summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
-rw-r--r--examples/tiled.scm65
1 files changed, 52 insertions, 13 deletions
diff --git a/examples/tiled.scm b/examples/tiled.scm
index c64f7b6..0f7c4fa 100644
--- a/examples/tiled.scm
+++ b/examples/tiled.scm
@@ -1,6 +1,7 @@
(use-modules (chickadee)
(chickadee math vector)
(chickadee math rect)
+ (chickadee graphics color)
(chickadee graphics font)
(chickadee graphics tiled)
(ice-9 format)
@@ -8,35 +9,73 @@
(srfi srfi-11))
(define map #f)
-(define camera #v(0.0 0.0))
-(define text-position #v(4.0 4.0))
+(define prev-camera (vec2 0.0 0.0))
+(define camera (vec2 0.0 0.0))
+(define render-camera (vec2 0.0 0.0))
+(define text-position (vec2 4.0 4.0))
(define text "0, 0")
+(define (stats-message)
+ (format #f "fps: ~1,2f"
+ (/ 1000.0 avg-frame-time)))
+(define start-time 0.0)
+(define avg-frame-time 16)
+(define stats-text (stats-message))
+(define stats-text-pos (vec2 4.0 464.0))
+(define last-update start-time)
+(define scroll-speed 6.0)
(define (load)
(set! map (load-tile-map "maps/example.tmx")))
(define (draw alpha)
- (draw-tile-map map #:position camera)
- (draw-text text text-position))
+ ;; Linearly interpolate between the current camera position and the
+ ;; previous camera position based on the alpha value. This makes
+ ;; the scrolling appear much smoother because the Chickadee game
+ ;; loop does not render in lock-step with updates.
+ (let ((beta (- 1.0 alpha)))
+ (set-vec2-x! render-camera
+ (+ (* (vec2-x camera) alpha)
+ (* (vec2-x prev-camera) beta)))
+ (set-vec2-y! render-camera
+ (+ (* (vec2-y camera) alpha)
+ (* (vec2-y prev-camera) beta))))
+ (draw-tile-map map #:camera render-camera)
+ (draw-text text text-position #:color black)
+ (draw-text stats-text stats-text-pos #:color black)
+ (let ((current-time (elapsed-time)))
+ (set! avg-frame-time
+ (+ (* (- current-time start-time) 0.1)
+ (* avg-frame-time 0.9)))
+ (set! start-time current-time)
+ (when (>= (- current-time last-update) 1000)
+ (set! stats-text (stats-message))
+ (set! last-update current-time))))
+
+(define (update dt)
+ (vec2-copy! camera prev-camera)
+ (set-vec2-x! camera
+ (+ (vec2-x camera)
+ (if (key-pressed? 'right) scroll-speed 0.0)
+ (if (key-pressed? 'left) (- scroll-speed) 0.0)))
+ (set-vec2-y! camera
+ (+ (vec2-y camera)
+ (if (key-pressed? 'up) scroll-speed 0.0)
+ (if (key-pressed? 'down) (- scroll-speed) 0.0))))
-(define inc 8.0)
(define (key-press key modifiers repeat?)
(match key
- ('up (set-vec2-y! camera (- (vec2-y camera) inc)))
- ('down (set-vec2-y! camera (+ (vec2-y camera) inc)))
- ('right (set-vec2-x! camera (- (vec2-x camera) inc)))
- ('left (set-vec2-x! camera (+ (vec2-x camera) inc)))
- ('q (abort-game))
+ ((or 'escape 'q) (abort-game))
(_ #t)))
(define (mouse-move x y x-rel y-rel buttons)
- (let-values (((tx ty) (point->tile map x y)))
+ (let-values (((tx ty) (point->tile map (- x (vec2-x camera)) (- y (vec2-y camera)))))
(set! text (format #f "~d, ~d" tx ty))))
-(run-game #:window-width 320
- #:window-height 240
+(run-game #:window-width 640
+ #:window-height 480
#:window-title "tile map demo"
#:load load
#:draw draw
+ #:update update
#:key-press key-press
#:mouse-move mouse-move)