21 lines
710 B
Common Lisp
21 lines
710 B
Common Lisp
;; Trails effect - persistent motion trails
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(require-primitives "image" "blending")
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(define-effect trails
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:params (
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(persistence :type float :default 0.8 :range [0 0.99])
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)
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(let* ((buffer (state-get 'buffer nil))
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(current frame))
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(if (= buffer nil)
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(begin
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(state-set 'buffer (copy frame))
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frame)
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(let* ((faded (blending:blend-images buffer
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(make-image (image:width frame) (image:height frame) (list 0 0 0))
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(- 1 persistence)))
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(result (blending:blend-mode faded current "lighten")))
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(begin
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(state-set 'buffer result)
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result)))))
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