140 lines
4.6 KiB
C++
140 lines
4.6 KiB
C++
/*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*/
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#include "simulation_solver.hh"
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#include "BKE_customdata.h"
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#include "BLI_rand.hh"
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namespace blender::sim {
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ParticleForce::~ParticleForce()
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{
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}
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class CustomDataAttributesRef {
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private:
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Vector<void *> buffers_;
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uint size_;
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std::unique_ptr<fn::AttributesInfo> info_;
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public:
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CustomDataAttributesRef(CustomData &custom_data, uint size)
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{
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fn::AttributesInfoBuilder builder;
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for (const CustomDataLayer &layer : Span(custom_data.layers, custom_data.totlayer)) {
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buffers_.append(layer.data);
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switch (layer.type) {
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case CD_PROP_INT32: {
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builder.add<int32_t>(layer.name, 0);
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break;
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}
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case CD_PROP_FLOAT3: {
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builder.add<float3>(layer.name, {0, 0, 0});
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break;
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}
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}
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}
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info_ = std::make_unique<fn::AttributesInfo>(builder);
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size_ = size;
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}
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operator fn::MutableAttributesRef()
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{
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return fn::MutableAttributesRef(*info_, buffers_, size_);
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}
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operator fn::AttributesRef() const
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{
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return fn::AttributesRef(*info_, buffers_, size_);
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}
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};
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static void ensure_attributes_exist(ParticleSimulationState *state)
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{
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if (CustomData_get_layer_named(&state->attributes, CD_PROP_FLOAT3, "Position") == nullptr) {
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CustomData_add_layer_named(
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&state->attributes, CD_PROP_FLOAT3, CD_CALLOC, nullptr, state->tot_particles, "Position");
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}
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if (CustomData_get_layer_named(&state->attributes, CD_PROP_FLOAT3, "Velocity") == nullptr) {
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CustomData_add_layer_named(
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&state->attributes, CD_PROP_FLOAT3, CD_CALLOC, nullptr, state->tot_particles, "Velocity");
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}
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if (CustomData_get_layer_named(&state->attributes, CD_PROP_INT32, "ID") == nullptr) {
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CustomData_add_layer_named(
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&state->attributes, CD_PROP_INT32, CD_CALLOC, nullptr, state->tot_particles, "ID");
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}
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}
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void initialize_simulation_states(Simulation &simulation,
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Depsgraph &UNUSED(depsgraph),
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const SimulationInfluences &UNUSED(influences))
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{
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RandomNumberGenerator rng;
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LISTBASE_FOREACH (ParticleSimulationState *, state, &simulation.states) {
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state->tot_particles = 1000;
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CustomData_realloc(&state->attributes, state->tot_particles);
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ensure_attributes_exist(state);
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CustomDataAttributesRef custom_data_attributes{state->attributes, (uint)state->tot_particles};
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fn::MutableAttributesRef attributes = custom_data_attributes;
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MutableSpan<float3> positions = attributes.get<float3>("Position");
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MutableSpan<float3> velocities = attributes.get<float3>("Velocity");
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MutableSpan<int32_t> ids = attributes.get<int32_t>("ID");
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for (uint i : positions.index_range()) {
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positions[i] = {i / 100.0f, 0, 0};
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velocities[i] = {0, rng.get_float() - 0.5f, rng.get_float() - 0.5f};
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ids[i] = i;
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}
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}
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}
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void solve_simulation_time_step(Simulation &simulation,
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Depsgraph &UNUSED(depsgraph),
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const SimulationInfluences &influences,
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float time_step)
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{
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LISTBASE_FOREACH (ParticleSimulationState *, state, &simulation.states) {
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ensure_attributes_exist(state);
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CustomDataAttributesRef custom_data_attributes{state->attributes, (uint)state->tot_particles};
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fn::MutableAttributesRef attributes = custom_data_attributes;
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MutableSpan<float3> positions = attributes.get<float3>("Position");
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MutableSpan<float3> velocities = attributes.get<float3>("Velocity");
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Array<float3> force_vectors{(uint)state->tot_particles, {0, 0, 0}};
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const Vector<const ParticleForce *> *forces = influences.particle_forces.lookup_ptr(
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state->head.name);
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if (forces != nullptr) {
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for (const ParticleForce *force : *forces) {
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force->add_force(attributes, force_vectors);
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}
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}
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for (uint i : positions.index_range()) {
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velocities[i] += force_vectors[i] * time_step;
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positions[i] += velocities[i] * time_step;
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}
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}
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}
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} // namespace blender::sim
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