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Add a slider to displace pendula via GUI.

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------------------------------------------------
The slider applies the selected displacement force according to the chosen scalar and falls back to zero when moved below an absolute value of 0.2.
This commit is contained in:
Benjamin Ellenberger
2016-07-11 23:07:48 +02:00
parent 5112de3e3f
commit ed13cc6c26
4 changed files with 166 additions and 65 deletions
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6
examples/ExampleBrowser/ExampleEntries.cpp
View File

@@ -282,9 +282,9 @@ static ExampleEntry gDefaultExamples[]=
ExampleEntry(1,"Simple Chain", "Create a simple chain using a pair of point2point/distance constraints. You may click and drag any box to see the chain respond.", ET_ChainCreateFunc),
ExampleEntry(1,"Simple Bridge", "Create a simple bridge using a pair of point2point/distance constraints. You may click and drag any plank to see the bridge respond.", ET_BridgeCreateFunc),
ExampleEntry(1,"Inclined Plane", "Create an inclined plane to show restitution and different types of friction. Use the sliders to vary restitution and friction and press space to reset the scene.", ET_InclinedPlaneCreateFunc),
ExampleEntry(1,"Newton's Cradle", "Create a Newton's Cradle using a pair of point2point/slider constraints. Press 1/2 to lengthen/shorten the pendula, press 3 to displace pendula. Use the sliders to select the number of pendula in total (reset simulation), the number of displaced pendula and other options.", ET_NewtonsCradleCreateFunc),
ExampleEntry(1,"Newton's Rope Cradle", "Create a Newton's Cradle using ropes. Press 3 to displace pendula. Use the sliders to select the number of pendula in total (reset simulation) and the number of displaced pendula.",ET_NewtonsRopeCradleCreateFunc),
ExampleEntry(1,"Multi-Pendulum", "Create a Multi-Pendulum using point2point/slider constraints. Press 1/2 to lengthen/shorten the pendula, press 3 to displace pendula. Use the sliders to select the number of pendula in total (reset simulation), the number of displaced pendula and other options.",ET_MultiPendulumCreateFunc),
ExampleEntry(1,"Newton's Cradle", "Create a Newton's Cradle using a pair of point2point/slider constraints. Press 1/2 to lengthen/shorten the pendula, press 3 to displace pendula. Use the sliders to select the number (reset simulation), length and restitution of pendula, the number of displaced pendula and apply the displacement force.", ET_NewtonsCradleCreateFunc),
ExampleEntry(1,"Newton's Rope Cradle", "Create a Newton's Cradle using ropes. Press 3 to displace pendula. Use the sliders to select the number (reset simulation), length and restitution of pendula and the number of displaced pendula and apply the displacement force.",ET_NewtonsRopeCradleCreateFunc),
ExampleEntry(1,"Multi-Pendulum", "Create a Multi-Pendulum using point2point/slider constraints. Press 1/2 to lengthen/shorten the pendula, press 3 to displace pendula. Use the sliders to select the number (reset simulation), length and restitution of pendula, the number of displaced pendula and apply the displacement force.",ET_MultiPendulumCreateFunc),
//todo: create a category/tutorial about advanced topics, such as optimizations, using different collision detection algorithm, different constraint solvers etc.

62
examples/ExtendedTutorials/MultiPendulum.cpp
View File

@@ -38,6 +38,8 @@ static btScalar gInitialPendulumLength = 8; // Default pendulum length (distance
static btScalar gDisplacementForce = 30; // The default force with which we move the pendulum
static btScalar gForceScalar = 0; // default force scalar to apply a displacement
struct MultiPendulumExample: public CommonRigidBodyBase {
MultiPendulumExample(struct GUIHelperInterface* helper) :
CommonRigidBodyBase(helper) {
@@ -47,21 +49,13 @@ struct MultiPendulumExample: public CommonRigidBodyBase {
}
virtual void initPhysics(); // build a multi pendulum
virtual void renderScene(); // render the scene to screen
virtual void createMultiPendulum(btSphereShape* colShape,
btScalar pendulaQty, btScalar xPosition, btScalar yPosition,btScalar zPosition,
btScalar length, btScalar mass); // create a multi pendulum at the indicated x and y position, the specified number of pendula formed into a chain, each with indicated length and mass
virtual void createMultiPendulum(btSphereShape* colShape, btScalar pendulaQty, btScalar xPosition, btScalar yPosition,btScalar zPosition, btScalar length, btScalar mass); // create a multi pendulum at the indicated x and y position, the specified number of pendula formed into a chain, each with indicated length and mass
virtual void changePendulaLength(btScalar length); // change the pendulum length
virtual void changePendulaRestitution(btScalar restitution); // change the pendula restitution
virtual void stepSimulation(float deltaTime); // step the simulation
virtual bool keyboardCallback(int key, int state); // handle keyboard callbacks
virtual void applyPendulumForce(btScalar pendulumForce);
void resetCamera() {
float dist = 41;
float pitch = 52;
@@ -72,7 +66,6 @@ struct MultiPendulumExample: public CommonRigidBodyBase {
}
std::vector<btSliderConstraint*> constraints; // keep a handle to the slider constraints
std::vector<btRigidBody*> pendula; // keep a handle to the pendula
};
@@ -84,6 +77,8 @@ void onMultiPendulaRestitutionChanged(float pendulaRestitution); // change the p
void floorMSliderValue(float notUsed); // floor the slider values which should be integers
void applyMForceWithForceScalar(float forceScalar);
void MultiPendulumExample::initPhysics() { // Setup your physics scene
{ // create a slider to change the number of pendula
@@ -135,6 +130,15 @@ void MultiPendulumExample::initPhysics() { // Setup your physics scene
slider);
}
{ // create a slider to apply the force by slider
SliderParams slider("Apply displacement force", &gForceScalar);
slider.m_minVal = -1;
slider.m_maxVal = 1;
slider.m_clampToNotches = false;
m_guiHelper->getParameterInterface()->registerSliderFloatParameter(
slider);
}
m_guiHelper->setUpAxis(1);
createEmptyDynamicsWorld();
@@ -168,10 +172,12 @@ void MultiPendulumExample::initPhysics() { // Setup your physics scene
}
void MultiPendulumExample::stepSimulation(float deltaTime) {
applyMForceWithForceScalar(gForceScalar); // apply force defined by apply force slider
if (m_dynamicsWorld) {
m_dynamicsWorld->stepSimulation(deltaTime);
}
}
void MultiPendulumExample::createMultiPendulum(btSphereShape* colShape,
@@ -352,7 +358,7 @@ bool MultiPendulumExample::keyboardCallback(int key, int state) {
//key 1, key 2, key 3
switch (key) {
case 49 /*ASCII for 1*/: {
case '1' /*ASCII for 1*/: {
//assumption: Sphere are aligned in Z axis
btScalar newLimit = btScalar(gCurrentPendulumLength + 0.1);
@@ -363,7 +369,7 @@ bool MultiPendulumExample::keyboardCallback(int key, int state) {
b3Printf("Increase pendulum length to %f", gCurrentPendulumLength);
return true;
}
case 50 /*ASCII for 2*/: {
case '2' /*ASCII for 2*/: {
//assumption: Sphere are aligned in Z axis
btScalar newLimit = btScalar(gCurrentPendulumLength - 0.1);
@@ -377,11 +383,8 @@ bool MultiPendulumExample::keyboardCallback(int key, int state) {
b3Printf("Decrease pendulum length to %f", gCurrentPendulumLength);
return true;
}
case 51 /*ASCII for 3*/: {
for (int i = floor(gPendulaQty)-1; i >= gPendulaQty-gDisplacedPendula; i--) {
if (gDisplacedPendula >= 0 && gDisplacedPendula < gPendulaQty)
pendula[i]->applyCentralForce(btVector3(gDisplacementForce, 0, 0));
}
case '3' /*ASCII for 3*/: {
applyPendulumForce(gDisplacementForce);
return true;
}
}
@@ -389,6 +392,16 @@ bool MultiPendulumExample::keyboardCallback(int key, int state) {
return false;
}
void MultiPendulumExample::applyPendulumForce(btScalar pendulumForce){
if(pendulumForce != 0){
b3Printf("Apply %f to pendulum",pendulumForce);
for (int i = 0; i < gDisplacedPendula; i++) {
if (gDisplacedPendula >= 0 && gDisplacedPendula <= gPendulaQty)
pendula[i]->applyCentralForce(btVector3(pendulumForce, 0, 0));
}
}
}
// GUI parameter modifiers
void onMultiPendulaLengthChanged(float pendulaLength) { // Change the pendula length
@@ -411,6 +424,17 @@ void floorMSliderValue(float notUsed) { // floor the slider values which should
gDisplacedPendula = floor(gDisplacedPendula);
}
void applyMForceWithForceScalar(float forceScalar) {
if(mex){
btScalar appliedForce = forceScalar * gDisplacementForce;
if(fabs(gForceScalar) < 0.2f)
gForceScalar = 0;
mex->applyPendulumForce(appliedForce);
}
}
CommonExampleInterface* ET_MultiPendulumCreateFunc(
CommonExampleOptions& options) {
mex = new MultiPendulumExample(options.m_guiHelper);

65
examples/ExtendedTutorials/NewtonsCradle.cpp
View File

@@ -38,7 +38,9 @@ static btScalar gCurrentPendulumLength = 8; // current pendula length
static btScalar gInitialPendulumLength = 8; // default pendula length
static btScalar gForcingForce = 30; // default force to displace the pendula
static btScalar gDisplacementForce = 30; // default force to displace the pendula
static btScalar gForceScalar = 0; // default force scalar to apply a displacement
struct NewtonsCradleExample: public CommonRigidBodyBase {
NewtonsCradleExample(struct GUIHelperInterface* helper) :
@@ -53,6 +55,7 @@ struct NewtonsCradleExample: public CommonRigidBodyBase {
virtual void changePendulaRestitution(btScalar restitution);
virtual void stepSimulation(float deltaTime);
virtual bool keyboardCallback(int key, int state);
virtual void applyPendulumForce(btScalar pendulumForce);
void resetCamera() {
float dist = 41;
float pitch = 52;
@@ -62,17 +65,19 @@ struct NewtonsCradleExample: public CommonRigidBodyBase {
targetPos[2]);
}
std::vector<btSliderConstraint*> constraints;
std::vector<btRigidBody*> pendula;
std::vector<btSliderConstraint*> constraints; // keep a handle to the slider constraints
std::vector<btRigidBody*> pendula; // keep a handle to the pendula
};
static NewtonsCradleExample* nex = NULL;
void onPendulaLengthChanged(float pendulaLength);
void onPendulaLengthChanged(float pendulaLength); // Change the pendula length
void onPendulaRestitutionChanged(float pendulaRestitution);
void onPendulaRestitutionChanged(float pendulaRestitution); // change the pendula restitution
void floorSliderValue(float notUsed);
void floorSliderValue(float notUsed); // floor the slider values which should be integers
void applyForceWithForceScalar(float forceScalar);
void NewtonsCradleExample::initPhysics() {
@@ -117,7 +122,7 @@ void NewtonsCradleExample::initPhysics() {
}
{ // create a slider to change the force to displace the lowest pendulum
SliderParams slider("Displacement force", &gForcingForce);
SliderParams slider("Displacement force", &gDisplacementForce);
slider.m_minVal = 0.1;
slider.m_maxVal = 200;
slider.m_clampToNotches = false;
@@ -125,6 +130,15 @@ void NewtonsCradleExample::initPhysics() {
slider);
}
{ // create a slider to apply the force by slider
SliderParams slider("Apply displacement force", &gForceScalar);
slider.m_minVal = -1;
slider.m_maxVal = 1;
slider.m_clampToNotches = false;
m_guiHelper->getParameterInterface()->registerSliderFloatParameter(
slider);
}
m_guiHelper->setUpAxis(1);
createEmptyDynamicsWorld();
@@ -162,10 +176,12 @@ void NewtonsCradleExample::initPhysics() {
}
void NewtonsCradleExample::stepSimulation(float deltaTime) {
applyForceWithForceScalar(gForceScalar); // apply force defined by apply force slider
if (m_dynamicsWorld) {
m_dynamicsWorld->stepSimulation(deltaTime);
}
}
void NewtonsCradleExample::createPendulum(btSphereShape* colShape,btVector3 position, btScalar length, btScalar mass) {
@@ -281,7 +297,7 @@ bool NewtonsCradleExample::keyboardCallback(int key, int state) {
//key 1, key 2, key 3
switch (key) {
case 49 /*ASCII for 1*/: {
case '1' /*ASCII for 1*/: {
//assumption: Sphere are aligned in Z axis
btScalar newLimit = btScalar(gCurrentPendulumLength + 0.1);
@@ -292,7 +308,7 @@ bool NewtonsCradleExample::keyboardCallback(int key, int state) {
b3Printf("Increase pendulum length to %f", gCurrentPendulumLength);
return true;
}
case 50 /*ASCII for 2*/: {
case '2' /*ASCII for 2*/: {
//assumption: Sphere are aligned in Z axis
btScalar newLimit = btScalar(gCurrentPendulumLength - 0.1);
@@ -306,11 +322,8 @@ bool NewtonsCradleExample::keyboardCallback(int key, int state) {
b3Printf("Decrease pendulum length to %f", gCurrentPendulumLength);
return true;
}
case 51 /*ASCII for 3*/: {
for (int i = 0; i < gDisplacedPendula; i++) {
if (gDisplacedPendula >= 0 && gDisplacedPendula <= gPendulaQty)
pendula[i]->applyCentralForce(btVector3(gForcingForce, 0, 0));
}
case '3' /*ASCII for 3*/: {
applyPendulumForce(gDisplacementForce);
return true;
}
}
@@ -318,6 +331,16 @@ bool NewtonsCradleExample::keyboardCallback(int key, int state) {
return false;
}
void NewtonsCradleExample::applyPendulumForce(btScalar pendulumForce){
if(pendulumForce != 0){
b3Printf("Apply %f to pendulum",pendulumForce);
for (int i = 0; i < gDisplacedPendula; i++) {
if (gDisplacedPendula >= 0 && gDisplacedPendula <= gPendulaQty)
pendula[i]->applyCentralForce(btVector3(pendulumForce, 0, 0));
}
}
}
// GUI parameter modifiers
void onPendulaLengthChanged(float pendulaLength) {
@@ -336,6 +359,18 @@ void onPendulaRestitutionChanged(float pendulaRestitution) {
void floorSliderValue(float notUsed) {
gPendulaQty = floor(gPendulaQty);
gDisplacedPendula = floor(gDisplacedPendula);
}
void applyForceWithForceScalar(float forceScalar) {
if(nex){
btScalar appliedForce = forceScalar * gDisplacementForce;
if(fabs(gForceScalar) < 0.2f)
gForceScalar = 0;
nex->applyPendulumForce(appliedForce);
}
}
CommonExampleInterface* ET_NewtonsCradleCreateFunc(

98
examples/ExtendedTutorials/NewtonsRopeCradle.cpp
View File

@@ -44,7 +44,9 @@ static btScalar gInitialPendulumHeight = 8; // default pendula height
static btScalar gRopeResolution = 1; // default rope resolution (number of links as in a chain)
static btScalar gForcingForce = 30; // default force to displace the pendula
static btScalar gDisplacementForce = 30; // default force to displace the pendula
static btScalar gForceScalar = 0; // default force scalar to apply a displacement
struct NewtonsRopeCradleExample : public CommonRigidBodyBase {
NewtonsRopeCradleExample(struct GUIHelperInterface* helper) :
@@ -52,7 +54,9 @@ struct NewtonsRopeCradleExample : public CommonRigidBodyBase {
}
virtual ~NewtonsRopeCradleExample(){}
virtual void initPhysics();
virtual void stepSimulation(float deltaTime);
virtual void renderScene();
virtual void applyPendulumForce(btScalar pendulumForce);
void createEmptyDynamicsWorld()
{
m_collisionConfiguration = new btSoftBodyRigidBodyCollisionConfiguration();
@@ -105,6 +109,8 @@ void onRopePendulaRestitutionChanged(float pendulaRestitution);
void floorRSliderValue(float notUsed);
void applyRForceWithForceScalar(float forceScalar);
void NewtonsRopeCradleExample::initPhysics()
{
@@ -167,47 +173,56 @@ void NewtonsRopeCradleExample::initPhysics()
}
{ // create a slider to change the force to displace the lowest pendulum
SliderParams slider("Displacement force", &gForcingForce);
SliderParams slider("Displacement force", &gDisplacementForce);
slider.m_minVal = 0.1;
slider.m_maxVal = 200;
slider.m_clampToNotches = false;
m_guiHelper->getParameterInterface()->registerSliderFloatParameter(
slider);
}
{ // create a slider to apply the force by slider
SliderParams slider("Apply displacement force", &gForceScalar);
slider.m_minVal = -1;
slider.m_maxVal = 1;
slider.m_clampToNotches = false;
m_guiHelper->getParameterInterface()->registerSliderFloatParameter(
slider);
}
m_guiHelper->setUpAxis(1);
createEmptyDynamicsWorld();
// create a debug drawer
m_guiHelper->createPhysicsDebugDrawer(m_dynamicsWorld);
if (m_dynamicsWorld->getDebugDrawer())
m_dynamicsWorld->getDebugDrawer()->setDebugMode(
btIDebugDraw::DBG_DrawWireframe
+ btIDebugDraw::DBG_DrawContactPoints
+ btIDebugDraw::DBG_DrawConstraints
+ btIDebugDraw::DBG_DrawConstraintLimits);
m_guiHelper->createPhysicsDebugDrawer(m_dynamicsWorld);
if (m_dynamicsWorld->getDebugDrawer())
m_dynamicsWorld->getDebugDrawer()->setDebugMode(
btIDebugDraw::DBG_DrawWireframe
+ btIDebugDraw::DBG_DrawContactPoints
+ btIDebugDraw::DBG_DrawConstraints
+ btIDebugDraw::DBG_DrawConstraintLimits);
{ // create the pendula starting at the indicated position below and where each pendulum has the following mass
btScalar pendulumMass(1.0f);
{ // create the pendula starting at the indicated position below and where each pendulum has the following mass
btScalar pendulumMass(1.0f);
btVector3 position(0.0f,15.0f,0.0f); // initial left-most pendulum position
btQuaternion orientation(0,0,0,1); // orientation of the pendula
btVector3 position(0.0f,15.0f,0.0f); // initial left-most pendulum position
btQuaternion orientation(0,0,0,1); // orientation of the pendula
// Re-using the same collision is better for memory usage and performance
btSphereShape* pendulumShape = new btSphereShape(gSphereRadius);
m_collisionShapes.push_back(pendulumShape);
// Re-using the same collision is better for memory usage and performance
btSphereShape* pendulumShape = new btSphereShape(gSphereRadius);
m_collisionShapes.push_back(pendulumShape);
for (int i = 0; i < floor(gPendulaQty); i++) {
for (int i = 0; i < floor(gPendulaQty); i++) {
// create pendulum
createRopePendulum(pendulumShape, position, orientation,gInitialPendulumWidth,
gInitialPendulumHeight, pendulumMass);
// create pendulum
createRopePendulum(pendulumShape, position, orientation,gInitialPendulumWidth,
gInitialPendulumHeight, pendulumMass);
// displace the pendula 1.05 sphere size, so that they all nearly touch (small spacings in between)
position.setX(position.x()-2.1f * gSphereRadius);
}
// displace the pendula 1.05 sphere size, so that they all nearly touch (small spacings in between)
position.setX(position.x()-2.1f * gSphereRadius);
}
}
m_guiHelper->autogenerateGraphicsObjects(m_dynamicsWorld);
}
@@ -229,6 +244,15 @@ void NewtonsRopeCradleExample::connectWithRope(btRigidBody* body1, btRigidBody*
getSoftDynamicsWorld()->addSoftBody(softBodyRope0);
}
void NewtonsRopeCradleExample::stepSimulation(float deltaTime) {
applyRForceWithForceScalar(gForceScalar); // apply force defined by apply force slider
if (m_dynamicsWorld) {
m_dynamicsWorld->stepSimulation(deltaTime);
}
}
void NewtonsRopeCradleExample::createRopePendulum(btSphereShape* colShape,
btVector3 position, btQuaternion pendulumOrientation, btScalar width, btScalar height, btScalar mass) {
@@ -312,11 +336,8 @@ bool NewtonsRopeCradleExample::keyboardCallback(int key, int state) {
// key 3
switch (key) {
case 51 /*ASCII for 3*/: {
for (int i = 0; i < gDisplacedPendula; i++) {
if (gDisplacedPendula >= 0 && gDisplacedPendula <= gPendulaQty)
pendula[i]->applyCentralForce(btVector3(gForcingForce, 0, 0));
}
case '3' /*ASCII for 3*/: {
applyPendulumForce(gDisplacementForce);
return true;
}
}
@@ -324,6 +345,16 @@ bool NewtonsRopeCradleExample::keyboardCallback(int key, int state) {
return false;
}
void NewtonsRopeCradleExample::applyPendulumForce(btScalar pendulumForce){
if(pendulumForce != 0){
b3Printf("Apply %f to pendulum",pendulumForce);
for (int i = 0; i < gDisplacedPendula; i++) {
if (gDisplacedPendula >= 0 && gDisplacedPendula <= gPendulaQty)
pendula[i]->applyCentralForce(btVector3(pendulumForce, 0, 0));
}
}
}
// GUI parameter modifiers
void onRopePendulaRestitutionChanged(float pendulaRestitution) {
@@ -338,6 +369,17 @@ void floorRSliderValue(float notUsed) {
gRopeResolution = floor(gRopeResolution);
}
void applyRForceWithForceScalar(float forceScalar) {
if(nex){
btScalar appliedForce = forceScalar * gDisplacementForce;
if(fabs(gForceScalar) < 0.2f)
gForceScalar = 0;
nex->applyPendulumForce(appliedForce);
}
}
CommonExampleInterface* ET_NewtonsRopeCradleCreateFunc(
CommonExampleOptions& options) {
nex = new NewtonsRopeCradleExample(options.m_guiHelper);