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New emitter concept for variable velocity and velocity profiles #369

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7bf5480
new emitter concept for variable velocity
lukashof Nov 5, 2025
8179611
introducing velocity profiles for circular emitters
lukashof Nov 6, 2025
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559 changes: 187 additions & 372 deletions SPlisHSPlasH/Emitter.cpp
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28 changes: 14 additions & 14 deletions SPlisHSPlasH/Emitter.h
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Expand Up @@ -11,26 +11,27 @@ namespace SPH
class Emitter
{
public:
Emitter(FluidModel *model,
const unsigned int width, const unsigned int height,
const Vector3r &pos, const Matrix3r & rotation,
const Real velocity,
const unsigned int type = 0);
virtual ~Emitter();
Emitter(FluidModel* model, const unsigned int width, const unsigned int height, const Vector3r& pos,
const Matrix3r& rotation, const Real velocity, const unsigned int type = 0, const bool useBoundary = false,
const unsigned int velocityProfile = 0);
virtual ~Emitter();

protected:
FluidModel *m_model;
unsigned int m_width;
unsigned int m_height;
unsigned int m_depth;
Vector3r m_size{0, 0, 0};
Vector3r m_x;
Matrix3r m_rotation;
Real m_velocity;
unsigned int m_type;
Real m_nextEmitTime;
Real m_emitStartTime;
Real m_emitEndTime;
unsigned int m_emitCounter;
Real m_emitStartTime{0};
Real m_emitEndTime{std::numeric_limits<Real>::max()};
unsigned int m_emitCounter{0};
unsigned int m_objectId;
bool m_useBoundary;
unsigned int m_velocityProfile;// 0: constant, 1: linear, 2: quadratic

FORCE_INLINE bool inBox(const Vector3r &x, const Vector3r &xBox, const Matrix3r &rotBox, const Vector3r &scaleBox)
{
Expand All @@ -53,12 +54,11 @@ namespace SPH

public:
void emitParticles(std::vector <unsigned int> &reusedParticles, unsigned int &indexReuse, unsigned int &numEmittedParticles);
void emitParticlesCircle(std::vector <unsigned int> &reusedParticles, unsigned int &indexReuse, unsigned int &numEmittedParticles);
Real getNextEmitTime() const { return m_nextEmitTime; }
void setNextEmitTime(Real val) { m_nextEmitTime = val; }
void setEmitStartTime(Real val) { m_emitStartTime = val; setNextEmitTime(val); }
void setEmitStartTime(Real val) { m_emitStartTime = val; }
void setEmitEndTime(Real val) { m_emitEndTime = val; }
static int getDepth();
static Vector3r getSize(const Real width, const Real height, const int type);
static Vector3r getSizeExtraMargin(const Real width, const Real height, const int type);

void step(std::vector <unsigned int> &reusedParticles, unsigned int &indexReuse, unsigned int &numEmittedParticles);
virtual void reset();
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25 changes: 5 additions & 20 deletions SPlisHSPlasH/EmitterSystem.cpp
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Expand Up @@ -59,17 +59,6 @@ void EmitterSystem::step()
// reset particle state
Simulation *sim = Simulation::getCurrent();
const unsigned int nModels = sim->numberOfFluidModels();
for (unsigned int m = 0; m < nModels; m++)
{
FluidModel *fm = sim->getFluidModel(m);
const unsigned int numParticles = fm->numActiveParticles();
#pragma omp parallel for schedule(static) default(shared)
for (int i = 0; i < (int)numParticles; i++)
{
if (fm->getParticleState(i) == ParticleState::AnimatedByEmitter)
fm->setParticleState(i, ParticleState::Active);
}
}

reuseParticles();
unsigned int indexReuse = 0;
Expand All @@ -93,16 +82,12 @@ void EmitterSystem::reset()
}
}

void EmitterSystem::addEmitter(const unsigned int width, const unsigned int height,
const Vector3r &pos, const Matrix3r & rotation,
const Real velocity,
const unsigned int type)
void EmitterSystem::addEmitter(const unsigned int width, const unsigned int height, const Vector3r& pos,
const Matrix3r& rotation, const Real velocity, const unsigned int type,
const bool useBoundary, const unsigned int velocityProfile)
{
m_emitters.push_back(new Emitter(m_model,
width, height,
pos, rotation,
velocity,
type));
m_emitters.push_back(
new Emitter(m_model, width, height, pos, rotation, velocity, type, useBoundary, velocityProfile));
}

void EmitterSystem::enableReuseParticles(const Vector3r &boxMin /*= Vector3r(-1, -1, -1)*/, const Vector3r &boxMax /*= Vector3r(1, 1, 1)*/)
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7 changes: 3 additions & 4 deletions SPlisHSPlasH/EmitterSystem.h
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Expand Up @@ -32,10 +32,9 @@ namespace SPH
public:
void enableReuseParticles(const Vector3r &boxMin = Vector3r(-1, -1, -1), const Vector3r &boxMax = Vector3r(1, 1, 1));
void disableReuseParticles();
void addEmitter(const unsigned int width, const unsigned int height,
const Vector3r &pos, const Matrix3r & rotation,
const Real velocity,
const unsigned int type);
void addEmitter(const unsigned int width, const unsigned int height, const Vector3r& pos, const Matrix3r& rotation,
const Real velocity, const unsigned int type, const bool useBoundary = false,
const unsigned int velocityProfile = 0);
unsigned int numEmitters() const { return static_cast<unsigned int>(m_emitters.size()); }
std::vector<Emitter*> &getEmitters() { return m_emitters; }

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11 changes: 11 additions & 0 deletions SPlisHSPlasH/Utilities/SceneParameterObjects.cpp
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Expand Up @@ -17,6 +17,7 @@ int FluidBlockParameterObject::FLUID_BLOCK_VISMESH = -1;
int FluidBlockParameterObject::FLUID_BLOCK_MODE = -1;
int FluidBlockParameterObject::FLUID_BLOCK_INITIAL_VEL = -1;
int FluidBlockParameterObject::FLUID_BLOCK_INITIAL_ANGVEL = -1;
int EmitterParameterObject::EMITTER_USEBOUNDARY = -1;

void FluidBlockParameterObject::initParameters()
{
Expand Down Expand Up @@ -138,6 +139,7 @@ int EmitterParameterObject::EMITTER_ROTANGLE = -1;
int EmitterParameterObject::EMITTER_STARTTIME = -1;
int EmitterParameterObject::EMITTER_ENDTIME = -1;
int EmitterParameterObject::EMITTER_TYPE = -1;
int EmitterParameterObject::EMITTER_VELOCITYPROFILE = -1;

void EmitterParameterObject::initParameters()
{
Expand Down Expand Up @@ -180,6 +182,15 @@ void EmitterParameterObject::initParameters()
EMITTER_TYPE = createNumericParameter<unsigned int>("type", "Emitter type", &type);
setGroup(EMITTER_TYPE, "Emitter");
setDescription(EMITTER_TYPE, "Defines the shape of the emitter: 0: box, 1: circle.");

EMITTER_USEBOUNDARY = createBoolParameter("useBoundary", "Use Boundary", &useBoundary);
setGroup(EMITTER_USEBOUNDARY, "Emitter");
setDescription(EMITTER_USEBOUNDARY, "Creates a boundary model around the emitter if defined");

EMITTER_VELOCITYPROFILE =
createNumericParameter<unsigned int>("velocityProfile", "Velocity Profile", &velocityProfile);
setGroup(EMITTER_VELOCITYPROFILE, "Emitter");
setDescription(EMITTER_VELOCITYPROFILE, "Defines the velocity profile of the emitter.");
}


Expand Down
13 changes: 11 additions & 2 deletions SPlisHSPlasH/Utilities/SceneParameterObjects.h
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Expand Up @@ -144,6 +144,8 @@ namespace Utilities
Real emitStartTime;
Real emitEndTime;
unsigned int type; // type: 0 = rectangular, 1 = circle
bool useBoundary;
unsigned int velocityProfile;

EmitterParameterObject()
{
Expand All @@ -158,10 +160,13 @@ namespace Utilities
emitStartTime = 0.0;
emitEndTime = std::numeric_limits<Real>::max();
type = 0;
useBoundary = false;
velocityProfile = 0;
}

EmitterParameterObject(std::string id_, unsigned int width_, unsigned int height_, Vector3r x_, Real velocity_, Vector3r axis_,
Real angle_, Real emitStartTime_, Real emitEndTime_, unsigned int type_)
EmitterParameterObject(std::string id_, unsigned int width_, unsigned int height_, Vector3r x_, Real velocity_,
Vector3r axis_, Real angle_, Real emitStartTime_, Real emitEndTime_, unsigned int type_,
bool useBoundary_, unsigned int velocityProfile_)
{
id = id_;
width = width_;
Expand All @@ -173,6 +178,8 @@ namespace Utilities
emitStartTime = emitStartTime_;
emitEndTime = emitEndTime_;
type = type_;
useBoundary = useBoundary_;
velocityProfile = velocityProfile_;
}

static int EMITTER_ID;
Expand All @@ -185,6 +192,8 @@ namespace Utilities
static int EMITTER_STARTTIME;
static int EMITTER_ENDTIME;
static int EMITTER_TYPE;
static int EMITTER_USEBOUNDARY;
static int EMITTER_VELOCITYPROFILE;

virtual void initParameters();
};
Expand Down
2 changes: 1 addition & 1 deletion Simulator/PositionBasedDynamicsWrapper/PBDBoundarySimulator.cpp
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Expand Up @@ -70,7 +70,7 @@ void PBDBoundarySimulator::initBoundaryData()
PBDWrapper::RBData rb;
rb.x = ed->x;
rb.R = AngleAxisr(ed->angle, ed->axis).toRotationMatrix();
rb.scale = Emitter::getSize(static_cast<Real>(ed->width), static_cast<Real>(ed->height), ed->type);
rb.scale = Emitter::getSizeExtraMargin(static_cast<Real>(ed->width), static_cast<Real>(ed->height), ed->type);
rb.restitution = 0.6;
rb.friction = 0.1;
if (ed->type == 0)
Expand Down
68 changes: 35 additions & 33 deletions Simulator/SimulatorBase.cpp
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Expand Up @@ -1314,39 +1314,41 @@ void SimulatorBase::createEmitters()
ed->width = 1;
ed->type = 0;
}
Matrix3r rot = AngleAxisr(ed->angle, ed->axis).toRotationMatrix();
model->getEmitterSystem()->addEmitter(
ed->width, ed->height,
ed->x, rot,
ed->velocity,
ed->type);

// Generate boundary geometry around emitters
Emitter *emitter = model->getEmitterSystem()->getEmitters().back();
BoundaryParameterObject *emitterBoundary = new BoundaryParameterObject();
emitterBoundary->dynamic = false;
emitterBoundary->isWall = false;
emitterBoundary->color = { 0.2f, 0.2f, 0.2f, 1.0f };
emitterBoundary->axis = ed->axis;
emitterBoundary->angle = ed->angle;
const Real supportRadius = sim->getSupportRadius();
const Vector3r & emitDir = rot.col(0);
emitterBoundary->scale = Emitter::getSize(static_cast<Real>(ed->width), static_cast<Real>(ed->height), ed->type);
const Vector3r pos = ed->x;
emitterBoundary->translation = pos;
emitterBoundary->samplesFile = "";
emitterBoundary->mapInvert = false;
emitterBoundary->mapResolution = Eigen::Matrix<unsigned int, 3, 1, Eigen::DontAlign>(20, 20, 20);
emitterBoundary->mapThickness = 0.0;

if (sim->is2DSimulation())
emitterBoundary->scale[2] = 2 * supportRadius;

if (ed->type == 0)
emitterBoundary->meshFile = FileSystem::normalizePath(getExePath() + "/resources/emitter_boundary/EmitterBox.obj");
else if (ed->type == 1)
emitterBoundary->meshFile = FileSystem::normalizePath(getExePath() + "/resources/emitter_boundary/EmitterCylinder.obj");
scene.boundaryModels.push_back(emitterBoundary);
Matrix3r rot = AngleAxisr(ed->angle, ed->axis.normalized()).toRotationMatrix();
model->getEmitterSystem()->addEmitter(ed->width, ed->height, ed->x, rot, ed->velocity, ed->type,
ed->useBoundary, ed->velocityProfile);

Emitter* emitter = model->getEmitterSystem()->getEmitters().back();
if (ed->useBoundary) {
// Generate boundary geometry around emitters
BoundaryParameterObject* emitterBoundary = new BoundaryParameterObject();
emitterBoundary->dynamic = false;
emitterBoundary->isWall = false;
emitterBoundary->color = {0.2f, 0.2f, 0.2f, 1.0f};
emitterBoundary->axis = ed->axis;
emitterBoundary->angle = ed->angle;
const Real supportRadius = sim->getSupportRadius();
const Vector3r& emitDir = rot.col(0);
emitterBoundary->scale =
Emitter::getSizeExtraMargin(static_cast<Real>(ed->width), static_cast<Real>(ed->height), ed->type);
const Vector3r pos = ed->x;
emitterBoundary->translation = pos;
emitterBoundary->samplesFile = "";
emitterBoundary->mapInvert = false;
emitterBoundary->mapResolution = Eigen::Matrix<unsigned int, 3, 1, Eigen::DontAlign>(20, 20, 20);
emitterBoundary->mapThickness = 0.0;

if (sim->is2DSimulation())
emitterBoundary->scale[2] = 2 * supportRadius;

if (ed->type == 0)
emitterBoundary->meshFile =
FileSystem::normalizePath(getExePath() + "/resources/emitter_boundary/EmitterBox.obj");
else if (ed->type == 1)
emitterBoundary->meshFile =
FileSystem::normalizePath(getExePath() + "/resources/emitter_boundary/EmitterCylinder.obj");
scene.boundaryModels.push_back(emitterBoundary);
}

// reuse particles if they are outside of a bounding box
bool emitterReuseParticles = false;
Expand Down
3 changes: 0 additions & 3 deletions pySPlisHSPlasH/EmitterModule.cpp
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Expand Up @@ -28,9 +28,6 @@ void EmitterModule(py::module m_sub){
return SPH::Emitter(model, width, height, pos, rotation, velocity, type);
}))
.def("emitParticles", &SPH::Emitter::emitParticles)
.def("emitParticlesCircle", &SPH::Emitter::emitParticlesCircle)
.def("getNextEmitTime", &SPH::Emitter::getNextEmitTime)
.def("setNextEmitTime", &SPH::Emitter::setNextEmitTime)
.def("setEmitStartTime", &SPH::Emitter::setEmitStartTime)
.def("setEmitEndTime", &SPH::Emitter::setEmitEndTime)
.def("getPosition", &SPH::Emitter::getPosition)
Expand Down
13 changes: 8 additions & 5 deletions pySPlisHSPlasH/UtilitiesModule.cpp
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Expand Up @@ -339,10 +339,12 @@ void UtilitiesModule(py::module m) {

py::class_<Utilities::EmitterParameterObject, GenParam::ParameterObject>(m_sub_sub, "EmitterData")
.def(py::init<>())
.def(py::init<std::string, unsigned int, unsigned int, Vector3r, Real, Vector3r, Real, Real, Real, unsigned int>(),
"id"_a="Fluid", "width"_a=5, "height"_a=5, "x"_a=Vector3r::Zero(),
"velocity"_a=1, "axis"_a = Vector3r(1, 0, 0), "angle"_a = 0.0, "emitStartTime"_a=0,
"emitEndTime"_a=std::numeric_limits<Real>::max(), "type"_a=0)
.def(py::init<std::string, unsigned int, unsigned int, Vector3r, Real, Vector3r, Real, Real, Real, unsigned int,
bool, unsigned int>(),
"id"_a = "Fluid", "width"_a = 5, "height"_a = 5, "x"_a = Vector3r::Zero(), "velocity"_a = 1,
"axis"_a = Vector3r(1, 0, 0), "angle"_a = 0.0, "emitStartTime"_a = 0,
"emitEndTime"_a = std::numeric_limits<Real>::max(), "type"_a = 0, "useBoundary"_a = false,
"velocityProfile"_a = 0)
.def_readwrite("id", &Utilities::EmitterParameterObject::id)
.def_readwrite("width", &Utilities::EmitterParameterObject::width)
.def_readwrite("height", &Utilities::EmitterParameterObject::height)
Expand All @@ -352,7 +354,8 @@ void UtilitiesModule(py::module m) {
.def_readwrite("angle", &Utilities::EmitterParameterObject::angle)
.def_readwrite("emitStartTime", &Utilities::EmitterParameterObject::emitStartTime)
.def_readwrite("emitEndTime", &Utilities::EmitterParameterObject::emitEndTime)
.def_readwrite("type", &Utilities::EmitterParameterObject::type);
.def_readwrite("type", &Utilities::EmitterParameterObject::type)
.def_readwrite("useBoundary", &Utilities::EmitterParameterObject::useBoundary);

py::class_<Utilities::AnimationFieldParameterObject, GenParam::ParameterObject>(m_sub_sub, "AnimationFieldData")
.def(py::init<>())
Expand Down