Viewport, Platform: Refactored platform interface. Removed need to use imgui_internal.h in backends. Split viewport into public facing ImGuiViewport and internal structure. Exposing enough data to provide custom tweaked renderers. Renamed handlers, fixed lots of inconsistencies. (#1542, #1042)

examples/opengl2_example/main.cpp

@@ -106,13 +106,13 @@ int main(int, char**)
         }
 
         // Rendering
+        ImGui::Render();
         int display_w, display_h;
         glfwGetFramebufferSize(window, &display_w, &display_h);
         glViewport(0, 0, display_w, display_h);
         glClearColor(clear_color.x, clear_color.y, clear_color.z, clear_color.w);
         glClear(GL_COLOR_BUFFER_BIT);
         //glUseProgram(0); // You may want this if using this code in an OpenGL 3+ context where shaders may be bound, but prefer using the GL3+ code.
-        ImGui::Render();
         ImGui_ImplOpenGL2_RenderDrawData(ImGui::GetDrawData());
         glfwSwapBuffers(window);
     }