Moving an object in a circular path

Question

I want to move one object (dot) in a circular path. How should I change the X and Y coordinates to accomplish this?

Answer 1

You can make it by using simple math.

X := originX + sin(angle)*Size;
Y := originY + cos(angle)*Size;

Origin is the center of your circle. Size is the radius of that circle. Thats it.

Answer 2

There's another trick, where you use the sin(x+a) and cos(x+a) formulas, and that allows you to compute sin(a) and cos(a) -- a being the angle by which you want to move from your current position -- only once and do simply multiplication and additions at each step.

sin(x+a) = sin(x)*cos(a) + cos(x)*sin(a), iirc.

Of course, that assumes constant angular velocity.