Make a Picture look to the Mouse-y&&x-pos..

[dataFRAME]

Hello Everybody!

I got a question 'bout to make a Picture via the "r" Variable look at the MousePosition..
I dont know how to start! :C

Thanks from yet till end :X!

[osuf oboys]

Problem:
Find the angle a of the line from (px, py) to (mx, my). (where the angle is computed from the line segment (0,0)-(1,0) )

Solution:
Assume (px, py) != (mx, my) and let dx = mx - px, dy = my - py, and d = (dx^2 + dy^2)^0.5. Then,
if dx >= 0 then
a = math.deg(math.acos(dx / d))
else
a = 180 - math.deg(math.acos(dx / d)),
where math.acos is the "inverse" of cos. e.g. cos(45 degrees) = 1/sqrt(2) and acos(1/sqrt(2)) = 45 degrees. However, acos(-1/sqrt(2)) is also 45 degrees and so you must take 180 minus the value if dx is less than 0. math.deg just goes transforms radians to degrees, radians being the default unit for the trigonometric functions.

The necessary rotation r is the angle a plus some offset (0,90,180 or 270) depending on the direction the image looks in, e.g. looking to the left or up.

[Kaze]

Use math.atan2 to get the angle from a position:

Code: Select all

local angle = math.atan2( y, x ) -- Where x and y are "mouse x - picture x" and "mouse y - picture y"
-- angle is in radians, use math.deg( angle ) to get the degrees.