diff options
Diffstat (limited to '2d/game-loop.scm')
| -rw-r--r-- | 2d/game-loop.scm | 76 |
1 files changed, 55 insertions, 21 deletions
diff --git a/2d/game-loop.scm b/2d/game-loop.scm index aeb8889..37e8036 100644 --- a/2d/game-loop.scm +++ b/2d/game-loop.scm @@ -35,6 +35,9 @@ #:use-module (2d mvars) #:use-module (2d window) #:export (current-fps + push-scene + replace-scene + pop-scene run-game quit-game-loop!)) @@ -50,9 +53,7 @@ ;;; (define game-fps 0) -(define game-running #f) -(define game-scene #f) -(define game-next-scene #f) +(define running #f) ;;; ;;; Event Handling @@ -69,28 +70,28 @@ "Calls the relevant callback for the event." (case (SDL:event:type e) ((active) - (scene-trigger game-scene 'active)) + (scene-trigger current-scene 'active)) ((video-resize) - (scene-trigger game-scene + (scene-trigger current-scene 'resize (SDL:event:resize:w e) (SDL:event:resize:h e))) ((quit) - (scene-trigger game-scene 'quit)) + (scene-trigger current-scene 'quit)) ((key-down) - (scene-trigger game-scene + (scene-trigger current-scene 'key-down (SDL:event:key:keysym:sym e) (SDL:event:key:keysym:mod e) (SDL:event:key:keysym:unicode e))) ((key-up) - (scene-trigger game-scene + (scene-trigger current-scene 'key-up (SDL:event:key:keysym:sym e) (SDL:event:key:keysym:mod e) (SDL:event:key:keysym:unicode e))) ((mouse-motion) - (scene-trigger game-scene + (scene-trigger current-scene 'mouse-motion (SDL:event:motion:state e) (SDL:event:motion:x e) @@ -98,13 +99,13 @@ (SDL:event:motion:xrel e) (SDL:event:motion:yrel e))) ((mouse-button-down) - (scene-trigger game-scene + (scene-trigger current-scene 'mouse-press (SDL:event:button:button e) (SDL:event:button:x e) (SDL:event:button:y e))) ((mouse-button-up) - (scene-trigger game-scene + (scene-trigger current-scene 'mouse-click (SDL:event:button:button e) (SDL:event:button:x e) @@ -143,7 +144,7 @@ (set-gl-matrix-mode (matrix-mode modelview)) (gl-load-identity) (gl-clear (clear-buffer-mask color-buffer depth-buffer)) - (scene-draw game-scene) + (scene-draw current-scene) (SDL:gl-swap-buffers)) (define (update accumulator) @@ -152,7 +153,7 @@ many times as tick-interval can divide accumulator. The return value is the unused accumulator time." (if (>= accumulator tick-interval) (begin - (scene-update game-scene) + (scene-update current-scene) (update-agenda) (update (- accumulator tick-interval))) accumulator)) @@ -190,11 +191,43 @@ INPUT, OUTPUT, and ERROR ports." ;;; Scene management ;;; -(define (set-game-scene scene) - (when game-scene - (scene-trigger game-scene 'stop)) +(define scenes '()) +(define current-scene #f) +(define next-scene #f) + +(define (push-scene scene) + "Pause the current scene and start SCENE upon next game tick." + (set! scenes (cons scene scenes)) + (set! next-scene scene)) + +(define (replace-scene scene) + (set! scenes (cons scene (cdr scenes))) + (set! next-scene scene)) + +(define (pop-scene) + "Exit the current scene and resume the previous scene. If there is +no previous scene, the game loop will terminate." + (if (null? scenes) + (quit-game-loop!) + (begin + (set! next-scene (car scenes)) + (set! scenes (cdr scenes))))) + +(define (switch-scenes-maybe) + "Switch scenes if the current scene is not the scene at the top of +the stack." + (when next-scene + (scene-trigger current-scene 'stop) + (set-current-scene next-scene) + (set! next-scene #f))) + +(define (set-current-scene scene) (scene-trigger scene 'start) - (set! game-scene scene)) + (set! current-scene scene)) + +(define (set-initial-scene scene) + (set! scenes (list scene)) + (set-current-scene scene)) ;;; ;;; Game Loop @@ -202,7 +235,7 @@ INPUT, OUTPUT, and ERROR ports." (define (game-loop last-time next-time accumulator) "Runs input, render, and update hooks." - (when game-running + (when running (handle-events) (let* ((time (SDL:get-ticks)) (dt (- time last-time)) @@ -210,6 +243,7 @@ INPUT, OUTPUT, and ERROR ports." (remainder (update accumulator))) (run-repl) (render) + (switch-scenes-maybe) (accumulate-fps! dt) (SDL:delay (time-left (SDL:get-ticks) next-time)) (game-loop time @@ -221,8 +255,8 @@ INPUT, OUTPUT, and ERROR ports." (open-window (game-title game) (game-resolution game) (game-fullscreen? game)) - (set! game-running #t) - (set-game-scene ((game-first-scene game))) + (set! running #t) + (set-initial-scene ((game-first-scene game))) (spawn-server) (agenda-schedule show-fps) (let ((time (SDL:get-ticks))) @@ -232,4 +266,4 @@ INPUT, OUTPUT, and ERROR ports." (define (quit-game-loop!) "Tell the game loop to finish up the current frame and then terminate." - (set! game-running #f)) + (set! running #f)) |