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Fix(Animation): Drive Pac-Man mouth animation from game loop, not draw callback

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The draw callback receives no delta-time, so animation was stuck at 0.
Split draw-pacman! into draw (position/rotation) and animate-pacman!
(sprite sequence advancement). Animation is now called from the game
loop which has the real delta-time.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
This commit is contained in:
joren
2026-03-23 11:12:56 +01:00
parent caac996acd
commit 1ac72f03a7
2 changed files with 16 additions and 11 deletions
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22
pacman-project/adt/draw.rkt
View File

@@ -147,9 +147,17 @@
((key-sprite 'set-x!) (grid->pixel-x (pos 'col)))
((key-sprite 'set-y!) (grid->pixel-y (pos 'row))))))
;; draw-pacman! :: pacman, number -> /
;; animate-pacman! :: number -> /
;; Advances the Pac-Man sprite animation based on elapsed time.
(define (animate-pacman! delta-time)
(set! time-since-last-animation (+ time-since-last-animation delta-time))
(when (>= time-since-last-animation animation-interval-ms)
((pacman-sprite 'set-next!))
(set! time-since-last-animation 0)))
;; draw-pacman! :: pacman -> /
;; Draws Pac-Man at its current position with correct rotation.
(define (draw-pacman! pacman delta-time)
(define (draw-pacman! pacman)
(let* ((pos (pacman 'position))
(direction (pacman 'direction)))
;; Set position
@@ -159,12 +167,7 @@
(cond ((eq? direction 'right) ((pacman-sprite 'rotate!) rotation-right))
((eq? direction 'left) ((pacman-sprite 'rotate!) rotation-left))
((eq? direction 'up) ((pacman-sprite 'rotate!) rotation-up))
((eq? direction 'down) ((pacman-sprite 'rotate!) rotation-down)))
;; Animation
(set! time-since-last-animation (+ time-since-last-animation delta-time))
(when (>= time-since-last-animation animation-interval-ms)
((pacman-sprite 'set-next!))
(set! time-since-last-animation 0))))
((eq? direction 'down) ((pacman-sprite 'rotate!) rotation-down)))))
;; draw-ui! :: score, timer -> /
;; Draws the score and time limit on screen.
@@ -202,7 +205,7 @@
;; Draws the full game (registered as draw callback).
(define (draw-game! game)
(let ((level (game 'level)))
(draw-pacman! (level 'pacman) 0)
(draw-pacman! (level 'pacman))
(draw-key! (level 'key))
(draw-coins! (level 'maze))
(draw-ui! (level 'score) (level 'timer))
@@ -237,6 +240,7 @@
(cond ((eq? msg 'set-game-loop!) set-game-loop!)
((eq? msg 'set-key-callback!) set-key-callback!)
((eq? msg 'start-drawing!) start-drawing!)
((eq? msg 'animate-pacman!) animate-pacman!)
(else (error "Draw ADT -- Unknown message:" msg))))
dispatch-draw))))

5
pacman-project/adt/game.rkt
View File

@@ -28,9 +28,10 @@
((level 'key-press!) key)))
;; game-loop :: number -> /
;; Called each frame for game state updates.
;; Called each frame for game state updates and animation.
(define (game-loop delta-time)
((level 'update!) delta-time))
((level 'update!) delta-time)
((draw 'animate-pacman!) delta-time))
;; start! :: -> /
;; Starts the game by registering all callbacks.