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Action:
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Creates a new pattern by applying an alternating scale to an existing pattern.
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Filename:
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kern/kern_scm/pattern_scm.cxx
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APIs:
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api_alternating_scale_pattern
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Syntax:
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(pattern:alternating-scale pat scale1 scale2
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which-dim root [merge=#t])
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Arg Types:
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pat
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pattern
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scale1
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real | gvector
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scale2
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real | gvector
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which-dim
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integer
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root
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position
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merge
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boolean
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Returns:
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pattern
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Description:
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Applies an alternating scale to an existing pattern, merging with any existing scaling or, optionally (with merge=#f), replacing it.
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pat specifies a pattern.
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scale1 and
scale2 specifies the alternating scales. The scale values must be greater than zero. They may be given as vectors when non-uniform scaling is desired.
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which-dim specifies the dimension in which the scale is applied.
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root specifies the neutral point about which the scaling takes place (i.e., the point on the seed entity that remains fixed while the entity's dimensions are altered).
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If
merge is false (#f), the existing pattern is replaced.
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Example:
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; pattern:alternating-scale
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; make a prism
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(define height 1)
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;; height
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(define maj_rad 1)
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;; maj_rad
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(define min_rad 0.5)
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;; min_rad
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(define num_sides 3)
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;; num_sides
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(define prism (solid:prism height
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maj_rad min_rad num_sides))
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;; prism
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; position the prism
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(define origin (position 1 2 3))
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;; origin
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(define transform (entity:transform prism
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(transform:axes
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origin (gvector 1 0 0) (gvector 0 1 0))))
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;; transform
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; make a pattern
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(define x-vec (gvector 4 0 0))
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;; x-vec
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(define num_x 8)
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;; num_x
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(define y-vec (gvector 0 2 0))
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;; y-vec
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(define num_y 10)
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;; num_y
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(define pat (pattern:linear x-vec num_x y-vec num_y))
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;; pat
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; modify the pattern
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(define scale1 0.8)
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;; scale1
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(define scale2 1.2)
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;; scale2
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(define dim 1)
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;; dim
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(define root origin)
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;; root
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(set! pat (pattern:alternating-scale
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pat scale1 scale2 dim root))
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;; #[pattern
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;; trans-vec:
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"DOMAIN(X*VEC(4,0,0)+X2*VEC
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;; (0,2,0),0,7,0,9)"
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;; x-vec:
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"null_law"
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;; y-vec:
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"null_law"
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;; z-vec:
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"null_law"
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;; scale:
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"null_law"
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;; keep:
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"null_law"
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;; no list]
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; apply the pattern to the prism
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(define body (entity:pattern prism pat))
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;; body
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