Category:Gamevar manipulation

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Revision as of 08:25, 8 February 2020 by Doom64hunter (talk | contribs) (→‎Gamevar Flags: Updated gamevar flag list to current information taken from source code definitions and comments. It seems to be possible to assign, for instance, the read-only flag to user-defined gamevars, so contrary to what the page stated, flags > 2 can be assigned in CON)
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Definition

gamevar <varname> <value> <flags>

var <varname> <value> <flags>

A gamevar is a variable that can be used to store numerical data which can then be referenced between actors, states and events. var is hereby semantically equivalent to gamevar.

The gamevar's flags define a bitmap that determines how the variable is treated by the game. For instance, a gamevar with flags of 0 is known as a global variable. A global variable exists once in the code, and any time a global variable is set, the new value is seen by all actors and events. A gamevar with flag bit 1 set is a per-player variable, which exists once for each player in the game. A gamevar with flag bit 2 set is a per-actor variable, which exists as many times in the code as there are sprites in the map. This means that each sprite has its own copy of a per-actor variable stored in memory. Note that a gamevar can only be defined as either global, per-player, or per-actor, but not as a combination thereof.

Gamevars are stored as signed 32-bit integers and therefore have a value range of -2.147.483.648 (-231) to 2.147.483.647 (231-1). Going above and below this range causes the value to overflow and underflow respectively.

Note that it is possible to omit the <value> and <flags> parameters entirely to define a global variable with an initial value of 0, with no other flags set. Example:

var TEMP1

It is also possible to chain flags separately at the end of the gamevar definition, instead of compiling them into a single value, as follows:

var TEMP2 10 1 4096    // This defines a per-player (1), read-only (4096) variable with initial value 10.

The following pages contain information on basic gamevar operations as well as conditional statements:

Gamevar Flags

The following table shows all currently defined gamevar flags. The first 3 are the only ones needed under normal circumstances, but one can also assign higher flags to user-defined gamevars (given that you know what you are doing).

Name Number Hex Description Page where such variables should be listed
GAMEVAR_GLOBAL 0 0x000000 global variable; this is the default
GAMEVAR_PERPLAYER 1 0x000001 per-player variable
GAMEVAR_PERACTOR 2 0x000002 per-actor variable
GAMEVAR_RESET 8 0x000008 Internal, don't use.
GAMEVAR_DEFAULT 256 0x000100 unused, but always cleared for user-defined gamevars
GAMEVAR_NODEFAULT 1024 0x000400 Don't reset on actor spawn
GAMEVAR_SYSTEM 2048 0x000800 cannot change mode flags...(only default value)
GAMEVAR_READONLY 4096 0x001000 values are read-only (no setvar allowed)
GAMEVAR_INT32PTR 8192 0x002000 plValue is a pointer to an int32_t Constantly updated gamevars
GAMEVAR_FLOATPTR 16384 0x004000 plValue is a pointer to a float Constantly updated gamevars
GAMEVAR_INT16PTR 32768 0x008000 plValue is a pointer to a short (int16_t) Constantly updated gamevars
GAMEVAR_CHARPTR 65536 0x010000 plValue is a pointer to a char Constantly updated gamevars
GAMEVAR_NORESET 131072 0x020000 var values are not reset when restoring map state
GAMEVAR_SPECIAL 262144 0x040000 flag for structure member shortcut vars
GAMEVAR_NOMULTI 524288 0x080000 don't attach to multiplayer packets
GAMEVAR_Q16PTR 1048576 0x100000 plValues is a pointer to a q16.16
GAMEVAR_SERIALIZE 2097152 0x200000 write into permasaves