Add support for runtime fall-back from o3d to o2d.

plugin/cross/o3d_glue.cc

Index: plugin/cross/o3d_glue.cc
===================================================================
--- plugin/cross/o3d_glue.cc	(revision 75475)
+++ plugin/cross/o3d_glue.cc	(working copy)
@@ -257,6 +257,7 @@
 }
 
 void PluginObject::CreateRenderer(const o3d::DisplayWindow& display_window) {
+#if !defined(FORCE_CAIRO)
   if (!o3d::CheckConfig(npp_)) {
     renderer_init_status_ = o3d::Renderer::GPU_NOT_UP_TO_SPEC;
   } else {
@@ -269,6 +270,27 @@
       DeleteRenderer();
     }
   }
+#else
+  // To force cairo, pretend all previous renderer initialization has failed.

[Tristan Schmelcher 2, 2011/02/23 19:27:30]

You shouldn't need this, because renderer_init_status_ is set to UNINITIALIZED
in the constructor.

Hmm, though actually, it looks like CreateRenderer() could be called more than
once, so it may not be UNINITIALIZED at the start of this function. But the
original code does not appear to do the right thing in that case because it does
not delete the renderer_ before assigning the new one to it.

So actually, I think you should add this to the start of the function:

DeleteRenderer();
renderer_init_status_ = o3d::Renderer::UNINITIALIZED;

+  renderer_init_status_ = o3d::Renderer::GPU_NOT_UP_TO_SPEC;
+#endif
+
+#if defined(SUPPORT_CAIRO)
+  if (renderer_init_status_ != o3d::Renderer::SUCCESS) {
+    // Attempt to fall back to o2d renderer
+    renderer_ = o3d::Renderer::Create2DRenderer(&service_locator_);
+    if (renderer_) {
+      if (renderer_->Init(display_window, false) != o3d::Renderer::SUCCESS) {

[Tristan Schmelcher 2, 2011/02/23 19:27:30]

I think we might as well just assign this result directly to
renderer_init_status_. If both 3D and 2D initialization fails, the error code
from the 2D failure is probably more appropriate since it is the more
fundamental error. For example, 3D may have failed with GPU_NOT_UP_TO_SPEC, but
it would not be accurate to say that that is the cause of initialization failure
because there is no requirement for any particular GPU when 2D is supported.

+        DeleteRenderer();
+      } else {
+        renderer_init_status_ = o3d::Renderer::SUCCESS;
+        ClientInfoManager* client_info_manager =
+              service_locator()->GetService<ClientInfoManager>();
+        client_info_manager->SetRender2d(true);
+      }
+    }
+  }
+#endif
 }
 
 void PluginObject::DeleteRenderer() {