tasks a-s

Task/Ray-casting-algorithm/PicoLisp/ray-casting-algorithm.l

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+(scl 4)
+
+(de intersects (Px Py Ax Ay Bx By)
+   (when (> Ay By)
+      (xchg 'Ax 'Bx)
+      (xchg 'Ay 'By) )
+   (when (or (= Py Ay) (= Py By))
+      (inc 'Py) )
+   (and
+      (>= Py Ay)
+      (>= By Py)
+      (>= (max Ax Bx) Px)
+      (or
+         (> (min Ax Bx) Px)
+         (= Ax Px)
+         (and
+            (<> Ax Bx)
+            (>=
+               (*/ (- Py Ay) 1.0 (- Px Ax))            # Blue
+               (*/ (- By Ay) 1.0 (- Bx Ax)) ) ) ) ) )  # Red
+
+(de inside (Pt Poly)
+   (let Res NIL
+      (for Edge Poly
+         (when (apply intersects Edge (car Pt) (cdr Pt))
+            (onOff Res) ) )
+      Res ) )