VolumeFieldProcessor spreading a field into its neighbourhood by implicit Jacobi iteration. More...

#include <DiffuseProcessor.hpp>

Inheritance diagram for MayaFlux::Buffers::DiffuseProcessor:

Collaboration diagram for MayaFlux::Buffers::DiffuseProcessor:

Public Member Functions
	DiffuseProcessor (std::string target_field, std::string scratch_field, const Portal::Graphics::ShaderSpec &spec, uint32_t iterations=20)
	Construct a diffusion stage from a generated ShaderSpec.

	DiffuseProcessor (std::string target_field, std::string scratch_field, const std::string &shader_path, uint32_t iterations=20)
	Construct a diffusion stage.

const std::string &	get_scratch_field () const
	Name of the field holding pre-diffusion values across passes.

const std::string &	get_target_field () const
	Name of the field this stage diffuses.

void	set_rate (float rate)
	Set the diffusion rate.

void	set_time_step (float dt)
	Set the integration step.

Public Member Functions inherited from MayaFlux::Buffers::VolumeFieldProcessor
const std::shared_ptr< VolumeGridBuffer > &	get_volume () const
	The attached volume, or null if attachment failed validation.

Public Member Functions inherited from MayaFlux::Buffers::ComputeProcessor
	ComputeProcessor (const Portal::Graphics::ShaderSpec &spec)
	Construct processor from a generated ShaderSpec.

	ComputeProcessor (const std::string &shader_path, uint32_t workgroup_x=256)
	Construct processor with shader path.

const ShaderDispatchConfig &	get_dispatch_config () const
	Get current dispatch configuration.

uint32_t	get_iteration_count () const
	Dispatches recorded per execute cycle.

bool	is_pipeline_ready () const
	Check if pipeline is created.

void	set_custom_dispatch (std::function< std::array< uint32_t, 3 >(const std::shared_ptr< VKBuffer > &)> calculator)
	Set custom dispatch calculator.

void	set_dispatch_mode (ShaderDispatchConfig::DispatchMode mode)
	Set dispatch mode.

void	set_iteration_count (uint32_t count)
	Set how many dispatches are recorded per execute cycle.

void	set_manual_dispatch (uint32_t x, uint32_t y=1, uint32_t z=1)
	Set manual dispatch group counts.

void	set_workgroup_size (uint32_t x, uint32_t y=1, uint32_t z=1)
	Set workgroup size (should match shader local_size)

Public Member Functions inherited from MayaFlux::Buffers::ShaderProcessor
void	add_binding (const std::string &descriptor_name, const ShaderBinding &binding)
	Add descriptor binding configuration.

bool	are_bindings_complete () const
	Check if all required bindings are satisfied.

bool	are_descriptors_ready () const
	Check if descriptors are initialized.

void	auto_bind_buffer (const std::shared_ptr< VKBuffer > &buffer)
	Auto-bind buffer based on attachment order.

void	bind_buffer (const std::string &descriptor_name, const std::shared_ptr< VKBuffer > &buffer)
	Bind a VKBuffer to a named shader descriptor.

void	clear_specialization_constants ()
	Clear all specialization constants.

template<typename T >
bool	download_bound (const std::string &descriptor_name, std::vector< T > &data) const

bool	download_bound (const std::string &descriptor_name, void *data, size_t size, const std::shared_ptr< VKBuffer > &staging=nullptr) const
	Download the buffer currently bound to a named descriptor.

void	feed (const std::string &name, FeedSource source)
	Supply a shader input from a callable, resolved by name.

void	feed (const std::string &name, FeedSource source, uint32_t offset, size_t size=sizeof(float))
	Supply a push constant from a callable at an explicit offset.

std::vector< std::string >	get_binding_names () const
	Get all configured descriptor names.

std::shared_ptr< VKBuffer >	get_bound_buffer (const std::string &descriptor_name) const
	Get bound buffer for a descriptor name.

size_t	get_bound_buffer_count () const
	Get number of bound buffers.

virtual BufferUsageHint	get_buffer_usage_hint (const std::string &descriptor_name) const
	Get buffer usage hint for a descriptor.

const ShaderConfig &	get_config () const
	Get current configuration.

std::vector< std::string >	get_feed_names () const
	Names of every registered feed.

virtual std::shared_ptr< VKBuffer >	get_output_buffer () const
	Get the output buffer after compute dispatch.

std::vector< uint8_t > &	get_push_constant_data ()

const std::vector< uint8_t > &	get_push_constant_data () const
	Get current push constant data.

const std::string &	get_shader_path () const
	Get current shader path.

bool	has_binding (const std::string &descriptor_name) const
	Check if a descriptor binding exists.

virtual bool	has_executed () const
	Check if compute has been executed at least once.

bool	has_feed (const std::string &name) const
	Whether a feed of this name is registered.

bool	hot_reload_shader ()
	Hot-reload shader from ShaderFoundry.

bool	is_compatible_with (const std::shared_ptr< Buffer > &buffer) const override
	Checks if this processor can handle the specified buffer type.

bool	is_deferred_submission () const
	Whether this processor submits asynchronously.

bool	is_dispatch_pending () const
	True while an asynchronous submission is outstanding.

virtual bool	is_in_place_operation (const std::string &descriptor_name) const
	Check if shader modifies a specific buffer in-place.

bool	is_shader_loaded () const
	Check if shader is loaded.

void	on_detach (const std::shared_ptr< Buffer > &buffer) override
	Called when this processor is detached from a buffer.

void	remove_feed (const std::string &name)
	Remove a feed.

bool	resolve_pending_dispatch (bool block)
	Resolve an outstanding asynchronous submission.

void	set_config (const ShaderConfig &config)
	Update entire configuration.

void	set_deferred_submission (bool deferred)
	Submit asynchronously and resolve at the top of a later cycle.

template<typename T >
void	set_push_constant_data (const T &data)
	Update push constant data (type-safe)

virtual void	set_push_constant_data_raw (const void *data, size_t size)
	Update push constant data (raw bytes)

template<typename T >
void	set_push_constant_size ()
	Set push constant size from type.

void	set_push_constant_size (size_t size)
	Set push constant size.

void	set_shader (const std::string &shader_path)
	Update shader path and reload.

void	set_specialization_constant (uint32_t constant_id, uint32_t value)
	Set specialization constant.

	ShaderProcessor (const std::string &shader_path)
	Construct processor with shader path.

	ShaderProcessor (ShaderConfig config)
	Construct processor with full configuration.

void	unbind_buffer (const std::string &descriptor_name)
	Unbind a buffer from a descriptor.

	~ShaderProcessor () override

Public Member Functions inherited from MayaFlux::Buffers::BufferProcessor
virtual ProcessingToken	get_processing_token () const
	Gets the current processing token for this buffer.

void	process (const std::shared_ptr< Buffer > &buffer)
	Applies a computational transformation to the data in the provided buffer.

virtual void	set_processing_token (ProcessingToken token)
	Gets the preferred processing backend for this processor.

virtual	~BufferProcessor ()=default
	Virtual destructor for proper cleanup of derived classes.

Protected Member Functions
bool	on_iteration (Portal::Graphics::CommandBufferID cmd_id, const std::shared_ptr< VKBuffer > &buffer, uint32_t index) override
	Write this pass's parity and first-pass flag.

void	on_iteration_barrier (Portal::Graphics::CommandBufferID cmd_id, const std::shared_ptr< VKBuffer > &buffer, uint32_t index) override
	Barrier both target slots and the scratch between passes.

void	on_volume_ready () override
	Write the coefficient into the shared prefix.

bool	wants_swap () const override
	Swap only when the pass count leaves the result in the write slot.

Protected Member Functions inherited from MayaFlux::Buffers::VolumeFieldProcessor
void	add_swap_field (std::string field)
	Register a field to swap after each dispatch.

void	on_attach (const std::shared_ptr< Buffer > &buffer) override
	Cache and validate the volume, size the dispatch, write the shared parameter prefix, then call on_volume_ready.

bool	on_before_execute (Portal::Graphics::CommandBufferID cmd_id, const std::shared_ptr< VKBuffer > &buffer) override
	Reject buffers that are not the validated volume.

void	on_descriptors_created () override
	Write every binding in the table for the current slot assignment.

void	processing_function (const std::shared_ptr< Buffer > &buffer) override
	Rewrite field descriptors, run the shader, then swap.

void	reserve_param_size (size_t size)
	Raise the push constant block to at least this size.

	VolumeFieldProcessor (std::vector< FieldBinding > bindings, const Portal::Graphics::ShaderSpec &spec)
	Construct from a generated ShaderSpec.

	VolumeFieldProcessor (std::vector< FieldBinding > bindings, const std::string &shader_path)
	Construct from a shader path.

void	write_lattice_params ()
	Write the lattice dimensions and cell size into the staged push constant block, preserving word three.

void	write_lattice_word3 (uint32_t value)
	Write word three of the shared prefix.

void	write_lattice_word7 (float value)
	Write word seven of the parameter prefix, at byte offset 28.

void	write_param_tail (size_t offset, const void *data, size_t size)
	Write subclass parameters past the shared prefix.

Protected Member Functions inherited from MayaFlux::Buffers::ComputeProcessor
virtual std::array< uint32_t, 3 >	calculate_dispatch_size (const std::shared_ptr< VKBuffer > &buffer)
	Calculate dispatch size from buffer.

void	cleanup () override

void	initialize_descriptors (const std::shared_ptr< VKBuffer > &buffer) override

void	initialize_pipeline (const std::shared_ptr< VKBuffer > &buffer) override

Protected Member Functions inherited from MayaFlux::Buffers::ShaderProcessor
virtual void	on_after_execute (Portal::Graphics::CommandBufferID cmd_id, const std::shared_ptr< VKBuffer > &buffer)
	Called after each process callback.

virtual void	on_before_compile (const std::string &shader_path)
	Called before shader compilation.

virtual void	on_before_descriptors_create ()
	Called before descriptor sets are created.

virtual void	on_before_pipeline_create (Portal::Graphics::ComputePipelineID pipeline_id)
	Called before pipeline creation.

virtual void	on_dispatch_complete (const std::shared_ptr< VKBuffer > &buffer)
	Called once when an asynchronous submission is observed complete.

virtual void	on_pipeline_created (Portal::Graphics::ComputePipelineID pipeline_id)
	Called after pipeline is created.

virtual void	on_shader_loaded (Portal::Graphics::ShaderID shader_id)
	Called after shader is loaded.

void	pump_feeds ()
	Pull every feed and write its result.

std::optional< uint32_t >	resolve_ds_index (uint32_t set) const
	Resolve logical descriptor set index to actual index.

size_t	resolve_push_constant_size (const std::shared_ptr< VKBuffer > &buffer) const
	Byte width of this processor's push constant block, extended to cover any fragment staged on the buffer.

std::vector< uint8_t >	resolve_push_constants (const std::shared_ptr< VKBuffer > &buffer) const
	This processor's push constant data with buffer-staged fragments overlaid at their declared offsets.

void	submit_recorded (Portal::Graphics::CommandBufferID cmd_id, const std::shared_ptr< VKBuffer > &buffer)
	Submit a recorded command buffer honoring the submission mode.

virtual void	update_descriptors (const std::shared_ptr< VKBuffer > &buffer)

Protected Member Functions inherited from MayaFlux::Buffers::VKBufferProcessor
void	ensure_initialized (const std::shared_ptr< VKBuffer > &buffer)

void	initialize_buffer_service ()

void	initialize_compute_service ()

Private Member Functions
void	write_coefficient ()
	Write the product of rate and time step into word seven.

Static Private Member Functions
static std::vector< FieldBinding >	make_bindings (const std::string &target_field, const std::string &scratch_field)
	Build the binding table for the two field names.

Private Attributes
float	m_rate { 0.0F }

std::string	m_scratch_field

std::string	m_target_field

float	m_time_step { 1.0F / 60.0F }

Additional Inherited Members
Public Types inherited from MayaFlux::Buffers::VolumeFieldProcessor
enum class	FieldAccess { READ , WRITE }
	Which slot of a field a binding resolves to. More...

Public Types inherited from MayaFlux::Buffers::ShaderProcessor
enum class	BufferUsageHint : uint8_t { NONE = 0 , INPUT_READ = 1 << 0 , OUTPUT_WRITE = 1 << 1 , BIDIRECTIONAL = INPUT_READ \| OUTPUT_WRITE }
	Get buffer usage characteristics needed for safe data flow. More...

using	FeedSource = std::function< FeedValue()>
	A callable pulled once per processing cycle.

using	FeedValue = std::variant< double, Kakshya::DataVariant >
	What a feed callable returns.

Protected Attributes inherited from MayaFlux::Buffers::ShaderProcessor
size_t	m_auto_bind_index {}

std::unordered_map< std::string, std::shared_ptr< VKBuffer > >	m_bound_buffers

ShaderConfig	m_config

bool	m_deferred_submission {}
	False submits synchronously, preserving pre-existing behaviour.

std::vector< Portal::Graphics::DescriptorSetID >	m_descriptor_set_ids

bool	m_engine_owns_set_zero {}
	Whether the engine reserves set=0 for global resources.

bool	m_initialized {}

Portal::Graphics::CommandBufferID	m_last_command_buffer = Portal::Graphics::INVALID_COMMAND_BUFFER

std::shared_ptr< VKBuffer >	m_last_processed_buffer

bool	m_needs_descriptor_rebuild = true

bool	m_needs_pipeline_rebuild = true

std::shared_ptr< VKBuffer >	m_pending_buffer
	Buffer retained for the outstanding submission.

Portal::Graphics::FenceID	m_pending_fence { Portal::Graphics::INVALID_FENCE }
	Outstanding async submission, if any.

std::vector< uint8_t >	m_push_constant_data

Portal::Graphics::ShaderID	m_shader_id = Portal::Graphics::INVALID_SHADER

Protected Attributes inherited from MayaFlux::Buffers::VKBufferProcessor
Registry::Service::BufferService *	m_buffer_service = nullptr

Registry::Service::ComputeService *	m_compute_service = nullptr

Protected Attributes inherited from MayaFlux::Buffers::BufferProcessor
ProcessingToken	m_processing_token { ProcessingToken::AUDIO_BACKEND }

Detailed Description

VolumeFieldProcessor spreading a field into its neighbourhood by implicit Jacobi iteration.

Solves the backward Euler form rather than stepping the heat equation forward, so the result is stable at any coefficient. The explicit form diverges once the coefficient exceeds a sixth of the squared cell spacing, which at a sixty-fourth-of-a-unit lattice is reached by ordinary viscosities.

Applied to velocity this is viscosity. Applied to a scalar it blurs density or temperature, which softens the filaments first-order advection leaves behind.

Requires a scratch field alongside the target. Jacobi needs the pre-diffusion values on every pass, and the two target slots are both consumed by the ping-pong, so the first pass copies what it reads into the scratch and later passes read it from there. The scratch is bound once, unqualified, and must have the same stride as the target. It may be single-buffered and is never swapped.

Shares PressureProcessor's parity arrangement: both target slots bound simultaneously, the pass's read and write selected by a push constant word, since a descriptor set bound into an open command buffer cannot be rewritten mid-recording.

Definition at line 34 of file DiffuseProcessor.hpp.

The documentation for this class was generated from the following files:

Public Member Functions

Protected Member Functions

Private Member Functions

Static Private Member Functions

Private Attributes

Additional Inherited Members

Detailed Description