A defined region of space with a containment test and crossing actions. More...

#include <Expanse.hpp>

Collaboration diagram for MayaFlux::Nexus::Expanse:

Public Types
using	ContainsFn = std::function< bool(const glm::vec3 &)>

using	CrossingFn = std::function< void(uint32_t)>

Public Member Functions
bool	contains (const glm::vec3 &p) const
	Test whether a world position lies within the Expanse.

void	evaluate (uint32_t fabric_id, std::span< const std::pair< uint32_t, glm::vec3 > > snapshot)
	Evaluate a spatial snapshot from one Fabric against this Expanse.

	Expanse (ContainsFn contains, CrossingFn on_enter, CrossingFn on_exit)
	Construct with a containment predicate and crossing actions.

	Expanse (std::string fn_name, ContainsFn contains, CrossingFn on_enter, CrossingFn on_exit)
	Construct with a named containment predicate and crossing actions.

	Expanse (std::string fn_name, std::string on_enter_fn_name, std::string on_exit_fn_name, ContainsFn contains, CrossingFn on_enter, CrossingFn on_exit)
	Construct with named containment predicate and named crossing actions.

const std::string &	fn_name () const
	Identifier assigned to the containment predicate, empty if anonymous.

uint32_t	id () const
	Stable id assigned by Fabric on registration.

const std::unordered_set< uint32_t > *	occupants (uint32_t fabric_id) const
	Entity ids inside this Expanse for `fabric_id`, or nullptr if that fabric has no occupants.

std::vector< uint32_t >	occupied_fabrics () const
	All fabric ids that currently have at least one occupant inside this Expanse.

const std::string &	on_enter_fn_name () const
	Identifier assigned to the on_enter callable, empty if anonymous.

const std::string &	on_exit_fn_name () const
	Identifier assigned to the on_exit callable, empty if anonymous.

void	set_fn_name (std::string name)
	Set or replace the predicate identifier.

void	set_on_enter_fn_name (std::string name)
	Set or replace the on_enter callable identifier.

void	set_on_exit_fn_name (std::string name)
	Set or replace the on_exit callable identifier.

Private Attributes
ContainsFn	m_contains

std::string	m_fn_name

uint32_t	m_id { 0 }

std::unordered_map< uint32_t, std::unordered_set< uint32_t > >	m_occupants_by_fabric

CrossingFn	m_on_enter

std::string	m_on_enter_fn_name

CrossingFn	m_on_exit

std::string	m_on_exit_fn_name

Friends
class	Fabric

Detailed Description

A defined region of space with a containment test and crossing actions.

An Expanse is an extent, not a point. It holds a containment predicate that answers whether a world position lies within it, and two actions fired when an entity crosses its edge: one on entry, one on exit. The Fabric evaluates the predicate against every indexed position on each commit and diffs membership against the previous commit, firing the actions for the difference. The Expanse does not query; the Fabric drives it, because only the Fabric sees consecutive snapshots.

The containment predicate is a plain function from position to bool. A fixed box, a sphere, a half-space, or an extent driven by an evolving value are all the same kind of thing: the predicate closes over whatever state shapes the region, so an Expanse whose bounds move or breathe is expressed by a predicate that reads that state, with no change to the mechanism.

The entry and exit actions receive the crossing entity id. What crossing means computationally is the action's decision: a tone gated, a parameter written, another entity activated, a value pushed. The Expanse supplies the spatial fact of crossing; the action supplies the consequence.

The id is assigned by Fabric on registration and is stable for the Expanse's lifetime.

Definition at line 31 of file Expanse.hpp.

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

Public Types

Public Member Functions

Private Attributes

Friends

Detailed Description