From b0d980371c99b5762f261b8ea5a8b71021c4171f Mon Sep 17 00:00:00 2001
From: David Rose <david@ddrose.com>
Date: Tue, 8 Apr 2008 23:50:50 +0000
Subject: [PATCH] fix stack recursion issues

---
 panda/src/egg/eggPrimitive.cxx | 39 +++++++++++++++++++++++++++++++++-
 panda/src/egg/eggPrimitive.h   | 11 ++++++++++
 2 files changed, 49 insertions(+), 1 deletion(-)

diff --git a/panda/src/egg/eggPrimitive.cxx b/panda/src/egg/eggPrimitive.cxx
index dc792cf73d..20fa02728d 100644
--- a/panda/src/egg/eggPrimitive.cxx
+++ b/panda/src/egg/eggPrimitive.cxx
@@ -1172,6 +1172,42 @@ do_apply_flat_attribute(int vertex_index, EggAttributes *attrib) {
 void EggPrimitive::
 set_connected_shading(EggPrimitive::Shading shading, 
                       const EggAttributes *neighbor) {
+  ConnectedShadingNodes connected_nodes;
+
+  r_set_connected_shading(0, shading, neighbor, connected_nodes);
+  
+  // Pick up any additional nodes we couldn't visit because of the
+  // stack depth restrictions.
+  while (!connected_nodes.empty()) {
+    ConnectedShadingNodes next_nodes;
+    next_nodes.swap(connected_nodes);
+
+    ConnectedShadingNodes::iterator ni;
+    for (ni = next_nodes.begin(); ni != next_nodes.end(); ++ni) {
+      r_set_connected_shading(0, (*ni)._shading, (*ni)._neighbor, connected_nodes);
+    }
+  }
+}
+
+////////////////////////////////////////////////////////////////////
+//     Function: EggPrimitive::r_set_connected_shading
+//       Access: Private
+//  Description: Implements set_connected_shading, with some
+//               restrictions to prevent stack overflow.
+////////////////////////////////////////////////////////////////////
+void EggPrimitive::
+r_set_connected_shading(int stack_depth, EggPrimitive::Shading shading, 
+                        const EggAttributes *neighbor, 
+                        ConnectedShadingNodes &next_nodes) {
+  if (stack_depth > 10000) {
+    // Too deep.  Limit recursion.
+    ConnectedShadingNode next;
+    next._shading = shading;
+    next._neighbor = neighbor;
+    next_nodes.push_back(next);
+    return;
+  }
+
   bool propagate = false;
 
   if (_connected_shading == S_unknown) {
@@ -1218,7 +1254,8 @@ set_connected_shading(EggPrimitive::Shading shading,
       for (pi = vertex->pref_begin();
            pi != vertex->pref_end();
            ++pi) {
-        (*pi)->set_connected_shading(_connected_shading, this);
+        (*pi)->r_set_connected_shading(stack_depth + 1, _connected_shading, this,
+                                       next_nodes);
       }
     }
   }
diff --git a/panda/src/egg/eggPrimitive.h b/panda/src/egg/eggPrimitive.h
index 4842c6dcdf..60f7fdee85 100644
--- a/panda/src/egg/eggPrimitive.h
+++ b/panda/src/egg/eggPrimitive.h
@@ -212,6 +212,17 @@ protected:
 private:
   void set_connected_shading(Shading shading, const EggAttributes *neighbor);
 
+  class ConnectedShadingNode {
+  public:
+    Shading _shading;
+    const EggAttributes *_neighbor;
+  };
+  typedef pvector<ConnectedShadingNode> ConnectedShadingNodes;
+
+  void r_set_connected_shading(int depth_count,
+                               Shading shading, const EggAttributes *neighbor,
+                               ConnectedShadingNodes &connected_nodes);
+
 private:
   typedef vector_PT_EggTexture Textures;
   Textures _textures;