indexing

	description:

		"[
			If you implement a scene with user interaction and
			want to use the 2d mode with openGL acceleration
			inherit from EM_SCENE_GL_2D and implement the deferred features.

			initialize_scene: called first by the caller
			run: called after initialize_scene by the caller
			others: called by event_loop.dispatch

			If you want to end the scene just call event_loop.stop. This will end the
			scene and the caller gets the control back. If you want that another
			scene is executed after your scene ends pass it to next_scene. If you want
			to end the program pass void to next_scene.

			See the implementation of the main loop in SPRITES_EM.
			
			Subclasses should call `make_scene' at creation.
			
		]"
	date: "$Date$"
	revision: "$Revision$"

deferred class EM_SCENE_GL_2D

inherit

	EM_SCENE
		redefine
			run
		end

	EM_SHARED_SUBSYSTEMS
		export {NONE} all 	end

feature -- Commands

	run (a_screen: EM_SURFACE) is
			-- Run the scene
		do
			a_screen.gl_enter_2d

			Precursor (a_screen)

				-- Leave gl 2d mode
			a_screen.gl_leave_2d
		end

end