Code/EnginePlugins/ParticlePlugin/Behavior/ParticleBehavior_Attract.h - dev - redgpu/ezEngine

Code/EnginePlugins/ParticlePlugin/Behavior/ParticleBehavior_Attract.h

50 строк2 KB

Jan Krassnigg

Added Expression Particle Behavior (#1884)

29 мар 2026, 23:32

29 мар 2026, 23:32071fa9d

#pragma once

#include <ParticlePlugin/Behavior/ParticleBehavior.h>

/// \brief Pulls particles toward a point with distance-based falloff.
///
/// Can modify velocity (physically correct acceleration) or position directly (snapping).
/// MinDistance prevents singularity at the attractor center.
///
/// When \a Target is set to \a Attractors, the behavior queries the spatial system for nearby
/// ezParticleAttractorComponents and applies each one's contribution per particle. The attractor
/// list is refreshed roughly once per second for performance.
class EZ_PARTICLEPLUGIN_DLL ezParticleBehaviorFactory_Attract final : public ezParticleBehaviorFactory
{
  EZ_ADD_DYNAMIC_REFLECTION(ezParticleBehaviorFactory_Attract, ezParticleBehaviorFactory);

public:
  ezParticleBehaviorFactory_Attract();

  virtual const ezRTTI* GetBehaviorType() const override;
  virtual void CopyBehaviorProperties(ezParticleBehavior* pObject, bool bFirstTime) const override;
  virtual void QueryFinalizerDependencies(ezSet<const ezRTTI*>& inout_finalizerDeps) const override;

  virtual void Save(ezStreamWriter& inout_stream) const override;
  virtual void Load(ezStreamReader& inout_stream, const ezParticleEffectDescriptor& ownerEffectDescriptor, const ezParticleSystemDescriptor& ownerSystemDescriptor) override;

  float m_fInfluence = 5.0f;
  bool m_bAffectVelocity = true;

  /// \brief Maximum number of nearby attractors to consider. Higher values are more expensive.
  ezUInt8 m_uiMaxAttractors = 1;
};

class EZ_PARTICLEPLUGIN_DLL ezParticleBehavior_Attract final : public ezParticleBehavior
{
  EZ_ADD_DYNAMIC_REFLECTION(ezParticleBehavior_Attract, ezParticleBehavior);

public:
  float m_fInfluence = 5.0f;
  bool m_bAffectVelocity = true;

  ezUInt8 m_uiMaxAttractors = 1;

protected:
  virtual void CreateRequiredStreams() override;
  virtual void Process(ezUInt64 uiNumElements) override;

  ezProcessingStream* m_pStreamPosition = nullptr;
  ezProcessingStream* m_pStreamVelocity = nullptr;
};