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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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62
examples/ExtendedTutorials/MultiPendulum.cpp
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@@ -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);