Steering behaviours and wrap-around worlds

XiotexStudios · 2006-04-27T20:08:40

I have a wrap around world (only in X direction) and I intend to use steering behviours to control AI units so that they seek and arrive at the player. Now this in theory works fine except when the player crosses the wrap-around barrier. For example if the player is in a world that is 0 - 100 and crosses the 0 barrier the AI units immediately switch direction because the player is now at somewhere near 100. This would be fine if the camera were static and the whole world was in the view frustum but in my case the camera chases the player so you get AI units that suddently veer away from the player for no apparent reason (the wrap-around points are not obvious to the player). I have thought of two of solutions to this, both of which introduce complexity: 1, Keep track of what the AI unit is chasing and if the distance suddenly increases by a huge amount (target crossed the barrier for example) then compensate for the barrier crossing. 2, Transform the AI and the target into a common screen space rather than world space whenever seeking and arriving is in operation. They will be in relation to each other at all points then. Anybody have any other ideas?

Artificial Intelligence Programming

Started by XiotexStudios April 22, 2006 06:10 PM

11 comments, last by Timkin 18 years, 7 months ago

NQ

328

April 27, 2006 02:16 AM

Hey man, take it easy...
I withdraw my previous statement "which doesn't work", and replace it with the more accurate version "which solves a problem which likely is different from what the OP was talking about".
I didn't write the long version, because it didn't explain the humour I saw in it.

Let's forget about that and get back on-topic...

XiotexStudios, if you're still looking for a solution, then this might help:

halfworld = worldsize / 2; targetX = player.x; if (targetX < (agent.x - halfworld))	targetX += worldsize;if (targetX > (agent.x + halfworld))	targetX -= worldsize;targetX -= agent.x;targetY = player.y - agent.y; Move_In_Direction(Get_Direction_To(targetX, targetY));

The 2 if-statements, plus the following 2 lines, is what converts the players coordinate to agent-space. The Get_Dir_To()-function calculates a direction from coordinate 0:0 towards the supplied parameter.
You are probably already using such a function, and only need to modify it to assume that the from-coordinate is always at 0:0.

Good luck!

----------------------~NQ - semi-pro graphical artist and hobbyist programmer

XiotexStudios

Author

160

April 27, 2006 03:42 PM

Thanks - I'll give it a go..

Byron Atkinson-JonesXiotex Studioswww.xiotex.com

Timkin

864

April 27, 2006 08:08 PM

Quote: Original post by NQ
I withdraw my previous statement "which doesn't work", and replace it with the more accurate version "which solves a problem which likely is different from what the OP was talking about".

*sigh*.

If you have evidence as to any error in what I wrote, then please post it. If not, then your opinions are based only on supposition and misunderstanding and are therefore inappropriate and inflammatory. Please do not treat other forums users in this manner.

Timkin

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