CrosRoad95: typo

2018-05-25T11:34:32Z

typo

← Older revision		Revision as of 11:34, 25 May 2018
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	{{Useful Function}}		{{Useful Function}}
	__NOTOC__		__NOTOC__
	This function compute area of ~~ony~~ polygon.		This function compute area of any polygon.

	==Syntax==		==Syntax==

CrosRoad95: Created page with "{{Useful Function}} NOTOC This function compute area of ony polygon. ==Syntax== float math.polygonArea(float vertex1x, float vertex1y, float v..."

2018-05-25T11:33:29Z

Created page with "{{Useful Function}} __NOTOC__ This function compute area of ony polygon. ==Syntax== <syntaxhighlight lang="lua">float math.polygonArea(float vertex1x, float vertex1y, float v..."

New page

{{Useful Function}}
__NOTOC__
This function compute area of ony polygon.

==Syntax==
<syntaxhighlight lang="lua">float math.polygonArea(float vertex1x, float vertex1y, float vertex2x, float vertex2y, float vertex3x, float vertex3y, [...] )</syntaxhighlight>

===Required Arguments===
* '''vertex1x, vertex1y''': First vertex, position `x` and `y`
* '''vertex2x, vertex2y''': Second vertex, position `x` and `y`
* '''vertex3x, vertex3y''': Third vertex, position `x` and `y`
===Optional Arguments===
* '''vertexNx, vertexNy''': Another vertex, any numbers of vertices.
{{OptionalArg}}
===Returns===
Return polygon area in meters^2

==Code==
<section name="Server- and/or clientside Script" class="both" show="true">
<syntaxhighlight lang="lua">
function math.polygonArea( ...)
local vertices = {...}
local points= {}

for i=1, #vertices-1, 2 do
points[#points+1] = { x=vertices[i], y=vertices[i+1] }
end
local count = #points

local area = 0
local j = count

for i=1, count do
area = area + (points[j].x + points[i].x) * (points[j].y - points[i].y)
j = i
end

return math.abs(area/2)
end
</syntaxhighlight>
</section>

==Example==
<section name="Example usage" class="shared" show="true">
This example compute area of cube 1x1 and triangle, base=5, height=4
<syntaxhighlight lang="lua" lang="lua">
local cubeArea = math.polygonArea(0,0, 1,0, 1,1, 0,1) -- cube -- 1
local triangleArea = math.polygonArea(0,0, 5,4, 5,0) -- triangle -- 10
-- triangleArea
--[[
height: 4
base: 5
area = 1/2 * height * base = 10
area = 1/2 * 4 = 2 * 5 = 10
]]--
print( cubeArea, triangleArea )
</syntaxhighlight>
</section>

Author: CrosRoad95, based on https://www.mathopenref.com/coordpolygonarea2.html

==See Also==
{{Useful_Functions}}

Math.polygonArea - Revision history

CrosRoad95: typo

CrosRoad95: Created page with "{{Useful Function}} __NOTOC__ This function compute area of ony polygon. ==Syntax== float math.polygonArea(float vertex1x, float vertex1y, float v..."

CrosRoad95: Created page with "{{Useful Function}} NOTOC This function compute area of ony polygon. ==Syntax== float math.polygonArea(float vertex1x, float vertex1y, float v..."