Bart/bullet3
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

Add a slider to displace pendula via GUI.

Browse Source 
------------------------------------------------
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
Download Patch File Download Diff File Expand all files Collapse all files

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(