Oberon/ETH Oberon/2.3.7/OGLDisplay.Mod
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< Oberon | ETH Oberon
(* ETH Oberon, Copyright 1990-2003 Computer Systems Institute, ETH Zurich, CH-8092 Zurich.
Refer to the license.txt file provided with this distribution. *)
MODULE OGLDisplay; (** AUTHOR "fkuhn"; PURPOSE "Oberon Graphics Library display base"; *)
TYPE
State* = POINTER TO StateDesc;
StateDesc* = RECORD
activate*: PROCEDURE(state, oldState: State);
deactivate*: PROCEDURE(state, newState: State)
END;
VAR
cardBase, linBase: LONGINT;
cardSet, linSet: BOOLEAN;
currentState* : State;
(**
sets the address of the Graphic Registers
this has to be done exactly once by the Display module
**)
PROCEDURE SetCardBase*(adr: LONGINT);
BEGIN
cardBase := adr; cardSet := TRUE
END SetCardBase;
(**
sets the address of the framebuffer:
this has to be done exactly once by the Display module
**)
PROCEDURE SetLinearBase*(adr: LONGINT);
BEGIN
linBase := adr; linSet := TRUE
END SetLinearBase;
(** returns the address of the Graphic Card Registers **)
PROCEDURE CardBase*(): LONGINT;
BEGIN
IF cardSet THEN
RETURN cardBase
ELSE
HALT(1000)
END
END CardBase;
(** returns the address of the framebuffer **)
PROCEDURE LinearBase*(): LONGINT;
BEGIN
IF linSet THEN
RETURN linBase
ELSE
HALT(1000)
END
END LinearBase;
(** a default for the activate method of state, does nothing **)
PROCEDURE ActivateState*(state, oldState: State);
BEGIN
END ActivateState;
(** a default for the deactivate method of state, does nothing **)
PROCEDURE DeactivateState*(state, newState: State);
BEGIN
END DeactivateState;
(** ensures that the given state is active **)
PROCEDURE SwitchState*(state: State);
VAR
current: State;
BEGIN
current := currentState; currentState := state;
current.deactivate(current, state);
state.activate(state, current)
END SwitchState;
(*
(** ensures that the given state is active **)
PROCEDURE SwitchState*(state: State);
BEGIN
currentState.deactivate(currentState, state);
state.activate(state, currentState)
END SwitchState;
*)
BEGIN
cardSet := FALSE; linSet := FALSE;
NEW(currentState);
currentState.activate := ActivateState; currentState.deactivate := DeactivateState
END OGLDisplay.
05.01.03 20:13:02