Carecast

# Carecast · weather sonification in Sonic Pi
# Sonic Pi code by the Carecast team, 2025
# Excerpt: the map function, the rain layers and the wind
#
# Credits
# Birdsong (sunny clip): "Woodpecker and other birds on a spring morning"
#   by Kyster, https://freesound.org/s/182740/ (CC BY 4.0), slowed and filtered
# Comments translated from Chinese

# map function
define :map_val do |v, in_min, in_max, out_min, out_max|
  return out_min if in_min == in_max  # avoid dividing by zero
  v = [[v, in_min].max, in_max].min  # clamp to the range
  ratio = (v - in_min).to_f / (in_max - in_min).to_f
  out_min + ratio * (out_max - out_min)
end

#--------------------------------------------
#rain drop, overlap with all weather
#--------------------------------------------

define :dual_synth_drop do |s1, s2, note, amp_base|
  unless playing_weather?
    sleep 1
    next
  end
  use_synth s1
  play note,
    amp: amp_base * 0.6,
    attack: 0.01,
    release: 0.35
  use_synth s2
  play note + [0, 2].choose,
    amp: amp_base * 0.4,
    attack: 0.0,
    release: 0.45
end

# 1. Drizzle: high notes, sparse
live_loop :drizzle do
  unless playing_weather?
    sleep 1
    next
  end
  rain_mm  = get(:rain_mm)
  rain_norm = map_val(rain_mm, 0, 30, 0.0, 1.0)

  with_fx :echo, phase: 0.45, decay: 2.5, mix: 0.35 do
    note = (scale :e5, :minor_pentatonic).choose
    if rand < (0.9 * (1 - rain_norm))
      dual_synth_drop :sine, :tri, note, rain_norm*0.8
    end
  end

  # rainfall maps to 3.0 s → 0.2 s
  sleep map_val(rain_mm, 0, 30, 3.0, 0.2)
end

# 2. Middle rain: middle register
live_loop :middle_rain do
  unless playing_weather?
    sleep 1
    next
  end
  rain_mm  = get(:rain_mm)
  rain_norm = map_val(rain_mm, 0, 30, 0.0, 0.8)

  with_fx :echo, phase: 0.28, decay: 2.2, mix: 0.5 do
    if rand < map_val(rain_mm, 0, 30, 0.05, 0.95)
      note = (scale :e4, :minor_pentatonic).choose
      amp_val =  rain_norm*0.8
      dual_synth_drop :tri, :beep, note, amp_val
    end
  end

  sleep map_val(rain_mm, 0, 30, 1.5, 0.5)
end

# 3. Heavy rain: low register
live_loop :heavy_rain do
  unless playing_weather?
    sleep 1
    next
  end
  rain_mm  = get(:rain_mm)
  rain_norm = map_val(rain_mm, 0, 30, 0.0, 1.0)

  with_fx :echo, phase: 0.16, decay: 3.5, mix: 0.75 do
    if rand < rain_norm
      low_note = (scale :e3, :minor_pentatonic).choose
      dual_synth_drop :beep, :tri, low_note, rain_norm*0.8

      if rand < rain_norm
        use_synth :sine
        play (scale :e5, :minor_pentatonic).choose,
          amp: rain_norm*0.15,
          attack: 0.0,
          release: 0.2
      end
    end
  end

  sleep map_val(rain_mm, 0, 30, 0.7, 0.45)
end

#--------------------------------------------
# wind, overlap with all weather
#--------------------------------------------
live_loop :wind do
  wind_speed  = get(:wind_speed)
  unless playing_weather?
    sleep 1
    next
  end
  if wind_speed < 3
    sleep 1
    next
  end

  wind_amp = map_val(wind_speed, 0, 20, 0.3, 1.2)
  cutoff   = map_val(wind_speed, 3, 15, 70, 110)

  with_fx :reverb, room: 0.9, mix: 0.7 do
    with_fx :lpf, cutoff: cutoff + rrand(-10, 10) do
      synth :noise, amp: wind_amp,
        attack: 1.0,
        sustain: 2.0,
        release: rrand(4.0, 8.0)
    end
  end

  sleep rrand(3, 5)
end