Add EndAllViewsRender event, emitted when Renderer::Render() is finished. Closes #1830.

Source/Urho3D/Graphics/GraphicsEvents.h

@@ -120,6 +120,11 @@ URHO3D_EVENT(E_ENDVIEWRENDER, EndViewRender)
     URHO3D_PARAM(P_CAMERA, Camera);                // Camera pointer
 }
 
+/// Render of all views is finished for the frame.
+URHO3D_EVENT(E_ENDALLVIEWSRENDER, EndAllViewsRender)
+{
+}
+
 /// A render path event has occurred.
 URHO3D_EVENT(E_RENDERPATHEVENT, RenderPathEvent)
 {

Source/Urho3D/Graphics/Renderer.cpp

@@ -759,6 +759,9 @@ void Renderer::Render()
 
     // Remove unused occlusion buffers and renderbuffers
     RemoveUnusedBuffers();
+
+    // All views done, custom rendering can now be done before UI
+    SendEvent(E_ENDALLVIEWSRENDER);
 }
 
 void Renderer::DrawDebugGeometry(bool depthTest)