How do I fake physics collision redirection?

I'm experimenting with some physics-like movement without the Physics Behavior. I'm sure it's been done on here before.. can't find any examples though.

I'm using basic Behaviors: CustomMovement and Bullet. I'm trying to redirect a 'block' based on speed/mass/angle of another block it collides with.

I need to somehow not add additional speed to the collision. I'm using a one-time Acceleration action like 'force'.. although that may be a bad idea? not sure. All I really care about is the CustomMovement one.. the Bullet one I might just destroy and therefore not care about that trajectory/speed etc..

I have to somehow take the speed of each object and it's angle to determine the force..since force cancellation would happen if angling directly toward each other - but also if going in slightly the same angle the only force would be the difference in speed. No idea how to do that.

Maybe I am oversimplifying this... maybe there's a physics behavior for a reason?

any help?

https://www.dropbox.com/s/z0v2rkibaipnq ... .capx?dl=0

Yup that is why physics commands exist becuase it does all those complicated adjustments for you automatically if the settings are correct.

You can do some pseudo-physics using the bullet behavior and it does have a gravity setting and velocity but determining impact speed is pretty complex.

What kind of game are you making?

lamar there's no gravity.. just angles and speed - would like to use mass if possible. I have it sort of working without using mass.

it does NOT work when the collision happen and the objects are going somewhat in the same direction - it just adds all this speed and does not look natural.

just experimenting for a top down space game..

Try this:

MPPlantOfficial yup already downloaded that old Yann example.. gravity is not needed..just outerspace collisions. I couldn't figure a way to apply it.

I probably need to use sin and cos.. . just don't know really how...

lamar there's no gravity.. just angles and speed - would like to use mass if possible. I have it sort of working without using mass.

it does NOT work when the collision happen and the objects are going somewhat in the same direction - it just adds all this speed and does not look natural.

just experimenting for a top down space game..

I used the bullet behavior for one of my first pinball games and I was able to make it loook almost like real physics but like you said you could tell it was not natural physics and when two bullets collide you get strange effects that don't look natural.

You can use the Sine effect to some extent to get a more natural effect.

R0J0hound any chance you could recommend something? just curious if this is even doable or if its more complicated than I'm making it.

I just want to figure out how to take into account the moving angles, speed and how that would effect the 'force' or one-off acceleration.

I can live with setting the Moving angle of the GreenBlock after a collision to:

 angle(BlueBlock.X,BlueBlock.Y,GreenBlock.X,GreenBlock.Y)  -  180[/code:3ak5bxur]  
I  just  can't  figure  out  how  much  to  accelerate  by.  
 
I  started  with  some  arbitrary  numbers  and  found  some  that  work  for  most  collisions.   Then  I  tried  to  come  up  with  a  calculation  that  would  fit  those  numbers.   Most  of  it  works  well.  
 
But  it  all  fails  in  this  one  scenario  where  the  BlueBlock  is  traveling  right,  and  a  GreenBlock  is  also  traveling  right  but  is  going  faster.   When  it  catches  up  to  the  BlueBlock,  the  move  angles  are  correct,  except  my  calc  fails  miserably  by  adding  way  too  much  speed  to  the  BlueBlock.   My  calculation  doesn't  account  for  trajectory. 

This link explains the math of a physics bounce:

https://gamedevelopment.tutsplus.com/tu ... medev-6331

I always found it hard to fake physics because it never looks right.

(VB-VA)·n+j*(j*nmassA+j*nmassB)*n+e*(VB-VA)·n=0?(1+e)((VB-VA)·n)+j*(j*nmassA+j*nmassB)*n=0?j=-(1+e)((VB-VA)·n)1massA+1massB

yup that's what I figured..

yeah I'm not trying to do actual physics calculations.. just trying to get it 'approximate' .. it's a video game, so it doesn't need to be a perfect simulation by any means. The background is moving and the camera is lerped, so there's a high fudge factor. The biggest issue is the one I mentioned where the vectors are similar. I need to add that to my calculation and I'll be fine with it.

ended up making this work..

again it's "fake physics" under a controlled environment

After Collision Accelerate by this much:

 (BlueBlock.Bullet.speed  *  BlueBlock.scale)  *  (min(50,anglediff(GreenBlock.CustomMovement.MovingAngle,  BlueBlock.Bullet.AngleOfMotion)/3))[/code:2phzshzm]  
 
then  I  have  a  catch-all  that  makes  sure  the  GreenBlock  doesn't  go  beyond  my  top  speed  of  300  just  in  case  I  have  a  situation  where  it  does  add  too  much  accel..  
 
this  is  all  done  based  on  "looks"  and  watching  it  for  long  periods  of  time..  now  THAT  is  some  hacky  math!  
 
btw  the  GreenBlock  is  the  "player"  which  never  changes  and  has  a  top  speed,  so  all  the  other  obstacles  are  based  on  that  constant.