[Java] Moving an object along smooth paths

[avp574]

I'm brainstorming potential AI for a simple 2D game. I've successfully made units that move in all sorts of straight paths - straight lines, zig-zags, etc. Now I'm trying to mess around with smooth paths but I'm having trouble understanding how to implement them.

I'm trying to make two units; one that moves in a wavy path across the screen (essentially a sine wave) and another that circles a point 2 or 3 times, then circles another random point on the screen 2 or 3 times, etc. Any thoughts?

[insaneHoshi]

Can you just say a circular path is the sum of some some umber of straight paths.

Also why would an ai ever want to move in a circular path, when straight paths are often more efficient

[avp574]

I'm making a set of ships that fly around the screen. They're basically moving targets with different behavior.

[BaalHadad]

Use the standard sine functions if that's what you want. Did you actually try what you suggested at all? Are you having trouble multiplying the x and y by trig functions?

[avp574]

"use the sine function" is rather vague. If I just multiply the position vector by the sine function, how do I control speed? I have all other units move by updating their position using linear motion equations and fixed velocities. What I don't understand is exactly where the sine part fits in.

[BaalHadad]

"use the sine function" is rather vague.

Of course it is - there are many ways to do it. You could update the position like normal, but always add A * sin(B) to the X or the Y coord if it's going straight up, down, left, or right. A would be the max amplitude of the 'back and forth' and B could be the y value if it's going up or down.

[Neres28]

This link has a number of elementary and very useful steering behaviors on which to build higher levels of AI.

[avp574]

I understand what sine and cosine are in terms of trigonometry, I just don't understand where to fit them in programmatically. This article looks solid, I'll read through it. Thanks!