diff options
Diffstat (limited to 'animation.scm')
| -rw-r--r-- | animation.scm | 33 |
1 files changed, 24 insertions, 9 deletions
diff --git a/animation.scm b/animation.scm index f166bff..5753bc1 100644 --- a/animation.scm +++ b/animation.scm @@ -26,16 +26,27 @@ (define (frame-by-idx frames frame-idx) (list-ref frames (modulo frame-idx (length frames)))) +;; A "timed" frame is =(tile-id tick-budget)= — a two-element proper list. +;; A bare tile id is a number (or other atom). +(define (timed-frame? frame-def) + (and (pair? frame-def) + (pair? (cdr frame-def)) + (null? (cddr frame-def)))) + ;; The tile ID is 1-indexed. (define (frame->tile-id frames frame-idx) (let ((frame-def (frame-by-idx frames frame-idx))) - (if (list? frame-def) + (if (timed-frame? frame-def) (car frame-def) frame-def))) -(define (frame->duration animation frame-idx) +;; Tick budget for one frame, in this order: +;; 1. Per-frame duration from =(tile duration)= in #:frames +;; 2. Else the animation alist's #:duration +;; 3. Else +default-anim-duration+ (global default) +(define (animation-frame-duration animation frame-idx) (let ((frame-def (frame-by-idx (animation-frames animation) frame-idx))) - (if (list? frame-def) + (if (timed-frame? frame-def) (cadr frame-def) (animation-ref animation #:duration +default-anim-duration+)))) @@ -63,22 +74,26 @@ ;; Advance the animation tick/frame counter for one game tick. ;; Pass the animation table for this entity's type. ;; Entities without #:anim-name are returned unchanged. +;; Tick threshold is always (animation-frame-duration anim frame) — per-frame pair, +;; then animation #:duration, then +default-anim-duration+. #:anim-duration +;; on the entity is set every step to that resolved value. (define (advance-animation entity anim dt) - (let ((tick (+ dt (entity-ref entity #:anim-tick 0))) - (duration (entity-ref entity #:duration +default-anim-duration+)) - (frames (animation-frames anim)) - (frame (entity-ref entity #:anim-frame 0))) + (let* ((frame (entity-ref entity #:anim-frame 0)) + (frames (animation-frames anim)) + (duration (animation-frame-duration anim frame)) + (tick (+ dt (entity-ref entity #:anim-tick 0)))) (if (>= tick duration) (let ((new-frame-id (modulo (+ frame 1) (length frames)))) (entity-set-many entity `((#:anim-tick . 0) (#:anim-frame . ,new-frame-id) (#:tile-id . ,(frame->tile-id frames new-frame-id)) - (#:duration . ,(frame->duration anim new-frame-id))))) + (#:anim-duration . ,(animation-frame-duration anim new-frame-id))))) (entity-set-many entity `((#:anim-tick . ,tick) - (#:tile-id . ,(frame->tile-id frames frame))))))) + (#:tile-id . ,(frame->tile-id frames frame)) + (#:anim-duration . ,duration)))))) (define (animate-entity entity animations dt) (let* ((anim-name (entity-ref entity #:anim-name #f)) |