Fluid API reference

API Reference

namespace Fluid

Enums

enum VelocityOp

Operator when applying velocity to velocity field: add or set.

Values:

Add
Set

Functions

VORTEX_API LinearSolver::Parameters Vortex::Fluid::FixedParams(unsigned iterations)

Create a linear solver parameters object with fixed solver type.

Return
parameters
Parameters
  • iterations: number of iterations to do

VORTEX_API LinearSolver::Parameters Vortex::Fluid::IterativeParams(float errorTolerance)

Create a linear solver parameters object, solver will continue until error tolerance is reached.

Return
parameters
Parameters
  • errorTolerance: tolerance to reach before exiting

VORTEX_API float Vortex::Fluid::DefaultParticleSize()

Variables

VORTEX_API Renderer::ColorBlendState Vortex::Fluid::IntersectionBlend
VORTEX_API Renderer::ColorBlendState Vortex::Fluid::UnionBlend
VORTEX_API std::shared_ptr<Renderer::Clear> Vortex::Fluid::BoundariesClear
class Advection
#include <Advection.h>

Advects particles, velocity field or any field using a velocity field.

Public Functions

VORTEX_API Advection(Renderer::Device &device, const glm::ivec2 &size, float dt, Velocity &velocity, Velocity::InterpolationMode interpolationMode)

Initialize advection kernels and related object.

Parameters
  • device: vulkan device
  • size: size of velocity field
  • dt: delta time for integration
  • velocity: velocity field

VORTEX_API void Vortex::Fluid::Advection::AdvectVelocity()

Self advect velocity.

VORTEX_API void Vortex::Fluid::Advection::AdvectBind(Density & density)

Binds a density field to be advected.

Parameters
  • density: density field

VORTEX_API void Vortex::Fluid::Advection::Advect()

Performs an advection of the density field. Asynchronous operation.

VORTEX_API void Vortex::Fluid::Advection::AdvectParticleBind(Renderer::GenericBuffer & particles, Renderer::Texture & levelSet, Renderer::IndirectBuffer < Renderer::DispatchParams > & dispatchParams)

Binds praticles to be advected. Also use a level set to project out the particles if they enter it.

Parameters
  • particles: particles to be advected
  • levelSet: level set to project out particles
  • dispatchParams: contains number of particles

VORTEX_API void Vortex::Fluid::Advection::AdvectParticles()

Advect particles. Asynchrounous operation.

class Cfl
#include <Cfl.h>

Calculates the CFL number of the velocity field. It’s an indication on how to choose your time step size. Ideally, the time step should be smaller than the CFL number.

Public Functions

VORTEX_API void Vortex::Fluid::Cfl::Compute()

Compute the CFL number. Non-blocking.

VORTEX_API float Vortex::Fluid::Cfl::Get()

Returns the CFL number. Blocking.

Return
cfl number

class Circle : public Vortex::Renderer::Transformable, public Vortex::Renderer::Drawable
#include <Boundaries.h>

Signed distance field of circle.

Public Functions

VORTEX_API Circle(Renderer::Device &device, float radius, float extent = 10.0f)

Initialize the circle with radius and extend of signed distance.

Parameters
  • device: vulkan device.
  • radius: radius of circle.
  • extent: extend how far from the circle the signed distance field is calculated.

VORTEX_API void Vortex::Fluid::Circle::Initialize(const Renderer::RenderState & renderState)

Initialize the drawable for a particular state. This might include creating the correct pipeline. If it was already initialized, it will do nothing.

Parameters
  • renderState: the state to initialize with.

VORTEX_API void Vortex::Fluid::Circle::Update(const glm::mat4 & projection, const glm::mat4 & view)

Update the MVP matrix of the drawable.

Parameters
  • projection: the projection matrix
  • view: the view matrix

VORTEX_API void Vortex::Fluid::Circle::Draw(Renderer::CommandEncoder & commandEncoder, const Renderer::RenderState & renderState)

Draw for the given render state. This has to be initialized before.

Parameters
  • commandBuffer: the command buffer to record into.
  • renderState: the render state to use.

class ConjugateGradient : public Vortex::Fluid::LinearSolver
#include <ConjugateGradient.h>

An iterative preconditioned conjugate linear solver. The preconditioner can be specified.

Public Functions

VORTEX_API ConjugateGradient(Renderer::Device &device, const glm::ivec2 &size, Preconditioner &preconditioner)

Initialize the solver with a size and preconditioner.

Parameters
  • device: vulkan device
  • size:
  • preconditioner:

VORTEX_API void Vortex::Fluid::ConjugateGradient::Bind(Renderer::GenericBuffer & d, Renderer::GenericBuffer & l, Renderer::GenericBuffer & b, Renderer::GenericBuffer & x)

Bind the buffers for the linear solver.

Parameters
  • d: the diagonal of the matrxi
  • l: the lower matrix
  • b: the right hand side
  • x: the unknowns

VORTEX_API void Vortex::Fluid::ConjugateGradient::BindRigidbody(float delta, Renderer::GenericBuffer & d, RigidBody & rigidBody)

Bind rigidbody with the linear solver’s matrix.

Parameters
  • delta: solver delta
  • d: diagonal matrix
  • rigidBody: rigidbody to bind to

VORTEX_API void Vortex::Fluid::ConjugateGradient::Solve(Parameters & params, const std::vector< RigidBody *> & rigidbodies = {})

Solve iteratively solve the linear equations in data.

VORTEX_API float Vortex::Fluid::ConjugateGradient::GetError()

Return
the max error

class Contour
#include <Boundaries.h>

The Contour class.

class Density : public Vortex::Renderer::RenderTexture, public Vortex::Renderer::Sprite
#include <Density.h>

Density field, used to represent smoke swirling.

class Depth
#include <Multigrid.h>

Contains the sizes of the multigrid hierarchy.

Public Functions

Depth(const glm::ivec2 &size)

Initialize with the finest size.

Parameters
  • size: the base size.

int GetMaxDepth() const

The calculated depth of the multigrid.

Return
the depth.

glm::ivec2 GetDepthSize(std::size_t i) const

Gets the depth for a given level.

Return
the size
Parameters
  • i: the level

class Diagonal : public Vortex::Fluid::Preconditioner
#include <Diagonal.h>

Diagonal preconditioner. Simplest of preconditioner, useful to verify if the preconditioned conjugate gradient works.

Public Functions

VORTEX_API void Vortex::Fluid::Diagonal::Bind(Renderer::GenericBuffer & d, Renderer::GenericBuffer & l, Renderer::GenericBuffer & b, Renderer::GenericBuffer & x)

Bind the linear equation buffers.

Parameters
  • d: the diagonal of the matrix
  • l: the lower matrix
  • b: the right hand side
  • x: the unknown buffer

void Record(Renderer::CommandEncoder &command)

Record the preconditioner.

Parameters
  • commandBuffer: the command buffer to record into.

class DistanceField : public Vortex::Renderer::AbstractSprite
#include <Boundaries.h>

Sprite of a distance field.

Public Functions

VORTEX_API DistanceField(Renderer::Device &device, Renderer::RenderTexture &levelSet, float scale = 1.0f)

Initialize the price with the level set and scale.

Parameters
  • device: vulkan device
  • levelSet: level set to use as sprite
  • scale: scale of the level set

VORTEX_API void Vortex::Fluid::DistanceField::Draw(Renderer::CommandEncoder & commandEncoder, const Renderer::RenderState & renderState)

Draw for the given render state. This has to be initialized before.

Parameters
  • commandBuffer: the command buffer to record into.
  • renderState: the render state to use.

class Extrapolation
#include <Extrapolation.h>

Class to extrapolate values into the neumann and/or dirichlet boundaries.

Public Functions

VORTEX_API void Vortex::Fluid::Extrapolation::Extrapolate()

Will extrapolate values from buffer into the dirichlet and neumann boundaries.

VORTEX_API void Vortex::Fluid::Extrapolation::ConstrainBind(Renderer::Texture & solidPhi)

Binds a solid level set to use later and constrain the velocity against.

Parameters
  • solidPhi: solid level set

VORTEX_API void Vortex::Fluid::Extrapolation::ConstrainVelocity()

Constrain the velocity, i.e. ensure that the velocity normal to the solid level set is 0.

class GaussSeidel : public Vortex::Fluid::LinearSolver, public Vortex::Fluid::Preconditioner
#include <GaussSeidel.h>

An iterative black and red successive over relaxation linear solver.

Public Functions

VORTEX_API void Vortex::Fluid::GaussSeidel::Bind(Renderer::GenericBuffer & d, Renderer::GenericBuffer & l, Renderer::GenericBuffer & b, Renderer::GenericBuffer & x)

Bind the buffers for the linear solver.

Parameters
  • d: the diagonal of the matrxi
  • l: the lower matrix
  • b: the right hand side
  • x: the unknowns

VORTEX_API void Vortex::Fluid::GaussSeidel::BindRigidbody(float delta, Renderer::GenericBuffer & d, RigidBody & rigidBody)

Bind rigidbody with the linear solver’s matrix.

Parameters
  • delta: solver delta
  • d: diagonal matrix
  • rigidBody: rigidbody to bind to

VORTEX_API void Vortex::Fluid::GaussSeidel::Solve(Parameters & params, const std::vector< RigidBody *> & rigidbodies = {})

Iterative solving of the linear equations in data.

VORTEX_API float Vortex::Fluid::GaussSeidel::GetError()

Return
the max error

void Record(Renderer::CommandEncoder &command)

Record the preconditioner.

Parameters
  • commandBuffer: the command buffer to record into.

void Record(Renderer::CommandEncoder &command, int iterations)

Record a determined number of iterations.

Parameters
  • commandBuffer:
  • iterations:

VORTEX_API void Vortex::Fluid::GaussSeidel::SetW(float w)

Set the w factor of the GS iterations : x_new = w * x_new + (1-w) * x_old.

Parameters
  • w:

VORTEX_API void Vortex::Fluid::GaussSeidel::SetPreconditionerIterations(int iterations)

set number of iterations to be used when GS is a preconditioner

Parameters
  • iterations:

class IncompletePoisson : public Vortex::Fluid::Preconditioner
#include <IncompletePoisson.h>

Incomplete poisson preconditioner. Slightly better than a simple diagonal preconditioner.

Public Functions

VORTEX_API void Vortex::Fluid::IncompletePoisson::Bind(Renderer::GenericBuffer & d, Renderer::GenericBuffer & l, Renderer::GenericBuffer & b, Renderer::GenericBuffer & x)

Bind the linear equation buffers.

Parameters
  • d: the diagonal of the matrix
  • l: the lower matrix
  • b: the right hand side
  • x: the unknown buffer

void Record(Renderer::CommandEncoder &command)

Record the preconditioner.

Parameters
  • commandBuffer: the command buffer to record into.

class Jacobi : public Vortex::Fluid::Preconditioner
#include <Jacobi.h>

An iterative jacobi linear solver.

Public Functions

void Bind(Renderer::GenericBuffer &d, Renderer::GenericBuffer &l, Renderer::GenericBuffer &b, Renderer::GenericBuffer &x)

Bind the linear equation buffers.

Parameters
  • d: the diagonal of the matrix
  • l: the lower matrix
  • b: the right hand side
  • x: the unknown buffer

void Record(Renderer::CommandEncoder &command)

Record the preconditioner.

Parameters
  • commandBuffer: the command buffer to record into.

void SetW(float w)

Set the w factor of the GS iterations : x_new = w * x_new + (1-w) * x_old.

Parameters
  • w:

void SetPreconditionerIterations(int iterations)

set number of iterations to be used when GS is a preconditioner

Parameters
  • iterations:

class LevelSet : public Vortex::Renderer::RenderTexture
#include <LevelSet.h>

A signed distance field, which can be re-initialized. In other words, a level set.

Public Functions

VORTEX_API void Vortex::Fluid::LevelSet::Reinitialise()

Reinitialise the level set, i.e. ensure it is a correct signed distance field.

VORTEX_API void Vortex::Fluid::LevelSet::ExtrapolateBind(Renderer::Texture & solidPhi)

Bind a solid level set, which will be used to extrapolate into this level set.

Parameters
  • solidPhi:

VORTEX_API void Vortex::Fluid::LevelSet::Extrapolate()

Extrapolate this level set into the solid level set it was attached to. This only performs a single cell extrapolation.

struct LinearSolver
#include <LinearSolver.h>

An interface to represent a linear solver.

Subclassed by Vortex::Fluid::ConjugateGradient, Vortex::Fluid::GaussSeidel, Vortex::Fluid::Multigrid

Public Functions

virtual void Bind(Renderer::GenericBuffer &d, Renderer::GenericBuffer &l, Renderer::GenericBuffer &b, Renderer::GenericBuffer &x) = 0

Bind the buffers for the linear solver.

Parameters
  • d: the diagonal of the matrxi
  • l: the lower matrix
  • b: the right hand side
  • x: the unknowns

virtual void BindRigidbody(float delta, Renderer::GenericBuffer &d, RigidBody &rigidBody) = 0

Bind rigidbody with the linear solver’s matrix.

Parameters
  • delta: solver delta
  • d: diagonal matrix
  • rigidBody: rigidbody to bind to

virtual void Solve(Parameters &params, const std::vector<RigidBody *> &rigidBodies = {}) = 0

Solves the linear equations.

Parameters
  • params: solver iteration/error parameters
  • rigidBodies: rigidbody to include in solver’s matrix

virtual float GetError() = 0

Return
the max error

struct Data
#include <LinearSolver.h>

The various parts of linear equations.

struct DebugCopy
#include <LinearSolver.h>

Copies the linear solver data in the debug linear solver data.

Public Functions

VORTEX_API void Vortex::Fluid::LinearSolver::DebugCopy::Copy()

Copies the linear solver data in the debug linear solver data.

struct DebugData
#include <LinearSolver.h>

Contains the linear equations as texture, so it can easily be visualised in RenderDoc.

class Error
#include <LinearSolver.h>

Calculates the max residual error of the linear system.

Public Functions

VORTEX_API void Vortex::Fluid::LinearSolver::Error::Bind(Renderer::GenericBuffer & d, Renderer::GenericBuffer & l, Renderer::GenericBuffer & div, Renderer::GenericBuffer & pressure)

Bind the linear system.

Parameters
  • d: the diagonal of the matrxi
  • l: the lower matrix
  • b: the right hand side
  • x: the unknowns

VORTEX_API Error& Vortex::Fluid::LinearSolver::Error::Submit()

Submit the error calculation.

Return
this.

VORTEX_API Error& Vortex::Fluid::LinearSolver::Error::Wait()

Wait for error to be calculated.

Return
this.

VORTEX_API float Vortex::Fluid::LinearSolver::Error::GetError()

Get the maximum error.

Return
The error.

struct Parameters
#include <LinearSolver.h>

Parameters for an iterative linear solvers.

Public Types

enum SolverType

Run the solver a fixed number of step or until we reached a minimum error.

Values:

Fixed
Iterative

Public Functions

VORTEX_API Parameters(SolverType type, unsigned iterations, float errorTolerance = 0.0f)

Construct parameters with max iterations and max error.

Parameters
  • type: fixed or iterative type of solver
  • iterations: max number of iterations to perform
  • errorTolerance: solver stops when the error is smaller than this.

bool IsFinished(float initialError) const

Checks if we’ve reacched the parameters.

Return
if we can stop the linear solver.
Parameters
  • initialError: the initial error

void Reset()

Sets the out error and out iterations to 0.

class LocalGaussSeidel : public Vortex::Fluid::Preconditioner
#include <GaussSeidel.h>

A version of the gauss seidel that can only be applied on sizes (16,16) or smaller.

Public Functions

void VORTEX_API Vortex::Fluid::LocalGaussSeidel::Bind(Renderer::GenericBuffer & d, Renderer::GenericBuffer & l, Renderer::GenericBuffer & b, Renderer::GenericBuffer & x)

Bind the linear equation buffers.

Parameters
  • d: the diagonal of the matrix
  • l: the lower matrix
  • b: the right hand side
  • x: the unknown buffer

void Record(Renderer::CommandEncoder &command)

Record the preconditioner.

Parameters
  • commandBuffer: the command buffer to record into.

class Multigrid : public Vortex::Fluid::LinearSolver, public Vortex::Fluid::Preconditioner
#include <Multigrid.h>

Multigrid preconditioner. It creates a hierarchy of twice as small set of linear equations. It applies a few iterations of jacobi on each level and transfers the error on the level above. It then copies the error down, adds to the current solution and apply a few more iterations of jacobi.

Public Functions

VORTEX_API Multigrid(Renderer::Device &device, const glm::ivec2 &size, float delta, int numSmoothingIterations = 3, SmootherSolver smoother = SmootherSolver::Jacobi)

Initialize multigrid for given size and delta.

Parameters
  • device: vulkan device
  • size: of the linear equations
  • delta: timestep delta

VORTEX_API void Vortex::Fluid::Multigrid::Bind(Renderer::GenericBuffer & d, Renderer::GenericBuffer & l, Renderer::GenericBuffer & b, Renderer::GenericBuffer & x)

Bind the buffers for the linear solver.

Parameters
  • d: the diagonal of the matrxi
  • l: the lower matrix
  • b: the right hand side
  • x: the unknowns

VORTEX_API void Vortex::Fluid::Multigrid::BuildHierarchiesBind(Pressure & pressure, Renderer::Texture & solidPhi, Renderer::Texture & liquidPhi)

Bind the level sets from which the hierarchy is built.

Parameters
  • pressure: The current linear equations
  • solidPhi: the solid level set
  • liquidPhi: the liquid level set

VORTEX_API void Vortex::Fluid::Multigrid::BuildHierarchies()

Computes the hierarchy to be used by the multigrid. Asynchronous operation.

void Record(Renderer::CommandEncoder &command)

Record the preconditioner.

Parameters
  • commandBuffer: the command buffer to record into.

void BindRigidbody(float delta, Renderer::GenericBuffer &d, RigidBody &rigidBody)

Bind rigidbody with the linear solver’s matrix.

Parameters
  • delta: solver delta
  • d: diagonal matrix
  • rigidBody: rigidbody to bind to

VORTEX_API void Vortex::Fluid::Multigrid::Solve(Parameters & params, const std::vector< RigidBody *> & rigidBodies = {})

Solves the linear equations.

Parameters
  • params: solver iteration/error parameters
  • rigidBodies: rigidbody to include in solver’s matrix

VORTEX_API float Vortex::Fluid::Multigrid::GetError()

Return
the max error

class ParticleCount : public Vortex::Renderer::RenderTexture
#include <Particles.h>

Container for particles used in the advection of the fluid simulation. Also a level set that is built from the particles.

Public Functions

VORTEX_API void Vortex::Fluid::ParticleCount::Scan()

Count the number of particles and update the internal data structures.

VORTEX_API int Vortex::Fluid::ParticleCount::GetTotalCount()

Calculate the total number of particles and return it.

Return

VORTEX_API Renderer::IndirectBuffer<Renderer::DispatchParams>& Vortex::Fluid::ParticleCount::GetDispatchParams()

Calculate the dispatch parameters to use on the particle buffer.

Return

VORTEX_API void Vortex::Fluid::ParticleCount::LevelSetBind(LevelSet & levelSet)

Bind a solid level set, which will be used to interpolate the particles out of.

Parameters
  • levelSet:

VORTEX_API void Vortex::Fluid::ParticleCount::Phi()

Calculate the level set from the particles.

VORTEX_API void Vortex::Fluid::ParticleCount::VelocitiesBind(Velocity & velocity, Renderer::GenericBuffer & valid)

Bind the velocities, used for advection of the particles.

Parameters
  • velocity:
  • valid:

VORTEX_API void Vortex::Fluid::ParticleCount::TransferToGrid()

Interpolate the velocities of the particles to the velocities field.

VORTEX_API void Vortex::Fluid::ParticleCount::TransferFromGrid()

Interpolate the velocities field in to the particles’ velocity.

class Polygon : public Vortex::Renderer::Transformable, public Vortex::Renderer::Drawable
#include <Boundaries.h>

Signed distance field of a poylgon.

Subclassed by Vortex::Fluid::Rectangle

Public Functions

VORTEX_API Polygon(Renderer::Device &device, std::vector<glm::vec2> points, bool inverse = false, float extent = 10.0f)

Initialize polygon with set of points and extent of signed distance.

Parameters
  • device: vulkan device
  • points: clockwise oriented set of points (mininum 3).
  • inverse: flag if the distance field should be inversed.
  • extent: extend how far from the poylon the signed distance field is calculated.

VORTEX_API void Vortex::Fluid::Polygon::Initialize(const Renderer::RenderState & renderState)

Initialize the drawable for a particular state. This might include creating the correct pipeline. If it was already initialized, it will do nothing.

Parameters
  • renderState: the state to initialize with.

VORTEX_API void Vortex::Fluid::Polygon::Update(const glm::mat4 & projection, const glm::mat4 & view)

Update the MVP matrix of the drawable.

Parameters
  • projection: the projection matrix
  • view: the view matrix

VORTEX_API void Vortex::Fluid::Polygon::Draw(Renderer::CommandEncoder & commandEncoder, const Renderer::RenderState & renderState)

Draw for the given render state. This has to be initialized before.

Parameters
  • commandBuffer: the command buffer to record into.
  • renderState: the render state to use.

struct Preconditioner
#include <Preconditioner.h>

An interface to represent a linear solver preconditioner.

Subclassed by Vortex::Fluid::Diagonal, Vortex::Fluid::GaussSeidel, Vortex::Fluid::IncompletePoisson, Vortex::Fluid::Jacobi, Vortex::Fluid::LocalGaussSeidel, Vortex::Fluid::Multigrid

Public Functions

virtual void Bind(Renderer::GenericBuffer &d, Renderer::GenericBuffer &l, Renderer::GenericBuffer &b, Renderer::GenericBuffer &x) = 0

Bind the linear equation buffers.

Parameters
  • d: the diagonal of the matrix
  • l: the lower matrix
  • b: the right hand side
  • x: the unknown buffer

virtual void Record(Renderer::CommandEncoder &command) = 0

Record the preconditioner.

Parameters
  • commandBuffer: the command buffer to record into.

class PrefixScan
#include <PrefixScan.h>

The prefix sum operator. 

void PrefixSym(int input[], int n, int output[])
{
    output[0] = input[0];

    for (int i = 1; i < n; i++)
        output[i] = output[i-1] + input[i];
}

class Bound
#include <PrefixScan.h>

A prefix scan object bound with input/output buffers, ready to be dispatched.

class Pressure
#include <Pressure.h>

build the linear equation and compute the divergence from the resulting solution.

Public Functions

Renderer::Work::Bound BindMatrixBuild(const glm::ivec2 &size, Renderer::GenericBuffer &diagonal, Renderer::GenericBuffer &lower, Renderer::Texture &liquidPhi, Renderer::Texture &solidPhi)

Bind the various buffes for the linear system Ax = b.

Return
Parameters
  • size: size of the linear system
  • diagonal: diagonal of A
  • lower: lower matrix of A
  • liquidPhi: liquid level set
  • solidPhi: solid level set

VORTEX_API void Vortex::Fluid::Pressure::BuildLinearEquation()

Build the matrix A and right hand side b.

VORTEX_API void Vortex::Fluid::Pressure::ApplyPressure()

Apply the solution of the equation Ax = b, i.e. the pressure to the velocity to make it non-divergent.

class Rectangle : public Vortex::Fluid::Polygon
#include <Boundaries.h>

Signed distance field of a rectangle.

Public Functions

VORTEX_API Rectangle(Renderer::Device &device, const glm::vec2 &size, bool inverse = false, float extent = 10.0f)

Initialize rectangle with size and extend of signed distance.

Parameters
  • device: vulkan device.
  • size: rectangle size
  • inverse: flag if the distance field should be inverted.
  • extent: extent how far from the rectangle the signed distance field is calculated.

VORTEX_API void Vortex::Fluid::Rectangle::Initialize(const Renderer::RenderState & renderState)

Initialize the drawable for a particular state. This might include creating the correct pipeline. If it was already initialized, it will do nothing.

Parameters
  • renderState: the state to initialize with.

VORTEX_API void Vortex::Fluid::Rectangle::Update(const glm::mat4 & projection, const glm::mat4 & view)

Update the MVP matrix of the drawable.

Parameters
  • projection: the projection matrix
  • view: the view matrix

VORTEX_API void Vortex::Fluid::Rectangle::Draw(Renderer::CommandEncoder & commandEncoder, const Renderer::RenderState & renderState)

Draw for the given render state. This has to be initialized before.

Parameters
  • commandBuffer: the command buffer to record into.
  • renderState: the render state to use.

class Reduce
#include <Reduce.h>

Parallel reduction of a buffer into one value. The operator and type of data is specified by inheriting the class.

Subclassed by Vortex::Fluid::ReduceJ, Vortex::Fluid::ReduceMax, Vortex::Fluid::ReduceSum

Public Functions

VORTEX_API Reduce::Bound Vortex::Fluid::Reduce::Bind(Renderer::GenericBuffer & input, Renderer::GenericBuffer & output)

Bind the reduce operation.

Return
a bound object that can be recorded in a command buffer.
Parameters
  • input: input buffer
  • output: output buffer

class Bound
#include <Reduce.h>

Bound input and output buffer for a reduce operation.

Public Functions

VORTEX_API void Vortex::Fluid::Reduce::Bound::Record(Renderer::CommandEncoder & command)

Record the reduce operation.

Parameters
  • commandBuffer: the command buffer to record into.

class ReduceJ : public Vortex::Fluid::Reduce
#include <Reduce.h>

Reduce operation on a struct with a 2d vector and 1 float (i.e. 3 floats) with addition.

Public Functions

VORTEX_API ReduceJ(Renderer::Device &device, int size)

Initialize reduce with device and 2d size.

Parameters
  • device:
  • size:

class ReduceMax : public Vortex::Fluid::Reduce
#include <Reduce.h>

Reduce operation on float with max of absolute.

Public Functions

VORTEX_API ReduceMax(Renderer::Device &device, int size)

Initialize reduce with device and 2d size.

Parameters
  • device:
  • size:

class ReduceSum : public Vortex::Fluid::Reduce
#include <Reduce.h>

Reduce operation on float with addition.

Public Functions

VORTEX_API ReduceSum(Renderer::Device &device, int size)

Initialize reduce with device and 2d size.

Parameters
  • device:
  • size:

class RigidBody : public Vortex::Renderer::Transformable
#include <Rigidbody.h>

Rigidbody that can interact with the fluid: either be push by it, or influence it, or both.

Public Functions

virtual VORTEX_API void Vortex::Fluid::RigidBody::ApplyForces()

function to override and apply forces from this rigidbody to the external rigidbody

virtual VORTEX_API void Vortex::Fluid::RigidBody::ApplyVelocities()

Override and apply velocities from the external rigidbody to the this rigidbody.

VORTEX_API void Vortex::Fluid::RigidBody::SetMassData(float mass, float inertia)

Sets the mass and inertia of the rigidbody.

Parameters
  • mass: of the body
  • inertia: of the body

VORTEX_API void Vortex::Fluid::RigidBody::SetVelocities(const glm::vec2 & velocity, float angularVelocity)

sets the velocities and angular velocities of the body

Parameters
  • velocity:
  • angularVelocity:

VORTEX_API void Vortex::Fluid::RigidBody::UpdatePosition()

Upload the transform matrix to the GPU.

VORTEX_API void Vortex::Fluid::RigidBody::RenderPhi()

Render the current object orientation in an internal texture and the external one.

VORTEX_API void Vortex::Fluid::RigidBody::BindPhi(Renderer::RenderTexture & phi)

Bind the rendertexture where this rigidbodies shape will be rendered.

Parameters
  • phi: render texture of the world

VORTEX_API void Vortex::Fluid::RigidBody::BindDiv(Renderer::GenericBuffer & div, Renderer::GenericBuffer & diagonal)

Bind a the right hand side and diagonal of the linear system Ax = b. This is to apply the rigid body influence to the system.

Parameters
  • div: right hand side of the linear system Ax=b
  • diagonal: diagonal of matrix A

VORTEX_API void Vortex::Fluid::RigidBody::BindVelocityConstrain(Fluid::Velocity & velocity)

Bind velocities to constrain based on the body’s velocity.

Parameters
  • velocity:

VORTEX_API void Vortex::Fluid::RigidBody::BindForce(Renderer::GenericBuffer & d, Renderer::GenericBuffer & pressure)

Bind pressure, to have the pressure update the body’s forces.

Parameters
  • d: diagonal of matrix A
  • pressure: solved pressure buffer

VORTEX_API void Vortex::Fluid::RigidBody::BindPressure(float delta, Renderer::GenericBuffer & d, Renderer::GenericBuffer & s, Renderer::GenericBuffer & z)

Bind pressure, to have the pressure update the body’s forces.

Parameters
  • delta:
  • d:
  • s:
  • z:

VORTEX_API void Vortex::Fluid::RigidBody::Div()

Apply the body’s velocities to the linear equations matrix A and right hand side b.

VORTEX_API void Vortex::Fluid::RigidBody::Force()

Apply the pressure to body, updating its forces.

VORTEX_API void Vortex::Fluid::RigidBody::Pressure()

Reduce the force for pressure update.

VORTEX_API void Vortex::Fluid::RigidBody::VelocityConstrain()

Constrain the velocities field based on the body’s velocity.

VORTEX_API Velocity Vortex::Fluid::RigidBody::GetForces()

Download the forces from the GPU and return them.

Return

VORTEX_API Type Vortex::Fluid::RigidBody::GetType()

Type of this body.

Return

VORTEX_API void Vortex::Fluid::RigidBody::SetType(Type type)

Set the type of the body.

Parameters
  • type:

VORTEX_API Renderer::RenderTexture& Vortex::Fluid::RigidBody::Phi()

the local level set of the body

Return

class RigidBodySolver
#include <Rigidbody.h>

Interface to call the external rigidbody solver.

Public Functions

virtual void Step(float delta) = 0

perfoms a single step of the solver.

Parameters
  • delta: of simulation

class SmokeWorld : public Vortex::Fluid::World
#include <World.h>

A concrete implementation of World to simulate ‘smoke’, or more accurately dye in a liquid. The liquid cannot change location or size.

Public Functions

VORTEX_API void Vortex::Fluid::SmokeWorld::FieldBind(Density & density)

Bind a density field to be moved around with the fluid.

Parameters
  • density: the density field

class Transfer
#include <Transfer.h>

Prolongates or restrict a level set on a finer or coarser level set.

Public Functions

VORTEX_API Transfer(Renderer::Device &device)

Initialize prolongate and restrict compute pipelines.

Parameters
  • device:

VORTEX_API void Vortex::Fluid::Transfer::ProlongateBind(std::size_t level, const glm::ivec2 & fineSize, Renderer::GenericBuffer & fine, Renderer::GenericBuffer & fineDiagonal, Renderer::GenericBuffer & coarse, Renderer::GenericBuffer & coarseDiagonal)

Prolongate a level set on a finer level set. Setting the 4 cells to the value of the coarser grid. Multiple level sets can be bound and indexed.

Parameters
  • level: the index of the bound level set to prolongate
  • fineSize: size of the finer level set
  • fine: the finer level set
  • fineDiagonal: the diagonal of the linear equation matrix at size fineSize
  • coarse: the coarse level set
  • coarseDiagonal: the diagonal of the linear equation matrix at size half of fineSize

VORTEX_API void Vortex::Fluid::Transfer::RestrictBind(std::size_t level, const glm::ivec2 & fineSize, Renderer::GenericBuffer & fine, Renderer::GenericBuffer & fineDiagonal, Renderer::GenericBuffer & coarse, Renderer::GenericBuffer & coarseDiagonal)

Restricing the level set on a coarser level set. Averages 4 cells into one. Multiple level sets can be bound and indexed.

Parameters
  • level: the index of the bound level set to prolongate
  • fineSize: size of the finer level set
  • fine: the finer level set
  • fineDiagonal: the diagonal of the linear equation matrix at size fineSize
  • coarse: the coarse level set
  • coarseDiagonal: the diagonal of the linear equation matrix at size half of fineSize

VORTEX_API void Vortex::Fluid::Transfer::Prolongate(Renderer::CommandEncoder & command, std::size_t level)

Prolongate the level set, using the bound level sets at the specified index.

Parameters
  • commandBuffer: command buffer to record into.
  • level: index of bound level sets.

VORTEX_API void Vortex::Fluid::Transfer::Restrict(Renderer::CommandEncoder & command, std::size_t level)

Restrict the level set, using the bound level sets at the specified index.

Parameters
  • commandBuffer: command buffer to record into.
  • level: index of bound level sets.

class Velocity : public Vortex::Renderer::RenderTexture
#include <Velocity.h>

The Velocity field. Can be used to calculate a difference between different states. Contains three fields: intput and output, used for ping-pong algorithms, and d, the difference between two velocity fields.

Public Types

enum InterpolationMode

Velocity interpolation when querying in the shader with non-integer locations.

Values:

Linear = 0
Cubic = 1

Public Functions

VORTEX_API Renderer::Texture& Vortex::Fluid::Velocity::Output()

An output texture used for algorithms that used the velocity as input and need to create a new velocity field.

Return

VORTEX_API Renderer::Texture& Vortex::Fluid::Velocity::D()

A difference velocity field, calculated with the difference between this velocity field, and the output velocity field.

Return

VORTEX_API void Vortex::Fluid::Velocity::CopyBack(Renderer::CommandEncoder & command)

Copy the output field to the main field.

Parameters
  • commandBuffer:

VORTEX_API void Vortex::Fluid::Velocity::Clear(Renderer::CommandEncoder & command)

Clear the velocity field.

Parameters
  • commandBuffer:

VORTEX_API void Vortex::Fluid::Velocity::SaveCopy()

Copy to the difference field.

VORTEX_API void Vortex::Fluid::Velocity::VelocityDiff()

Calculate the difference between the difference field and this velocity field, store it in the diference field.

class WaterWorld : public Vortex::Fluid::World
#include <World.h>

A concrete implementation of World to simulate water.

Public Functions

VORTEX_API Renderer::RenderCommand Vortex::Fluid::WaterWorld::RecordParticleCount(Renderer::RenderTarget::DrawableList drawables)

The water simulation uses particles to define the water area. In fact, the level set is built from the particles. This means to be able to set an area, we can’t use RecordLiquidPhi. To define the particle area, simply draw a regular shape. The colour r is used to determine if we add or remove particles, use r = 4 to add and r = -4 to remove.

Return
render command
Parameters
  • drawables: list of drawables object with colour 8 or -8

VORTEX_API void Vortex::Fluid::WaterWorld::ParticlePhi()

Using the particles, create a level set (phi) encompassing all the particles. This can be viewed with LiquidDistanceField.

class World
#include <World.h>

The main class of the framework. Each instance manages a grid and this class is used to set forces, define boundaries, solve the incompressbility equations and do the advection.

Subclassed by Vortex::Fluid::SmokeWorld, Vortex::Fluid::WaterWorld

Public Functions

World(Renderer::Device &device, const glm::ivec2 &size, float dt, int numSubSteps = 1, Velocity::InterpolationMode interpolationMode = Velocity::InterpolationMode::Linear)

Construct an Engine with a size and time step.

Parameters
  • device: vulkan device
  • size: dimensions of the simulation
  • dt: timestamp of the simulation, e.g. 0.016 for 60FPS simulations.
  • numSubSteps: the number of sub-steps to perform per step call. Reduces loss of fluid.

VORTEX_API void Vortex::Fluid::World::Step(LinearSolver::Parameters & params)

Perform one step of the simulation.

VORTEX_API Renderer::RenderCommand Vortex::Fluid::World::RecordVelocity(Renderer::RenderTarget::DrawableList drawables, VelocityOp op)

Record drawables to the velocity field. The colour (r,g) will be used as the velocity (x, y)

Return
render command
Parameters
  • drawables: a list of drawable field
  • op: operation of the render: add velocity or set velocity

VORTEX_API void Vortex::Fluid::World::SubmitVelocity(Renderer::RenderCommand & renderCommand)

submit the render command created with RecordVelocity

Parameters
  • renderCommand: the render command

VORTEX_API Renderer::RenderCommand Vortex::Fluid::World::RecordLiquidPhi(Renderer::RenderTarget::DrawableList drawables)

Record drawables to the liquid level set, i.e. to define the fluid area. The drawables need to make a signed distance field, if not the result is undefined.

Return
render command
Parameters
  • drawables: a list of signed distance field drawables

VORTEX_API Renderer::RenderCommand Vortex::Fluid::World::RecordStaticSolidPhi(Renderer::RenderTarget::DrawableList drawables)

Record drawables to the solid level set, i.e. to define the boundary area. The drawables need to make a signed distance field, if not the result is undefined.

Return
render command
Parameters
  • drawables: a list of signed distance field drawables

VORTEX_API std::shared_ptr<DistanceField> Vortex::Fluid::World::MakeLiquidDistanceField()

Create sprite that can be rendered to visualize the liquid level set.

Return
a sprite

VORTEX_API std::shared_ptr<DistanceField> Vortex::Fluid::World::MakeSolidDistanceField()

Create sprite that can be rendered to visualize the solid level set.

Return
a sprite

VORTEX_API void Vortex::Fluid::World::AddRigidbody(RigidBody & rigidbody)

Add a rigibody to the solver.

Parameters
  • rigidbody:

VORTEX_API void Vortex::Fluid::World::RemoveRigidBody(RigidBody & rigidbody)

Remove a rigidbody from the solver.

Parameters
  • rigidbody:

VORTEX_API void Vortex::Fluid::World::AttachRigidBodySolver(RigidBodySolver & rigidbodySolver)

Attach a rigidbody solver, e.g. box2d.

Parameters
  • rigidbodySolver:

VORTEX_API float Vortex::Fluid::World::GetCFL()

Calculate the CFL number, i.e. the width divided by the max velocity.

Return
CFL number

VORTEX_API Renderer::Texture& Vortex::Fluid::World::GetVelocity()

Get the velocity, can be used to display it.

Return
velocity field reference