Difference between revisions of "Particles In Code"

Latest revision as of 21:10, 14 April 2011

This page details the management of "Orange Box" particles in C++ code. It does not cover the old, hard-coded particle tech.

Precaching

Particle systems must be precached before they can be used. This can be achieved by listing the PCF file containing them in particles_manifest.txt and utilizing the function PrecacheParticleSystem() in code. As an alternative all particle effects within a PCF can be precached by adding a '!' character as a prefix to the path used in particles_manifest.txt.

Precache via code:

PrecacheParticleSystem( "your_particle_effect_name" );

Precache via script:

particles_manifest
{
	"file"		"!particles/blood_impact.pcf"	// all effects will be precached on map spawn
	"file"		"particles/fire_01.pcf"		// effects contained in this file will have to be precached manually

	[...]
}

Shared

Dispatching

When dispatched from the server, the particle systems will be networked as temporary entities.

#include "particle_parse.h"

// Create at world co-ords
DispatchParticleEffect( "my_particle", vecOrigin, angAngles, pOwnerEntity )

// Create at model attachment
DispatchParticleEffect( "my_particle", ParticleAttachment_t, pOwner, iAttachment, bResetAllParticlesOnEntity )

• See also ParticleAttachment_t, below.
• vecStart, taken by some overloads of DispatchParticleEffect(), defines the location of control point 1. If you don't specify vecStart, the value of vecOrigin is used instead.

Bug: Valve's code for dispatching a particle on a model attachment is broken. Get the fix here.

Destroying

StopParticleEffects( CBaseEntity* )

Stops all effects on the given entity.

Client

Creating

For more control over the effect, a particle system can be created by a new CNewParticleEffect object and managed through the owning entity's ParticleProp() accessor:

#include "particles_new.h"

C_MyEntity::MessWithParticles()
{
	// Create a new system
	CNewParticleEffect* pEffect = ParticleProp()->Create( "my_particles", PATTACH_ABSORIGIN );
	
	// System already exists
	CNewParticleEffect* pEffect = ParticleProp()->FindEffect( "my_particles" );
}

Particles_new.h must also be #included here.

Alternatively, you can hook into particle creation events:

void C_MyEntity::OnNewParticleEffect( const char* pszParticleName, CNewParticleEffect* pNewParticleEffect )
{
	if ( V_strcmp(pszParticleName, "target_effect_name") == 0 )
	{
		// Do something
	}
}

Warning: A dispatch message from the server configures both control point 0 AND 1. The values are applied after OnNewParticleEffect() is called, so don't bother trying to assign either of those CPs from it!

Control points

When dispatching an effect from the server you can define the location of control points 0 (with vecOrigin) and 1 (with vecStart).

On the client, you can configure the location, rotation and parent entity of any CP with these CNewParticleEffect functions:

SetControlPoint( Vector )

Arbitrary set the CP's value.

SetControlPointEntity( CBaseEntity* )

Follow the given entity's origin.

Confirm:Set to NULL to disable following.

SetControlPointOrientation( QAngle )

SetControlPointRightVector()

SetControlPointForwardVector()

SetControlPointUpVector()

Set orientation with a QAngle or a series of Vectors.

Destroying

StopParticleEffects( CBaseEntity* )

Stops all effects on the given entity.

ParticleProp()->StopParticlesInvolving( CBaseEntity* )

Stops all effects with a control point attached to the given entity. To do: Global or only on current entity?

ParticleProp()->StopParticlesNamed( const char* )

Stops all effects with the given system name. To do: Global or only on current entity?

CNewParticleEffect::StopEmission( bool bInfiniteOnly, bool bRemoveAllParticles, bool bWakeOnStop)

Stops the current particle system, without removing it. To do: Meaning of first and third arguments.

ParticleAttachment_t

One of these values is passed when dispatching or creating an effect:

PATTACH_ABSORIGIN

PATTACH_ABSORIGIN_FOLLOW

Spawn at (and optionally follow) the entity's origin.

PATTACH_POINT

PATTACH_POINT_FOLLOW

Spawn at (and optionally follow) an attachment point on the entity's model.

PATTACH_CUSTOMORIGIN

Spawn at a given origin.

PATTACH_WORLDORIGIN

Don't associate with an entity at all. Use with caution - could easily cause memory leaks.