BulletFold

Simple, lightweight bullet handler for Defold.

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Features

• Central Bullet handler module.

• Per Bullet ray casting and Collision Groups.

• Per Bullet hit response functions and hit marker functions.

• Per Bullet update behaviour.

• Two Bullet movement types: handled by [go.animate()] or updated using [go.set()] (significantly slower).

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Installation

TO DO...

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Guide

TO DO...

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Quick Start

Please see the quick_start.script_snippet for a basic implementation.

GameObjects

• Bullets: Create a GameObject named "bullets" and create a Factory component named "factory" within the GameObject.

• Hit Markers: Create a GameObject named "hit_markers" and create a Factory component named "factory" within the GameObject.

Module

local bulletfold = require "bulletfold_directory.bulletfold"

Initialize

1. Default Bullet Factory:

   bulletfold.factory = "/bullets#factory"

2. Default Ray Cast Collsion Groups:

   bulletfold.raycast_groups = { hash("collision_group1"), hash("collision_group2") }

3. (Optional) Default Hit Marker Function. If not initialized, spawns a default hit marker:

   bulletfold.hitmarker = function(position, bullet_id, object_id) factory.create("/hit_markers#factory", position) end

   Parameters

   • [position] vmath.vector3 The Bullet collision position.

   • [bullet_id] hash The Bullet GameObject ID.

   • [object_id] hash The ID of the GameObject the Bullet collided with.

Spawn

• Spawn a Bullet updated using [go.animate()] (Best Performance):

  bullet_id = bulletfold.spawn(speed, time, position, direction, accuracy, [raycast_groups], [factory], [hit_response])

• Spawn a Bullet updated using [go.set()] (Slower, Full Control Over Movement):

  bullet_id = bulletfold.spawn_update(speed, time, position, direction, accuracy, [raycast_groups], [factory], [hit_response])

• Custom Bullet hit response function:

  hit_response = function(bullet_id, result) hitmarker(result.position) ; bulletfold.delete(bullet_id) end

Update

• Update the BulletFold buffer:

  function update(self, dt)
      bulletfold.update(dt)
  end

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API

Properties

bulletfold.bullets table

• The Bullet buffer. Contains all active bullets. Bullet GameObject ID hashes are used as table keys.

  Bullet Parameters

  • [time] double The time remaining before the Bullet is deleted.

  • [speed] double The Bullet speed.

  • [position] vmath.vector3 The current Bullet position. If spawned using bulletfold.spawn() and is not ray casting, the position is not updated after spawning (improves performance).

  • [direction] vmath.vector3 The current Bullet travel direction. Can only be changed if the Bullet was spawned using bulletfold.spawn_update().

  • [raycast_groups] hash table The Collision Groups the Bullet ray cast can collide with. nil to disable ray casting.

  • [hit] function The function called when the Bullet hits an object. Default calls the Bullet Hit Marker function and deletes the Bullet.

  • [hitmark] function The function called when the Bullet hits an object, if a custom hit response function was not provided.

bulletfold.bullet_count unsigned int

• The number of Bullets in the bulletfold.bullets buffer.

bulletfold.factory URL string

• Default Bullet Factory. Used if no Factory is provided during spawning.

  bulletfold.factory = "/game_object#factory_component"

bulletfold.raycast_groups hash table

• Default Ray Cast Collsion Groups. Used if no table of Collision Groups is provided during spawning.

  bulletfold.raycast_groups = { hash("collision_group1"), hash("collision_group2") }

bulletfold.hitmarker function

• (Optional) Default Hit Marker function, called if no hit response function is provided during spawning. If not initialized, spawns a default hit marker using the function below.

  Parameters

  • [position] vmath.vector3 The Bullet collision position.

  • [bullet_id] hash The Bullet GameObject ID.

  • [object_id] hash The ID of the GameObject the Bullet collided with.

  bulletfold.hitmarker = function(position, bullet_id, object_id)
      local hitmark_id = factory.create("/hit_markers#factory", position)
      go.animate(msg.url(nil, hitmark_id, "sprite"), "tint.w", go.PLAYBACK_ONCE_FORWARD, 0, go.EASING_LINEAR, 1, 0, function() go.delete(hitmark_id) end)
  end 

Spawn Functions

bulletfold.spawn(speed, time, position, direction, accuracy, [raycast_groups], [factory], [hit_response])

• Spawn a Bullet updated using [go.animate()] (Best Performance):

  Parameters

  • [speed] double The Bullet speed.

  • [time] double The Bullet life time, in seconds.

  • [position] vmath.vector3 The Bullet spawn position.

  • [direction] vmath.vector3 The Bullet travel direction.

  • [accuracy] double The Bullet accuracy, used to randomize the direction. 0 for perfect accuracy.

  • [raycast_groups] hash table (Optional) The Collision Groups the Bullet ray cast can collide with. nil to disable ray casting.

  • [factory] string (Optional) The URL string of the Factory component used to spawn the Bullet GameObject. Default is the BulletFold Factory.

  • [hit_response] function (Optional) The function called when the Bullet hits an object. Default calls the Bullet Hit Marker function and deletes the Bullet.

    Parameters

    • [bullet_id] hash The Bullet GameObject ID.

    • [result] table The result of the Bullet ray cast collision.

      • [normal] vmath.vector3 The surface normal of the Collision Object the Bullet collided with.

      • [fraction] double The fraction along the ray cast where the collision occured. 0 is the start, 1 is the end.

      • [position] vmath.vector3 The collision position.

      • [group] hash The Collision Group ID of the Collision Object.

      • [id] hash The ID of the GameObject the Bullet collided with.

  Returns

  • [bullet_id] hash The Bullet GameObject ID.

  bullet_id = bulletfold.spawn(speed, time, position, direction, accuracy, [raycast_groups], [factory], [hit_response])

bulletfold.spawn_update(speed, time, position, direction, accuracy, [raycast_groups], [factory], [hit_response])

• Spawn a Bullet updated using [go.set()] (Slower, Full Control Over Movement):

  Parameters

  • [speed] double The Bullet speed.

  • [time] double The Bullet life time, in seconds.

  • [position] vmath.vector3 The Bullet spawn position.

  • [direction] vmath.vector3 The Bullet travel direction.

  • [accuracy] double The Bullet accuracy, used to randomize the direction. 0 for perfect accuracy.

  • [raycast_groups] hash table (Optional) The Collision Groups the Bullet ray cast can collide with. nil to disable ray casting.

  • [factory] string (Optional) The URL string of the Factory component used to spawn the Bullet GameObject. Default is the BulletFold Factory.

  • [hit_response] function (Optional) The function called when the Bullet hits an object. Default calls the Bullet Hit Marker function and deletes the Bullet.

    Parameters

    • [bullet_id] hash The Bullet GameObject ID.

    • [result] table The result of the Bullet ray cast collision.

      • [normal] vmath.vector3 The surface normal of the Collision Object the Bullet collided with.

      • [fraction] double The fraction along the ray cast where the collision occured. 0 is the start, 1 is the end.

      • [position] vmath.vector3 The collision position.

      • [group] hash The Collision Group ID of the Collision Object.

      • [id] hash The ID of the GameObject the Bullet collided with.

  Returns

  • [bullet_id] hash The Bullet GameObject ID.

  bullet_id = bulletfold.spawn_update(speed, time, position, direction, accuracy, [raycast_groups], [factory], [hit_response])

Update Functions

bulletfold.update(dt)

• Updates the BulletFold buffer.

  Parameters

  • [dt] double The time elapsed since the previous frame.

Delete Functions

bulletfold.delete(bullet_id)

• Deletes a Bullet and removes it from the BulletFold buffer.

  Parameters

  • [bullet_id] hash The Bullet GameObject ID.

bulletfold.clear()

• Deletes every Bullet from the BulletFold buffer.

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Credits

BulletFold is based on DefBullet by SubSoap.