add GraphicsPipe::OT_texture_buffer

panda/src/display/graphicsPipe.h

@@ -70,6 +70,7 @@ PUBLISHED:
     OT_window            = 0x0001,
     OT_fullscreen_window = 0x0002,
     OT_buffer            = 0x0004,
+    OT_texture_buffer    = 0x0008,
   };
 
   INLINE bool is_valid() const;

panda/src/glxdisplay/glxGraphicsPipe.cxx

@@ -51,7 +51,7 @@ glxGraphicsPipe(const string &display) {
   setlocale(LC_ALL, "");
 
   _is_valid = false;
-  _supported_types = OT_window | OT_buffer;
+  _supported_types = OT_window | OT_buffer | OT_texture_buffer;
   _display = NULL;
   _screen = 0;
   _root = (Window)NULL;

panda/src/mesadisplay/mesaGraphicsPipe.cxx

@@ -32,7 +32,7 @@ TypeHandle MesaGraphicsPipe::_type_handle;
 ////////////////////////////////////////////////////////////////////
 MesaGraphicsPipe::
 MesaGraphicsPipe() {
-  _supported_types = OT_buffer;
+  _supported_types = OT_buffer | OT_texture_buffer;
   _is_valid = true;
 }