Class: ParticleFX2D::Emitter

Inherits:
Object
  • Object
show all
Defined in:
lib/particlefx2d/emitter.rb

Overview

A particle effect emitter

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(opts = {}) ⇒ Emitter

Create a new particle emitter

  • quantity Number of total particles in the emitter's pool
  • emission_rate Number of particles to emit per second
  • particle_config Options are used to configure each particle when it is emitted, which are as follows:
    • x Initial x-axis position of emission
    • x_range optional range from which a random value is chosen to add to the initial x; default is 0
    • y Initial y-axis position of emission
    • y_range optional range from which a random value is chosen to add to the initial y; default is 0
    • start_color optional initial colour of the emitted particle. See Particle for default
    • end_color optional end colour of the particle by the end of its life. See Particle for default
    • start_scale optional initial size scale factor of the emitted particle relative to its size; default is 1
    • end_scale optional end size scale factor of the particle by the end of its life; default is 1
    • angle optional angle at which the particle is emitted, in degrees. See Particle for default
    • angle_range optional range from which a random value is chosen to add to the angle; default is 0
    • speed optional speed at which the particle is emitted, in pixels/s. See Particle for default
    • speed_range optional range from which a random value is chosen to add to the speed; default is 0
    • size optional size of the particle when emitted, in pixels. See Particle for default
    • size_range optional range from which a random value is chosen to add to the size; default is 0
    • gravity_x optional linear acceleration in pixels/second squared along the x axis, default is 0
    • gravity_y optional linear acceleration in pixels/second squared along the y axis, default is 0
    • radial_acceleration optional radial accelation in pixel/seconds squared, default is 0
    • tangential_acceleration optional tangential accelation in pixel/seconds squared, default is 0
    • life_time of each particle in seconds. See Particle for default
    • life_time_range optional range from which a random value is chosen to add to the life_time; default is 0

Parameters:

  • opts (defaults to: {}) —

    Options to configure the emitter as follows:



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# File 'lib/particlefx2d/emitter.rb', line 38

def initialize(opts = {})
  @quantity = (opts[:quantity] || 128).to_i
  @emission_rate = opts[:emission_rate].to_f
  @emission = 0
  @particle_config = opts[:particle_config]
  @renderer_factory = opts[:renderer_factory]
  setup_particle_pool
end

Instance Attribute Details

#emission_rate ⇒ Object

Returns the value of attribute emission_rate.



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# File 'lib/particlefx2d/emitter.rb', line 8

def emission_rate
  @emission_rate
end

#particle_config ⇒ Object

Returns the value of attribute particle_config.



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# File 'lib/particlefx2d/emitter.rb', line 8

def particle_config
  @particle_config
end

Instance Method Details

#stats ⇒ Object

Retrieve statistics about the emitter's current status

  • quantity The total number of particles in the emitter
  • emission_rate The emission rate (particles per second)
  • active The number of active particles
  • unused The number of inactive particles in the pool

Returns:

  • A hash with the following properties:



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# File 'lib/particlefx2d/emitter.rb', line 71

def stats
  {
    quantity: @quantity,
    emission_rate: @emission_rate,
    active: @active.count,
    unused: @pool.count
  }
end

#update(frame_time) ⇒ Object

Update the particle effect emission, called for each frame of the animation cycle.

Parameters:

  • frame_time (Float) —

    in seconds (essentially, 1 / fps)



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# File 'lib/particlefx2d/emitter.rb', line 52

def update(frame_time)
  @renderer_factory.on_update_start
  emit_particles frame_time
  @active.each do |p|
    p.update frame_time
    free_particle p unless p.alive?
  end
  @renderer_factory.on_update_end
end