Initial data commit

Task/Ray-casting-algorithm/11l/ray-casting-algorithm.11l

@@ -0,0 +1,84 @@
+T Pt
+   Float x, y
+
+   F (x, y)
+      .x = x
+      .y = y
+
+   F String()
+      R ‘Pt(x=#., y=#.)’.format(.x, .y)
+
+T Edge
+   Pt a, b
+
+   F (a, b)
+      .a = a
+      .b = b
+
+   F String()
+      R ‘Edge(a=#., b=#.)’.format(.a, .b)
+
+T Poly
+   String name
+   [Edge] edges
+
+   F (name, edges)
+      .name = name
+      .edges = edges
+
+V _eps = 0.00001
+V _huge = 1e+100
+V _tiny = 1e-100
+
+F rayintersectseg(=p, edge)
+   V a = edge.a
+   V b = edge.b
+   I a.y > b.y
+      swap(&a, &b)
+   I p.y == a.y | p.y == b.y
+      p = Pt(p.x, p.y + :_eps)
+
+   V intersect = 0B
+
+   I (p.y > b.y | p.y < a.y) | (p.x > max(a.x, b.x))
+      R 0B
+
+   I p.x < min(a.x, b.x)
+      intersect = 1B
+   E
+      Float m_red, m_blue
+      I abs(a.x - b.x) > :_tiny
+         m_red = (b.y - a.y) / Float(b.x - a.x)
+      E
+         m_red = :_huge
+      I abs(a.x - p.x) > :_tiny
+         m_blue = (p.y - a.y) / Float(p.x - a.x)
+      E
+         m_blue = :_huge
+      intersect = m_blue >= m_red
+   R intersect
+
+F ispointinside(p, poly)
+   R sum(poly.edges.map(edge -> Int(rayintersectseg(@p, edge)))) % 2 == 1
+
+F polypp(poly)
+   print("\n  Polygon(name='#.', edges=(".format(poly.name))
+   print(‘    ’(poly.edges.map(e -> String(e)).join(",\n    ")"\n    ))"))
+
+V polys = [
+  Poly(name' ‘square’, edges' [Edge(Pt(0, 0), Pt(10, 0)), Edge(Pt(10, 0), Pt(10, 10)), Edge(Pt(10, 10), Pt(0, 10)), Edge(Pt(0, 10), Pt(0, 0))]),
+  Poly(name' ‘square_hole’, edges' [Edge(Pt(0, 0), Pt(10, 0)), Edge(Pt(10, 0), Pt(10, 10)), Edge(Pt(10, 10), Pt(0, 10)), Edge(Pt(0, 10), Pt(0, 0)), Edge(Pt(2.5, 2.5), Pt(7.5, 2.5)), Edge(Pt(7.5, 2.5), Pt(7.5, 7.5)), Edge(Pt(7.5, 7.5), Pt(2.5, 7.5)), Edge(Pt(2.5, 7.5), Pt(2.5, 2.5))]),
+  Poly(name' ‘strange’, edges' [Edge(Pt(0, 0), Pt(2.5, 2.5)), Edge(Pt(2.5, 2.5), Pt(0, 10)), Edge(Pt(0, 10), Pt(2.5, 7.5)), Edge(Pt(2.5, 7.5), Pt(7.5, 7.5)), Edge(Pt(7.5, 7.5), Pt(10, 10)), Edge(Pt(10, 10), Pt(10, 0)), Edge(Pt(10, 0), Pt(2.5, 2.5))]),
+  Poly(name' ‘exagon’, edges' [Edge(Pt(3, 0), Pt(7, 0)), Edge(Pt(7, 0), Pt(10, 5)), Edge(Pt(10, 5), Pt(7, 10)), Edge(Pt(7, 10), Pt(3, 10)), Edge(Pt(3, 10), Pt(0, 5)), Edge(Pt(0, 5), Pt(3, 0))])]
+
+V testpoints = [Pt(5, 5), Pt(5, 8),
+                Pt(-10, 5), Pt(0, 5),
+                Pt(10, 5), Pt(8, 5),
+                Pt(10, 10)]
+
+print("\n TESTING WHETHER POINTS ARE WITHIN POLYGONS")
+L(poly) polys
+   polypp(poly)
+   print(‘    ’testpoints[0.<3].map(p -> ‘#.: #.’.format(p, I ispointinside(p, @poly) {‘True’} E ‘False’)).join("\t"))
+   print(‘    ’testpoints[3.<6].map(p -> ‘#.: #.’.format(p, I ispointinside(p, @poly) {‘True’} E ‘False’)).join("\t"))
+   print(‘    ’testpoints[6.. ].map(p -> ‘#.: #.’.format(p, I ispointinside(p, @poly) {‘True’} E ‘False’)).join("\t"))