1 files changed, 118 insertions, 0 deletions
diff --git a/Runtime/Graphics/ParticleSystem/Modules/ExternalForcesModule.cpp b/Runtime/Graphics/ParticleSystem/Modules/ExternalForcesModule.cpp
new file mode 100644
index 0000000..0b86e79
--- /dev/null
+++ b/Runtime/Graphics/ParticleSystem/Modules/ExternalForcesModule.cpp
@@ -0,0 +1,118 @@
+#include "UnityPrefix.h"
+#include "ExternalForcesModule.h"
+#include "Runtime/BaseClasses/ObjectDefines.h"
+#include "Runtime/Serialize/TransferFunctions/SerializeTransfer.h"
+#include "../ParticleSystemUtils.h"
+#include "Runtime/Graphics/Transform.h"
+#include "Runtime/Geometry/Intersection.h"
+#include "Runtime/Geometry/Sphere.h"
+#include "Runtime/Terrain/Wind.h"
+#include "Runtime/Input/TimeManager.h"
+
+
+void ApplyRadialForce(ParticleSystemParticles& ps, const size_t fromIndex, const size_t toIndex, const Vector3f position, const float radius, const float force, const float dt)
+{
+	for(int q = fromIndex; q < toIndex; q++)
+	{
+		Vector3f toForce = position - ps.position[q];
+		float distanceToForce = Magnitude(toForce);
+		toForce = NormalizeSafe(toForce);
+		float forceFactor = clamp(distanceToForce/radius, 0.0f, 1.0f);
+		forceFactor = 1.0f - forceFactor * forceFactor;
+		Vector3f delta = toForce * force * forceFactor * dt;
+		ps.velocity[q] += delta;
+	}
+}
+
+void ApplyDirectionalForce(ParticleSystemParticles& ps, const size_t fromIndex, const size_t toIndex, const Vector3f position, const Vector3f direction, const float radius, const float force, const float dt)
+{
+	for(int q = fromIndex; q < toIndex; q++)
+	{
+		Vector3f delta = direction * force * dt;
+		ps.velocity[q] += delta;
+	}
+}
+
+ExternalForcesModule::ExternalForcesModule () : ParticleSystemModule(false)
+,	m_Multiplier (1.0f)
+{
+}
+
+void ExternalForcesModule::Update (const ParticleSystemReadOnlyState& roState, const ParticleSystemState& state, ParticleSystemParticles& ps, const size_t fromIndex, const size_t toIndex, float dt)
+{
+	Matrix4x4f matrix = Matrix4x4f::identity;
+	if(roState.useLocalSpace)
+		Matrix4x4f::Invert_General3D(state.localToWorld, matrix);
+
+	AABB aabb = state.minMaxAABB;
+	for(int i = 0; i < state.numCachedForces; i++)
+	{
+		const ParticleSystemExternalCachedForce& cachedForce = state.cachedForces[i];
+		const Vector3f position = matrix.MultiplyPoint3(cachedForce.position);
+		const Vector3f direction = matrix.MultiplyVector3(cachedForce.direction);
+		const float radius = cachedForce.radius;
+		const float force = cachedForce.forceMain * m_Multiplier;
+
+		const WindZone::WindZoneMode forceType = (WindZone::WindZoneMode)cachedForce.forceType;
+		if(WindZone::Spherical == forceType)
+		{
+			Sphere sphere (position, radius);
+			if(!IntersectAABBSphere (aabb, sphere))
+				continue;
+			ApplyRadialForce(ps, fromIndex, toIndex, position, radius, force, dt);
+		}
+		else if(WindZone::Directional == forceType)
+			ApplyDirectionalForce(ps, fromIndex, toIndex, position, direction, radius, force, dt);
+	}
+}
+
+// TODO: Perform culling here, instead of caching all of them
+void ExternalForcesModule::AllocateAndCache(const ParticleSystemReadOnlyState& roState, ParticleSystemState& state)
+{
+	float time = GetTimeManager ().GetTimeSinceLevelLoad ();
+	WindManager::WindZoneList& windZones = WindManager::GetInstance().GetList();
+
+	state.numCachedForces = 0;
+	for (WindManager::WindZoneList::iterator it = windZones.begin (); it != windZones.end (); ++it)
+		state.numCachedForces++;
+
+	// Allocate
+	state.cachedForces = ALLOC_TEMP_MANUAL(ParticleSystemExternalCachedForce, state.numCachedForces);
+
+	// Cache
+	int i = 0;
+	for (WindManager::WindZoneList::iterator it = windZones.begin (); it != windZones.end (); ++it)
+	{
+		const WindZone& zone = **it;
+		ParticleSystemExternalCachedForce& cachedForce = state.cachedForces[i++];
+		cachedForce.position = zone.GetComponent (Transform).GetPosition();
+		cachedForce.direction = zone.GetComponent (Transform).GetLocalToWorldMatrix().GetAxisZ();
+		cachedForce.forceType = zone.GetMode();
+		cachedForce.radius = zone.GetRadius();
+
+		float phase = time * kPI * zone.GetWindPulseFrequency();
+		float pulse = (cos (phase) + cos (phase * 0.375f) + cos (phase * 0.05f)) * 0.333f;
+		pulse = 1.0f + (pulse * zone.GetWindPulseMagnitude());
+		cachedForce.forceMain = zone.GetWindMain() * pulse;
+		// Maybe implement using turbulence and time based phasing?
+		// ForceTurbulenceMultiply (maybe) // @TODO: Figure out what to do about turbulence. Do perlin field? Expensive but maybe cool! If use it: only do it when turbulence force is set to something
+
+		//cachedForce.force = 1.0f;
+	}
+}
+
+void ExternalForcesModule::FreeCache(ParticleSystemState& state)
+{
+	if(state.cachedForces)
+		FREE_TEMP_MANUAL(state.cachedForces);
+	state.cachedForces = NULL;
+	state.numCachedForces = 0;
+}
+
+template<class TransferFunction>
+void ExternalForcesModule::Transfer (TransferFunction& transfer)
+{
+	ParticleSystemModule::Transfer (transfer);
+	transfer.Transfer (m_Multiplier, "multiplier");
+}
+INSTANTIATE_TEMPLATE_TRANSFER(ExternalForcesModule)