POV-Ray : Newsgroups : povray.general : Aiming a spaceship : Re: Aiming a spaceship Server Time: 18 Jun 2019 04:45:11 GMT
 Re: Aiming a spaceship
 From: Mike Horvath Date: 1 Apr 2019 11:45:23
```Does your spaceship adhere to Newtonian physics? In which case your ship
will slide around a lot and not necessarily point in the direction you
are moving.

Mike

On 3/20/2019 9:26 PM, Tom A. wrote:
> Finally got a routine to point my spaceships.  Each is built along the X axis,
> in the positive X direction.  I've used a spline to define the spaceships
> motion, but getting the ship to point into the direction it is going.
> But here it is:
>
> #macro aimAt(p_cur, p_new )
> // given an object around origin pointing in the x direction,
> // generate a rotation so it can go from p_cur to p_new
>
> #local p_diff = p_new - p_cur; // where it's headed (vector normalized to
> origin)
> #local y_angle =  -  atan2d(p_diff.z,p_diff.x) ;
> #local xy_diff = sqrt(p_diff.x*p_diff.x + p_diff.z*p_diff.z);
> #local z_angle =  atan2d(p_diff.y,xy_diff) ;
> // #if (p_diff.y < 1) #local z_angle = -z_angle; #end
>
> rotate <0,0,z_angle>
> rotate <0,y_angle,0>
>
> #end // aim at
>
> And an example of it's use (cccc is a variable based off of the clock):
>
> object{ Freebooter(1) aimAt( moveSpline(cccc), moveSpline(cccc+.001) )
>               translate moveSpline(cccc) - <-90,-100,-100>  no_shadow  }
>
> Enjoy!
>
> Tom A.
>
>
```