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Add interframe time delta to frame-events

This commit is contained in:
Tony Garnock-Jones 2015-10-23 21:56:47 -04:00
parent 8083ddf890
commit 71bd34ac5b
2 changed files with 23 additions and 19 deletions
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20
prospect-gl/2d.rkt
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@ -34,7 +34,7 @@
(struct window (width height) #:transparent) (struct window (width height) #:transparent)
;; Message sent by world. Describes frame about to be rendered. ;; Message sent by world. Describes frame about to be rendered.
(struct frame-event (counter timestamp target-frame-rate) #:transparent) (struct frame-event (counter timestamp elapsed-ms target-frame-rate) #:transparent)
;; Message sent by world. Describes a key event. Key is a sealed ;; Message sent by world. Describes a key event. Key is a sealed
;; key-event%. `press?` is #t when the key is pressed (or ;; key-event%. `press?` is #t when the key is pressed (or
@ -223,6 +223,7 @@
(define counter 0) (define counter 0)
(define start-time (current-inexact-milliseconds)) (define start-time (current-inexact-milliseconds))
(define prev-frame-time start-time)
(define/public (sim-time) (define/public (sim-time)
(- (current-inexact-milliseconds) start-time)) (- (current-inexact-milliseconds) start-time))
@ -239,18 +240,16 @@
(define world (make-world boot-actions)) (define world (make-world boot-actions))
(define event-queue (make-queue)) (define event-queue (make-queue))
(define target-frame-rate 30) (define target-frame-rate 60)
(define frame-count 0)
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
(define (sleep-and-refresh) (define (sleep-and-refresh)
(define target-sim-time (* frame-count (/ target-frame-rate))) (define target-sim-time (* counter (/ target-frame-rate)))
(define sleep-time (- target-sim-time (/ (sim-time) 1000.0))) (define sleep-time (- target-sim-time (/ (sim-time) 1000.0)))
(when (positive? sleep-time) (when (positive? sleep-time)
(sleep/yield sleep-time)) (sleep/yield sleep-time))
(refresh) (refresh))
(set! frame-count (+ frame-count 1)))
(define/public (set-target-frame-rate! r) (define/public (set-target-frame-rate! r)
(set! target-frame-rate r)) (set! target-frame-rate r))
@ -320,8 +319,13 @@
(define/override (on-paint) (define/override (on-paint)
(with-gl-context (with-gl-context
(lambda () (lambda ()
(inject-event! (message (frame-event counter (sim-time) target-frame-rate))) (let ((this-frame-time (sim-time)))
(set! counter (+ counter 1)) (inject-event! (message (frame-event counter
this-frame-time
(- this-frame-time prev-frame-time)
target-frame-rate)))
(set! counter (+ counter 1))
(set! prev-frame-time this-frame-time))
(quiesce!) (quiesce!)
(unless initialised? (unless initialised?
(glBlendFunc GL_ONE GL_ONE_MINUS_SRC_ALPHA) ;; premultiplied (glBlendFunc GL_ONE GL_ONE_MINUS_SRC_ALPHA) ;; premultiplied

22
prospect-gl/examples/basic.rkt
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@ -45,35 +45,35 @@
(patch-project/set/single p key-pressed-projection)) (patch-project/set/single p key-pressed-projection))
(define new-keys-down (set-subtract (set-union keys-down added) removed)) (define new-keys-down (set-subtract (set-union keys-down added) removed))
(transition (list x y new-keys-down) '())] (transition (list x y new-keys-down) '())]
[(message (at-meta (frame-event _ _ target-frame-rate))) [(message (at-meta (frame-event _ _ elapsed-ms _)))
(define-values (old-x old-y) (values x y)) (define-values (old-x old-y) (values x y))
(define speed (/ 360.0 target-frame-rate)) (define distance (* 0.360 elapsed-ms))
(let* ((x (if (set-member? keys-down 'left) (- x speed) x)) (let* ((x (if (set-member? keys-down 'left) (- x distance) x))
(x (if (set-member? keys-down 'right) (+ x speed) x)) (x (if (set-member? keys-down 'right) (+ x distance) x))
(y (if (set-member? keys-down 'up) (- y speed) y)) (y (if (set-member? keys-down 'up) (- y distance) y))
(y (if (set-member? keys-down 'down) (+ y speed) y))) (y (if (set-member? keys-down 'down) (+ y distance) y)))
(and (not (and (= x old-x) (= y old-y))) (and (not (and (= x old-x) (= y old-y)))
(move-to x y keys-down)))] (move-to x y keys-down)))]
[_ #f])) [_ #f]))
(list 100 100 (set)) (list 100 100 (set))
(update-sprites (update-sprites
(simple-sprite -0.5 100 100 (image-width CC) (image-height CC) CC)) (simple-sprite -0.5 100 100 (image-width CC) (image-height CC) CC))
(sub (frame-event ? ? ?) #:meta-level 1) (sub (frame-event ? ? ? ?) #:meta-level 1)
(sub (key-pressed ?)))) (sub (key-pressed ?))))
(define (spawn-frame-counter) (define (spawn-frame-counter)
(spawn (lambda (e s) (spawn (lambda (e s)
(match e (match e
[(message (at-meta (frame-event counter elapsed-ms _))) [(message (at-meta (frame-event counter sim-time-ms _ _)))
(and (> elapsed-ms 0) (and (> sim-time-ms 0)
(let ((i (text (format "~a fps" (/ counter (/ elapsed-ms 1000.0))) 22 "black"))) (let ((i (text (format "~a fps" (/ counter (/ sim-time-ms 1000.0))) 22 "black")))
(transition s (update-sprites (simple-sprite -10 300 10 (transition s (update-sprites (simple-sprite -10 300 10
(image-width i) (image-width i)
(image-height i) (image-height i)
i)))))] i)))))]
[_ #f])) [_ #f]))
(void) (void)
(sub (frame-event ? ? ?) #:meta-level 1))) (sub (frame-event ? ? ? ?) #:meta-level 1)))
(2d-world (spawn-keyboard-integrator) (2d-world (spawn-keyboard-integrator)
(spawn-background) (spawn-background)