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;; load the SDL module and some useful srfi's
(use-modules (srfi srfi-1)
(srfi srfi-9)
(2d game)
(2d scene)
(2d sprite)
(2d texture)
(2d vector2))
(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-record-type <demo-state>
(make-demo-state stars particles)
demo-state?
(stars demo-stars)
(particles demo-particles))
(define (generate-particles n)
(let ((particle-image (load-texture "images/bullet.png"))
(game-size (game-resolution particles)))
(list-tabulate n (lambda (n)
(make-particle (make-sprite particle-image)
(vector2 (random (vx game-size))
(random (vy game-size)))
(vector2 (* (random:normal) 1)
(* (random:normal) 1)))))))
(define particle-count 500)
(define batch (make-sprite-batch (* particle-count 4)))
(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 state)
(draw-sprite (demo-stars state))
(draw-particles (demo-particles state)))
(define (update state)
(for-each update-particle! (demo-particles state)))
(define (init)
(make-demo-state (load-sprite "images/stars.png"
#:anchor null-vector2)
(generate-particles particle-count)))
(define particles-scene
(make-scene
"Particles"
#:draw draw
#:update update
#:init init))
(define particles
(make-game
#:title "Particles"
#:first-scene particles-scene))
(run-game particles)
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