41 lines
1023 B
Plaintext
41 lines
1023 B
Plaintext
(cross product for two vectors 1-2 and 3-2 having a common vertex 2)
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(ccw ==> + result but note:)
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(if traversing 1->2->3, a cw cross product ==> a ccw traverse)
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(return:)
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( _cross:z magnitude)
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( _cross:dir 1 for ccw per convention)
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o<cross> sub
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(not_a_subfile)
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#<x1> = #1
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#<y1> = #2
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#<x2> = #3
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#<y2> = #4
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#<x3> = #5
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#<y3> = #6
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#<_cross:z> = [[#<x1>-#<x2>]*[#<y3>-#<y2>]-[#<x3>-#<y2>]*[#<y1>-#<y2>]]
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#<_cross:dir> = 0 (default: 0)
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o<l10> if [#<_cross:z> GT 0]
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#<_cross:dir> = 1 (ccw)
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o<l10> endif
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o<l20> if [#<_cross:z> LT 0]
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#<_cross:dir> = -1 (cw)
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o<l20> endif
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o<line> call [#<x2>][#<y2>][#<x1>][#<y1>]
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#<len21> = #<_line:len>
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o<line> call [#<x2>][#<y2>][#<x3>][#<y3>]
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#<len23> = #<_line:len>
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(print cross: #<x1> #<y1> #<x2> #<y2> #<x3> #<y3> #<x4> #<y4>)
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(print cross: #<x1> #<x2> #<x3>)
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(print cross: #<y1> #<y2> #<y3>)
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(print cross: z=#<_cross:z> dir=#<_cross:dir>)
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(print )
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(debug cross: z=#<_cross:z> dir=#<_cross:dir>)
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o<cross> endsub
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