draw weapon sight cone

Hi I am using this code below for 2d pan and zoom:


http://www.blitzbasic.com/codearcs/codearcs.php?code=2269


It lets you draw polys, which is nice, and I want to draw a triangle to show the sight cone for a gun. I know the range of the weapon and its angle of movement,e.g. 65 degrees each way. =130 degrees and range of 6 squares

I can already calculate if the weapon is in range and within the right angle but I dont know how to get the co-ords of a point that is 65 degrees away and a range of 60 units for instance.
and of course the sight cone would have to correspond to the angle of the gun:):)

The coordinate of a point which 65 degrees away and a range of 60 units away goes something like this. Assuming that your person with the gun is at PersonX,PersonY :

Angle=65
Range=60
X = (Cos(Angle)*Range) + PersonX
Y = (Sin(Angle)*Range) + PersonY

Again, this is working with the 0 angle being right, not up, consistent with your previous question.

This might help as well.

Glad you're finding my code useful :)

Suppose you've got a gun at gunx#,guny#, and its angle is gunangle#
You want to draw a cone out from gunx,guny, covering everything within +/- 65 degrees of gunangle and up to 60 units away.
This shape is a segment of a circle, but drawing a segment of a circle is a bit tricky, so you've correctly realised you need to draw a poly. We can approximate a circle segment by working out a few points on the edge of the circle, and making a polygon out of them, plus the centre point.

SuperStrict

Local gunangle:Float 'Gun is at (gunx,guny) pointing in angle 'gunangle'
Local gunx:Float
Local guny:Float

Local numsegments:Int = 12	'split the cone into 12 segments

Local poly:Float[(numsegments+1)*2]	'we will store the co-ordinates of the vertices of the polygon her

Local anrange:Float=130		'the cone is 130 degrees wide
Local coneradius:Float=60	'and reaches 60 units out

Local an:Float,x:Float,y:Float
poly[0]=gunx	'the first vertex of the cone is the centre
poly[1]=guny

For Local i:Int=0 To numsegments-1
	an=gunangle-anrange/2.0+Float(i)/Float(numsegments)*anrange
	x=gunx+coneradius*Cos(an)	'gets a point at the given angle and distance away from the gun
	y=guny+coneradius*Sin(an)
	poly[i*2+2]=x		'store these co-ordinates in the cone array
	poly[i*2+3]=y
Next

DrawPoly poly	'draw the cone

thanks gab
whoa it actually worked!

and luckily I can use the blitz rotation commands to align the lines to the right direction,

tonyg thanks for the link

warpy, I plugged your code into my game, it looked great because the cone is a poly it can be colored made transparent and filled-in,
It didnt respond to scale
ill try changing it to zoompoly
EDIT: tried that and it worked,
now to set the rotation
the co-ordinates are messed up when rotation is applied, im trying to see why

EDIT:
Possibly because of 'handling' I have automidhandle set to true,
it does seem to be a 'handle' issue, unless the code is wrong (which I doubt)

What are you doing with rotation? The code I wrote already takes into account the gun's rotation.

oh yeah I had to set the rotation to zero

it works now thanks!