66 lines
2.3 KiB
Common Lisp
66 lines
2.3 KiB
Common Lisp
;; Cell Pattern effect - custom patterns within cells
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;;
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;; Demonstrates building arbitrary per-cell visuals from primitives.
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;; Uses local coordinates within cells to draw patterns scaled by luminance.
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(require-primitives "xector")
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(define-effect cell_pattern
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:params (
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(cell-size :type int :default 16 :range [8 48] :desc "Cell size")
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(pattern :type string :default "diagonal" :desc "Pattern: diagonal, cross, ring")
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)
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(let* (
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;; Pool to get cell colors
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(pooled (pool-frame frame cell-size))
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(cell-r (nth pooled 0))
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(cell-g (nth pooled 1))
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(cell-b (nth pooled 2))
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(cell-lum (α/ (nth pooled 3) 255))
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;; Cell indices for each pixel
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(cell-idx (cell-indices frame cell-size))
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;; Look up cell values for each pixel
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(pix-r (gather cell-r cell-idx))
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(pix-g (gather cell-g cell-idx))
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(pix-b (gather cell-b cell-idx))
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(pix-lum (gather cell-lum cell-idx))
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;; Local position within cell [0, 1]
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(lx (local-x-norm frame cell-size))
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(ly (local-y-norm frame cell-size))
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;; Pattern mask based on pattern type
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(mask
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(cond
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;; Diagonal lines - thickness based on luminance
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((= pattern "diagonal")
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(let* ((diag (αmod (α+ lx ly) 0.25))
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(thickness (α* pix-lum 0.125)))
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(α< diag thickness)))
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;; Cross pattern
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((= pattern "cross")
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(let* ((cx (αabs (α- lx 0.5)))
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(cy (αabs (α- ly 0.5)))
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(thickness (α* pix-lum 0.25)))
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(αor (α< cx thickness) (α< cy thickness))))
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;; Ring pattern
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((= pattern "ring")
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(let* ((dx (α- lx 0.5))
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(dy (α- ly 0.5))
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(dist (αsqrt (α+ (α² dx) (α² dy))))
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(target (α* pix-lum 0.4))
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(thickness 0.05))
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(α< (αabs (α- dist target)) thickness)))
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;; Default: solid
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(else (α> pix-lum 0)))))
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;; Apply mask: show cell color where mask is true, black elsewhere
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(rgb (where mask pix-r 0)
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(where mask pix-g 0)
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(where mask pix-b 0))))
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