diff options
| -rw-r--r-- | starling/kernel.scm | 25 |
1 files changed, 18 insertions, 7 deletions
diff --git a/starling/kernel.scm b/starling/kernel.scm index 193eb7b..25e92b6 100644 --- a/starling/kernel.scm +++ b/starling/kernel.scm @@ -52,9 +52,11 @@ update-hz window gl-context + avg-frame-time current-kernel boot-kernel elapsed-time + fps current-scene push-scene pop-scene @@ -75,6 +77,7 @@ (window #:accessor window) (gl-context #:accessor gl-context) (default-viewport #:accessor default-viewport) + (avg-frame-time #:accessor avg-frame-time #:init-form 0.0) (controllers #:accessor controllers #:init-thunk make-hash-table) (repl #:accessor repl) ;; The scene stack. @@ -208,13 +211,18 @@ (gpu-reap!)) (define-method (render* (kernel <kernel>) alpha) - ;; Switch to the null viewport to ensure that - ;; the default viewport will be re-applied and - ;; clear the screen. - (gpu-state-set! *viewport-state* null-viewport) - (with-viewport (default-viewport kernel) - (next-method)) - (swap-gl-window (window kernel))) + (let ((start-time (elapsed-time))) + ;; Switch to the null viewport to ensure that + ;; the default viewport will be re-applied and + ;; clear the screen. + (gpu-state-set! *viewport-state* null-viewport) + (with-viewport (default-viewport kernel) + (next-method)) + (swap-gl-window (window kernel)) + ;; Compute FPS. + (set! (avg-frame-time kernel) + (+ (* (- (elapsed-time) start-time) 0.1) + (* (avg-frame-time kernel) 0.9))))) (define-method (on-error (kernel <kernel>) stack key args) (if (developer-mode? kernel) @@ -227,6 +235,9 @@ (define (elapsed-time) (sdl-ticks)) +(define-method (fps kernel) + (/ 1000.0 (avg-frame-time kernel))) + (define-method (boot-kernel (kernel <kernel>) (scene <scene>)) (sdl-init) ;; This will throw an error if any audio subsystem is unavailable, |