Particles: new Age Reached Event, Kill Particle and Random Float node

The hardcoded age limit is now gone. The behavior can be implemented
with an Age Reached Event and Kill Particle node. Other utility nodes
to handle age limits of particles can be added later. Adding an
Age Limit attribute to particles on birth will be useful for some effects,
e.g. when you want to control the color or size of a particle over its
life time.

The Random Float node takes a seed currently. Different nodes will
produce different values even with the same seed. However, the same
node will generate the same random number for the same seed every
time. The "Hash" of a particle can be used as seed. Later, we'd want
to have more modes in the node to make it more user friendly.
Modes could be: Per Particle, Per Time, Per Particle Per Time,
Per Node Instance, ...
Also a Random Vector node will be useful, as it currently has to be
build using three Random Float nodes.

1 files changed, 10 insertions, 0 deletions

diff --git a/source/blender/simulation/intern/particle_mesh_emitter.cc b/source/blender/simulation/intern/particle_mesh_emitter.cc
index c1482a29cb7..26541d550eb 100644
--- a/source/blender/simulation/intern/particle_mesh_emitter.cc
+++ b/source/blender/simulation/intern/particle_mesh_emitter.cc
@@ -346,6 +346,16 @@ void ParticleMeshEmitter::emit(ParticleEmitterContext &context) const
     attributes.get<float3>("Position").copy_from(new_positions);
     attributes.get<float3>("Velocity").copy_from(new_velocities);
     attributes.get<float>("Birth Time").copy_from(new_birth_times);
+
+    if (action_ != nullptr) {
+      ParticleChunkContext particles{
+          *context.solve_context.state_map.lookup<ParticleSimulationState>(name),
+          IndexRange(amount),
+          attributes,
+          nullptr};
+      ParticleActionContext action_context{context.solve_context, particles};
+      action_->execute(action_context);
+    }
   }
 }