fix crash with identity state

panda/src/glstuff/glGraphicsStateGuardian_src.cxx

@@ -306,6 +306,34 @@ reset() {
   free_pointers();
   GraphicsStateGuardian::reset();
 
+  // Build _inv_state_mask as a mask of 1's where we don't care, and
+  // 0's where we do care, about the state.
+  _inv_state_mask = RenderState::SlotMask::all_on();
+  _inv_state_mask.clear_bit(ShaderAttrib::get_class_slot());
+  _inv_state_mask.clear_bit(AlphaTestAttrib::get_class_slot());
+  _inv_state_mask.clear_bit(AntialiasAttrib::get_class_slot());
+  _inv_state_mask.clear_bit(ClipPlaneAttrib::get_class_slot());
+  _inv_state_mask.clear_bit(ColorAttrib::get_class_slot());
+  _inv_state_mask.clear_bit(ColorScaleAttrib::get_class_slot());
+  _inv_state_mask.clear_bit(CullFaceAttrib::get_class_slot());
+  _inv_state_mask.clear_bit(DepthOffsetAttrib::get_class_slot());
+  _inv_state_mask.clear_bit(DepthTestAttrib::get_class_slot());
+  _inv_state_mask.clear_bit(DepthWriteAttrib::get_class_slot());
+  _inv_state_mask.clear_bit(RenderModeAttrib::get_class_slot());
+  _inv_state_mask.clear_bit(RescaleNormalAttrib::get_class_slot());
+  _inv_state_mask.clear_bit(ShadeModelAttrib::get_class_slot());
+  _inv_state_mask.clear_bit(TransparencyAttrib::get_class_slot());
+  _inv_state_mask.clear_bit(ColorWriteAttrib::get_class_slot());
+  _inv_state_mask.clear_bit(ColorBlendAttrib::get_class_slot());
+  _inv_state_mask.clear_bit(TextureAttrib::get_class_slot());
+  _inv_state_mask.clear_bit(TexGenAttrib::get_class_slot());
+  _inv_state_mask.clear_bit(TexMatrixAttrib::get_class_slot());
+  _inv_state_mask.clear_bit(MaterialAttrib::get_class_slot());
+  _inv_state_mask.clear_bit(LightAttrib::get_class_slot());
+  _inv_state_mask.clear_bit(StencilAttrib::get_class_slot());
+  _inv_state_mask.clear_bit(FogAttrib::get_class_slot());
+  _inv_state_mask.clear_bit(ScissorAttrib::get_class_slot());
+
   // Output the vendor and version strings.
   query_gl_version();
 
@@ -5961,7 +5989,7 @@ set_state_and_transform(const RenderState *target,
     do_issue_transform();
   }
 
-  if (target == _state_rs) {
+  if (target == _state_rs && (_state_mask | _inv_state_mask).is_all_on()) {
     return;
   }
   _target_rs = target;

panda/src/glstuff/glGraphicsStateGuardian_src.h

@@ -519,6 +519,8 @@ public:
   DeletedDisplayLists _deleted_display_lists;
   DeletedDisplayLists _deleted_queries;
 
+  RenderState::SlotMask _inv_state_mask;
+
   static PStatCollector _load_display_list_pcollector;
   static PStatCollector _primitive_batches_display_list_pcollector;
   static PStatCollector _vertices_display_list_pcollector;

panda/src/tinydisplay/tinyGraphicsStateGuardian.cxx

@@ -89,6 +89,19 @@ reset() {
   free_pointers();
   GraphicsStateGuardian::reset();
 
+  // Build _inv_state_mask as a mask of 1's where we don't care, and
+  // 0's where we do care, about the state.
+  _inv_state_mask = RenderState::SlotMask::all_on();
+  _inv_state_mask.clear_bit(ColorAttrib::get_class_slot());
+  _inv_state_mask.clear_bit(ColorScaleAttrib::get_class_slot());
+  _inv_state_mask.clear_bit(CullFaceAttrib::get_class_slot());
+  _inv_state_mask.clear_bit(RescaleNormalAttrib::get_class_slot());
+  _inv_state_mask.clear_bit(RenderModeAttrib::get_class_slot());
+  _inv_state_mask.clear_bit(TextureAttrib::get_class_slot());
+  _inv_state_mask.clear_bit(MaterialAttrib::get_class_slot());
+  _inv_state_mask.clear_bit(LightAttrib::get_class_slot());
+  _inv_state_mask.clear_bit(ScissorAttrib::get_class_slot());
+
   if (_c != (GLContext *)NULL) {
     glClose(_c);
     _c = NULL;
@@ -1403,7 +1416,7 @@ set_state_and_transform(const RenderState *target,
     do_issue_transform();
   }
 
-  if (target == _state_rs) {
+  if (target == _state_rs && (_state_mask | _inv_state_mask).is_all_on()) {
     return;
   }
   _target_rs = target;

panda/src/tinydisplay/tinyGraphicsStateGuardian.h

@@ -146,6 +146,7 @@ private:
   bool _texture_replace;
   bool _filled_flat;
   bool _auto_rescale_normal;
+  RenderState::SlotMask _inv_state_mask;
 
   CPT(TransformState) _scissor_mat;