Physics::Component::SoftBody Struct Reference

Soft body physics component. More...

#include <SoftBody.hpp>

Public Member Functions
size_t	GetVertexCount () const
	Get number of vertices (from invMasses size).
size_t	GetEdgeCount () const
	Get number of edge constraints.
void	PinVertex (uint32_t vertexIndex)
	Pin a vertex (fix it in space).
void	UnpinVertex (uint32_t vertexIndex, float mass=1.0f)
	Unpin a vertex.
bool	IsVertexPinned (uint32_t vertexIndex) const
	Check if a vertex is pinned.
bool	IsValid () const
	Check if the soft body configuration is valid.
	SoftBody ()=default
	Default constructor - creates an empty SoftBody.
	SoftBody (const SoftBodySettings &settings)
	Construct with specific settings.
	SoftBody (SoftBodyType bodyType, const SoftBodySettings &settings)
	Construct with type and settings.

Public Attributes
SoftBodyType	type = SoftBodyType::Custom
	Type of soft body (affects default settings).
SoftBodySettings	settings
	Simulation settings.
std::vector< float >	invMasses
	Vertex inverse masses (0 = pinned/fixed). Size must match Mesh.vertices.size().
std::vector< uint32_t >	pinnedVertices
	Indices of pinned (fixed) vertices.
std::vector< std::pair< uint32_t, uint32_t > >	edges

Detailed Description

Soft body physics component.

Represents the physics simulation data for a deformable object using Jolt's SoftBody system. This component works in conjunction with Object::Component::Mesh which holds the geometry.

Architecture

• Mesh (Object plugin): Contains vertices[], normals[], indices[] for rendering
• SoftBody (Physics plugin): Contains physics settings and per-vertex physics data
• Jolt: Maintains internal vertex copy for simulation (unavoidable)

The SoftBodySystem:

1. On construct: Auto-detects Mesh component and initializes physics data
2. On update: Writes Jolt simulation results back to Mesh.vertices

Usage

From existing Mesh (e.g., imported .obj):

auto mesh = OBJLoader("model.obj").GetMesh();
auto teapot = core.CreateEntity();
teapot.AddComponent<Transform>(core, position);
teapot.AddComponent<Mesh>(core, mesh);
teapot.AddComponent<SoftBody>(core, SoftBodySettings::Balloon(5000.0f));

Procedural cloth (using Object::Helper):

auto cloth = Object::Helper::CreateCloth(core, 10, 10, 0.1f, position);
auto& soft = cloth.AddComponent<SoftBody>(core, SoftBodySettings::Cloth(0.5f));
soft.PinVertex(0);   // Pin top-left corner
soft.PinVertex(9);   // Pin top-right corner

Note: Collider components (BoxCollider, SphereCollider, etc.) are ignored for SoftBody. Use SoftBodySettings::vertexRadius for collision detection.

See also

Object::Component::Mesh

Object::Helper::CreateCloth

Object::Helper::CreateRope

Examples

Creating a 2-unit jelly cube with 5x5x5 grid:, Creating a cloth for soft body simulation:, and Creating a rope for soft body simulation:.

Constructor & Destructor Documentation

SoftBody() [1/3]

Physics::Component::SoftBody::SoftBody ( )

default

Default constructor - creates an empty SoftBody.

The SoftBody will be configured automatically when added to an entity that already has a Mesh component. The InitSoftBodySystem hook will:

• Auto-detect the Mesh and initialize invMasses
• Generate edge constraints from mesh faces

SoftBody() [2/3]

Physics::Component::SoftBody::SoftBody ( const SoftBodySettings & settings )

inlineexplicit

Construct with specific settings.

Parameters

settings

Simulation settings (use factory methods like SoftBodySettings::Cloth())

SoftBody() [3/3]

Physics::Component::SoftBody::SoftBody ( SoftBodyType bodyType, const SoftBodySettings & settings )

inline

Construct with type and settings.

Parameters

bodyType	Type of soft body (affects internal processing)
settings	Simulation settings

Member Function Documentation

GetEdgeCount()

size_t Physics::Component::SoftBody::GetEdgeCount ( ) const

inlinenodiscard

Get number of edge constraints.

GetVertexCount()

size_t Physics::Component::SoftBody::GetVertexCount ( ) const

inlinenodiscard

Get number of vertices (from invMasses size).

IsValid()

bool Physics::Component::SoftBody::IsValid ( ) const

inlinenodiscard

Check if the soft body configuration is valid.

Note

Only checks if vertex data has been initialized

IsVertexPinned()

bool Physics::Component::SoftBody::IsVertexPinned ( uint32_t vertexIndex ) const

inlinenodiscard

Check if a vertex is pinned.

PinVertex()

void Physics::Component::SoftBody::PinVertex ( uint32_t vertexIndex )

inline

Pin a vertex (fix it in space).

Parameters

vertexIndex

Index of vertex to pin

Examples

Creating a cloth for soft body simulation:, and Creating a rope for soft body simulation:.

UnpinVertex()

void Physics::Component::SoftBody::UnpinVertex ( uint32_t vertexIndex, float mass = 1.0f )

inline

Unpin a vertex.

kMinMass is used to avoid instability from huge inverse masses.

Parameters

vertexIndex	Index of vertex to unpin
mass	Mass to assign (default 1.0)

Member Data Documentation

edges

std::vector<std::pair<uint32_t, uint32_t> > Physics::Component::SoftBody::edges

Edge constraints (pairs of vertex indices) for rope/chain without faces Auto-generated from Mesh.indices if empty

invMasses

std::vector<float> Physics::Component::SoftBody::invMasses

Vertex inverse masses (0 = pinned/fixed). Size must match Mesh.vertices.size().

pinnedVertices

std::vector<uint32_t> Physics::Component::SoftBody::pinnedVertices

Indices of pinned (fixed) vertices.

settings

SoftBodySettings Physics::Component::SoftBody::settings

Simulation settings.

type

SoftBodyType Physics::Component::SoftBody::type = SoftBodyType::Custom

Type of soft body (affects default settings).

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The documentation for this struct was generated from the following file:

• src/plugin/physics/src/component/SoftBody.hpp