diff options
Diffstat (limited to '2d')
| -rw-r--r-- | 2d/game-loop.scm | 60 |
1 files changed, 38 insertions, 22 deletions
diff --git a/2d/game-loop.scm b/2d/game-loop.scm index 5ba0889..c647ebe 100644 --- a/2d/game-loop.scm +++ b/2d/game-loop.scm @@ -25,6 +25,7 @@ #:use-module ((sdl sdl) #:prefix SDL:) #:use-module (figl gl) #:use-module (2d agenda) + #:use-module (2d coroutine) #:export (on-active-hook on-resize-hook on-quit-hook @@ -35,10 +36,12 @@ on-mouse-motion-hook on-mouse-button-down-hook on-mouse-button-up-hook - run-game-loop)) + run-game-loop + current-fps)) (define target-fps 60) -(define frame-interval (/ 1000 target-fps)) +(define *fps* 0) +(define tick-interval (/ 1000 target-fps)) ;;; ;;; Hooks @@ -105,6 +108,30 @@ (SDL:event:button:y e))))) ;;; +;;; Frames Per Second +;;; + +(define accumulate-fps! + (let* ((frame-time 0) + (alpha 1/5) + (inverse-alpha (- 1 alpha))) + (lambda (dt) + "Computes a weighted average FPS." + (set! frame-time (+ (* alpha dt) (* inverse-alpha frame-time))) + (unless (zero? frame-time) + (set! *fps* (/ 1000 frame-time)))))) + +(define (current-fps) + "Returns the current FPS value." + *fps*) + +(codefine (show-fps) + "Display the current FPS every second." + (wait 60) + (pk 'FPS (floor *fps*)) + (show-fps)) + +;;; ;;; Update and Render ;;; @@ -116,25 +143,15 @@ (run-hook on-render-hook) (SDL:gl-swap-buffers)) -(define (increment-fps fps fps-time) - "Increment frames-per-second counter. Resets to 0 when the -difference between time and fps-time is greater than or equal to one -second." - (if (>= fps-time 1000) - (begin - (pk 'FPS fps) - 0) - (1+ fps))) - (define (update accumulator) "Call the update callback. The update callback will be called as -many times as frame-interval can divide accumulator. The return value +many times as tick-interval can divide accumulator. The return value is the unused accumulator time." - (if (>= accumulator frame-interval) + (if (>= accumulator tick-interval) (begin (run-hook on-update-hook) (update-agenda) - (update (- accumulator frame-interval))) + (update (- accumulator tick-interval))) accumulator)) (define (time-left current-time next-time) @@ -146,21 +163,20 @@ is the unused accumulator time." (define (run-game-loop) "Runs event handling, update, and render loop." - (define (game-loop last-time next-time fps-time accumulator fps) + (define (game-loop last-time next-time accumulator) (handle-events) (let* ((time (SDL:get-ticks)) (dt (- time last-time)) (accumulator (+ accumulator dt)) - (current-fps-time (+ fps-time dt)) (remainder (update accumulator))) (render) + (accumulate-fps! dt) ;; Sleep for a bit if there's time in between frames (SDL:delay (time-left (SDL:get-ticks) next-time)) (game-loop time - (+ next-time frame-interval) - (modulo current-fps-time 1000) - remainder - (increment-fps fps current-fps-time)))) + (+ next-time tick-interval) + remainder))) + (agenda-schedule show-fps) (let ((time (SDL:get-ticks))) - (game-loop time (+ time frame-interval) 0 0 0))) + (game-loop time (+ time tick-interval) 0))) |