1. Trigger OnFrameStart.
2. Check if game has been closed/quit, and exit if necessary.
3. If game is inactive draw the screen as it was when it was last active, and skip the rest of the loop.
4. Trigger OnBeforeBeginScene.
5. Draw the main map.
6. Read players' input devices.
7. Trigger OnBeforeExecuteRules.
8. Execute the main map's rules.
9. Trigger OnBeforeDrawOverlay.
10. If an overlay map is active, draw it and execute its rules.
11. Draw the current debug output if debug mode is active, and clear the debug text buffer.
12. Trigger OnAfterDrawOverlay.

Reference