marted? 03 luglio owner-sdl at lokigames.com ha scritto:

ok, consider one of the two to be the origin, so you have

Sender: owner-sdl at lokigames.com

Precedence: bulko-----(x)

(y) X in (x, y)x = cos ( alpha )

y = sin ( alpha )tan ( alpha ) = sin / cos = y / x

alpha = atan ( y / x )

but there is still 2 problem:

y coul be 0

atan return either alpha or alpha + PIso =>

if( !x ) alpha = sign ( y ) * PI / 2

else alpha = atan ( y / x ) + ( x > 0 ? 0 : PI )

I will suggest you to

check also the C function "atan2"

that do the zero check and

the right angle adjustment.

So your code becomes simple:

alpha = atan2 (y,x)

Bye,

Enzo.> Reply-To: sdl at lokigames.com