drawploy : how does it work ?

I'm trying to create a polygon but I dont see what Im doing wrong.

To following code I thought would create a polygon shaped like a number 1. something like this :

_*
_*
_*
_*
***

but when i run it it looks nothing like that. So my question is can I create a polygon like that shape using drawploy or do I have to draw two 4 sided polys ?

Graphics 640,480

Local angle:Int
Local p:Float[8*2]

p[0] = -5
p[1] = -25

p[2] = 5
p[3] = -25

p[4] = 5
p[5] = 20

p[6] = 10
p[7] = 20

p[8] = 10
p[9] = 25

p[10] = -10
p[11] = 25

p[12] = -10
p[13] = 20

p[14] = -5
p[15] = 20
While Not KeyHit(key_space)
	Cls
	angle :+ 1
	If angle > 360 Then 
		angle :- 360
	End If
	SetOrigin 50,50
	SetRotation angle 
	DrawPoly(p)	
	Flip
Wend

drawpoly doesn't do concave angles, which is what the top of your "1" is. You need to break the "1" down into two separate polygons.

OK.. thats cool.. I can work with that.. I just wasnt sure I was using it correctly.

Thanx

I don't know if it's mentioned anywhere, but algorithms like drawpoly usually assume the points are in a particular order. The polygon must be traversed counterclockwise.

Graphics 640,480

Local angle:Int
Local p:Float[8*2]

p[0] = -5
p[1] = -25

p[2] = 5
p[3] = -25

p[4] = 5
p[5] = 20

p[6] = 10
p[7] = 20

p[8] = 10
p[9] = 25

p[10] = -10
p[11] = 25

p[12] = -10
p[13] = 20

p[14] = -5
p[15] = 20

' Quick fix, reverse order of vertices.

For n = 0 To 6 Step 2
	m = n
	temp = p[m] ; p[m] = p[14-m] ; p[14-m]=temp
	m = n + 1
	temp = p[m] ; p[m] = p[16-m] ; p[16-m]=temp
Next

While Not KeyHit(key_space)
	Cls
	angle :+ 1
	If angle > 360 Then 
		angle :- 360
	End If
	SetOrigin 50,50
	SetRotation angle 
	DrawPoly(p)	
	Flip
Wend

thanx floyd

I have already fixed my problem by drawing a collection of rectangles and it will be a bit of a rewrite to do it properly now but I will certainly remember it for next time.

If only I'd desgned the poly in reverse order I would never have hit this problem in the first place. :)