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Fix ghost and Pac-Man movement interpolation teleport

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Joren
2026-03-23 12:38:23 +01:00
parent 0e14140db9
commit f2cb49ad2b
1 changed files with 10 additions and 13 deletions
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23
pacman-project/adt/draw.rkt
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@@ -262,20 +262,18 @@
(+ a (* t (- b a)))) (+ a (* t (- b a))))
;; draw-pacman! :: pacman, number -> / ;; draw-pacman! :: pacman, number -> /
;; Draws Pac-Man with offset backward interpolation. Uses ;; Draws Pac-Man with smooth backward interpolation. Uses
;; lerp(prev, current, 0.5 + t/2) so the visual starts at the ;; lerp(prev, current, t) so the visual smoothly transitions
;; midpoint (max 0.5 tile lag) and arrives at current by t=1. ;; from the previous tile strictly to the current tile by t=1.
;; No jumps on direction changes unlike forward extrapolation.
(define (draw-pacman! pacman progress) (define (draw-pacman! pacman progress)
(let* ((pos (pacman 'position)) (let* ((pos (pacman 'position))
(row (pos 'row)) (row (pos 'row))
(col (pos 'col)) (col (pos 'col))
(prev-row (pacman 'prev-row)) (prev-row (pacman 'prev-row))
(prev-col (pacman 'prev-col)) (prev-col (pacman 'prev-col))
(t (min progress 1)) (t (max 0 (min progress 1)))
(factor (+ 0.5 (* 0.5 t))) (render-row (lerp prev-row row t))
(render-row (lerp prev-row row factor)) (render-col (lerp prev-col col t))
(render-col (lerp prev-col col factor))
(direction (pacman 'direction))) (direction (pacman 'direction)))
((pacman-sprite 'set-x!) (grid->pixel-x render-col)) ((pacman-sprite 'set-x!) (grid->pixel-x render-col))
((pacman-sprite 'set-y!) (grid->pixel-y render-row)) ((pacman-sprite 'set-y!) (grid->pixel-y render-row))
@@ -285,7 +283,7 @@
((eq? direction 'down) ((pacman-sprite 'rotate!) rotation-down))))) ((eq? direction 'down) ((pacman-sprite 'rotate!) rotation-down)))))
;; draw-ghosts! :: list -> / ;; draw-ghosts! :: list -> /
;; Updates all ghost sprite positions with offset backward interpolation. ;; Updates all ghost sprite positions with smooth backward interpolation.
(define (draw-ghosts! ghosts) (define (draw-ghosts! ghosts)
(for-each (for-each
(lambda (ghost ghost-draw) (lambda (ghost ghost-draw)
@@ -294,10 +292,9 @@
(col (pos 'col)) (col (pos 'col))
(prev-row (ghost 'prev-row)) (prev-row (ghost 'prev-row))
(prev-col (ghost 'prev-col)) (prev-col (ghost 'prev-col))
(t (min (/ (ghost 'movement-timer) ghost-speed-ms) 1)) (t (max 0 (min (/ (ghost 'movement-timer) ghost-speed-ms) 1)))
(factor (+ 0.5 (* 0.5 t))) (render-row (lerp prev-row row t))
(render-row (lerp prev-row row factor)) (render-col (lerp prev-col col t))
(render-col (lerp prev-col col factor))
(dir (ghost 'direction))) (dir (ghost 'direction)))
((ghost-draw 'update!) render-row render-col dir))) ((ghost-draw 'update!) render-row render-col dir)))
ghosts ghost-draw-states)) ghosts ghost-draw-states))