[ANY] Make entities bounce (or hop)

[VinciT]

To make entities bounce (or hop), something needs to act upon the entities with a certain amount of force in order to change their velocity.
With Source.Python, the easiest way to accomplish this is to change their velocity directly with the teleport virtual function.

Syntax: Select all

entity.teleport(origin, angle, velocity)

Or with the apply_force_center function by accessing the PhysicsObject of the entity (thank you L'In20Cible).

Syntax: Select all

entity.physics_object.apply_force_center(velocity)

Here's a very simple class that you can use to make any entity bounce randomly with ease.



And here's how'd you use this to make entities bounce:

Syntax: Select all

from events import Event


@Event('bomb_dropped')
def bomb_dropped(event):
    bouncy_bomb = bouncy_instances[event['entindex']]
    # The bomb will only bounce when it's on the ground, until it is picked up.
    bouncy_bomb.start_bouncing(tickrate=0.3, multiplier=1.3, ground_check=True)

Syntax: Select all

from entities.entity import BaseEntity
from entities.hooks import EntityPreHook, EntityCondition


@EntityPreHook(EntityCondition.is_player, 'drop_weapon')
def drop_weapon_pre(stack_data):
    base_entity = BaseEntity._obj(stack_data[1])

    bouncy_weapon = bouncy_instances[base_entity.index]
    # The weapon will bounce once a second no matter where it is, either in the
    # air or on the ground, for the next 10 seconds or until it is picked up.
    bouncy_weapon.start_bouncing(
        tickrate=1, 
        multiplier=0.5,
        ground_check=False, 
        duration=10
        )

By adjusting the bounce_multiplier, you can make entities wiggle, hit the skybox, and everything in between.

[L'In20Cible]

That's funny!

Here are some suggestions/improvements:

• Instead of using Repeat combined with an EntityDictionary, you could just use Entity.repeat.
• Instead of retrieving the m_hMoveParent property, you could just do:
  

  Syntax: Select all

  if self.parent is not None:

• Instead of tracking the z axis to know if the entity is on the ground, you could just use:
  

  Syntax: Select all

  if int(self.physics_object.velocity[0].length):

• Instead of delaying the stop yourself, you could just pass it to the repeat and let it handle that for you:
  

  Syntax: Select all

  self.think.start(interval=tickrate, limit=(duration / tickrate))

• Instead of using Entity.teleport, you could use (you may need to add more force than 300 units, though):
  

  Syntax: Select all

  self.physics_object.apply_force_center(velocity)

• Should forward the caching keyword to Entity.__init__.

[VinciT]

Oh wow, thank you for the amazing suggestions, I would've never thought to use PhysicsObject. I went ahead and changed everything you mentioned.
I solved the force issue by multiplying the new velocity with the mass of the object.

That's funny!

Glad you liked it.

[L'In20Cible]

I solved the force issue by multiplying the new velocity with the mass of the object.

That's actually a great idea! That means every bounce will be consistent regardless if the object is heavier than another or not.

[decompile]

Funny idea. :D Good job