Subclass ParticleSystem to support limit on the number of particles

components/nifosg/nifloader.cpp

@@ -571,7 +571,7 @@ namespace NifOsg
 
     void Loader::handleParticleSystem(const Nif::Node *nifNode, osg::Group *parentNode, int animflags, int particleflags)
     {
-        osg::ref_ptr<osgParticle::ParticleSystem> partsys (new osgParticle::ParticleSystem);
+        osg::ref_ptr<ParticleSystem> partsys (new ParticleSystem);
         partsys->setSortMode(osgParticle::ParticleSystem::SORT_BACK_TO_FRONT);
 
         const Nif::NiAutoNormalParticlesData *particledata = NULL;
@@ -630,6 +630,8 @@ namespace NifOsg
             created->setSizeRange(osgParticle::rangef(size, size));
         }
 
+        partsys->setQuota(partctrl->numParticles);
+
         partsys->getDefaultParticleTemplate().setSizeRange(osgParticle::rangef(partctrl->size, partctrl->size));
         partsys->getDefaultParticleTemplate().setColorRange(osgParticle::rangev4(osg::Vec4f(1.f,1.f,1.f,1.f), osg::Vec4f(1.f,1.f,1.f,1.f)));
         partsys->getDefaultParticleTemplate().setAlphaRange(osgParticle::rangef(1.f, 1.f));

components/nifosg/particle.cpp

@@ -1,5 +1,7 @@
 #include "particle.hpp"
 
+#include <limits>
+
 #include <osg/MatrixTransform>
 
 #include <components/nif/controlled.hpp>
@@ -9,6 +11,30 @@
 namespace NifOsg
 {
 
+ParticleSystem::ParticleSystem()
+    : osgParticle::ParticleSystem()
+    , mQuota(std::numeric_limits<int>::max())
+{
+}
+
+ParticleSystem::ParticleSystem(const ParticleSystem &copy, const osg::CopyOp &copyop)
+    : osgParticle::ParticleSystem(copy, copyop)
+    , mQuota(copy.mQuota)
+{
+}
+
+void ParticleSystem::setQuota(int quota)
+{
+    mQuota = quota;
+}
+
+osgParticle::Particle* ParticleSystem::createParticle(const osgParticle::Particle *ptemplate)
+{
+    if (numParticles()-numDeadParticles() < mQuota)
+        return osgParticle::ParticleSystem::createParticle(ptemplate);
+    return NULL;
+}
+
 void InverseWorldMatrix::operator()(osg::Node *node, osg::NodeVisitor *nv)
 {
     if (nv && nv->getVisitorType() == osg::NodeVisitor::UPDATE_VISITOR)

components/nifosg/particle.hpp

@@ -20,6 +20,23 @@ namespace Nif
 namespace NifOsg
 {
 
+    // Subclass ParticleSystem to support a limit on the number of active particles.
+    class ParticleSystem : public osgParticle::ParticleSystem
+    {
+    public:
+        ParticleSystem();
+        ParticleSystem(const ParticleSystem& copy, const osg::CopyOp& copyop);
+
+        META_Object(NifOsg, NifOsg::ParticleSystem)
+
+        virtual osgParticle::Particle* createParticle(const osgParticle::Particle *ptemplate);
+
+        void setQuota(int quota);
+
+    private:
+        int mQuota;
+    };
+
     // HACK: Particle doesn't allow setting the initial age, but we need this for loading the particle system state
     class ParticleAgeSetter : public osgParticle::Particle
     {