On start!, connects level's coin/maze change callbacks to the draw ADT's mark-coins-dirty! and mark-maze-dirty! methods. This completes the event chain: level state change -> dirty flag -> redraw next frame. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
54 lines
1.9 KiB
Racket
54 lines
1.9 KiB
Racket
#lang r7rs
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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;; Game ADT ;;
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;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
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;; Top-level game object that connects the level (logic) with the draw ADT
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;; (graphics). Registers callbacks for the game loop, keys, and drawing.
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(define-library (pacman-project adt game)
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(import (scheme base)
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(pacman-project constants)
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(pacman-project adt level)
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(pacman-project adt draw))
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(export make-game)
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(begin
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;; make-game :: -> game
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(define (make-game)
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(let ((level (make-level))
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(draw (make-draw window-width-px window-height-px)))
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;; key-handler :: symbol, any -> /
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;; Processes key presses and forwards them to the level.
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(define (key-handler status key)
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(when (eq? status 'pressed)
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((level 'key-press!) key)))
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;; game-loop :: number -> /
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;; Called each frame for game state updates and animation.
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(define (game-loop delta-time)
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((level 'update!) delta-time)
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((draw 'animate-pacman!) delta-time))
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;; start! :: -> /
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;; Starts the game by registering all callbacks and change listeners.
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(define (start!)
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;; Wire level change events to draw dirty flags.
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((level 'set-on-coins-changed!) (draw 'mark-coins-dirty!))
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((level 'set-on-maze-changed!) (draw 'mark-maze-dirty!))
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;; Register graphics callbacks.
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((draw 'set-game-loop!) game-loop)
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((draw 'set-key-callback!) key-handler)
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((draw 'start-drawing!) dispatch-game))
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;; dispatch-game :: symbol -> any
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(define (dispatch-game msg)
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(cond ((eq? msg 'start!) start!)
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((eq? msg 'level) level)
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(else (error "Game ADT -- Unknown message:" msg))))
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dispatch-game))))
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