object - Java Rotate Image Towards Point from any X/Y position on screen

Question

I have a ship object that I want to be able to rotate towards any certain point I click on the screen (See pic of ship and sqaures as points). I can get the ship to face the general direction, but it has this strange behavior of as it rotates the ship itself; the image moves around an circular axis, instead of rotating from the center point of the image itself.

Can someone please, give me the formula to get the angle from the center xy point of image to the destination sqaure(mouse click)?

Answer 1

First you have to find the difference on the x axis and the difference on the y axis. Since you seem to say that your ship is centered, you only have to get the (x,y) coordinates of the click. To find the angle, you must know that sin(your angle) = y/sqrt(y^2 + x^2), therefore, your angle = sin^-1(y/sqrt(y^2 + x^2)). It is basic maths, but it's always good to refresh basic knowledge, as it can cause quite the headache when debugging if you made a small mistake there, so I suggest you check out this page: https://www.mathsisfun.com/algebra/trig-finding-angle-right-triangle.html