Button constants (AMX Mod X)

Usage

Button constants are generally used to determine when an entity is doing a certain action, such as jumping, attacking, or moving. This is used because +/- commands cannot be hooked by the HL engine (if they are made by the HL engine).

For example, this would work:

register_concmd("+explode","explode");

However this would not:

register_concmd("+attack","hook_attack");

Constants

A full list of constants can be found here: http://amxmodx.org/funcwiki.php?go=module&id=3#const_buttons

Implementation

If, for example, it is desired to check when a player is attacking, one would use the following:

#include <amxmodx>
#include <engine>

public plugin_init()
{
	register_plugin("Attack Test","1.0","Hawk552");
}

public client_PreThink(id)
{
	if(entity_get_int(id,EV_INT_BUTTON) & IN_ATTACK)
	{
		// do something
	}
}

Notice how this uses the & operator, rather than the && operator. This is because a bit value is returned, and the & operator checks if a bit value is contained in another bit value.

To set an entity's button, the same type of idea can be implemented:

#include <amxmodx>
#include <engine>

public plugin_init()
{
	register_plugin("Attack Test","1.0","Hawk552");
}

public client_PreThink(id)
{
	entity_set_int(id,EV_INT_button,IN_ATTACK);
}

This sets the client's attack flag to on every time a frame is rendered.

To get an entity's buttons, and then ommit a certain button, one would use the following:

#include <amxmodx>
#include <engine>

public plugin_init()
{
	register_plugin("Attack Test","1.0","Hawk552");
}

public client_PreThink(id)
{
	entity_set_int(id,EV_INT_button,entity_get_int(id,EV_INT_button) & ~IN_ATTACK);
}

Say, for example, during a certain time, the client is jumping and attacking at the same time. In this case, the entity_get_int(id,EV_INT_button) function would return IN_ATTACK and IN_JUMP. Using the ~ operator removes the certain bit value, making it into merely IN_JUMP.

There are many more ways to use button constants, and not all must be used on players. They are simply more commonly implemented when dealing with players.