Java-Gaming.org Hi !
 Featured games (84) games approved by the League of Dukes Games in Showcase (565) Games in Android Showcase (151) games submitted by our members Games in WIP (605) games currently in development
 News: Read the Java Gaming Resources, or peek at the official Java tutorials
Pages: [1]
 ignore  |  Print
 Enemy AI - turn towards player  (Read 1540 times) 0 Members and 1 Guest are viewing this topic.
MickeyB

Senior Devvie

my game will work, my game will work!

 « Posted 2004-10-27 18:55:09 »

I have an nme and a player.  Both have vector3f locations and a heading.  What is the best way to have the nme come up with how much to turn to face player?

Dot product is in there somewhere (I think) but that gives me a very odd number.

This is in 3D.

Thanks a ton!

MickeyB

Current Project: http://www22.brinkster.com/mbowles/
ewills

Junior Devvie

Java skeletal animation systems rock!

 « Reply #1 - Posted 2004-10-28 13:48:00 »

For normalized vectors, v1.dot(v2) = cos(theta), so theta = acos(v1.dot(v2)).  The Vector3f class also supports v1.angle(v2).  Note that both vectors must be in the same coordinate frame, but it sounds like they are in your case
MickeyB

Senior Devvie

my game will work, my game will work!

 « Reply #2 - Posted 2004-10-28 14:26:01 »

thanks.  I failed to mention that the vector3f is a class I wrote to use iwth LWJGL.  It has a Dot calc.

I guess I could also try to send a Ray out from my nme and rotate him until he has a collision fo ray and player??

MickeyB

Current Project: http://www22.brinkster.com/mbowles/
ewills

Junior Devvie

Java skeletal animation systems rock!

 « Reply #3 - Posted 2004-10-29 00:50:55 »

Yes.  It would be good to first know the direction that you're going to turn.  Why rotate 270 degrees when you only need to rotate 90?    This can be done by transforming the normalized vector between the player and enemy into the player's coordinate space and then evaluating the x coordinate of the transformed vector.  You can just turn until the dot product between the transformed vector and the local y-axis is arbitratily close to 1.0.  Hope this helps!
MickeyB

Senior Devvie

my game will work, my game will work!

 « Reply #4 - Posted 2004-11-02 12:24:52 »

Thanks for your help.  All set now.  Now to "tone" down the accuracy of the nme's   LOL

Thanks again.

MickeyB

Current Project: http://www22.brinkster.com/mbowles/
Pages: [1]
 ignore  |  Print

You cannot reply to this message, because it is very, very old.

 theagentd (11 views) 2015-03-27 23:08:20 wxwsk8er (52 views) 2015-03-20 15:39:46 Fairy Tailz (46 views) 2015-03-15 21:52:20 Olo (28 views) 2015-03-13 17:51:59 Olo (30 views) 2015-03-13 17:50:51 Olo (37 views) 2015-03-13 17:50:16 Olo (43 views) 2015-03-13 17:47:07 ClaasJG (40 views) 2015-03-10 11:36:42 ClaasJG (41 views) 2015-03-10 11:33:01 Pippogeek (47 views) 2015-03-05 14:36:23
 LiquidNitrogen 23x KevinWorkman 21x basil_ 21x BurntPizza 21x EgonOlsen 17x theagentd 16x Roquen 16x princec 12x Riven 12x Varkas 10x SHC 9x Ashedragon 8x NegativeZero 8x lcass 7x ClaasJG 7x teletubo 7x
 How to: JGO Wikiby Mac702015-02-17 20:56:162D Dynamic Lighting2015-01-01 20:25:42How do I start Java Game Development?by gouessej2014-12-27 19:41:21Resources for WIP gamesby kpars2014-12-18 10:26:14Understanding relations between setOrigin, setScale and setPosition in libGdx2014-10-09 22:35:00Definite guide to supporting multiple device resolutions on Android (2014)2014-10-02 22:36:02List of Learning Resources2014-08-16 10:40:00List of Learning Resources2014-08-05 19:33:27
 java-gaming.org is not responsible for the content posted by its members, including references to external websites, and other references that may or may not have a relation with our primarily gaming and game production oriented community. inquiries and complaints can be sent via email to the info‑account of the company managing the website of java‑gaming.org