gobj: use range for where possible in PreparedGraphicsObjects

This makes the code easier to read and maintain.

panda/src/gobj/preparedGraphicsObjects.cxx

@@ -274,11 +274,7 @@ release_all_textures() {
 
   int num_textures = (int)_prepared_textures.size() + (int)_enqueued_textures.size();
 
-  Textures::iterator tci;
-  for (tci = _prepared_textures.begin();
-       tci != _prepared_textures.end();
-       ++tci) {
-    TextureContext *tc = (*tci);
+  for (TextureContext *tc : _prepared_textures) {
     tc->get_texture()->clear_prepared(tc->get_view(), this);
     tc->_object = nullptr;
 
@@ -599,11 +595,7 @@ release_all_geoms() {
 
   int num_geoms = (int)_prepared_geoms.size() + (int)_enqueued_geoms.size();
 
-  Geoms::iterator gci;
-  for (gci = _prepared_geoms.begin();
-       gci != _prepared_geoms.end();
-       ++gci) {
-    GeomContext *gc = (*gci);
+  for (GeomContext *gc : _prepared_geoms) {
     gc->_geom->clear_prepared(this);
     gc->_geom = nullptr;
 
@@ -774,11 +766,7 @@ release_all_shaders() {
 
   int num_shaders = (int)_prepared_shaders.size() + (int)_enqueued_shaders.size();
 
-  Shaders::iterator sci;
-  for (sci = _prepared_shaders.begin();
-       sci != _prepared_shaders.end();
-       ++sci) {
-    ShaderContext *sc = (*sci);
+  for (ShaderContext *sc : _prepared_shaders) {
     sc->_shader->clear_prepared(this);
     sc->_shader = nullptr;
 
@@ -952,11 +940,8 @@ release_all_vertex_buffers() {
 
   int num_vertex_buffers = (int)_prepared_vertex_buffers.size() + (int)_enqueued_vertex_buffers.size();
 
-  Buffers::iterator vbci;
-  for (vbci = _prepared_vertex_buffers.begin();
-       vbci != _prepared_vertex_buffers.end();
-       ++vbci) {
-    VertexBufferContext *vbc = (VertexBufferContext *)(*vbci);
+  for (BufferContext *bc : _prepared_vertex_buffers) {
+    VertexBufferContext *vbc = (VertexBufferContext *)bc;
     vbc->get_data()->clear_prepared(this);
     vbc->_object = nullptr;
 
@@ -973,9 +958,8 @@ release_all_vertex_buffers() {
        ++bci) {
     BufferList &buffer_list = (*bci).second;
     nassertr(!buffer_list.empty(), num_vertex_buffers);
-    BufferList::iterator li;
-    for (li = buffer_list.begin(); li != buffer_list.end(); ++li) {
-      VertexBufferContext *vbc = (VertexBufferContext *)(*li);
+    for (BufferContext *bc : buffer_list) {
+      VertexBufferContext *vbc = (VertexBufferContext *)bc;
       _released_vertex_buffers.push_back(vbc);
     }
   }
@@ -1150,11 +1134,8 @@ release_all_index_buffers() {
 
   int num_index_buffers = (int)_prepared_index_buffers.size() + (int)_enqueued_index_buffers.size();
 
-  Buffers::iterator ibci;
-  for (ibci = _prepared_index_buffers.begin();
-       ibci != _prepared_index_buffers.end();
-       ++ibci) {
-    IndexBufferContext *ibc = (IndexBufferContext *)(*ibci);
+  for (BufferContext *bc : _prepared_index_buffers) {
+    IndexBufferContext *ibc = (IndexBufferContext *)bc;
     ibc->get_data()->clear_prepared(this);
     ibc->_object = nullptr;
 
@@ -1171,10 +1152,9 @@ release_all_index_buffers() {
        ++bci) {
     BufferList &buffer_list = (*bci).second;
     nassertr(!buffer_list.empty(), num_index_buffers);
-    BufferList::iterator li;
-    for (li = buffer_list.begin(); li != buffer_list.end(); ++li) {
-      IndexBufferContext *vbc = (IndexBufferContext *)(*li);
-      _released_index_buffers.push_back(vbc);
+    for (BufferContext *bc : buffer_list) {
+      IndexBufferContext *ibc = (IndexBufferContext *)bc;
+      _released_index_buffers.push_back(ibc);
     }
   }
   _index_buffer_cache.clear();
@@ -1337,12 +1317,7 @@ release_all_shader_buffers() {
 
   int num_shader_buffers = (int)_prepared_shader_buffers.size() + (int)_enqueued_shader_buffers.size();
 
-  Buffers::iterator bci;
-  for (bci = _prepared_shader_buffers.begin();
-       bci != _prepared_shader_buffers.end();
-       ++bci) {
-
-    BufferContext *bc = (BufferContext *)(*bci);
+  for (BufferContext *bc : _prepared_shader_buffers) {
     ((ShaderBuffer *)bc->_object)->clear_prepared(this);
     bc->_object = nullptr;
     _released_shader_buffers.push_back(bc);