37 lines
1.1 KiB
Common Lisp
37 lines
1.1 KiB
Common Lisp
;; Vignette effect using xector operations
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;; Demonstrates α (element-wise) and β (reduction) patterns
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(require-primitives "xector")
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(define-effect xector_vignette
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:params (
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(strength :type float :default 0.5 :range [0 1])
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(radius :type float :default 1.0 :range [0.5 2])
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)
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(let* (
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;; Get normalized distance from center for each pixel
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(dist (dist-from-center frame))
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;; Calculate max distance (corner distance)
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(max-dist (* (βmax dist) radius))
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;; Calculate brightness factor per pixel: 1 - (dist/max-dist * strength)
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;; Using explicit α operators
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(factor (α- 1 (α* (α/ dist max-dist) strength)))
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;; Clamp factor to [0, 1]
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(factor (αclamp factor 0 1))
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;; Extract channels as xectors
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(r (red frame))
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(g (green frame))
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(b (blue frame))
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;; Apply factor to each channel (implicit element-wise via Xector operators)
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(r-out (* r factor))
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(g-out (* g factor))
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(b-out (* b factor)))
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;; Combine back to frame
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(rgb r-out g-out b-out)))
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