane(EggGroup *egg_group, CollisionNode *cnode,
           create_collision_plane(DCAST(EggPolygon, *ci), egg_group);
         if (csplane != nullptr) {
           apply_collision_flags(csplane, flags);
+          csplane->xform(cnode->get_transform()->get_mat());
           cnode->add_solid(csplane);
           return;
         }
@@ -3004,6 +3017,7 @@ make_collision_sphere(EggGroup *egg_group, CollisionNode *cnode,
     CollisionSphere *cssphere =
       new CollisionSphere(center, radius);
     apply_collision_flags(cssphere, flags);
+    cssphere->xform(cnode->get_transform()->get_mat());
     cnode->add_solid(cssphere);
   }
 }
@@ -3017,8 +3031,8 @@ make_collision_box(EggGroup *egg_group, CollisionNode *cnode,
                    EggGroup::CollideFlags flags) {
   LPoint3 min_p;
   LPoint3 max_p;
-  LColor dummycolor;
-  if (make_box(egg_group, flags, min_p, max_p, dummycolor)) {
+  CPT(TransformState) transform = cnode->get_transform();
+  if (make_box(egg_group, flags, transform->get_mat(), min_p, max_p)) {
     CollisionBox *csbox =
       new CollisionBox(min_p, max_p);
     apply_collision_flags(csbox, flags);
@@ -3040,6 +3054,7 @@ make_collision_inv_sphere(EggGroup *egg_group, CollisionNode *cnode,
     CollisionInvSphere *cssphere =
       new CollisionInvSphere(center, radius);
     apply_collision_flags(cssphere, flags);
+    cssphere->xform(cnode->get_transform()->get_mat());
     cnode->add_solid(cssphere);
   }
 }
@@ -3234,6 +3249,7 @@ make_collision_capsule(EggGroup *egg_group, CollisionNode *cnode,
           new CollisionCapsule(LCAST(PN_stdfloat, point_a), LCAST(PN_stdfloat, point_b),
                             radius);
         apply_collision_flags(cscapsule, flags);
+        cscapsule->xform(cnode->get_transform()->get_mat());
         cnode->add_solid(cscapsule);
       }
     }
@@ -3395,6 +3411,7 @@ create_collision_polygons(CollisionNode *cnode, EggPolygon *egg_poly,
         new CollisionPolygon(vertices_begin, vertices_end);
       if (cspoly->is_valid()) {
         apply_collision_flags(cspoly, flags);
+        cspoly->xform(cnode->get_transform()->get_mat());
         cnode->add_solid(cspoly);
       }
     }
@@ -3485,6 +3502,7 @@ create_collision_floor_mesh(CollisionNode *cnode,
     CollisionFloorMesh::TriangleIndices triangle = *ti;
     csfloor->add_triangle(triangle.p1, triangle.p2, triangle.p3);
   }
+  csfloor->xform(cnode->get_transform()->get_mat());
   cnode->add_solid(csfloor);
 }
 

panda/src/egg2pg/eggLoader.h

@@ -163,6 +163,8 @@ private:
   bool make_sphere(EggGroup *start_group, EggGroup::CollideFlags flags,
                    LPoint3 &center, PN_stdfloat &radius, LColor &color);
 
+  bool make_box(EggGroup *start_group, EggGroup::CollideFlags flags,
+                const LMatrix4 &xform, LPoint3 &min_p, LPoint3 &max_p);
   bool make_box(EggGroup *start_group, EggGroup::CollideFlags flags,
                 LPoint3 &min_p, LPoint3 &max_p, LColor &color);