[RESOLVED] Avoiding an obstacle on your way to target.

http://img600.imageshack.us/img600/4782/90850346.jpg

My character is moving to the money, a little step every second.
Every tick - he is casting a beam towards the money, to check for collision.
He needs to steer away from possible obstacle - but, he needs to continiue on his way to money.

Best trajectory to do his is moving along to the red dot, but I just cannot wrap my head around this one - how do i calculate it's position?

It took me a really long time before I crawled here, for help. I surrender now.
Anyone? Please?

If the obstacles and target are not moving its probably best to set up red dots manually as nodes for path. Then you can use simple and well-researched path-finding algorithm like A-Star from node to node.

In case of dynamic environment, you could try something like this:
*cast beam to target, if does not hit any obstacles, move to target
*if beam hits obstacles, cast 2 new beams with length of distance to target
*one new beam 1 degree clockwise from original, other new beam 1 degree counter-clockwise
*if both new beams also hit obstacles, cast new beams 2 degrees away
*continue until one of new beams misses the obstacles
*pick that beam and move in that direction couple of steps
*after some distance start over with beam to target

Thanks for your insight.

I got this figured on my own though, yesterday before going to sleep.
I rotate my beam -X degrees, where X is obstacle radius based. somewhere close to 40 degrees(Hacky). Most problematic was to implement this. I found some "rotate point around point" class on the net (http://www.tdotblog.info/?q=node/16) and used it.
Cause it's seems I just cannot rotate my beam (sprite made with drawingAPI) accordingly.


Your method is more precise though. If only I knew simplier way to "cast 1 degree away". How do you calculate that new coordinate? I know the answer sits in that class I found, but I'm a sucker at math.

Code:

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Point newPoint = rotatePoint(targetPoint, originPoint, oneDegree);

---

Err.. I knew how to use that class method. I just could not understand how it operates.

anyway I found the way in the Math section of forums. It was the basic stuff, which makes me ashamed of myself, cause I've read a book on this one year ago.

newPoint.x= originPoint.x + Math.cos(degrees*Math.PI/180) * distanceToObstacle;
newPoint.y=originPoint.y + Math.sin(degrees*Math.PI/180)* distanceToObstacle;

Anyway, thanks for "cast 2 new beams with length " idea, Tonypa. Otherwise it looked silly, when my char ran around obstacle always in clockwise direction, even when it was not the shortest way.