From f268bc13f1e69e150e26871af2ae308615200607 Mon Sep 17 00:00:00 2001
From: Frederic Chardon <chardon.frederic@gmail.com>
Date: Wed, 1 Jul 2020 11:04:18 +0000
Subject: [PATCH] Do not set particle lifetime to 0 (#5472)

---
 CHANGELOG.md                    |  1 +
 components/nifosg/nifloader.cpp | 13 +++++++++----
 components/nifosg/particle.cpp  |  3 ++-
 3 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index ab1b61a7c..633685887 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -29,6 +29,7 @@
     Bug #5441: Enemies can't push a player character when in critical strike stance
     Bug #5451: Magic projectiles don't disappear with the caster
     Bug #5452: Autowalk is being included in savegames
+    Bug #5472: Mistify mod causes CTD in 0.46 on Mac
     Bug #5479: NPCs who should be walking around town are standing around without walking
     Bug #5484: Zero value items shouldn't be able to be bought or sold for 1 gold
     Bug #5485: Intimidate doesn't increase disposition on marginal wins
diff --git a/components/nifosg/nifloader.cpp b/components/nifosg/nifloader.cpp
index 88e89b400..6830e792f 100644
--- a/components/nifosg/nifloader.cpp
+++ b/components/nifosg/nifloader.cpp
@@ -923,15 +923,18 @@ namespace NifOsg
             osg::BoundingBox box;
 
             int i=0;
-            for (std::vector<Nif::NiParticleSystemController::Particle>::const_iterator it = partctrl->particles.begin();
-                 i<particledata->activeCount && it != partctrl->particles.end(); ++it, ++i)
+            for (const auto& particle : partctrl->particles)
             {
-                const Nif::NiParticleSystemController::Particle& particle = *it;
+                if (i++ >= particledata->activeCount)
+                    break;
+
+                if (particle.lifespan <= 0)
+                    continue;
 
                 ParticleAgeSetter particletemplate(std::max(0.f, particle.lifetime));
 
                 osgParticle::Particle* created = partsys->createParticle(&particletemplate);
-                created->setLifeTime(std::max(0.f, particle.lifespan));
+                created->setLifeTime(particle.lifespan);
 
                 // Note this position and velocity is not correct for a particle system with absolute reference frame,
                 // which can not be done in this loader since we are not attached to the scene yet. Will be fixed up post-load in the SceneManager.
@@ -970,6 +973,8 @@ namespace NifOsg
             osgParticle::ConstantRateCounter* counter = new osgParticle::ConstantRateCounter;
             if (partctrl->emitFlags & Nif::NiParticleSystemController::NoAutoAdjust)
                 counter->setNumberOfParticlesPerSecondToCreate(partctrl->emitRate);
+            else if (partctrl->lifetime == 0 && partctrl->lifetimeRandom == 0)
+                counter->setNumberOfParticlesPerSecondToCreate(0);
             else
                 counter->setNumberOfParticlesPerSecondToCreate(partctrl->numParticles / (partctrl->lifetime + partctrl->lifetimeRandom/2));
 
diff --git a/components/nifosg/particle.cpp b/components/nifosg/particle.cpp
index 804a8f8ab..f71dcdd96 100644
--- a/components/nifosg/particle.cpp
+++ b/components/nifosg/particle.cpp
@@ -125,7 +125,7 @@ void ParticleShooter::shoot(osgParticle::Particle *particle) const
     particle->setVelocity(dir * vel);
 
     // Not supposed to set this here, but there doesn't seem to be a better way of doing it
-    particle->setLifeTime(mLifetime + mLifetimeRandom * Misc::Rng::rollClosedProbability());
+    particle->setLifeTime(std::max(std::numeric_limits<float>::epsilon(), mLifetime + mLifetimeRandom * Misc::Rng::rollClosedProbability()));
 }
 
 GrowFadeAffector::GrowFadeAffector(float growTime, float fadeTime)
@@ -184,6 +184,7 @@ ParticleColorAffector::ParticleColorAffector(const ParticleColorAffector &copy,
 
 void ParticleColorAffector::operate(osgParticle::Particle* particle, double /* dt */)
 {
+    assert(particle->getLifeTime() > 0);
     float time = static_cast<float>(particle->getAge()/particle->getLifeTime());
     osg::Vec4f color = mData.interpKey(time);
     float alpha = color.a();