Constant

Constants refer to "variables" that are
accessible everywhere, but whose value cannot change. That is, all
constants are read-only. Because of this, a constant isn't technically a
variable, but it is included with them for completeness and
categorization.

Below is a complete list of constants or pages with lists of constants.

• pi and M_PI = 3.14...; The mathematical pi
  constant represents the ratio of the circumference of a circle to
  its diameter, and is used in many trigonometric calculations. The
  M_PI constant is specific to ENIGMA.

• Boolean constants true (1) and false
  (0) which indicate that a condition is met
  or not, respectively.

• Color constants can be used wherever a color is
  needed, such as arguments to drawing and blending functions. All
  color constants are prefixed with c_, for example c_blue.

• DLL constants dll_stdcall and dll_cdecl define the type of
  dll cleanup method, while ty_real and ty_string define the
  data types.

• File constants and Font
  Alignment constants start with fa_, for example fa_hidden,
  fa_center.

• Event constants start with ev_, for example
  ev_alarm.

• Particle constants start with ef_, pt_, and
  ps_.
  • Effect constants start with ef_, for
    example ef_cloud.
  • Particle type constants start with
    pt_, and in fact they also all start with pt_shape_, for
    example pt_shape_circle.
  • Particle system constants cover a
    variety of constants used in various functions. They all start
    with ps_, for example ps_distr_linear.

• Render state constants used with d3d
  render mode/state functions

• Keyboard

• Textures

• Audio for the audio system

• Device

• Physics for the
  world of Box2D

• Networking

• Shader

Special object-placeholder constants:

• self = -1; Represents this object. Useful for
  referring to the original object while inside a
  with construct.
• other = -2; Represents the other object in a
  collision event.
• all = -3; Represents all objects. Can be used in a
  with construct to execute code on all active
  instances in the room. Can also be used in
  many functions in place of an object argument.
• noone = -4; Represents a null
  object, or that no object or instance is stored.
• global = -5; Used with dot
  access to globally access a variable. Also
  used as a keyword to define such variables so that dot access is not
  needed.
• local = -7; Used to allow otherwise
  scoped variables to continue to exist throughout
  other events of an instance. Otherwise, it is
  used in Game Maker with dot access to refer to variables local to
  the current scope (declared with var).

Deprecated constants (see individual pages
for deprecation information and replacements):

• Sound effect constants used with
  sounds start with se_, for example se_reverb.