diff options
Diffstat (limited to '2d/game-loop.scm')
-rw-r--r-- | 2d/game-loop.scm | 144 |
1 files changed, 75 insertions, 69 deletions
diff --git a/2d/game-loop.scm b/2d/game-loop.scm index 39fde9e..79e09b7 100644 --- a/2d/game-loop.scm +++ b/2d/game-loop.scm @@ -33,6 +33,7 @@ #:use-module (2d mvars) #:use-module (2d repl server) #:use-module (2d repl repl) + #:use-module (2d scene) #:use-module (2d stage) #:use-module (2d window) #:export (current-fps @@ -44,6 +45,74 @@ game-paused?)) ;;; +;;; Game Loop +;;; + +(define running? #f) +(define paused? #f) + +(define (tick dt accumulator) + "Advance the game by one frame." + (if paused? + (begin + (run-repl) + (SDL:delay tick-interval) + accumulator) + (catch #t + (lambda () + (let* ((stage (current-stage)) + (remainder (update stage accumulator))) + (run-repl) + (render stage dt) + remainder)) + (lambda (key . args) + (pause-game) + accumulator) + (lambda (key . args) + (display-backtrace (make-stack #t) + (current-output-port)))))) + +(define (game-loop last-time accumulator) + "Update game state, and render. LAST-TIME is the time in +milliseconds of the last iteration of the loop. ACCUMULATOR is the +time in milliseconds that has passed since the last game update." + (when running? + (let* ((current-time (SDL:get-ticks)) + (dt (- current-time last-time)) + (accumulator (+ accumulator dt))) + (game-loop current-time (tick dt accumulator))))) + +(define (run-game game) + "Open a window and start the game loop for GAME." + (open-window (game-title game) + (game-resolution game) + (game-fullscreen? game)) + (set! running? #t) + (resume-game) + (push-scene (game-first-scene game)) + (spawn-server) + (game-loop (SDL:get-ticks) 0) + (close-window)) + +(define (game-running?) + (running?)) + +(define (game-paused?) + (paused?)) + +(define (pause-game) + "Pauses the game loop. Useful when developing." + (set! paused? #t)) + +(define (resume-game) + "Resumes the game loop." + (set! paused? #f)) + +(define (quit-game) + "Finish the current frame and terminate the game loop." + (set! running? #f)) + +;;; ;;; Constants ;;; @@ -54,6 +123,12 @@ ;;; Event Handling ;;; +;; By default, pressing the escape key will pop the current scene, and +;; closing the window will quit the game. +(default-events `((key-down . ,(lambda (key mod unicode) + (pop-scene))) + (quit . ,quit-game))) + (define handle-events (let ((e (SDL:make-event))) (lambda (stage) @@ -72,7 +147,6 @@ (SDL:event:resize:w e) (SDL:event:resize:h e))) ((quit) - (quit-game) (stage-trigger stage 'quit)) ((key-down) (stage-trigger stage @@ -182,71 +256,3 @@ INPUT, OUTPUT, and ERROR ports." (unless (mvar-empty? repl-input-mvar) (and-let* ((vals (try-take-mvar repl-input-mvar))) (apply run-repl-thunk vals)))) - -;;; -;;; Game Loop -;;; - -(define running? #f) -(define paused? #f) - -(define (tick dt accumulator) - "Advance the game by one frame." - (if paused? - (begin - (run-repl) - (SDL:delay tick-interval) - accumulator) - (catch #t - (lambda () - (let* ((stage (current-stage)) - (remainder (update stage accumulator))) - (run-repl) - (render stage dt) - remainder)) - (lambda (key . args) - (pause-game) - accumulator) - (lambda (key . args) - (display-backtrace (make-stack #t) - (current-output-port)))))) - -(define (game-loop last-time accumulator) - "Update game state, and render. LAST-TIME is the time in -milliseconds of the last iteration of the loop. ACCUMULATOR is the -time in milliseconds that has passed since the last game update." - (when running? - (let* ((current-time (SDL:get-ticks)) - (dt (- current-time last-time)) - (accumulator (+ accumulator dt))) - (game-loop current-time (tick dt accumulator))))) - -(define (run-game game) - "Open a window and start the game loop for GAME." - (open-window (game-title game) - (game-resolution game) - (game-fullscreen? game)) - (set! running? #t) - (resume-game) - (push-scene (game-first-scene game)) - (spawn-server) - (game-loop (SDL:get-ticks) 0) - (close-window)) - -(define (game-running?) - (running?)) - -(define (game-paused?) - (paused?)) - -(define (pause-game) - "Pauses the game loop. Useful when developing." - (set! paused? #t)) - -(define (resume-game) - "Resumes the game loop." - (set! paused? #f)) - -(define (quit-game) - "Finish the current frame and terminate the game loop." - (set! running? #f)) |