diff options
Diffstat (limited to 'source/blender/simulation/intern/particle_mesh_emitter.cc')
| -rw-r--r-- | source/blender/simulation/intern/particle_mesh_emitter.cc | 362 |
1 files changed, 362 insertions, 0 deletions
diff --git a/source/blender/simulation/intern/particle_mesh_emitter.cc b/source/blender/simulation/intern/particle_mesh_emitter.cc new file mode 100644 index 00000000000..26541d550eb --- /dev/null +++ b/source/blender/simulation/intern/particle_mesh_emitter.cc @@ -0,0 +1,362 @@ +/* + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version 2 + * of the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software Foundation, + * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. + */ + +#include "particle_mesh_emitter.hh" + +#include "BLI_float4x4.hh" +#include "BLI_rand.hh" +#include "BLI_vector_adaptor.hh" + +#include "BKE_mesh_runtime.h" + +#include "DNA_mesh_types.h" +#include "DNA_meshdata_types.h" +#include "DNA_object_types.h" + +namespace blender::sim { + +ParticleMeshEmitter::~ParticleMeshEmitter() = default; + +struct EmitterSettings { + Object *object; + float rate; +}; + +static BLI_NOINLINE void compute_birth_times(float rate, + TimeInterval emit_interval, + ParticleMeshEmitterSimulationState &state, + Vector<float> &r_birth_times) +{ + const float time_between_particles = 1.0f / rate; + int counter = 0; + while (true) { + counter++; + const float time_offset = counter * time_between_particles; + const float birth_time = state.last_birth_time + time_offset; + if (birth_time > emit_interval.stop()) { + break; + } + if (birth_time <= emit_interval.start()) { + continue; + } + r_birth_times.append(birth_time); + } +} + +static BLI_NOINLINE Span<MLoopTri> get_mesh_triangles(Mesh &mesh) +{ + const MLoopTri *triangles = BKE_mesh_runtime_looptri_ensure(&mesh); + int amount = BKE_mesh_runtime_looptri_len(&mesh); + return Span(triangles, amount); +} + +static BLI_NOINLINE void compute_triangle_areas(Mesh &mesh, + Span<MLoopTri> triangles, + MutableSpan<float> r_areas) +{ + assert_same_size(triangles, r_areas); + + for (int i : triangles.index_range()) { + const MLoopTri &tri = triangles[i]; + + const float3 v1 = mesh.mvert[mesh.mloop[tri.tri[0]].v].co; + const float3 v2 = mesh.mvert[mesh.mloop[tri.tri[1]].v].co; + const float3 v3 = mesh.mvert[mesh.mloop[tri.tri[2]].v].co; + + const float area = area_tri_v3(v1, v2, v3); + r_areas[i] = area; + } +} + +static BLI_NOINLINE void compute_triangle_weights(Mesh &mesh, + Span<MLoopTri> triangles, + MutableSpan<float> r_weights) +{ + assert_same_size(triangles, r_weights); + compute_triangle_areas(mesh, triangles, r_weights); +} + +static BLI_NOINLINE void compute_cumulative_distribution(Span<float> weights, + MutableSpan<float> r_cumulative_weights) +{ + BLI_assert(weights.size() + 1 == r_cumulative_weights.size()); + + r_cumulative_weights[0] = 0; + for (int i : weights.index_range()) { + r_cumulative_weights[i + 1] = r_cumulative_weights[i] + weights[i]; + } +} + +static void sample_cumulative_distribution_recursive(RandomNumberGenerator &rng, + int amount, + int start, + int one_after_end, + Span<float> cumulative_weights, + VectorAdaptor<int> &r_sampled_indices) +{ + BLI_assert(start <= one_after_end); + const int size = one_after_end - start; + if (size == 0) { + BLI_assert(amount == 0); + } + else if (amount == 0) { + return; + } + else if (size == 1) { + r_sampled_indices.append_n_times(start, amount); + } + else { + const int middle = start + size / 2; + const float left_weight = cumulative_weights[middle] - cumulative_weights[start]; + const float right_weight = cumulative_weights[one_after_end] - cumulative_weights[middle]; + BLI_assert(left_weight >= 0.0f && right_weight >= 0.0f); + const float weight_sum = left_weight + right_weight; + BLI_assert(weight_sum > 0.0f); + + const float left_factor = left_weight / weight_sum; + const float right_factor = right_weight / weight_sum; + + int left_amount = amount * left_factor; + int right_amount = amount * right_factor; + + if (left_amount + right_amount < amount) { + BLI_assert(left_amount + right_amount + 1 == amount); + const float weight_per_item = weight_sum / amount; + const float total_remaining_weight = weight_sum - + (left_amount + right_amount) * weight_per_item; + const float left_remaining_weight = left_weight - left_amount * weight_per_item; + const float left_remaining_factor = left_remaining_weight / total_remaining_weight; + if (rng.get_float() < left_remaining_factor) { + left_amount++; + } + else { + right_amount++; + } + } + + sample_cumulative_distribution_recursive( + rng, left_amount, start, middle, cumulative_weights, r_sampled_indices); + sample_cumulative_distribution_recursive( + rng, right_amount, middle, one_after_end, cumulative_weights, r_sampled_indices); + } +} + +static BLI_NOINLINE void sample_cumulative_distribution(RandomNumberGenerator &rng, + Span<float> cumulative_weights, + MutableSpan<int> r_samples) +{ + VectorAdaptor<int> sampled_indices(r_samples); + sample_cumulative_distribution_recursive(rng, + r_samples.size(), + 0, + cumulative_weights.size() - 1, + cumulative_weights, + sampled_indices); + BLI_assert(sampled_indices.is_full()); +} + +static BLI_NOINLINE bool sample_weighted_buckets(RandomNumberGenerator &rng, + Span<float> weights, + MutableSpan<int> r_samples) +{ + Array<float> cumulative_weights(weights.size() + 1); + compute_cumulative_distribution(weights, cumulative_weights); + + if (r_samples.size() > 0 && cumulative_weights.as_span().last() == 0.0f) { + /* All weights are zero. */ + return false; + } + + sample_cumulative_distribution(rng, cumulative_weights, r_samples); + return true; +} + +static BLI_NOINLINE void sample_looptris(RandomNumberGenerator &rng, + Mesh &mesh, + Span<MLoopTri> triangles, + Span<int> triangles_to_sample, + MutableSpan<float3> r_sampled_positions, + MutableSpan<float3> r_sampled_normals) +{ + assert_same_size(triangles_to_sample, r_sampled_positions, r_sampled_normals); + + MLoop *loops = mesh.mloop; + MVert *verts = mesh.mvert; + + for (uint i : triangles_to_sample.index_range()) { + const uint triangle_index = triangles_to_sample[i]; + const MLoopTri &triangle = triangles[triangle_index]; + + const float3 v1 = verts[loops[triangle.tri[0]].v].co; + const float3 v2 = verts[loops[triangle.tri[1]].v].co; + const float3 v3 = verts[loops[triangle.tri[2]].v].co; + + const float3 bary_coords = rng.get_barycentric_coordinates(); + + float3 position; + interp_v3_v3v3v3(position, v1, v2, v3, bary_coords); + + float3 normal; + normal_tri_v3(normal, v1, v2, v3); + + r_sampled_positions[i] = position; + r_sampled_normals[i] = normal; + } +} + +static BLI_NOINLINE bool compute_new_particle_attributes(ParticleEmitterContext &context, + EmitterSettings &settings, + ParticleMeshEmitterSimulationState &state, + Vector<float3> &r_positions, + Vector<float3> &r_velocities, + Vector<float> &r_birth_times) +{ + if (settings.object == nullptr) { + return false; + } + if (settings.rate <= 0.000001f) { + return false; + } + if (settings.object->type != OB_MESH) { + return false; + } + Mesh &mesh = *(Mesh *)settings.object->data; + if (mesh.totvert == 0) { + return false; + } + + const float start_time = context.emit_interval.start(); + const uint32_t seed = DefaultHash<StringRef>{}(state.head.name); + RandomNumberGenerator rng{(*(uint32_t *)&start_time) ^ seed}; + + compute_birth_times(settings.rate, context.emit_interval, state, r_birth_times); + const int particle_amount = r_birth_times.size(); + if (particle_amount == 0) { + return false; + } + + const float last_birth_time = r_birth_times.last(); + rng.shuffle(r_birth_times.as_mutable_span()); + + Span<MLoopTri> triangles = get_mesh_triangles(mesh); + if (triangles.is_empty()) { + return false; + } + + Array<float> triangle_weights(triangles.size()); + compute_triangle_weights(mesh, triangles, triangle_weights); + + Array<int> triangles_to_sample(particle_amount); + if (!sample_weighted_buckets(rng, triangle_weights, triangles_to_sample)) { + return false; + } + + r_positions.resize(particle_amount); + r_velocities.resize(particle_amount); + sample_looptris(rng, mesh, triangles, triangles_to_sample, r_positions, r_velocities); + + if (context.solve_context.dependency_animations.is_object_transform_changing(*settings.object)) { + Array<float4x4> local_to_world_matrices(particle_amount); + context.solve_context.dependency_animations.get_object_transforms( + *settings.object, r_birth_times, local_to_world_matrices); + + for (int i : IndexRange(particle_amount)) { + const float4x4 &position_to_world = local_to_world_matrices[i]; + const float4x4 normal_to_world = position_to_world.inverted_transposed_affine(); + r_positions[i] = position_to_world * r_positions[i]; + r_velocities[i] = normal_to_world * r_velocities[i]; + } + } + else { + const float4x4 position_to_world = settings.object->obmat; + const float4x4 normal_to_world = position_to_world.inverted_transposed_affine(); + for (int i : IndexRange(particle_amount)) { + r_positions[i] = position_to_world * r_positions[i]; + r_velocities[i] = normal_to_world * r_velocities[i]; + } + } + + for (int i : IndexRange(particle_amount)) { + r_velocities[i].normalize(); + } + + state.last_birth_time = last_birth_time; + return true; +} + +static BLI_NOINLINE EmitterSettings compute_settings(const fn::MultiFunction &inputs_fn, + ParticleEmitterContext &context) +{ + EmitterSettings parameters; + + fn::MFContextBuilder mf_context; + mf_context.add_global_context("PersistentDataHandleMap", &context.solve_context.handle_map); + + fn::MFParamsBuilder mf_params{inputs_fn, 1}; + bke::PersistentObjectHandle object_handle; + mf_params.add_uninitialized_single_output(&object_handle, "Object"); + mf_params.add_uninitialized_single_output(¶meters.rate, "Rate"); + + inputs_fn.call(IndexRange(1), mf_params, mf_context); + + parameters.object = context.solve_context.handle_map.lookup(object_handle); + return parameters; +} + +void ParticleMeshEmitter::emit(ParticleEmitterContext &context) const +{ + auto *state = context.lookup_state<ParticleMeshEmitterSimulationState>(own_state_name_); + if (state == nullptr) { + return; + } + + EmitterSettings settings = compute_settings(inputs_fn_, context); + + Vector<float3> new_positions; + Vector<float3> new_velocities; + Vector<float> new_birth_times; + + if (!compute_new_particle_attributes( + context, settings, *state, new_positions, new_velocities, new_birth_times)) { + return; + } + + for (StringRef name : particle_names_) { + ParticleAllocator *allocator = context.try_get_particle_allocator(name); + if (allocator == nullptr) { + continue; + } + + int amount = new_positions.size(); + fn::MutableAttributesRef attributes = allocator->allocate(amount); + + 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); + } + } +} + +} // namespace blender::sim |