Class: MiniGL::Effect

Inherits:
Sprite
  • Object
show all
Defined in:
lib/minigl/game_object.rb

Overview

Represents a visual effect, i.e., a graphic - usually animated - that shows up in the screen, lasts for a given time and “disappears”. You should explicitly dispose of references to effects whose attribute dead is set to true.

Instance Attribute Summary collapse

Attributes inherited from Sprite

#img_index, #x, #y

Instance Method Summary collapse

Methods inherited from Sprite

#animate, #visible?

Constructor Details

#initialize(x, y, img, sprite_cols = nil, sprite_rows = nil, interval = 10, indices = nil, lifetime = nil, sound = nil, sound_ext = '.wav', sound_volume = 1) ⇒ Effect

Creates a new Effect.

Parameters:

x

The x-coordinate in the screen (or map) where the effect will be drawn. This can be modified later via the x attribute.

y

The y-coordinate in the screen (or map) where the effect will be drawn. This can be modified later via the y attribute.

img

The image or spritesheet to use for this effect (see Sprite for details on spritesheets).

sprite_cols

(see Sprite)

sprite_rows

(see Sprite)

interval

The interval between steps of the animation, in updates.

indices

The indices to use in the animation. See Sprite#animate for details. If nil, it will be the sequence from 0 to sprite_cols * sprite_rows - 1.

lifetime

The lifetime of the effect, in updates. After update is called this number of times, the effect will no longer be visible, even when draw is called, and the dead flag will be set to true, so you get to know when to dispose of the Effect object. If nil, it will be set to @indices.length * interval, i.e., the exact time needed for one animation cycle to complete.

sound

The id of a sound to be played when the effect is created (id must be given in the format specified for the Res.sound method).

sound_ext

Extension of the sound file, if a sound is given. Default is ‘.wav’.

sound_volume

The volume (from 0 to 1) to play the sound, if any. Default is 1.



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# File 'lib/minigl/game_object.rb', line 248

def initialize(x, y, img, sprite_cols = nil, sprite_rows = nil, interval = 10, indices = nil, lifetime = nil,
               sound = nil, sound_ext = '.wav', sound_volume = 1)
  super x, y, img, sprite_cols, sprite_rows
  @timer = 0
  if indices
    @indices = indices
  else
    @indices = *(0..(@img.length - 1))
  end
  @interval = interval
  if lifetime
    @lifetime = lifetime
  else
    @lifetime = @indices.length * interval
  end
  Res.sound(sound, false, sound_ext).play(sound_volume) if sound
end

Instance Attribute Details

#dead ⇒ Object (readonly)

This is true when the effect’s lifetime has already passed.



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# File 'lib/minigl/game_object.rb', line 218

def dead
  @dead
end

Instance Method Details

#draw(map = nil, scale_x = 1, scale_y = 1, alpha = 0xff, color = 0xffffff, angle = nil, z_index = 0) ⇒ Object 



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# File 'lib/minigl/game_object.rb', line 275

def draw(map = nil, scale_x = 1, scale_y = 1, alpha = 0xff, color = 0xffffff, angle = nil, z_index = 0)
  super unless @dead
end

#update ⇒ Object

Updates the effect, animating and counting its remaining lifetime.



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# File 'lib/minigl/game_object.rb', line 267

def update
  unless @dead
    animate @indices, @interval
    @timer += 1
    @dead = true if @timer == @lifetime
  end
end