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Particles: simulate partial time steps on newly emitted particles

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This commit is contained in:
Jacques Lucke
2020-07-23 23:03:19 +02:00
parent f359672c35
commit 0b50ea51cc
2 changed files with 59 additions and 28 deletions
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77
source/blender/simulation/intern/simulation_solver.cc
View File

@@ -129,6 +129,41 @@ static void ensure_attributes_exist(ParticleSimulationState *state, const fn::At
}
}
BLI_NOINLINE static void simulate_particle_chunk(SimulationSolveContext &solve_context,
ParticleSimulationState &state,
fn::MutableAttributesRef attributes,
MutableSpan<float> remaining_durations,
float end_time)
{
int particle_amount = attributes.size();
Array<float3> force_vectors{particle_amount, {0, 0, 0}};
Span<const ParticleForce *> forces = solve_context.influences().get_particle_forces(
state.head.name);
ParticleChunkContext particle_chunk_context{IndexMask(particle_amount), attributes};
ParticleForceContext particle_force_context{
solve_context, particle_chunk_context, force_vectors};
for (const ParticleForce *force : forces) {
force->add_force(particle_force_context);
}
MutableSpan<float3> positions = attributes.get<float3>("Position");
MutableSpan<float3> velocities = attributes.get<float3>("Velocity");
MutableSpan<float> birth_times = attributes.get<float>("Birth Time");
MutableSpan<int> dead_states = attributes.get<int>("Dead");
for (int i : IndexRange(particle_amount)) {
const float time_step = remaining_durations[i];
velocities[i] += force_vectors[i] * time_step;
positions[i] += velocities[i] * time_step;
if (end_time - birth_times[i] > 2) {
dead_states[i] = true;
}
}
}
BLI_NOINLINE static void simulate_existing_particles(SimulationSolveContext &solve_context,
ParticleSimulationState &state,
const fn::AttributesInfo &attributes_info)
@@ -137,34 +172,9 @@ BLI_NOINLINE static void simulate_existing_particles(SimulationSolveContext &sol
state.attributes, state.tot_particles, attributes_info};
fn::MutableAttributesRef attributes = custom_data_attributes;
Array<float3> force_vectors{state.tot_particles, {0, 0, 0}};
const Vector<const ParticleForce *> *forces =
solve_context.influences().particle_forces.lookup_ptr(state.head.name);
if (forces != nullptr) {
ParticleChunkContext particle_chunk_context{IndexMask(state.tot_particles), attributes};
ParticleForceContext particle_force_context{
solve_context, particle_chunk_context, force_vectors};
for (const ParticleForce *force : *forces) {
force->add_force(particle_force_context);
}
}
MutableSpan<float3> positions = attributes.get<float3>("Position");
MutableSpan<float3> velocities = attributes.get<float3>("Velocity");
MutableSpan<float> birth_times = attributes.get<float>("Birth Time");
MutableSpan<int> dead_states = attributes.get<int>("Dead");
float end_time = solve_context.solve_interval().end();
float time_step = solve_context.solve_interval().duration();
for (int i : positions.index_range()) {
velocities[i] += force_vectors[i] * time_step;
positions[i] += velocities[i] * time_step;
if (end_time - birth_times[i] > 2) {
dead_states[i] = true;
}
}
Array<float> remaining_durations(state.tot_particles, solve_context.solve_interval().duration());
simulate_particle_chunk(
solve_context, state, attributes, remaining_durations, solve_context.solve_interval().end());
}
BLI_NOINLINE static void run_emitters(SimulationSolveContext &solve_context,
@@ -301,6 +311,17 @@ void solve_simulation_time_step(Simulation &simulation,
for (ParticleSimulationState *state : particle_simulation_states) {
ParticleAllocator &allocator = *particle_allocators.try_get_allocator(state->head.name);
for (fn::MutableAttributesRef attributes : allocator.get_allocations()) {
Array<float> remaining_durations(attributes.size());
Span<float> birth_times = attributes.get<float>("Birth Time");
const float end_time = solve_context.solve_interval().end();
for (int i : attributes.index_range()) {
remaining_durations[i] = end_time - birth_times[i];
}
simulate_particle_chunk(solve_context, *state, attributes, remaining_durations, end_time);
}
remove_dead_and_add_new_particles(*state, allocator);
}

10
source/blender/simulation/intern/simulation_solver_influences.hh
View File

@@ -48,9 +48,19 @@ class ParticleForce {
};
struct SimulationInfluences {
/* TODO: Use a special type for a map that contains vectors. */
Map<std::string, Vector<const ParticleForce *>> particle_forces;
Map<std::string, fn::AttributesInfoBuilder *> particle_attributes_builder;
Vector<const ParticleEmitter *> particle_emitters;
Span<const ParticleForce *> get_particle_forces(StringRef particle_name) const
{
const Vector<const ParticleForce *> *forces = particle_forces.lookup_ptr(particle_name);
if (forces == nullptr) {
return {};
}
return *forces;
}
};
class SimulationStateMap {