class Mittsu::Plane
Attributes
constant[RW]
normal[RW]
Public Class Methods
new(normal = Mittsu::Vector3.new(1, 0, 0), constant = 0.0)
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# File lib/mittsu/math/plane.rb, line 5 def initialize(normal = Mittsu::Vector3.new(1, 0, 0), constant = 0.0) @normal, @constant = normal, constant.to_f end
Public Instance Methods
==(plane)
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# File lib/mittsu/math/plane.rb, line 118 def ==(plane) plane.normal == @normal && plane.constant == @constant end
apply_matrix4(matrix, normal_matrix = Mittsu::Matrix3.new.normal_matrix(matrix))
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# File lib/mittsu/math/plane.rb, line 101 def apply_matrix4(matrix, normal_matrix = Mittsu::Matrix3.new.normal_matrix(matrix)) v1 = Mittsu::Vector3.new v2 = Mittsu::Vector3.new # compute new normal based on theory here: # http:#www.songho.ca/opengl/gl_normaltransform.html new_normal = v1.copy(@normal).apply_matrix3(normal_matrix) new_coplanar_point = self.coplanar_point(v2) new_coplanar_point.apply_matrix4(matrix) self.set_from_normal_and_coplanar_point(new_normal, new_coplanar_point) self end
clone()
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# File lib/mittsu/math/plane.rb, line 122 def clone Mittsu::Plane.new.copy(self) end
coplanar_point(target = Mittsu::Vector3.new)
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# File lib/mittsu/math/plane.rb, line 97 def coplanar_point(target = Mittsu::Vector3.new) target.copy(@normal).multiply_scalar(- @constant) end
copy(plane)
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# File lib/mittsu/math/plane.rb, line 36 def copy(plane) @normal.copy(plane.normal) @constant = plane.constant self end
distance_to_point(point)
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# File lib/mittsu/math/plane.rb, line 56 def distance_to_point(point) @normal.dot(point) + @constant end
distance_to_sphere(sphere)
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# File lib/mittsu/math/plane.rb, line 60 def distance_to_sphere(sphere) self.distance_to_point(sphere.center) - sphere.radius end
intersect_line(line, target = Mittsu::Vector3.new)
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# File lib/mittsu/math/plane.rb, line 80 def intersect_line(line, target = Mittsu::Vector3.new) v1 = Mittsu::Vector3.new direction = line.delta(v1) denominator = @normal.dot(direction) if denominator.zero? # line is coplanar, return origin if self.distance_to_point(line.start_point).zero? return target.copy(line.start_point) end # Unsure if this is the correct method to handle this case. return nil end t = -(line.start_point.dot(@normal) + @constant) / denominator return nil if t < 0 || t > 1 target.copy(direction).multiply_scalar(t).add(line.start_point) end
intersection_line?(line)
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# File lib/mittsu/math/plane.rb, line 73 def intersection_line?(line) # Note: self tests if a line intersects the plane, not whether it (or its end-points) are coplanar with it. start_sign = self.distance_to_point(line.start_point) end_sign = self.distance_to_point(line.end_point) (start_sign < 0 && end_sign > 0) || (end_sign < 0 && start_sign > 0) end
negate()
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# File lib/mittsu/math/plane.rb, line 50 def negate @constant *= -1.0 @normal.negate self end
normalize()
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# File lib/mittsu/math/plane.rb, line 42 def normalize # Note: will lead to a divide by zero if the plane is invalid. inverse_normal_length = 1.0 / @normal.length @normal.multiply_scalar(inverse_normal_length) @constant *= inverse_normal_length self end
ortho_point(point, target = Mittsu::Vector3.new)
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# File lib/mittsu/math/plane.rb, line 68 def ortho_point(point, target = Mittsu::Vector3.new) perpendicular_magnitude = self.distance_to_point(point) target.copy(@normal).multiply_scalar(perpendicular_magnitude) end
project_point(point, target = Mittsu::Vector3.new)
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# File lib/mittsu/math/plane.rb, line 64 def project_point(point, target = Mittsu::Vector3.new) self.ortho_point(point, target).sub(point).negate end
set(normal, constant)
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# File lib/mittsu/math/plane.rb, line 9 def set(normal, constant) @normal.copy(normal) @constant = constant.to_f self end
set_components(x, y, z, w)
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# File lib/mittsu/math/plane.rb, line 15 def set_components(x, y, z, w) @normal.set(x, y, z) @constant = w.to_f self end
set_from_coplanar_points(a, b, c)
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# File lib/mittsu/math/plane.rb, line 27 def set_from_coplanar_points(a, b, c) v1 = Mittsu::Vector3.new v2 = Mittsu::Vector3.new normal = v1.sub_vectors(c, b).cross(v2.sub_vectors(a, b)).normalize # Q: should an error be thrown if normal is zero (e.g. degenerate plane)? self.set_from_normal_and_coplanar_point(normal, a) self end
set_from_normal_and_coplanar_point(normal, point)
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# File lib/mittsu/math/plane.rb, line 21 def set_from_normal_and_coplanar_point(normal, point) @normal.copy(normal) @constant = -point.dot(@normal) # must be @normal, not normal, as @normal is normalized self end
translate(offset)
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# File lib/mittsu/math/plane.rb, line 113 def translate(offset) @constant = @constant - offset.dot(@normal) self end