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;; load the SDL module and some useful srfi's
(use-modules ((sdl sdl) #:prefix SDL:)
(figl gl)
(srfi srfi-1)
(srfi srfi-2)
(srfi srfi-9)
(ice-9 format)
(2d texture)
(2d sprite)
(2d game-loop)
(2d window)
(2d vector)
(2d input)
(2d helpers))
(set! *random-state* (random-state-from-platform))
;;;
;;; Particles
;;;
(define-record-type <particle>
(make-particle sprite position velocity)
particle?
(sprite particle-sprite)
(position particle-position set-particle-position!)
(velocity particle-velocity set-particle-velocity!))
(define (update-particle! particle)
(set-particle-position! particle
(v+ (particle-position particle)
(particle-velocity particle))))
;;;
;;; Demo
;;;
(define window-width 800)
(define window-height 600)
(open-window window-width window-height)
(define stars (load-sprite "stars.png" #:anchor #(0 0)))
(define particle-image (load-texture "bullet.png"))
(define particle-width (texture-width particle-image))
(define particle-height (texture-height particle-image))
(define particle-count 2000)
(define particles
(list-tabulate particle-count
(lambda (n)
(make-particle (make-sprite particle-image)
(vector (random window-width)
(random window-height))
(vector (* (random:normal) 1)
(* (random:normal) 1))))))
(define batch (make-sprite-batch (* particle-count 4)))
(define (draw-particles particles)
(with-sprite-batch batch
(for-each
(lambda (p)
(let* ((pos (particle-position p))
(x (vx pos))
(y (vy pos)))
(sprite-batch-draw batch particle-image x y 0 0
particle-width particle-height
1 1 0)))
particles)))
(set-render-callback (lambda () (render)))
(set-update-callback (lambda () (update)))
(set-key-down-callback (lambda (key mod unicode) (key-down key mod unicode)))
(define (key-down key mod unicode)
(cond ((any-equal? key (keycode escape) (keycode q))
(close-window)
(quit))))
(define (render)
(draw-sprite stars)
(draw-particles particles))
(define (update)
(for-each update-particle! particles))
(run-game-loop)
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