ensure_cluster_ids()

bool MayaFlux::Buffers::NetworkGeometryBuffer::ensure_cluster_ids

(

)

Ensure the hash_cluster_id state field exists, declaring and populating it from the network's own primary GraphicsOperator if nothing has already done so.

Returns

True if hash_cluster_id exists by the time this returns (already did, or was just created); false if there is no primary GraphicsOperator to size it from, or it reports zero vertices.

Sized to get_vertex_count(), not get_point_count(): a GPU consumer indexes this field in lockstep with the vertex buffer itself, and for an operator whose rendered vertex count differs from its source point count (TopologyOperator/PathOperator after interpolation) those are two different numbers. Coincide for PhysicsOperator's point-sprite geometry, so this changes nothing for the particle path.

has_state-guarded, so whichever caller reaches this first (a this buffer's own field-operator wiring, or a VertexFieldProcessor attaching with a cluster-scoped GpuFieldOperator binding) does the real work and the other finds it already done. Values come from GraphicsOperator::build_cluster_ids(): every entry 0 for any operator that has never overridden it, which is every one except PhysicsOperator today, so calling this against a PointCloudNetwork or plain FieldOperator-driven network is safe and simply declares a field whose only value is 0.

Definition at line 429 of file NetworkGeometryBuffer.cpp.

{
    if (has_state("hash_cluster_id")) {
        return true;
    }
 
    auto* graphics_op = m_network
        ? dynamic_cast<Nodes::Network::GraphicsOperator*>(m_network->get_operator())
        : nullptr;
    if (!graphics_op) {
        return false;
    }
 
    const size_t vertex_count = graphics_op->get_vertex_count();
    if (vertex_count == 0) {
        return false;
    }
 
    if (!declare_state("hash_cluster_id", vertex_count, sizeof(uint32_t), false)) {
        return false;
    }
 
    auto cluster_ids = graphics_op->build_cluster_ids();
    if (cluster_ids.size() != vertex_count) {
        cluster_ids.assign(vertex_count, 0U);
    }
 
    std::shared_ptr<VKBuffer> staging;
    upload_back_buffer(
        write_state_slot("hash_cluster_id"),
        cluster_ids.data(),
        cluster_ids.size() * sizeof(uint32_t),
        staging);
 
    return true;
}

References declare_state(), has_state(), m_network, MayaFlux::Buffers::upload_back_buffer(), and write_state_slot().

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