General Question Propeller animation [solved]

[johnnymanly]

I'd like to animate a prop in a Lua vessel.
I can set the animation like this:

pwr = vi:get_animation(anim_Prop)
  da = simdt * 0.1
  pwr_proc = pwr + da
  gas = vi:get_thrusterlevel(thmain)

   if
    gas > 0
   then
    vi:set_animation(anim_Prop,pwr_proc)
   end

but I don't know how to repeat the animation. (loop?)
Any hint would be appreciated.

Thanks.

 

[Thunder Chicken]

I'd like to animate a prop in a Lua vessel.
I can set the animation like this:

pwr = vi:get_animation(anim_Prop)
  da = simdt * 0.1
  pwr_proc = pwr + da
  gas = vi:get_thrusterlevel(thmain)

   if
    gas > 0
   then
    vi:set_animation(anim_Prop,pwr_proc)
   end

but I don't know how to repeat the animation. (loop?)
Any hint would be appreciated.

Thanks.

I'm assuming your animation state defines a full totation. The animation state can't exceed 1. So if it does, you have to subtract 1.

 

[johnnymanly]

Thanks for the answer.
Do you mean I have to set the animation state back to 0 before I can make another revolution?

 

[Thunder Chicken]

Thanks for the answer.
Do you mean I have to set the animation state back to 0 before I can make another revolution?

Not quite. Remember that the animation state variable really describes what angle the propeller should be oriented at a given time on a scale from 0 to 360 degrees (0 to 1 animation state). As an example, let's say that the propeller angle increases by 62 degrees every time step. After six steps, the total angle of rotation would be 6*62 = 372 degrees. This would be equivalent to an animation state of 1.03333. You don't want to reset the state to 0 because that wouldn't give the correct angle. What you need to know is what is the angle on a 0 to 360 scale (0 to 1 animation state). So you subtract off 360 degrees (1 from your animation state) to get the proper angle of 12 degrees, at a corresponding animation state of 0.03333.

Mathematically what you want is the remainder of the sum of your animation state increments divided by 1.

 

[johnnymanly]

Thanks for answering but your talking past me a bit. I assumed the angle would increase the correct amount so the animation would finish at 1. (or where I set it )

 

[johnnymanly]

This seems to do it and ties rpm to thrust.

  --configuration part
  anim_Prop = vi:create_animation(0)

  Prop1 = {
    type = 'rotation',
    mesh = 0,
    grp = 13,
    ref = {x=0,y=0.467,z=8.928},
    axis = {x=0,y=0,z=1},
    angle = -360*RAD
    }

  animcomp_Prop = oapi.create_animationcomponent(Prop1)

  vi:add_animationcomponent(anim_Prop,0,1,animcomp_Prop)
 
  --prop spinning part
function clbk_prestep(simt,simdt,mjd)

  pwr = vi:get_thrusterlevel(thmain)
  prp = vi:get_animation(anim_Prop)
  da = simdt * 0.1 + (pwr * 0.1)
  prp_proc = prp + da

  if
    prp < 1
  then
    vi:set_animation(anim_Prop,prp_proc)
  else
    vi:set_animation(anim_Prop, 0)
  end

end

 

[Matias Saibene]

This seems to do it and ties rpm to thrust.

  --configuration part
  anim_Prop = vi:create_animation(0)

  Prop1 = {
    type = 'rotation',
    mesh = 0,
    grp = 13,
    ref = {x=0,y=0.467,z=8.928},
    axis = {x=0,y=0,z=1},
    angle = -360*RAD
    }

  animcomp_Prop = oapi.create_animationcomponent(Prop1)

  vi:add_animationcomponent(anim_Prop,0,1,animcomp_Prop)
 
  --prop spinning part
function clbk_prestep(simt,simdt,mjd)

  pwr = vi:get_thrusterlevel(thmain)
  prp = vi:get_animation(anim_Prop)
  da = simdt * 0.1 + (pwr * 0.1)
  prp_proc = prp + da

  if
    prp < 1
  then
    vi:set_animation(anim_Prop,prp_proc)
  else
    vi:set_animation(anim_Prop)
  end

end

I was racking my brain all afternoon until I found this solution. Can you allow me to use it in my C++ project?
I think I know how to convert it from Lua to C++.

 

[johnnymanly]

I was racking my brain all afternoon until I found this solution. Can you allow me to use it in my C++ project?
I think I know how to convert it from Lua to C++.

Of course. Feel free to use it.
If you get any weird behavior pay attention to the other comments in this thread. I'm not a very good coder.