DragonRuby platformer attempt - first mockup of the game

main.rb

class World
  # PADDING = 10
end

class Player
  GUN_HEIGHT = 45
end

class Projectile
  SPEED = 4
  MAX_NUMBER = 8 # stop shooting, adds a "synthetic reload time" to the game
end

class Viewport
  WIDTH = 1280
  HEIGHT = 720
end

class Color
  # main colors
  GROUND = [130, 80, 100]         # maroon
  PLAYER = [120, 150, 150]        # teal
  PLAYER_HEAD = [140, 170, 170]   # teal (ligther)

  # standard colors
  RED   = [200, 128, 128]
  BLUE  = [128, 128, 200]
  GREEN = [128, 200, 128]
  WHITE = [200, 200, 200]
  GREY  = [128, 128, 128]
  BLACK = [20,  20,  20 ]
end

class Platformer
  attr_gtk

  def generate_ground
    [
      [0, 0, 1300, 200] << Color::GROUND
    ]
  end

  def player
    [100, 230, 60, 120] << Color::PLAYER
  end

  def player_head
    [80, 290, 40, 40] << Color::PLAYER_HEAD
  end

  def defaults
    # player
    state.player        ||= player
    state.player_head   ||= player_head
    state.player_facing ||= :left

    # emitters
    state.projectiles   ||= []

    # world
    state.time          ||= Time.now
    state.tiles         ||= generate_ground

    # timers
    state.projectile_shoot_at ||= Time.now
  end

  X_ADD = -> (state, x) {
    state[0] += x
    state
  }

  X_SUB = -> (state, x) {
    state[0] -= x
    state
  }

  TIME_DELTA = -> (seconds_diff) {
    Time.now + seconds_diff
  }

  SHOOT_PROJECTILE = -> (state) {
    return if state.projectiles.size > Projectile::MAX_NUMBER
    return if TIME_DELTA.(-0.2) < state.projectile_shoot_at
    delta_x = state.player_facing == :left ? -85 : 15
    player_center = state.player[2] + delta_x
    projectile = [ state.player[0]+player_center, state.player[1]+Player::GUN_HEIGHT, 10, 10 ] << Color::BLACK << { entity: :projectile, direction: state.player_facing }
    state.projectile_shoot_at = Time.now
    state.projectiles << projectile
  }

  def flip_player_head(side)
    flip_player_head_to side if side != state.player_facing
    state.player_facing = side
  end

  def flip_player_head_to(side)
    x_move = side == :left ? X_SUB : X_ADD
    x_move.(state.player_head, state.player[2]) # width
  end

  def animate_projectile(projectile)
    meta = projectile[7]
    speed = Projectile::SPEED
    if meta[:direction] == :left
      projectile[0] -= speed
    else
      projectile[0] += speed
    end
    remove_projectile projectile if outside_viewport? projectile
    projectile
  end

  def remove_projectile(projectile)
    state.projectiles -= [projectile]
  end

  def outside_viewport?(projectile)
    x = projectile[0]
    x < 0 || x > Viewport::WIDTH
  end

  def input
    return if inputs.click

    player_movement_speed = 2.5

    kb = inputs.keyboard

    if kb.key_down.left
      flip_player_head :left

      X_SUB.(state.player, player_movement_speed)
      X_SUB.(state.player_head, player_movement_speed)
    end

    if kb.key_held.left
      X_SUB.(state.player, player_movement_speed*2)
      X_SUB.(state.player_head, player_movement_speed*2)
    end

    if kb.key_down.right
      flip_player_head :right
      X_ADD.(state.player, player_movement_speed)
      X_ADD.(state.player_head, player_movement_speed)
    end

    if kb.key_held.right
      X_ADD.(state.player, player_movement_speed*2)
      X_ADD.(state.player_head, player_movement_speed*2)
    end

    if kb.key_down.space
      SHOOT_PROJECTILE.(state)
    end
  end

  def tick
    defaults
    input
    render
  end

  def render_ground(outs)
    outs.solids << state.tiles.map(&:to_a)
  end

  def render_player(outs)
    outs.solids << [ state.player, state.player_head ]
  end

  def render_projectiles(outs)
    outs.solids << state.projectiles
  end

  def animate_projectiles(outs)
    state.projectiles.each do |projectile|
      animate_projectile projectile
    end
  end

  def render
    outs = args.outputs
    render_ground outs
    render_player outs
    render_projectiles outs
    animate_projectiles outs
    # render_enemies # TODO
  end

end

def main!
  GAME = Platformer.new

  def tick args
    GAME.args = args
    GAME.tick
  end

  $gtk.reset
end

main!