20 lines
534 B
Factor
20 lines
534 B
Factor
USING: kernel prettyprint sequences arrays math math.vectors ;
|
|
IN: raycasting
|
|
|
|
: between ( a b x -- ? ) [ last ] tri@ [ < ] curry bi@ xor ;
|
|
|
|
: lincomb ( a b x -- w )
|
|
3dup [ last ] tri@
|
|
[ - ] curry bi@
|
|
[ drop ] 2dip
|
|
neg 2dup + [ / ] curry bi@
|
|
[ [ v*n ] curry ] bi@ bi* v+ ;
|
|
: leftof ( a b x -- ? ) dup [ lincomb ] dip [ first ] bi@ > ;
|
|
|
|
: ray ( a b x -- ? ) [ between ] [ leftof ] 3bi and ;
|
|
|
|
: raycast ( poly x -- ? )
|
|
[ dup first suffix [ rest-slice ] [ but-last-slice ] bi ] dip
|
|
[ ray ] curry 2map
|
|
f [ xor ] reduce ;
|