Java-Gaming.org Hi !
 Featured games (88) games approved by the League of Dukes Games in Showcase (681) Games in Android Showcase (196) games submitted by our members Games in WIP (744) games currently in development
 News: Read the Java Gaming Resources, or peek at the official Java tutorials
Pages: [1]
 ignore  |  Print
 [Solved] LibGdx - Wierd behavior with Sprite rotation  (Read 2069 times) 0 Members and 1 Guest are viewing this topic.
mrbenebob

Junior Newbie

 « Posted 2013-06-19 13:09:54 »

So I was going to have a go at making a little 2D space action combat game, but have unfortunately fallen at the first hurdle and cant seem to get the players ship going in the right direction.

The ship has an X and Y, an X Velocity value, a Y Velocity and an angle, all floats.

When the up key is pressed, a force is added to the X and Y velocities depending on the ships rotation.

if(Gdx.input.isKeyPressed(Keys.UP)){
shipVX += 0.05 * (float) Math.cos(shipAngle);
shipVY += 0.05 * (float) Math.sin(shipAngle);
}

However, the ships angle and the directions of the force don't seem to match up in any way. I've tried rejigging that bit of code, but cant get anything that makes any sense.

Its probably just my maths that's at fault, haven't had to do any physics since college, anyway, any thoughts and suggestions would be greatly appreciated.

Full code here: http://pastebin.java-gaming.org/053379f186d
heisenbergman

JGO Coder

Medals: 14

L___ o_ G___ a__ P___

 « Reply #1 - Posted 2013-06-19 13:59:57 »

^ Is your shipAngle variable in degrees? Because if it is, you need to convert it to radians:

 1  2 `            shipVX += 0.05 * (float) Math.cos(Math.toRadians(shipAngle));            shipVY += 0.05 * (float) Math.sin(Math.toRadians(shipAngle));`

davedes
 « Reply #2 - Posted 2013-06-19 14:08:19 »

Some useful LibGDX utilities worth noting:
 1  2  3  4  5  6  7  8  9  10  11 `MathUtils.cosDeg( angleInDegrees )MathUtils.sinDeg( angleInDegrees )MathUtils.cos( angleInRadians )MathUtils.sin( angleInRadians )MathUtils.PI2  //PI * 2, already cast to floatMathUtils.PI    //already cast to floatfloat rad = degrees * MathUtils.degRad //degrees to radiansfloat deg = radians * MathUtils.radDeg  //radians to degrees`

mrbenebob

Junior Newbie

 « Reply #3 - Posted 2013-06-19 14:44:21 »

Ah, that'll be it, knew I was missing something dumb.
Thanks guys, working now
Pages: [1]
 ignore  |  Print

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

 CopyableCougar4 (23 views) 2016-06-25 16:56:52 Hydroque (57 views) 2016-06-22 02:17:53 SwampChicken (59 views) 2016-06-20 13:22:57 SwampChicken (59 views) 2016-06-20 13:22:49 SwampChicken (55 views) 2016-06-20 13:22:26 Hydroque (98 views) 2016-06-15 08:22:50 Hydroque (89 views) 2016-06-13 06:40:55 DarkCart (215 views) 2016-05-29 02:30:33 Hydroque (175 views) 2016-05-26 14:45:46 Mac70 (173 views) 2016-05-24 21:16:33
 Spasi 49x theagentd 44x NegativeZero 39x KaiHH 30x princec 25x LiquidNitrogen 23x kingroka123 15x ags1 15x ra4king 12x CoDi^R 11x Opiop 10x purenickery 10x Hydroque 9x Archive 8x Ecumene 7x czak 7x
 Making a Dynamic Plugin Systemby Hydroque2016-06-25 00:13:25Java Data structures2016-06-13 21:22:09Java Data structures2016-06-13 21:20:42FPS Camera Tutorialby Hydroque2016-05-22 05:40:58Website offering 3D Models specifically for games for freeby vusman2016-05-18 17:23:09Website offering 3D Models specifically for games for freeby vusman2016-05-09 08:50:56Website offering 3D Models specifically for games for freeby vusman2016-05-06 11:10:21Website offering 3D Models specifically for games for freeby vusman2016-04-29 12:56:17
 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