Class: GamesParadise::Billiard::Ball

Inherits:
Object
  • Object
show all
Defined in:
lib/games_paradise/gui/gosu/billiard/ball.rb

Constant Summary collapse

POCKET_RADIUS =
#

POCKET_RADIUS

#
17.0
COLOUR_FOR_THE_CUE_BALL =
#

COLOUR_FOR_THE_CUE_BALL

Here you can specify the colour for the cue ball in use.

#
0xffFFDDAE

Instance Method Summary collapse

Constructor Details

#initialize(window, x, y, dir, vel, rad, id, colour) ⇒ Ball

#

initialize

#


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# File 'lib/games_paradise/gui/gosu/billiard/ball.rb', line 35

def initialize(
    window,
    x,
    y,
    dir,
    vel,
    rad,
    id,
    colour
  )
  @window, @x, @y, @dir, @radius, @id, @color = window, x, y, dir, rad, id, colour
  # ======================================================================= #
  # This defines the area of the ball, based on a circle.
  # ======================================================================= #
  @mass = 3.14 * (@radius ** 2) # A = π·r²
  @vel_x = ::Gosu.offset_x(@dir, vel)
  @vel_y = ::Gosu.offset_y(@dir, vel)
  # ======================================================================= #
  # === @collision_point_x
  # ======================================================================= #
  @collision_point_x = @x
  # ======================================================================= #
  # === @collision_point_y
  # ======================================================================= #
  @collision_point_y = @y
  # ======================================================================= #
  # Used only by the cue ball
  # ======================================================================= #
  @release_force = 0.02
  @placement_collision = false

  # ======================================================================= #
  # Is the ball out of the game? (AKA did the ball
  # reach the pocket yet?).
  # ======================================================================= #
  @out = false
  reset
end

Instance Method Details

#check_collision(inst) ⇒ Object

#

check_collision

This method is only called once for each pair of balls.

#


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# File 'lib/games_paradise/gui/gosu/billiard/ball.rb', line 332

def check_collision(inst)
  if @x + @radius + inst.radius > inst.x and
     @x < inst.x + @radius + inst.radius and
     @y + @radius + inst.radius > inst.y and
     @y < inst.y + @radius + inst.radius

    dist = Gosu.distance(inst.x, inst.y, @x, @y)

    if dist < (@radius + inst.radius)
      @collision_point_x = ((@x * inst.radius) + (inst.x * @radius))/(@radius + inst.radius)
      @collision_point_y = ((@y * inst.radius) + (inst.y * @radius))/(@radius + inst.radius)

      @collision_point = true

      new_vel_self = new_velocity(
        @mass, inst.mass, Vector[@vel_x, @vel_y], Vector[inst.vel_x, inst.vel_y], Vector[@x, @y], Vector[inst.x, inst.y]
      )
      new_vel_inst = new_velocity(
        inst.mass, @mass, Vector[inst.vel_x, inst.vel_y], Vector[@vel_x, @vel_y], Vector[inst.x, inst.y], Vector[@x, @y]
      )

      # CALCULATE THE HIT SOUND VOLUME #######
      v1 = Vector[@vel_x, @vel_y]
      v2 = Vector[inst.vel_x, inst.vel_y]
      c1 = Vector[@x, @y]
      c2 = Vector[inst.x, inst.y]
      
      dv = v1 - v2  ### Vector
      dc = c1 - c2  ### Vector

      hit_force = dv.inner_product(dc)  ### Number

      if hit_force < 0 # If the balls are moving towards each other
        # ================================================================= #
        # Play the following sound upon hitting a ball.
        # ================================================================= #
        HIT_SOUND.play(-hit_force * 1.00/100.00) # When hit_force = 6 : Volume = 1 : Which means full volume
        # puts hit_force
      end

      collision_response(new_vel_self)
      inst.collision_response(new_vel_inst)

    end
  end
end

#check_collision_line(x1, y1, x2, y2) ⇒ Object

#

check_collision_line

#


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# File 'lib/games_paradise/gui/gosu/billiard/ball.rb', line 169

def check_collision_line(x1, y1, x2, y2)

  vector_x = x2 - x1
  vector_y = y2 - y1

  point_to_vector_x = @x - x1
  point_to_vector_y = @y - y1

  vector_product = vector_x * point_to_vector_x + vector_y * point_to_vector_y

  vec_length_squared = vector_x**2 + vector_y**2

  projection_factor = vector_product / vec_length_squared

  if projection_factor > 0 and projection_factor < 1 ### If the projected point is on the line. Projection factor is between 0 and 1.
    
    projected_point_x = projection_factor * vector_x + x1
    projected_point_y = projection_factor * vector_y + y1

    dist_to_player = Gosu.distance(@x, @y, projected_point_x, projected_point_y)

    if dist_to_player < radius
      ## Collision with projected point!
      vec = new_velocity(0, 10, Vector[@vel_x, @vel_y], Vector[0, 0], Vector[@x, @y], Vector[projected_point_x, projected_point_y])
      collision_response(vec)
    end
    
  end
  
end

#check_collision_pocket(x, y) ⇒ Object

#

check_collision_pocket

#


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# File 'lib/games_paradise/gui/gosu/billiard/ball.rb', line 151

def check_collision_pocket(x, y)
  dist2 = (x - @x)**2+(y - @y)**2 # Optimisation
  if dist2 < POCKET_RADIUS**2  # Optimisation
    ### Collision!
    # if @color == COLOUR_FOR_THE_CUE_BALL
      # @x = $universe_width*3/4
      # @y = $universe_height/2
      # @vel_x = 0.0
      # @vel_y = 0.0
    # else
      self.in_hole
    # end
  end
end

#check_collision_point(x, y) ⇒ Object

#

check_collision_point

#


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# File 'lib/games_paradise/gui/gosu/billiard/ball.rb', line 203

def check_collision_point(x, y)
  dist2 = (x - @x)**2 + (y - @y)**2
  if dist2 < @radius**2
    # Collision!
    vec = new_velocity(0, 10, Vector[@vel_x, @vel_y], Vector[0, 0], Vector[@x, @y], Vector[x, y])
    collision_response(vec)
  end
end

#check_placement_collision ⇒ Object

#

check_placement_collision

This method is used by the cue ball only

#


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# File 'lib/games_paradise/gui/gosu/billiard/ball.rb', line 413

def check_placement_collision
  if @x < 0+@radius or
     @x > $universe_width-@radius or 
     @y < 0+@radius or 
     @y > $universe_height-@radius
    @placement_collision = true
  end
end

#checkMouseClick ⇒ Object

#

checkMouseClick

This method is used in particular for relocating the cue ball via the mouse.

#


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# File 'lib/games_paradise/gui/gosu/billiard/ball.rb', line 218

def checkMouseClick
  # First calculate the net-distance.
  dist = Gosu.distance(
    @window.mouse_x-$window_width/2+$camera_x,
    @window.mouse_y-$window_height/2+$camera_y,
    @x,
    @y
  )
  if dist < @radius
    case @color
    when COLOUR_FOR_THE_CUE_BALL
      if @out == false
        # ================================================================= #
        # The next line is not completely correct because it should be
        # increased upon a mouse-release event. But it is easier to
        # handle for now via this variable, so we retain it.
        # ================================================================= #
        @the_cue_ball_was_hit_n_times += 1
        @pulled = true
      else
        # The following clause handles replacing the cue ball.
        if @being_replaced
          if @placement_collision == false
            e 'The cue ball was placed down.'
            @being_replaced = false
            @out = false
          end
        else
          @being_replaced = true
          e 'being replaced'
        end
      end
    end
  end
end

#collision_path(x1, y1, x2, y2) ⇒ Object

#

collision_path

Basically the same as “check_collison_line” except the radius is different and there is no collision response

#


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# File 'lib/games_paradise/gui/gosu/billiard/ball.rb', line 283

def collision_path(x1, y1, x2, y2)  

  if @color != COLOUR_FOR_THE_CUE_BALL and @out == false

    vector_x = x2 - x1
    vector_y = y2 - y1

    point_to_vector_x = @x - x1
    point_to_vector_y = @y - y1
    
    vector_product = vector_x * point_to_vector_x + vector_y * point_to_vector_y
    
    vec_length_squared = vector_x**2 + vector_y**2
    
    projection_factor = vector_product / vec_length_squared
    
    if projection_factor > 0 and projection_factor < 1 ### If the projected point is on the line. Projection factor is between 0 and 1.
      
      projected_point_x = projection_factor * vector_x + x1
      projected_point_y = projection_factor * vector_y + y1
      
      dist_to_player = Gosu.distance(@x, @y, projected_point_x, projected_point_y)
      
      if dist_to_player < radius*2 # this balls radius, and the cue balls radius. They are the same.

        @colliding = true

        dt = Math.sqrt((radius*2)**2 - dist_to_player**2) / Math.sqrt(vec_length_squared)

        # Intersection point nearest to A
        t1 = projection_factor - dt
        int_x = x1 + t1 * vector_x
        int_y = y1 + t1 * vector_y
        col_x = (@x + int_x) / 2
        col_y = (@y + int_y) / 2

        $path_blockers << [int_x, int_y, col_x, col_y, 'ball']

      end

    end
  end
end

#collision_response(i) ⇒ Object

#

collision_response

#


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# File 'lib/games_paradise/gui/gosu/billiard/ball.rb', line 382

def collision_response(i)
  # @colliding = true
  @vel_x = i[0]
  @vel_y = i[1]
end

#collision_wall_path(x1, y1, x2, y2, wall_index) ⇒ Object

#

collision_wall_path

#


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# File 'lib/games_paradise/gui/gosu/billiard/ball.rb', line 525

def collision_wall_path(
    x1, y1, x2, y2, wall_index
  )
  if @pulled # Only called for the cue-ball

    ##### COLLISION BETWEEN TWO LINE SEGMENTS
    ##### Credits goes to this guy : http://stackoverflow.com/a/1968345
    x3 = @x
    y3 = @y

    dir = point_direction(
      @window.mouse_x, @window.mouse_y, @x+$window_width/2-$camera_x, @y+$window_height/2-$camera_y
    )

    x4 = @x + Gosu.offset_x(dir, 900)
    y4 = @y + Gosu.offset_y(dir, 900)

    s1_x = x2 - x1
    s1_y = y2 - y1

    s2_x = x4 - x3
    s2_y = y4 - y3

    s = (-s1_y * (x1 - x3) + s1_x * (y1 - y3)) / (-s2_x * s1_y + s1_x * s2_y)
    t = ( s2_x * (y1 - y3) - s2_y * (x1 - x3)) / (-s2_x * s1_y + s1_x * s2_y)

    if s >= 0 and s <= 1 and t >= 0 and t <= 1

      # Collision Detected
      int_x = x1 + (t * s1_x)
      int_y = y1 + (t * s1_y)
      
      # Which way does the wall face?
      # From that; calculate the predicted collision point on the wall
      case wall_index
      when 0, :top_left  # Top left
        col_x = int_x
        col_y = int_y-11.0
      when 1, :top_right  # Top right
        col_x = int_x
        col_y = int_y-11.0
      when 2, :bottom_left  # Bottom left
        col_x = int_x
        col_y = int_y+11.0
      when 3, :bottom_right  # Bottom right
        col_x = int_x
        col_y = int_y+11.0
      when 4, :left  # Left
        col_x = int_x-11.0
        col_y = int_y
      when 5, :right  # Right
        col_x = int_x+11.0
        col_y = int_y
      end

      $path_blockers << [
        int_x, int_y, col_x, col_y, 'wall', wall_index
      ]

    else
      ### No collison :(
    end
  end
end

#destroy ⇒ Object

#

destroy

#


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# File 'lib/games_paradise/gui/gosu/billiard/ball.rb', line 439

def destroy
  @window.destroy_ball(self)
end

#dir? ⇒ Boolean Also known as: dir

#

dir?

#

Returns:

  • (Boolean) 


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# File 'lib/games_paradise/gui/gosu/billiard/ball.rb', line 518

def dir?
  @dir
end

#do_play_the_cheer_sound ⇒ Object

#

do_play_the_cheer_sound

Invoke this method whenever you wish to play the cheer-sound.

#


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# File 'lib/games_paradise/gui/gosu/billiard/ball.rb', line 483

def do_play_the_cheer_sound
  CHEER_SOUND.play(0.8) # This is the volume; 1 means full-volume.
end

#draw ⇒ Object

#

draw

#


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# File 'lib/games_paradise/gui/gosu/billiard/ball.rb', line 686

def draw
  # ======================================================================= #
  # Put a shadow around the ball.
  # ======================================================================= #
  @window.circle_img.draw_rot(
    @x-3+$window_width/2-$camera_x,
    @y+9+$window_height/2-$camera_y,
    1,
    @dir,
    0.5,
    0.5,
    1.0 * (@radius/50.0),
    1.0 * (@radius/50.0),
    0x44000000
  )
  # The ball itself.
  if @being_replaced == false
    if @colliding == false
      @window.circle_img.draw_rot(@x+$window_width/2-$camera_x, @y+$window_height/2-$camera_y, 2, @dir, 0.5, 0.5, 1.0*(@radius/50.0), 1.0*(@radius/50.0), @color)
    else
      @window.circle_img.draw_rot(@x+$window_width/2-$camera_x, @y+$window_height/2-$camera_y, 2, @dir, 0.5, 0.5, 1.0*(@radius/50.0), 1.0*(@radius/50.0), 0xff00FF00)
      if @collision_point
      
        @window.circle_img.draw_rot(@collision_point_x+$window_width/2-$camera_x, @collision_point_y+$window_height/2-$camera_y, 2, @dir, 0.5, 0.5, 1.0*(5.0/50.0), 1.0*(5.0/50.0), 0xff0000FF)
      end
    end
  else
    if @placement_collision
      @window.circle_img.draw_rot(@x+$window_width/2-$camera_x, @y+$window_height/2-$camera_y, 2, @dir, 0.5, 0.5, 1.0*(@radius/50.0), 1.0*(@radius/50.0), 0xaaFF0000)
    else
      @window.circle_img.draw_rot(@x+$window_width/2-$camera_x, @y+$window_height/2-$camera_y, 2, @dir, 0.5, 0.5, 1.0*(@radius/50.0), 1.0*(@radius/50.0), 0xaa00FF00)
    end
  end
  
  # ======================================================================= #
  # Show specific instructions to the play when the cue ball is out
  # of the field.
  # ======================================================================= #
  if @color == COLOUR_FOR_THE_CUE_BALL and @out
    @window.font.draw_text(
      'The cue ball is out... Click the ball to replace it on the table',
      $universe_width/2-140+$window_width/2-$camera_x, -75+$window_height/2-$camera_y, 3, 1.0, 1.0,
      COLOUR_BLACK
    )
  end

  # ======================================================================= #
  # Light reflection
  # ======================================================================= #
  @window.circle_img.draw_rot(
    @x+1+$window_width/2-$camera_x, @y-5+$window_height/2-$camera_y, 2, @dir, 0.5, 0.5, 1.0*(4.0/50.0), 1.0*(4.0/50.0), 0x66ffffff
  )

  # ======================================================================= #
  # Numbers drawn on the ball.
  # ======================================================================= #
  if @color != COLOUR_FOR_THE_CUE_BALL
    @window.circle_img.draw_rot(@x+$window_width/2-$camera_x, @y+$window_height/2-$camera_y, 2, @dir, 0.5, 0.5, 1.0*(6.3/50.0), 1.0*(6.3/50.0), 0xffffffff)
    if @id > 9 # Numbers above 9, aka 10, 11 and so forth.
      @window.font_small.draw_text(
        "#{@id}", @x-6+$window_width/2-$camera_x, @y-6+$window_height/2-$camera_y, 3, 1.0, 1.0,
        ::Gosu::COLOUR_BLACK
      )
    else
      @window.font_small.draw_text(
        "#{@id}", @x-3+$window_width/2-$camera_x, @y-6+$window_height/2-$camera_y, 3, 1.0, 1.0,
        ::Gosu::COLOUR_BLACK
      )
    end
    if @id > 8
      # Refer to the stripe_img next:
      @window.stripe_img.draw_rot(
        @x+$window_width/2-$camera_x, @y+$window_height/2-$camera_y, 2, @dir, 0.5, 0.5, 1.0*(@radius/50.0), 1.0*(@radius/50.0), 0xffffffff
      )
    end
  end

  # ======================================================================= #
  # The release line will be drawn next.
  # ======================================================================= #
  if @pulled
    # ===================================================================== #
    # Calculate the direction from the mouse cursor to the cue ball.
    # ===================================================================== #
    dir = point_direction(@window.mouse_x, @window.mouse_y, @x+$window_width/2-$camera_x, @y+$window_height/2-$camera_y)
    # ===================================================================== #
    # Red line to the mouse
    # ===================================================================== #
    if ::Gosu.distance(@x+$window_width/2-$camera_x, @y+$window_height/2-$camera_y, @window.mouse_x, @window.mouse_y) < 300
      @window.draw_line(
        @x+$window_width/2-$camera_x, @y+$window_height/2-$camera_y, 0xffff0000, @window.mouse_x, @window.mouse_y, 0xffff0000, 2
      )
    else
      @window.draw_line(@x+$window_width/2-$camera_x, @y+$window_height/2-$camera_y, 0xffff0000, @x+$window_width/2-$camera_x+
      ::Gosu.offset_x(dir-180, 300), @y+$window_height/2-$camera_y+Gosu.offset_y(dir-180, 300), 0xffff0000, 2)
    end

    # Find the nearest collision point in $path_blockers
    d = 10000
    for i in 0..$path_blockers.length-1
      dist = Gosu.distance(@x, @y, $path_blockers[i][0], $path_blockers[i][1])
      if dist < d
        closest_int = $path_blockers[i].dup
        d = dist
      end
    end

    if !closest_int.nil?
      case closest_int[4]
      when 'ball' # The cue ball is hitting another ball

        @window.draw_line(@x+$window_width/2-$camera_x, @y+$window_height/2-$camera_y, 0xffffffff, closest_int[0]+$window_width/2-$camera_x, closest_int[1]+$window_height/2-$camera_y, 0xffffffff, 2)
        @window.circle_img.draw_rot(closest_int[2]+$window_width/2-$camera_x, closest_int[3]+$window_height/2-$camera_y, 3, @dir, 0.5, 0.5, 1.0*(3.5/50.0), 1.0*(3.5/50.0), 0xff0000FF)

        vel_vec = new_velocity(
          10, 10, Vector[closest_int[0]-@x, closest_int[1]-@y], Vector[0, 0], Vector[closest_int[0], closest_int[1]], Vector[closest_int[2], closest_int[3]]
        )

        predicted_response_x = closest_int[0] + vel_vec[0]
        predicted_response_y = closest_int[1] + vel_vec[1]

        dir = point_direction(closest_int[0], closest_int[1], predicted_response_x, predicted_response_y)

        @window.draw_line(closest_int[0]+$window_width/2-$camera_x, closest_int[1]+$window_height/2-$camera_y, 0xffffffff, closest_int[0]+Gosu.offset_x(dir, 40)+$window_width/2-$camera_x, closest_int[1]+Gosu.offset_y(dir, 40)+$window_height/2-$camera_y, 0xffffffff, 3)
        
      else # The cue ball is hitting a wall
        
        @window.draw_line(@x+$window_width/2-$camera_x, @y+$window_height/2-$camera_y, 0xffffffff, closest_int[0]+$window_width/2-$camera_x, closest_int[1]+$window_height/2-$camera_y, 0xffffffff, 2)
        @window.circle_img.draw_rot(closest_int[2]+$window_width/2-$camera_x, closest_int[3]+$window_height/2-$camera_y, 3, @dir, 0.5, 0.5, 1.0*(3.5/50.0), 1.0*(3.5/50.0), 0xff0000FF)
        
        dir = self.point_direction(@window.mouse_x, @window.mouse_y, @x+$window_width/2-$camera_x, @y+$window_height/2-$camera_y)
        
        predicted_vel_x = Gosu.offset_x(dir, 40)
        predicted_vel_y = Gosu.offset_y(dir, 40)

        case closest_int[5]
        when 0  ### Top left
          predicted_response_x = closest_int[0] + predicted_vel_x
          predicted_response_y = closest_int[1] - predicted_vel_y  ### vel_y gets reversed
        when 1  ### Top right
          predicted_response_x = closest_int[0] + predicted_vel_x
          predicted_response_y = closest_int[1] - predicted_vel_y  ### vel_y gets reversed
        when 2  ### Bottom left
          predicted_response_x = closest_int[0] + predicted_vel_x
          predicted_response_y = closest_int[1] - predicted_vel_y  ### vel_y gets reversed
        when 3  ### Bottom right
          predicted_response_x = closest_int[0] + predicted_vel_x
          predicted_response_y = closest_int[1] - predicted_vel_y  ### vel_y gets reversed
        when 4  ### Left
          predicted_response_x = closest_int[0] - predicted_vel_x  ### vel_x gets reversed
          predicted_response_y = closest_int[1] + predicted_vel_y
        when 5  ### Right
          predicted_response_x = closest_int[0] - predicted_vel_x  ### vel_x gets reversed
          predicted_response_y = closest_int[1] + predicted_vel_y
        end

        @window.draw_line(
          closest_int[0]+$window_width/2-$camera_x, closest_int[1]+$window_height/2-$camera_y, 0xffffffff, predicted_response_x+$window_width/2-$camera_x, predicted_response_y+$window_height/2-$camera_y, 0xffffffff, 3
        )
        
      end
    else
      ## White line showing the path
      @window.draw_line(@x+$window_width/2-$camera_x, @y+$window_height/2-$camera_y, 0xffffffff, @x+$window_width/2-$camera_x+Gosu.offset_x(dir, 900), @y+$window_height/2-$camera_y+Gosu.offset_y(dir, 900), 0xffffffff, 2)
    end
  end
end

#get_kin ⇒ Object

#

get_kin

#


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# File 'lib/games_paradise/gui/gosu/billiard/ball.rb', line 425

def get_kin
  return (@mass * (@vel_x ** 2 + @vel_y ** 2))
end

#id? ⇒ Boolean Also known as: id

#

id?

#

Returns:

  • (Boolean) 


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# File 'lib/games_paradise/gui/gosu/billiard/ball.rb', line 511

def id?
  @id
end

#in_hole ⇒ Object

#

in_hole

#


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# File 'lib/games_paradise/gui/gosu/billiard/ball.rb', line 453

def in_hole
  if is_this_the_cue_ball?
    # ===================================================================== #
    # This is the case when the white ball hits one of the holes.
    # ===================================================================== #
    @x = $universe_width/2
    @y = -100
    @vel_x = 0.0
    @vel_y = 0.0
    @out = true
  else
    # ===================================================================== #
    # Else one of the main balls is kicked into a hole by the white
    # cue ball. In this case we will play a cheering-crowd sound.
    # ===================================================================== #
    do_play_the_cheer_sound
    @x = 10 + @window.balls_in_hole*22.5
    @y = -100
    @vel_x = 0.0
    @vel_y = 0.0
    @out = true
    @window.ball_in_hole
  end
end

#is_this_the_cue_ball? ⇒ Boolean

#

is_this_the_cue_ball?

#

Returns:

  • (Boolean) 


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# File 'lib/games_paradise/gui/gosu/billiard/ball.rb', line 593

def is_this_the_cue_ball?
  @color == COLOUR_FOR_THE_CUE_BALL
end

#mass? ⇒ Boolean Also known as: mass

#

mass?

#

Returns:

  • (Boolean) 


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# File 'lib/games_paradise/gui/gosu/billiard/ball.rb', line 504

def mass?
  @mass
end

#move ⇒ Object

#

move

This method is the one that will move the cue ball on the game map.

#


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# File 'lib/games_paradise/gui/gosu/billiard/ball.rb', line 609

def move
  @x += @vel_x
  @y += @vel_y
  # Check collision with walls
  # Wall to the right
  if @x > ($universe_width-@radius) and @vel_x > 0 and 26 < @y and @y < $universe_height-26
    @vel_x = -@vel_x
  end

  # ======================================================================= #
  # Wall to the left
  # ======================================================================= #
  if @x < @radius and @vel_x < 0 and 26 < @y and @y < $universe_height-26
    @vel_x = -@vel_x
  end

  # ======================================================================= #
  # Wall at the bottom
  # ======================================================================= #
  if @y > ($universe_height-@radius) and @vel_y > 0
    if (26 < @x and @x < $universe_width/2-22) or ($universe_width/2+22 < @x and @x < $universe_width-26)
      @vel_y = -@vel_y
    end
  end
  
  # ======================================================================= #
  # Wall at the top
  # ======================================================================= #
  if @y < @radius and @vel_y < 0
    if (26 < @x and @x < $universe_width/2-22) or ($universe_width/2+22 < @x and @x < $universe_width-26)
      @vel_y = -@vel_y
    end
  end

  # ======================================================================= #
  # Check collision with lines
  # ======================================================================= #
  for i in 0..$lines_array.length-1
    check_collision_line($lines_array[i][0], $lines_array[i][1], $lines_array[i][2], $lines_array[i][3])
  end
  
  # ======================================================================= #
  # Check collision with corners
  # ======================================================================= #
  for i in 0..$pocket_coords.length-1
    check_collision_point($pocket_coords[i][0], $pocket_coords[i][1])
  end
  
  # ======================================================================= #
  # Check collision with pockets
  # ======================================================================= #
  for i in 0..$pocket_holes.length-1
    check_collision_pocket($pocket_holes[i][0], $pocket_holes[i][1])
  end

  # ======================================================================= #
  # Resistance
  # ======================================================================= #
  if (@vel_x**2+@vel_y**2) > 0.5**2
    @vel_x = @vel_x * @resistance
    @vel_y = @vel_y * @resistance
  else
    @vel_x = @vel_x * @resistance_strong
    @vel_y = @vel_y * @resistance_strong
  end
end

#new_velocity(m1, m2, v1, v2, c1, c2) ⇒ Object

#

new_velocity

#


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# File 'lib/games_paradise/gui/gosu/billiard/ball.rb', line 391

def new_velocity(m1, m2, v1, v2, c1, c2)

  f = (2*m2)/(m1+m2) # Number  --- f = 1  when both masses are the same

  dv = v1 - v2 # Vector
  dc = c1 - c2 # Vector

  v_new = v1 - f * (dv.inner_product(dc))/(dc.inner_product(dc)) * dc # Vector

  if dv.inner_product(dc) > 0  ### If the balls are NOT moving towards each other
    return v1     # Vector
  else
    return v_new  # Vector
  end
  
end

#point_direction(x1, y1, x2, y2) ⇒ Object

#

point_direction

#


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# File 'lib/games_paradise/gui/gosu/billiard/ball.rb', line 432

def point_direction(x1, y1, x2, y2)
  return ((Math.atan2(y2-y1, x2-x1) * (180/Math::PI)) + 450) % 360
end

#radius? ⇒ Boolean Also known as: radius

#

radius?

#

Returns:

  • (Boolean) 


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# File 'lib/games_paradise/gui/gosu/billiard/ball.rb', line 497

def radius?
  @radius
end

#release ⇒ Object

#

release

#


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# File 'lib/games_paradise/gui/gosu/billiard/ball.rb', line 257

def release
  if @pulled
    ## Direction from ball to mouse
    dir = point_direction(@x+$window_width/2-$camera_x, @y+$window_height/2-$camera_y, @window.mouse_x, @window.mouse_y)

    ## If the distance from mouse to ball is less than 300 pixels
    if Gosu.distance(@x+$window_width/2-$camera_x, @y+$window_height/2-$camera_y, @window.mouse_x, @window.mouse_y) < 300
      ## The distance from ball to mouse is proportional to the force
      @vel_x += -(@window.mouse_x-$window_width/2+$camera_x - @x) * @release_force
      @vel_y += -(@window.mouse_y-$window_height/2+$camera_y - @y) * @release_force
    else
      ## The ball gets pushed by a force asif the mouse was 300 pixels away.
      @vel_x += -(Gosu.offset_x(dir, 300)) * @release_force
      @vel_y += -(Gosu.offset_y(dir, 300)) * @release_force         
    end

    @pulled = false
  end
end

#reset ⇒ Object

#

reset (reset tag)

#


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# File 'lib/games_paradise/gui/gosu/billiard/ball.rb', line 77

def reset
  # ======================================================================= #
  # === @the_cue_ball_was_hit_n_times
  #
  # How many times the cue ball was hit via the stick.
  # ======================================================================= #
  @the_cue_ball_was_hit_n_times = 0
  # ======================================================================= #
  # === @pulled
  # ======================================================================= #
  @pulled = false
  # ======================================================================= #
  # === @being_replaced
  # ======================================================================= #
  @being_replaced = false
  # ======================================================================= #
  # === @colliding
  # ======================================================================= #
  @colliding = false
  # ======================================================================= #
  # === @collision_point
  #
  # True if you should draw the collision point.
  # ======================================================================= #
  @collision_point = false
  # ======================================================================= #
  # === @resistance
  # ======================================================================= #
  @resistance = Math.sqrt(0.995)
  # ======================================================================= #
  # === @resistance_strong
  # ======================================================================= #
  @resistance_strong = Math.sqrt(0.96)
end

#update ⇒ Object

#

update

#


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# File 'lib/games_paradise/gui/gosu/billiard/ball.rb', line 115

def update
  @colliding = false
  @collision_point = false

  if @being_replaced
    @x = @window.mouse_x-$window_width/2+$camera_x
    @y = @window.mouse_y-$window_height/2+$camera_y

    @placement_collision = false
    check_placement_collision
  else
    move # Call the move() method here.
  end

  # Direction from mouse to cue ball
  dir = point_direction(
    @window.mouse_x,
    @window.mouse_y,
    @x+$window_width/2-$camera_x,
    @y+$window_height/2-$camera_y
  )

  if @pulled and @color == COLOUR_FOR_THE_CUE_BALL
    @window.check_path_collision(
      @x,
      @y,
      @x+::Gosu.offset_x(dir, 900),
      @y+::Gosu.offset_y(dir, 900)
    )
    # p $path_blockers
  end
end

#vel_x? ⇒ Boolean Also known as: vel_x

#

vel_x?

#

Returns:

  • (Boolean) 


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# File 'lib/games_paradise/gui/gosu/billiard/ball.rb', line 679

def vel_x?
  @vel_x
end

#vel_y? ⇒ Boolean Also known as: vel_y

#

vel_y?

#

Returns:

  • (Boolean) 


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# File 'lib/games_paradise/gui/gosu/billiard/ball.rb', line 600

def vel_y?
  @vel_y
end

#x? ⇒ Boolean Also known as: x

#

x?

#

Returns:

  • (Boolean) 


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# File 'lib/games_paradise/gui/gosu/billiard/ball.rb', line 446

def x?
  @x
end

#y? ⇒ Boolean Also known as: y

#

y?

#

Returns:

  • (Boolean) 


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# File 'lib/games_paradise/gui/gosu/billiard/ball.rb', line 490

def y?
  @y
end