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#
# Copyright (c) 2001 by Jim Menard <jimm@io.com>
#
# Released under the same license as Ruby. See
# http://www.ruby-lang.org/en/LICENSE.txt.
#
class Point
attr_accessor :x, :y, :z
# Return a new Point that is the midpoint on the line between two
# points.
def Point.midpoint(a, b)
return Point.new((a.x + b.x) * 0.5, (a.y + b.y) * 0.5,
(a.z + b.z) * 0.5)
end
def initialize(x = 0, y = 0, z = 0)
if x.kind_of?(Point)
@x = x.x
@y = x.y
@z = x.z
else
@x = x
@y = y
@z = z
end
end
ORIGIN = Point.new(0, 0, 0)
def ==(point)
return point.kind_of?(Point) &&
@x == point.x && @y == point.y && @z == point.z
end
# Normalize this point.
def normalize!
mag = @x * @x + @y * @y + @z * @z
if mag != 1.0
mag = 1.0 / Math.sqrt(mag)
@x *= mag
@y *= mag
@z *= mag
end
return self
end
# Return a new point that is a normalized version of this point.
def normalize
return self.dup().normalize!()
end
# Return a new point that is the cross product of this point and another.
# The cross product of two unit vectors is another vector that's at
# right angles to the first two (for example, a surface normal).
def crossProduct(p)
return Point.new(@y * p.z - @z * p.y, @z * p.x - @x * p.z,
@x * p.y - @y * p.x)
end
# Return the (scalar) dot product of this vector and another.
# The dot product of two vectors produces the cosine of the angle
# between them, multiplied by the lengths of those vectors. (The dot
# product of two normalized vectors equals cosine of the angle.)
def dotProduct(p)
return @x * p.x + @y * p.y + @z * p.z
end
# Return square of distance between this point and another.
def squareOfDistanceTo(p)
dx = p.x - @x
dy = p.y - @y
dz = p.z - @z
return dx * dx + dy * dy + dz * dz
end
# Return distance between this point and another.
def distanceTo(p)
dx = p.x - @x
dy = p.y - @y
dz = p.z - @z
return Math.sqrt(dx * dx + dy * dy + dz * dz)
end
def add(d)
@x += d
@y += d
@z += d
return self
end
def addPoint(p)
@x += p.x
@y += p.y
@z += p.z
return self
end
def subtract(d)
@x -= d
@y -= d
@z -= d
return self
end
def subtractPoint(p)
@x -= p.x
@y -= p.y
@z -= p.z
return self
end
def multiplyBy(d)
@x *= d
@y *= d
@z *= d
return self
end
def multiplyByPoint(p)
@x *= p.x
@y *= p.y
@z *= p.z
return self
end
def divideBy(d)
@x = @x / d
@y = @y / d
@z = @z / d
return self
end
def divideByPoint(p)
@x = @x / p.x
@y = @y / p.y
@z = @z / p.z
return self
end
def to_a
return [@x, @y, @z]
end
def to_s
return "Point<#{@x}, #{@y}, #{@z}>"
end
end
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