void Box2DVehicleBody::Tire::updateDrive(float desiredSpeed) {
//find current speed in forward direction
b2Vec2 currentForwardNormal = m_body->GetWorldVector( b2Vec2(0,1) );
float currentSpeed = b2Dot( getForwardVelocity(), currentForwardNormal );
//apply necessary force
float force = 0;
if ( desiredSpeed > currentSpeed )
force = m_maxDriveForce;
else if ( desiredSpeed < currentSpeed )
force = -m_maxDriveForce;
else
return;
m_body->ApplyForce( m_currentTraction * force * currentForwardNormal, m_body->GetWorldCenter() , true);
}
void Box2DVehicleBody::Tire::updateFriction() {
//lateral linear velocity
b2Vec2 impulse = m_body->GetMass() * -getLateralVelocity();
if ( impulse.Length() > m_maxLateralImpulse )
impulse *= m_maxLateralImpulse / impulse.Length();
m_body->ApplyLinearImpulse( m_currentTraction * impulse, m_body->GetWorldCenter() , true);
//angular velocity
m_body->ApplyAngularImpulse( m_currentTraction * 0.1f * m_body->GetInertia() * -m_body->GetAngularVelocity() , true);
//forward linear velocity
b2Vec2 currentForwardNormal = getForwardVelocity();
float currentForwardSpeed = currentForwardNormal.Normalize();
float dragForceMagnitude = -2 * currentForwardSpeed;
m_body->ApplyForce( m_currentTraction * dragForceMagnitude * currentForwardNormal, m_body->GetWorldCenter() , true);
}
void CarModel::updateFriction()
{
//calculate the counter lateral impulse based on drift parameters
b2Vec2 impulse = m_body->GetMass() * -getLateralVelocity();
if (impulse.Length() > m_maxLateralImpulse)
impulse *= m_maxLateralImpulse / impulse.Length();
// apply the impulse
m_body->ApplyLinearImpulse(m_driftFriction * impulse, m_body->GetWorldCenter(), true);
//angular velocity
m_body->ApplyAngularImpulse(m_angularFriction * m_body->GetInertia() * -m_body->GetAngularVelocity(), true);
//forward linear velocity
b2Vec2 currentForwardNormal = getForwardVelocity();
float currentForwardSpeed = currentForwardNormal.Normalize();
float dragForceMagnitude = -2 * currentForwardSpeed * m_dragModifier;
m_body->ApplyForce(m_currentTraction * dragForceMagnitude * currentForwardNormal, m_body->GetWorldCenter(), true);
}
void GameState::update() {
updateControl(window);
updateCamera(camera);
double curTime = glfwGetTime();
double elapsedTime = curTime - prevTime;
prevTime = curTime;
for (int i = 0; i < actors.size(); i++) {
actors[i].step(elapsedTime);
}
if (curTime > timeToNextSphere) {
timeToNextSphere = curTime + 0.5;
spawnSphere();
}
checkCollisions();
camera->center += camera->direction * (float) elapsedTime
* getForwardVelocity();
glm::vec3 right = glm::cross(camera->direction, glm::vec3(0.0, 1.0, 0.0));
camera->center += right * (float) elapsedTime * getStrafeVelocity();
if(camera->center.y <= 0){
camera->center.y = 0;
}
if(camera->center.x >= XMAX){
camera->center.x = XMAX;
}
if(camera->center.x <= -XMAX){
camera->center.x = -XMAX;
}
if(camera->center.z >= ZMAX){
camera->center.z = ZMAX;
}
if(camera->center.z <= -ZMAX){
camera->center.z = -ZMAX;
}
printf("Current num of spheres is %d and Current num hit is %d\n", numCurSpheres, numSpheresHit);
}
void CarModel::updateDrive(float* controlState)
{
//wake the body, it could be in a sleep state
m_body->SetAwake(true);
//find desired speed
float desiredSpeed = 0;
if (controlState[OA_UP] > 0.0f)
desiredSpeed = m_maxForwardSpeed;
if (controlState[OA_DOWN] > 0.0f)
desiredSpeed = m_maxBackwardSpeed;
//find current speed in forward direction
b2Vec2 currentForwardNormal = m_body->GetWorldVector(b2Vec2(0, 1));
float currentSpeed = b2Dot(getForwardVelocity(), currentForwardNormal);
//apply necessary force
float force = (desiredSpeed > currentSpeed) ? m_maxDriveForce : -m_maxDriveForce;
if (desiredSpeed != currentSpeed)
{
m_body->ApplyForce(m_currentTraction * force * currentForwardNormal, m_body->GetWorldCenter(), true);
}
}
