Need help drawing a part of a circle

[Crashty]

Trying to draw a part of a circle using surface.DrawLine(), Trying to draw it in a specific pattern that my vocabulary cant explain ;_;

[lua]

function PartialCircle()

local w = ScrW()
local h = ScrH()

surface.SetDrawColor(Color(0,150,0))

for deg = 1,360 do

surface.DrawLine(w/2,h/2,w/2+math.sin(deg)*40,h/2+math.cos(deg)*40)

end

end

hook.Add("HUDPaint","PartialCircle",PartialCircle)

[/lua]

this draws a full circle, but if i draw up to 180 degrees it still draws a full circle, with 50% lines, am i failing my maths? Please help

[MakeR]

math.sin and math.cos assume the angle is in radians. If you loop from 1 to pi it should draw correctly.

[editline]14th August 2013[/editline]

You might want to loop from 1 to 180 and use math.rad to convert to radians instead.

[Crashty]

Thanks, Works perfectly now, Is there a better way to do this tho? I can see small spaces between the lines

and its not that fast

[Fredy]

I guess you want to fill a circle, right?
Then you should take a close look at this function:
[url]http://maurits.tv/data/garrysmod/wiki/wiki.garrysmod.com/index4287.html[/url]
(especially combined with the second example)

It should be like this then (only copied from maurits.tv):

local sin,cos,rad = math.sin,math.cos,math.rad; --Only needed when you constantly calculate a new polygon, it slightly increases the speed.
function GeneratePoly(x,y,radius,quality)
    local circle = {};
    local tmp = 0;
    for i=1,quality do
        tmp = rad(i*360)/quality
        circle[i] = {x = x + cos(tmp)*radius,y = y + sin(tmp)*radius};
    end
    return circle;
end

local function HUDPaint()
    surface.SetDrawColor( 255, 255, 255, 255 ) --set the additive color
    surface.DrawPoly( GeneratePoly(ScrW()/2, ScrH()/2, 40, 100)) --draw the circle
end
hook.Add("HUDPaint","Draw Circle", HUDPaint)