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;; load the SDL module and some useful srfi's
(use-modules (srfi srfi-1)
(srfi srfi-9)
(2d agenda)
(2d game)
(2d sprite)
(2d texture)
(2d vector2)
(2d window))
(load "common.scm")
(set! *random-state* (random-state-from-platform))
(define window-width 640)
(define window-height 480)
;;;
;;; 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))))
(define (generate-particles n)
(let ((particle-image (load-texture "images/bullet.png")))
(list-tabulate n (lambda (n)
(make-particle (make-sprite particle-image)
(vector2 (random window-width)
(random window-height))
(vector2 (* (random:normal) 1)
(* (random:normal) 1)))))))
(define particle-count 500)
(define batch (make-sprite-batch (* particle-count 4)))
(define background (load-sprite "images/stars.png"
#:anchor null-vector2))
(define particles (generate-particles particle-count))
(define (draw-particles particles)
(with-sprite-batch batch
(for-each
(lambda (p)
(let* ((sprite (particle-sprite p)))
(set-sprite-position! sprite (particle-position p))
(draw-sprite sprite)))
particles)))
(define (draw dt alpha)
(draw-sprite background)
(draw-particles particles))
(define (update)
(for-each update-particle! particles))
(schedule-every update)
(add-hook! draw-hook draw)
(with-window (make-window #:title "Particles"
#:resolution (vector2 window-width
window-height))
(run-game-loop))
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