diff options
| -rw-r--r-- | 2d/game.scm | 206 |
1 files changed, 96 insertions, 110 deletions
diff --git a/2d/game.scm b/2d/game.scm index 2e60ba4..72980fd 100644 --- a/2d/game.scm +++ b/2d/game.scm @@ -34,71 +34,88 @@ #:use-module (2d repl repl) #:use-module (2d signals) #:use-module (2d vector2) - #:export (<game> - make-game - game? - game-title - game-resolution - game-fullscreen? - current-fps - run-game + #:export (run-game quit-game pause-game resume-game game-running? - game-paused?)) + game-paused? + window-size + key-last-pressed + key-down? + mouse-position + mouse-down? + current-fps)) ;;; -;;; Games +;;; Game Loop ;;; -(define-record-type <game> - (%make-game draw) - game? - (draw game-draw)) - (define (default-draw) #f) -(define* (make-game #:optional #:key - (draw default-draw)) - "Create a new game." - (%make-game draw)) +(define (default-update) + #f) -(define (draw-game game) - ((game-draw game))) +;; Possible states are: +;; * stopped +;; * running +;; * paused +(define %state 'stopped) +(define %draw #f) +(define %update #f) +;; TODO: Make this configurable +(define ticks-per-second 60) +(define tick-interval (floor (/ 1000 ticks-per-second))) (define* (run-game #:optional #:key - (draw default-draw)) + (draw default-draw) + (update default-update)) "Start the game loop." - (set! running? #t) + (set! %state 'running) + (set! %draw draw) + (set! %update update) (resume-game) (spawn-server) - (game-loop (make-game #:draw draw) (SDL:get-ticks) 0)) + (game-loop (SDL:get-ticks) 0)) -;;; -;;; Game Loop -;;; +(define (draw dt) + "Render a frame." + (set-gl-matrix-mode (matrix-mode modelview)) + (gl-load-identity) + (gl-clear (clear-buffer-mask color-buffer depth-buffer)) + (%draw) + (SDL:gl-swap-buffers) + (accumulate-fps! dt)) -(define running? #f) -(define paused? #f) +(define (update accumulator) + "Call the update callback. The update callback will be called as +many times as `tick-interval` can divide ACCUMULATOR. The return value +is the unused accumulator time." + (if (>= accumulator tick-interval) + (begin + (handle-events) + (update-agenda) + (%update) + (update (- accumulator tick-interval))) + accumulator)) -(define (update-and-render game dt accumulator) +(define (update-and-render dt accumulator) (let ((remainder (update accumulator))) (run-repl) - (draw game dt) + (draw dt) remainder)) -(define (tick game dt accumulator) +(define (tick dt accumulator) "Advance the game by one frame." - (if paused? + (if (game-paused?) (begin (run-repl) (SDL:delay tick-interval) accumulator) (catch #t (lambda () - (update-and-render game dt accumulator)) + (update-and-render dt accumulator)) (lambda (key . args) (pause-game) accumulator) @@ -106,53 +123,44 @@ (display-backtrace (make-stack #t) (current-output-port)))))) -(define (game-loop game last-time accumulator) +(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? + (when (game-running?) (let* ((current-time (SDL:get-ticks)) (dt (- current-time last-time)) (accumulator (+ accumulator dt))) - (game-loop game current-time (tick game dt accumulator))))) + (game-loop current-time (tick dt accumulator))))) + +;;; +;;; State management +;;; (define (game-running?) - running?) + (or (eq? %state 'running) + (eq? %state 'paused))) (define (game-paused?) - paused?) + (eq? %state 'paused)) (define (pause-game) "Pauses the game loop. Useful when developing." - (set! paused? #t)) + (set! %state 'paused)) (define (resume-game) "Resumes the game loop." - (set! paused? #f)) + (when (game-paused?) + (set! %state 'running))) (define (quit-game) "Finish the current frame and terminate the game loop." - (set! running? #f)) - -;;; -;;; Constants -;;; - -(define target-fps 60) -(define tick-interval (floor (/ 1000 target-fps))) + (set! %state 'stopped)) ;;; ;;; 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 (state key mod unicode) -;; (when (eq? key 'escape) -;; (pop-scene)))) -;; (quit . ,(lambda (state) -;; (quit-game))))) - (define handle-events (let ((e (SDL:make-event))) (lambda () @@ -160,24 +168,31 @@ time in milliseconds that has passed since the last game update." (while (SDL:poll-event e) (handle-event e))))) -(define-public window-size (signal-identity (vector2 0 0))) -(define-public key-down (signal-identity)) -(define-public key-up (signal-identity)) -(define-public mouse-position (signal-identity (vector2 0 0))) -(define-public mouse-down (signal-identity)) -(define-public mouse-up (signal-identity)) - -(define-public (key-is-down key) - (make-signal (lambda (value prev from) - (cond ((and (eq? from key-down) - (eq? value key)) - #t) - ((and (eq? from key-up) - (eq? value key)) - #f) - (else - prev))) - #:connectors (list key-down key-up))) +;; Keyboard and mouse signals. +(define window-size (signal-identity (vector2 0 0))) +(define key-last-pressed (signal-identity)) +(define mouse-position (signal-identity (vector2 0 0))) +(define key-signals (make-hash-table)) +(define mouse-signals (make-hash-table)) + +(define (signal-hash-ref hash key) + (let ((signal (hashq-ref hash key))) + (if (signal? signal) + signal + (let ((signal (signal-identity))) + (hashq-set! hash key signal) + signal)))) + +(define (signal-hash-set! hash key value) + (signal-set! (signal-hash-ref hash key) value)) + +(define (key-down? key) + "Return a signal for KEY." + (signal-hash-ref key-signals key)) + +(define (mouse-down? button) + "Return a signal for BUTTON." + (signal-hash-ref mouse-signals button)) (define (handle-event e) "Call the relevant callbacks for the event E." @@ -190,23 +205,19 @@ time in milliseconds that has passed since the last game update." ((quit) (quit-game)) ((key-down) - (signal-set! key-down (SDL:event:key:keysym:sym e))) + (let ((key (SDL:event:key:keysym:sym e))) + (signal-hash-set! key-signals key #t) + (signal-set! key-last-pressed key))) ((key-up) - (signal-set! key-up (SDL:event:key:keysym:sym e))) + (signal-hash-set! key-signals (SDL:event:key:keysym:sym e) #f)) ((mouse-motion) (signal-set! mouse-position (vector2 (SDL:event:motion:x e) (SDL:event:motion:y e)))) ((mouse-button-down) - (signal-set! mouse-down - (list (SDL:event:button:button e) - (SDL:event:button:x e) - (SDL:event:button:y e)))) + (signal-hash-set! mouse-signals (SDL:event:button:button e) #t)) ((mouse-button-up) - (signal-set! mouse-up - (list (SDL:event:button:button e) - (SDL:event:button:x e) - (SDL:event:button:y e)))))) + (signal-hash-set! mouse-signals (SDL:event:button:button e) #f)))) ;;; ;;; Frames Per Second @@ -236,31 +247,6 @@ second." game-fps) ;;; -;;; Update and Draw -;;; - -(define (draw game dt) - "Render a frame." - (set-gl-matrix-mode (matrix-mode modelview)) - (gl-load-identity) - (gl-clear (clear-buffer-mask color-buffer depth-buffer)) - (draw-game game) - (SDL:gl-swap-buffers) - (accumulate-fps! dt)) - -(define (update accumulator) - "Call the update callback. The update callback will be called as -many times as `tick-interval` can divide ACCUMULATOR. The return value -is the unused accumulator time." - (if (>= accumulator tick-interval) - (begin - (handle-events) - (update-agenda) - ;; (update-stage stage) - (update (- accumulator tick-interval))) - accumulator)) - -;;; ;;; REPL ;;; |