diff --git a/panda/src/glstuff/glGraphicsBuffer_src.cxx b/panda/src/glstuff/glGraphicsBuffer_src.cxx
index dd9b1e1348..46ac9a7ba6 100644
--- a/panda/src/glstuff/glGraphicsBuffer_src.cxx
+++ b/panda/src/glstuff/glGraphicsBuffer_src.cxx
@@ -409,20 +409,19 @@ rebuild_bitplanes() {
 
   // Now create the FBO's.
   _have_any_color = false;
-  _fbo.reserve(num_fbos);
-  for (int layer = 0; layer < num_fbos; ++layer) {
-    if (layer >= _fbo.size()) {
-      _fbo.push_back(0);
-    }
 
+  if (num_fbos > _fbo.size()) {
+    // Generate more FBO handles.
+    int start = _fbo.size();
+    _fbo.resize(num_fbos, 0);
+    glgsg->_glGenFramebuffers(num_fbos - start, &_fbo[start]);
+  }
+
+  for (int layer = 0; layer < num_fbos; ++layer) {
     // Bind the FBO
     if (_fbo[layer] == 0) {
-      glgsg->_glGenFramebuffers(1, &_fbo[layer]);
-
-      if (_fbo[layer] == 0) {
-        report_my_gl_errors();
-        return;
-      }
+      report_my_gl_errors();
+      return;
     }
     glgsg->bind_fbo(_fbo[layer]);
 
@@ -1118,11 +1117,7 @@ generate_mipmaps() {
     CLP(TextureContext) *gtc = *it;
 
     if (gtc->_generate_mipmaps) {
-      glgsg->_state_texture = 0;
-      glgsg->update_texture(gtc, true);
-      glgsg->apply_texture(gtc);
-      glgsg->_glGenerateMipmap(gtc->_target);
-      glBindTexture(gtc->_target, 0);
+      glgsg->generate_mipmaps(gtc);
     }
   }
 
diff --git a/panda/src/glstuff/glGraphicsStateGuardian_src.cxx b/panda/src/glstuff/glGraphicsStateGuardian_src.cxx
index 8d375e9dc4..bd797c249f 100644
--- a/panda/src/glstuff/glGraphicsStateGuardian_src.cxx
+++ b/panda/src/glstuff/glGraphicsStateGuardian_src.cxx
@@ -1877,6 +1877,15 @@ reset() {
 #endif  // OPENGLES
 #endif
 
+#ifndef OPENGLES
+  if (is_at_least_gl_version(4, 5) || has_extension("GL_ARB_direct_state_access")) {
+    _glGenerateTextureMipmap = (PFNGLGENERATETEXTUREMIPMAPPROC)
+      get_extension_func("glGenerateTextureMipmap");
+  } else {
+    _glGenerateTextureMipmap = NULL;
+  }
+#endif
+
   _supports_framebuffer_multisample = false;
   if ( has_extension("GL_EXT_framebuffer_multisample") ) {
     _supports_framebuffer_multisample = true;
@@ -11760,6 +11769,31 @@ upload_texture_image(CLP(TextureContext) *gtc, bool needs_reload,
   return true;
 }
 
+////////////////////////////////////////////////////////////////////
+//     Function: GLGraphicsStateGuardian::generate_mipmaps
+//       Access: Protected
+//  Description: Causes mipmaps to be generated for an uploaded
+//               texture.
+////////////////////////////////////////////////////////////////////
+void CLP(GraphicsStateGuardian)::
+generate_mipmaps(CLP(TextureContext) *gtc) {
+#ifndef OPENGLES
+  if (_glGenerateTextureMipmap != NULL) {
+    // OpenGL 4.5 offers an easy way to do this without binding.
+    _glGenerateTextureMipmap(gtc->_index);
+    return;
+  }
+#endif
+
+  if (_glGenerateMipmap != NULL) {
+    _state_texture = 0;
+    update_texture(gtc, true);
+    apply_texture(gtc);
+    _glGenerateMipmap(gtc->_target);
+    glBindTexture(gtc->_target, 0);
+  }
+}
+
 ////////////////////////////////////////////////////////////////////
 //     Function: GLGraphicsStateGuardian::upload_simple_texture
 //       Access: Protected
diff --git a/panda/src/glstuff/glGraphicsStateGuardian_src.h b/panda/src/glstuff/glGraphicsStateGuardian_src.h
index 62df6fe84c..7d5f796140 100644
--- a/panda/src/glstuff/glGraphicsStateGuardian_src.h
+++ b/panda/src/glstuff/glGraphicsStateGuardian_src.h
@@ -546,6 +546,7 @@ protected:
                             GLenum component_type,
                             bool one_page_only, int z,
                             Texture::CompressionMode image_compression);
+  void generate_mipmaps(CLP(TextureContext) *gtc);
   bool upload_simple_texture(CLP(TextureContext) *gtc);
 
   size_t get_texture_memory_size(CLP(TextureContext) *gtc);
@@ -794,6 +795,10 @@ public:
   PFNGLGENERATEMIPMAPEXTPROC _glGenerateMipmap;
   PFNGLBINDPROGRAMARBPROC _glBindProgram;
 
+#ifndef OPENGLES
+  PFNGLGENERATETEXTUREMIPMAPPROC _glGenerateTextureMipmap;
+#endif
+
   bool _supports_framebuffer_multisample;
   bool _supports_framebuffer_multisample_coverage_nv;
   INLINE bool get_supports_framebuffer_multisample();