diff options
Diffstat (limited to 'sly/render/particles.scm')
| -rw-r--r-- | sly/render/particles.scm | 62 |
1 files changed, 35 insertions, 27 deletions
diff --git a/sly/render/particles.scm b/sly/render/particles.scm index 88196c5..ca79a04 100644 --- a/sly/render/particles.scm +++ b/sly/render/particles.scm @@ -34,7 +34,8 @@ particle-system? particle-system-texture particle-system-duration - particle-system-emit-rate + particle-system-emit-interval + particle-system-emit-count particle-system-life-span particle-system-renderer render-particles)) @@ -53,53 +54,60 @@ time, and life span. PROC must return a 2D vector." (polar2 time n)))) (define-record-type <particle-system> - (%make-particle-system texture sprite-rect duration emit-rate - life-span renderer) + (%make-particle-system texture sprite-rect duration emit-interval + emit-count life-span renderer) particle-system? (texture particle-system-texture) (sprite-rect particle-system-sprite-rect) (duration particle-system-duration) - (emit-rate particle-system-emit-rate) + (emit-interval particle-system-emit-interval) + (emit-count particle-system-emit-count) (life-span particle-system-life-span) (renderer particle-system-renderer)) (define* (make-particle-system #:key (texture null-texture) duration - (emit-rate 1) (life-span 60) + (emit-interval 1) (emit-count 1) + (life-span 60) (renderer default-particle-renderer)) "Create a new particle system where each particle is rendered using -TEXTURE. Particles are emitted at a rate of EMIT-RATE per tick of the -game clock for DURATION ticks and each particle exists for LIFE-SPAN -ticks. The procedure RENDERER is responsible for placing and -rendering each particle, and takes the following arguments: graphics -context, sprite batch, texture, sprite rectangle, particle ID, time, -and life span." +TEXTURE. EMIT-COUNT particles are emitted every EMIT-INTERVAL ticks +of the game clock for DURATION ticks and each particle exists for +LIFE-SPAN ticks. The procedure RENDERER is responsible for placing +and rendering each particle, and takes the following arguments: +graphics context, sprite batch, texture, sprite rectangle, particle +ID, time, and life span." (let* ((w (texture-width texture)) (h (texture-height texture)) (sprite-rect (make-rect (- (/ w 2)) (- (/ h 2)) w h))) - (%make-particle-system texture sprite-rect duration emit-rate - life-span renderer))) + (%make-particle-system texture sprite-rect duration emit-interval + emit-count life-span renderer))) (define (render-particles particle-system batch time) "Create a renderer for PARTICLE-SYSTEM at TIME. The particles will be rendered using BATCH, a sprite batcher." (let* ((life-span (particle-system-life-span particle-system)) - (emit-rate (particle-system-emit-rate particle-system)) + (emit-count (particle-system-emit-count particle-system)) + (interval (particle-system-emit-interval particle-system)) (duration (particle-system-duration particle-system)) - (count (* emit-rate life-span)) - (first (* (- time life-span) emit-rate)) - (last (if duration - (min (+ first count) - (floor (* duration emit-rate))) - (+ first count))) + (first-wave (max (floor (/ (- time life-span) interval)) 0)) + (last-wave (floor + (/ (if duration + (min time duration) + time) + interval))) (render (particle-system-renderer particle-system)) (texture (particle-system-texture particle-system)) (sprite-rect (particle-system-sprite-rect particle-system))) (lambda (gfx) (with-sprite-batch batch gfx - (let loop ((particle (max first 0))) - (when (< particle last) - (let* ((start-time (/ particle emit-rate)) - (current-time (- time start-time))) - (render gfx batch texture sprite-rect particle - current-time life-span)) - (loop (1+ particle)))))))) + (let loop ((w first-wave)) + (when (<= w last-wave) + (let ((life-time (- time (* w interval))) + (first-particle (* w emit-count))) + (let loop ((p 0)) + (when (< p emit-count) + (render gfx batch texture sprite-rect + (+ first-particle p) + life-time life-span) + (loop (1+ p))))) + (loop (1+ w)))))))) |