def CastAgainst(self, other, cast_distance=1000.0):
if isinstance(other, Circle):
pass
elif isinstance(other, LineSegment):
ray_segment = LineSegment(point_a=self.point,
point_b=self.EvalParam(cast_distance))
hit_point = ray_segment.IntersectWith(other)
if hit_point is not None:
return self.CalcParam(hit_point)
elif isinstance(other, Ray):
pass
elif isinstance(other, Polygon):
pass
elif type(other) is list:
smallest_hit = None
for item in other:
hit = self.CastAgainst(item)
if hit is not None and hit >= 0.0 and (smallest_hit is None
or hit < smallest_hit):
smallest_hit = hit
return smallest_hit
def _Tessellate(self, given_mesh):
self.RemoveRedundantVertices()
if len(self.vertex_list) < 3:
return
elif len(self.vertex_list) == 3:
triangle = Triangle(self.vertex_list[0], self.vertex_list[1],
self.vertex_list[2])
given_mesh.AddTriangle(triangle)
else:
candidate_list = []
for i in range(len(self.vertex_list)):
for j in range(i + 1, len(self.vertex_list)):
if (i + 1) % len(self.vertex_list) != j and (i - 1) % len(
self.vertex_list) != j:
candidate_list.append((i, j))
# The idea here is that we might get better tessellations if we try the candidates in this order.
candidate_list.sort(key=lambda pair: (self.vertex_list[pair[
1]] - self.vertex_list[pair[0]]).Length(),
reverse=True)
for pair in candidate_list:
i = pair[0]
j = pair[1]
line_segment = LineSegment(self.vertex_list[i],
self.vertex_list[j])
try:
for k in range(len(self.vertex_list)):
if k != i and k != j:
if line_segment.ContainsPoint(self.vertex_list[k]):
raise Exception()
if k != i and (k + 1) % len(self.vertex_list) != i:
if k != j and (k + 1) % len(self.vertex_list) != j:
edge_segment = LineSegment(
self.vertex_list[k],
self.vertex_list[(k + 1) %
len(self.vertex_list)])
point = edge_segment.IntersectWith(
line_segment)
if point is not None:
raise Exception()
polygon_a = Polygon()
k = 0
while True:
r = (j + k) % len(self.vertex_list)
polygon_a.vertex_list.append(self.vertex_list[r])
if r == i:
break
k += 1
if polygon_a.IsWoundCW():
raise Exception()
polygon_b = Polygon()
k = 0
while True:
r = (i + k) % len(self.vertex_list)
polygon_b.vertex_list.append(self.vertex_list[r])
if r == j:
break
k += 1
if polygon_b.IsWoundCW():
raise Exception()
except:
pass
else:
polygon_a._Tessellate(given_mesh)
polygon_b._Tessellate(given_mesh)
break
else:
raise Exception('Failed to tessellate polygon!')