InsidePoly

This code has been declared by its author to be Public Domain code.

InsidePoly by skidracer (Posted 25 years ago)
check if a point is inside a polygon
Function dot(x0,y0,x1,y1,x2,y2) Return (x1-x0)(y2-y1)-(x2-x1)(y1-y0) End Function Function InsideQuad(px,py,x0,y0,x1,y1,x2,y2,x3,y3) If dot(x0,y0,x1,y1,px,py)>0 If dot(x1,y1,x2,y2,px,py)>0 If dot(x2,y2,x3,y3,px,py)>0 If dot(x3,y3,x0,y0,px,py)>0 Return True EndIf EndIf EndIf EndIf End Function

InsidePoly by skidracer

(Posted 25 years ago)

check if a point is inside a polygon

Function dot(x0,y0,x1,y1,x2,y2)
	Return (x1-x0)*(y2-y1)-(x2-x1)*(y1-y0)
End Function

Function InsideQuad(px,py,x0,y0,x1,y1,x2,y2,x3,y3)
	If dot(x0,y0,x1,y1,px,py)>0
		If dot(x1,y1,x2,y2,px,py)>0
			If dot(x2,y2,x3,y3,px,py)>0
				If dot(x3,y3,x0,y0,px,py)>0
					Return True
				EndIf
			EndIf
		EndIf
	EndIf
End Function

Comments

Psilo

(Posted 21 years ago)

Thanks for that :)

Jim Brown

(Posted 18 years ago)

markcw

(Posted 18 years ago)

Plash

(Posted 18 years ago)

...!

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