Class: Dopairb::Fx::Particles

Inherits:
Object
  • Object
show all
Defined in:
lib/dopairb/fx.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(rng = Random.new) ⇒ Particles

Returns a new instance of Particles.



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# File 'lib/dopairb/fx.rb', line 12

def initialize(rng = Random.new)
  @rng = rng
  @list = []
end

Instance Attribute Details

#list ⇒ Object (readonly)

Returns the value of attribute list.



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# File 'lib/dopairb/fx.rb', line 10

def list
  @list
end

Instance Method Details

#add(x, y, vx, vy, at:, life:, palette:, glyph: nil, gravity: 0.0, drag: 0.0) ⇒ Object 



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# File 'lib/dopairb/fx.rb', line 33

def add(x, y, vx, vy, at:, life:, palette:, glyph: nil, gravity: 0.0, drag: 0.0)
  @list << Particle.new(x, y, vx, vy, at, life, palette, glyph, gravity, drag)
end

#alive?(t) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/dopairb/fx.rb', line 41

def alive?(t)
  @list.any? { |p| t - p.born <= p.life }
end

#burst(x, y, n, at:, speed: 20.0, spread: 1.0, life: 0.6, palette: Color::FIRE, glyphs: nil, gravity: 18.0, angle: nil, arc: Math::PI * 2, drag: 1.5) ⇒ Object

speed in cells/sec; y velocity is squashed to respect the cell aspect



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# File 'lib/dopairb/fx.rb', line 21

def burst(x, y, n, at:, speed: 20.0, spread: 1.0, life: 0.6, palette: Color::FIRE, glyphs: nil,
          gravity: 18.0, angle: nil, arc: Math::PI * 2, drag: 1.5)
  n.times do
    a = angle ? angle + (@rng.rand - 0.5) * arc : @rng.rand * Math::PI * 2
    s = speed * (0.35 + @rng.rand * 0.65 * spread)
    g = glyphs && glyphs[@rng.rand(glyphs.size)]
    @list << Particle.new(x, y, Math.cos(a) * s, Math.sin(a) * s * 0.5, at, life * (0.6 + @rng.rand * 0.4),
                          palette, g, gravity, drag)
  end
  self
end

#clear ⇒ Object 



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# File 'lib/dopairb/fx.rb', line 17

def clear = @list.clear

#draw(canvas, t) ⇒ Object 



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# File 'lib/dopairb/fx.rb', line 45

def draw(canvas, t)
  @list.each do |p|
    age = t - p.born
    next if age < 0 || age > p.life
    x, y = position(p, age)
    col = Color.ramp(p.palette, age / p.life)
    if p.glyph
      canvas.put(x, y, p.glyph, col, bold: age < p.life * 0.3)
    else
      canvas.dot(x * 2, y * 4, col)
    end
  end
end

#empty? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/dopairb/fx.rb', line 18

def empty? = @list.empty?

#position(p, age) ⇒ Object 



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# File 'lib/dopairb/fx.rb', line 59

def position(p, age)
  if p.drag > 0
    k = (1 - Math.exp(-p.drag * age)) / p.drag
    [p.x + p.vx * k, p.y + p.vy * k + 0.5 * p.gravity * age * age * 0.25]
  else
    [p.x + p.vx * age, p.y + p.vy * age + 0.5 * p.gravity * age * age * 0.25]
  end
end

#prune(t) ⇒ Object 



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# File 'lib/dopairb/fx.rb', line 37

def prune(t)
  @list.reject! { |p| t - p.born > p.life }
end