More behavior control for particles:

- ParticleSystemSceneNode does now affect the particle movement direction by default. Can be disabled to get old behavior.
- Allow interpolating postions which is useful when particles are attached to fast-moving nodes (to avoid regular patterns).
- Invisible behavior flags from check-in yesterday re-implemented with new general behavior flags.


git-svn-id: svn://svn.code.sf.net/p/irrlicht/code/trunk@4770 dfc29bdd-3216-0410-991c-e03cc46cb475

changes.txt

 --------------------------
 Changes in 1.9 (not yet released)
 
-- Allow more control over particle behavior when the ParticleSystemSceneNode is invisible.
+- Allow more control over particle behavior. This also changed the default behavior.
 - ISceneNodeAnimators can now be disabled and paused.
 - Maya camera no longer get's stuck in "rotating" state when a mouse-up event is lost (thx @ JLouisB for reporting).
 - Focus behavior of IGUIEnvironment now controllable (right-click focus, mouse-over focus). Disabled elements no longer get the focus unless users enforce it.

include/IParticleSystemSceneNode.h

@@ -43,17 +43,29 @@ You can for example easily create a campfire by doing this:
 \endcode
 */
 
-//! Bitflags to control particle behavior when the IParticleSystemSceneNode is invisible
-enum EParticleInvisible
+//! Bitflags to control particle behavior
+enum EParticleBehavior
 {
-	//! Stop emitting new particles when invisible
-	EPI_STOP_EMITTERS = 1,
-	//! No longer affect particles when invisible
-	EPI_STOP_AFFECTORS = 2,
-	//! Stop updating particle positions or deleting them when invisible
-	EPI_STOP_ANIMATING = 4,
+	//! Continue emitting new particles even when the node is invisible
+	EPB_INVISIBLE_EMITTING = 1,
+
+	//! Continue affecting particles even when the node is invisible
+	EPB_INVISIBLE_AFFECTING = 2,
+
+	//! Continue updating particle positions or deleting them even when the node is invisible
+	EPB_INVISIBLE_ANIMATING = 4,
+
 	//! Clear all particles when node gets invisible
-	EPI_CLEAR_ON_INVISIBLE = 8
+	EPB_CLEAR_ON_INVISIBLE = 8,
+
+	//! Particle movement direction on emitting ignores the node rotation
+	//! This is mainly to allow backward compatible behavior to Irrlicht 1.8
+	EPB_EMITTER_VECTOR_IGNORE_ROTATION = 16,
+
+	//! On emitting global particles interpolate the positions randomly between the last and current node transformations.
+	//! This can be set to avoid gaps caused by fast node movement or low framerates, but will be somewhat
+	//! slower to calculate.
+	EPB_EMITTER_FRAME_INTERPOLATION = 32
 };
 
 class IParticleSystemSceneNode : public ISceneNode
@@ -66,7 +78,7 @@ public:
 		const core::vector3df& rotation = core::vector3df(0,0,0),
 		const core::vector3df& scale = core::vector3df(1.0f, 1.0f, 1.0f))
 			: ISceneNode(parent, mgr, id, position, rotation, scale)
-			, ParticleInvisibleBehavior(EPI_STOP_EMITTERS|EPI_STOP_AFFECTORS|EPI_STOP_ANIMATING|EPI_CLEAR_ON_INVISIBLE)
+			, ParticleBehavior(0)
 	{
 	}
 
@@ -80,22 +92,22 @@ public:
 	Default is true. */
 	virtual void setParticlesAreGlobal(bool global=true) = 0;
 
-	//! Sets how particles behave when this node is invisible
-	/** Default is: EPIB_STOP_EMITTERS|EPIB_STOP_AFFECTORS|EPIB_STOP_ANIMATING|EPI_CLEAR_ON_INVISIBLE
-	\param flags Any combination of ::EParticleInvisibleBehavior flags
-	*/
-	virtual void setInvisibleBehavior(irr::u32 flags)
+
+	//! Bitflags to change the particle behavior
+	/**
+	\param flags A combination of ::EParticleBehavior bit-flags. Default is 0.	*/
+	virtual void setParticleBehavior(irr::u32 flags)
 	{
-		ParticleInvisibleBehavior = flags;
+		ParticleBehavior = flags;
 	}
 
-	//! Gets how particles behave when this node is invisible
+
+	//! Gets how particles behave in different situations
 	/**
-	\return A combination of ::EParticleInvisibleBehavior flags
-	*/
-	virtual irr::u32 getInvisibleBehavior() const
+	\return A combination of ::EParticleBehavior flags */
+	virtual irr::u32 getParticleBehavior() const
 	{
-		return ParticleInvisibleBehavior;
+		return ParticleBehavior;
 	}
 
 	//! Remove all currently visible particles
@@ -541,17 +553,17 @@ public:
 	//! Writes attributes of the scene node.
 	virtual void serializeAttributes(io::IAttributes* out, io::SAttributeReadWriteOptions* options) const _IRR_OVERRIDE_
 	{
-		out->addInt("ParticleInvisibleBehavior", ParticleInvisibleBehavior);
+		out->addInt("ParticleBehavior", ParticleBehavior);
 	}
 
 	//! Reads attributes of the scene node.
 	virtual void deserializeAttributes(io::IAttributes* in, io::SAttributeReadWriteOptions* options) _IRR_OVERRIDE_
 	{
-		ParticleInvisibleBehavior = in->getAttributeAsInt("ParticleInvisibleBehavior", ParticleInvisibleBehavior);
+		ParticleBehavior = in->getAttributeAsInt("ParticleBehavior", ParticleBehavior);
 	}
 
 protected:
-	s32 ParticleInvisibleBehavior;
+	s32 ParticleBehavior;
 };
 
 } // end namespace scene

source/Irrlicht/CParticleSystemSceneNode.cpp

@@ -410,6 +410,7 @@ void CParticleSystemSceneNode::doParticleSystem(u32 time)
 	if (LastEmitTime==0)
 	{
 		LastEmitTime = time;
+		LastAbsoluteTransformation = AbsoluteTransformation;
 		return;
 	}
 
@@ -418,10 +419,11 @@ void CParticleSystemSceneNode::doParticleSystem(u32 time)
 	LastEmitTime = time;
 
 
-	int stop = isVisible() ? 0 : getInvisibleBehavior();
+	bool visible = isVisible();
+	int behavior = getParticleBehavior();
 	// run emitter
 
-	if (Emitter && !(stop & EPI_STOP_EMITTERS) )
+	if (Emitter && (visible || behavior & EPB_INVISIBLE_EMITTING) )
 	{
 		SParticle* array = 0;
 		s32 newParticles = Emitter->emitt(now, timediff, array);
@@ -435,15 +437,54 @@ void CParticleSystemSceneNode::doParticleSystem(u32 time)
 			for (s32 i=j; i<j+newParticles; ++i)
 			{
 				Particles[i]=array[i-j];
-				AbsoluteTransformation.rotateVect(Particles[i].startVector);
-				if (ParticlesAreGlobal)
-					AbsoluteTransformation.transformVect(Particles[i].pos);
+
+				if ( ParticlesAreGlobal && behavior & EPB_EMITTER_FRAME_INTERPOLATION )
+				{
+					// Interpolate between current node transformations and last ones.
+					// (Lazy solution - calculating twice and interpolating results)
+					f32 randInterpolate = (f32)(os::Randomizer::rand() % 101) / 100.f;	// 0 to 1
+					core::vector3df posNow(Particles[i].pos);
+					core::vector3df posLast(Particles[i].pos);
+
+					AbsoluteTransformation.transformVect(posNow);
+					LastAbsoluteTransformation.transformVect(posLast);
+					Particles[i].pos = posNow.getInterpolated(posLast, randInterpolate);
+
+					if ( !(behavior & EPB_EMITTER_VECTOR_IGNORE_ROTATION) )
+					{
+						core::vector3df vecNow(Particles[i].startVector);
+						core::vector3df vecOld(Particles[i].startVector);
+						AbsoluteTransformation.rotateVect(vecNow);
+						LastAbsoluteTransformation.rotateVect(vecOld);
+						Particles[i].startVector = vecNow.getInterpolated(vecOld, randInterpolate);
+
+						vecNow = Particles[i].vector;
+						vecOld = Particles[i].vector;
+						AbsoluteTransformation.rotateVect(vecNow);
+						LastAbsoluteTransformation.rotateVect(vecOld);
+						Particles[i].vector = vecNow.getInterpolated(vecOld, randInterpolate);
+					}
+				}
+				else
+				{
+					if (ParticlesAreGlobal)
+						AbsoluteTransformation.transformVect(Particles[i].pos);
+
+					if ( !(behavior & EPB_EMITTER_VECTOR_IGNORE_ROTATION) )
+					{
+						if (!ParticlesAreGlobal)
+							AbsoluteTransformation.rotateVect(Particles[i].pos);
+
+						AbsoluteTransformation.rotateVect(Particles[i].startVector);
+						AbsoluteTransformation.rotateVect(Particles[i].vector);
+					}
+				}
 			}
 		}
 	}
 
 	// run affectors
-	if ( !(stop & EPI_STOP_AFFECTORS) )
+	if ( visible || behavior & EPB_INVISIBLE_AFFECTING )
 	{
 		core::list<IParticleAffector*>::Iterator ait = AffectorList.begin();
 		for (; ait != AffectorList.end(); ++ait)
@@ -456,7 +497,7 @@ void CParticleSystemSceneNode::doParticleSystem(u32 time)
 		Buffer->BoundingBox.reset(core::vector3df(0,0,0));
 
 	// animate all particles
-	if ( !(stop & EPI_STOP_ANIMATING) )
+	if ( visible || behavior & EPB_INVISIBLE_ANIMATING )
 	{
 		f32 scale = (f32)timediff;
 
@@ -495,6 +536,8 @@ void CParticleSystemSceneNode::doParticleSystem(u32 time)
 		core::matrix4 absinv( AbsoluteTransformation, core::matrix4::EM4CONST_INVERSE );
 		absinv.transformBoxEx(Buffer->BoundingBox);
 	}
+
+	LastAbsoluteTransformation = AbsoluteTransformation;
 }
 
 
@@ -516,8 +559,11 @@ void CParticleSystemSceneNode::clearParticles()
 void CParticleSystemSceneNode::setVisible(bool isVisible)
 {
 	IParticleSystemSceneNode::setVisible(isVisible);
-	if ( !isVisible && getInvisibleBehavior() & EPI_CLEAR_ON_INVISIBLE )
+	if ( !isVisible && getParticleBehavior() & EPB_CLEAR_ON_INVISIBLE )
+	{
 		clearParticles();
+		LastEmitTime = 0;
+	}
 }
 
 //! Sets the size of all particles.

source/Irrlicht/CParticleSystemSceneNode.h

@@ -220,6 +220,7 @@ private:
 	core::array<SParticle> Particles;
 	core::dimension2d<f32> ParticleSize;
 	u32 LastEmitTime;
+	core::matrix4 LastAbsoluteTransformation;
 
 	SMeshBuffer* Buffer;