DragonRuby Game Toolkit - Many to Many Collision Performance - https://youtu.be/cc3Sx2j85mM

main.rb

def tick args
  # initialize state
  args.state.rects ||= []
  args.state.rect_size ||= 8
  args.state.move_squares ||= :no
  if args.inputs.keyboard.key_down.tab
    args.state.move_squares = args.state.move_squares == :yes ? :no : :yes
  end

  args.outputs.watch "FPS: #{GTK.current_framerate.to_sf}"
  args.outputs.watch "rect count: #{args.state.rects.length.to_i}"
  args.outputs.watch "move squares? (press tab to toggle) #{args.state.move_squares}"

  # if the mouse is clicked, add 100 random rects
  if args.inputs.mouse.click
    args.state.rects << { x: args.inputs.mouse.x,
                          y: args.inputs.mouse.y,
                          w: args.state.rect_size,
                          h: args.state.rect_size,
                          path: :solid,
                          a: 128,
                          speed: rand(5) + 5 }
    99.times do
      angle = rand(360)
      distance = rand(160) + 32
      args.state.rects << { x: args.inputs.mouse.x + angle.vector_x * distance,
                            y: args.inputs.mouse.y + angle.vector_y * distance,
                            w: args.state.rect_size,
                            h: args.state.rect_size,
                            path: :solid,
                            a: 128,
                            speed: (rand(5) + 5) * 1.randomize(:sign) }
    end
  end

  # set rect colors back to green (no collision)
  args.state.rects.each do |rect|
    rect.r = 0
    rect.g = 128
    rect.b = 0
  end

  # move rects if the state is set to move_squares
  if args.state.move_squares == :yes
    args.state.rects.each do |rect|
      rect.x += rect.speed
      if rect.x > 1280
        rect.x = 1280
        rect.speed = -rect.speed
      elsif rect.x < 0
        rect.x = 0
        rect.speed = -rect.speed
      end
    end
  end

  # check for collisions many to many
  Geometry.each_intersect_rect(args.state.rects, args.state.rects) do |rect_one, rect_two|
    rect_one.r = 255
    rect_one.g = 0
    rect_one.b = 0
    rect_two.r = 255
    rect_two.g = 0
    rect_two.b = 0
  end

  # render mouse cursor
  args.outputs.primitives << { x: args.inputs.mouse.x,
                               y: args.inputs.mouse.y,
                               w: 192,
                               h: 192,
                               anchor_x: 0.5,
                               anchor_y: 0.5,
                               path: :solid,
                               r: 0,
                               g: 0,
                               b: 0,
                               a: 32 }

  # render rects
  args.outputs.primitives << args.state.rects
end

$gtk.reset