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path: root/demo/topdown.scm
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(import scheme
        (chicken base)
        srfi-8
        (only srfi-197 chain)
        (only (list-utils alist) plist->alist)
        (prefix sdl2 "sdl2:")
        (prefix sdl2-ttf "ttf:")
        (prefix sdl2-image "img:")
        downstroke-engine
        downstroke-world
        downstroke-input
        downstroke-assets
        downstroke-entity
        downstroke-scene-loader)

(define (make-player)
  (plist->alist (list #:type 'player
                      #:x 100 #:y 100
                      #:width 16 #:height 16
                      #:vx 0 #:vy 0
                      #:gravity? #f
                      #:tile-id 1 #:tags '(player))))

(define (input->velocity input)
  (values (+ (if (input-held? input 'left)  -3 0)
             (if (input-held? input 'right)  3 0))
          (+ (if (input-held? input 'up)    -3 0)
             (if (input-held? input 'down)   3 0))))

(define (update-player player input)
  (receive (dx dy) (input->velocity input)
    (entity-set (entity-set player #:vx dx) #:vy dy)))

(define *game*
  (make-game
   title: "Demo: Top-down Explorer" width: 600 height: 400

   create: (lambda (game)
             (game-scene-set! game
                              (chain (game-load-scene! game "demo/assets/level-0.tmx")
                                     (scene-add-entity _ (make-player))
                                     (update-scene _ camera-target: 'player))))

   update: (lambda (game dt)
             (let* ((input  (game-input game))
                    (scene  (game-scene game))
                    (player (update-player (car (scene-entities scene)) input)))
               (game-scene-set! game
                                (update-scene scene entities: (list player)))))))

(game-run! *game*)