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102 lines
3.1 KiB
Lua
102 lines
3.1 KiB
Lua
--- TRIANGLE class with properties and methods for handling triangles. This class is mostly used by the POLYGON class, but you can use it on its own as well
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--
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-- ### Author: **nielsvaes/coconutcockpit**
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--
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--
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-- ===
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-- @module Shapes.TRIANGLE
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-- @image MOOSE.JPG
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--- LINE class.
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-- @type CUBE
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-- @field #string ClassName Name of the class.
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-- @field #number Points points of the line
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-- @field #number Coords coordinates of the line
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--
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-- ===
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---
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-- @field #TRIANGLE
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TRIANGLE = {
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ClassName = "TRIANGLE",
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Points = {},
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Coords = {},
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SurfaceArea = 0
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}
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--- Creates a new triangle from three points. The points need to be given as Vec2s
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-- @param #table p1 The first point of the triangle
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-- @param #table p2 The second point of the triangle
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-- @param #table p3 The third point of the triangle
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-- @return #TRIANGLE The new triangle
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function TRIANGLE:New(p1, p2, p3)
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local self = BASE:Inherit(self, SHAPE_BASE:New())
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self.Points = {p1, p2, p3}
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local center_x = (p1.x + p2.x + p3.x) / 3
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local center_y = (p1.y + p2.y + p3.y) / 3
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self.CenterVec2 = {x=center_x, y=center_y}
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for _, pt in pairs({p1, p2, p3}) do
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table.add(self.Coords, COORDINATE:NewFromVec2(pt))
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end
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self.SurfaceArea = math.abs((p2.x - p1.x) * (p3.y - p1.y) - (p3.x - p1.x) * (p2.y - p1.y)) * 0.5
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self.MarkIDs = {}
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return self
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end
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--- Checks if a point is contained within the triangle.
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-- @param #table pt The point to check
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-- @param #table points (optional) The points of the triangle, or 3 other points if you're just using the TRIANGLE class without an object of it
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-- @return #bool True if the point is contained, false otherwise
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function TRIANGLE:ContainsPoint(pt, points)
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points = points or self.Points
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local function sign(p1, p2, p3)
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return (p1.x - p3.x) * (p2.y - p3.y) - (p2.x - p3.x) * (p1.y - p3.y)
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end
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local d1 = sign(pt, self.Points[1], self.Points[2])
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local d2 = sign(pt, self.Points[2], self.Points[3])
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local d3 = sign(pt, self.Points[3], self.Points[1])
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local has_neg = (d1 < 0) or (d2 < 0) or (d3 < 0)
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local has_pos = (d1 > 0) or (d2 > 0) or (d3 > 0)
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return not (has_neg and has_pos)
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end
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--- Returns a random Vec2 within the triangle.
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-- @param #table points The points of the triangle, or 3 other points if you're just using the TRIANGLE class without an object of it
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-- @return #table The random Vec2
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function TRIANGLE:GetRandomVec2(points)
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points = points or self.Points
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local pt = {math.random(), math.random()}
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table.sort(pt)
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local s = pt[1]
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local t = pt[2] - pt[1]
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local u = 1 - pt[2]
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return {x = s * points[1].x + t * points[2].x + u * points[3].x,
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y = s * points[1].y + t * points[2].y + u * points[3].y}
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end
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--- Draws the triangle on the map, just for debugging
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function TRIANGLE:Draw()
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for i=1, #self.Coords do
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local c1 = self.Coords[i]
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local c2 = self.Coords[i % #self.Coords + 1]
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table.add(self.MarkIDs, c1:LineToAll(c2))
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end
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end
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--- Removes the drawing of the triangle from the map.
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function TRIANGLE:RemoveDraw()
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for _, mark_id in pairs(self.MarkIDs) do
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UTILS.RemoveMark(mark_id)
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end
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end
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