Fading Pillowcases Demo

Made in DragonRuby to get to know the engine.

def tick args
  args.state.solids.faders ||= []
    if args.inputs.mouse.down # Tracking mouse drag initial position…
    args.state.inputs.mouse.held.point ||= args.inputs.mouse.down.point
  end
  if args.inputs.mouse.up # …and whether it's currently held.
    args.state.inputs.mouse.held.point = nil
    
    if args.state.solids.pillowcase # Making the current pillowcase a new fader.
      args.state.solids.faders << args.state.solids.pillowcase
      args.state.solids.pillowcase = nil
    end
  end
    args.state.solids.faders.select! {|i| i[:a] > 1} # Culling the invisible faders.
  args.state.solids.faders.each do |i| # Defining faders' lifecycle.
    if i[:fresh] then i[:a] += 5 else i[:a] -= 1 end
    if i[:a] > 254 then i[:fresh] = false end
  end
    args.outputs.solids << args.state.solids.faders
    if args.state.inputs.mouse.held.point # Setting the current pillowcase.
    args.state.solids.pillowcase = {
      x: args.state.inputs.mouse.held.point.x,
      y: args.state.inputs.mouse.held.point.y,
      w: args.inputs.mouse.point.x - args.state.inputs.mouse.held.point.x,
      h: args.inputs.mouse.point.y - args.state.inputs.mouse.held.point.y,
      r: 255,
      g: 0,
      b: 0,
      a: 55,
      fresh: true
    }
  end
    args.outputs.solids << args.state.solids.pillowcase
    args.outputs.labels << [20, 20, 'Faders ' + args.state.solids.faders.size.to_s]
  # To make sure they do in fact get culled and not just invisible.
end