void SpaceshipGame::update(long elapsedTime)
{
// Calculate elapsed time in seconds
float t = (float)elapsedTime / 1000.0;
if (!_finished)
{
_time += t;
// Play the background track
if (_backgroundSound->getState() != AudioSource::PLAYING)
_backgroundSound->play();
}
else
{
// Stop the background track
if (_backgroundSound->getState() != AudioSource::STOPPED)
_backgroundSound->stop();
_throttle = 0.0f;
}
// Set initial force due to gravity
_force.set(0, -GRAVITATIONAL_FORCE);
// While we are pushing/touching the screen, apply a push force vector based on the distance from
// the touch point to the center of the space ship.
if (_pushing)
{
// Get the center point of the space ship in screen coordinates
Vector3 shipCenterScreen;
_scene->getActiveCamera()->project(getViewport(), _shipGroupNode->getBoundingSphere().center, &shipCenterScreen.x, &shipCenterScreen.y);
// Compute a screen-space vector between the center point of the ship and the touch point.
// We will use this vector to apply a "pushing" force to the space ship, similar to what
// happens when you hold a magnet close to an object with opposite polarity.
Vector2 pushForce((shipCenterScreen.x - _pushPoint.x), -(shipCenterScreen.y - _pushPoint.y));
// Transform the vector so that a smaller magnitude emits a larger force and applying the
// maximum touch distance.
float distance = (std::max)(TOUCH_DISTANCE_MAX - pushForce.length(), 0.0f);
pushForce.normalize();
pushForce.scale(distance * FORCE_SCALE);
_force.add(pushForce);
// Compute a throttle value based on our force vector, minus gravity
Vector2 throttleVector(_force.x, _force.y + GRAVITATIONAL_FORCE);
_throttle += throttleVector.length() / FORCE_MAX * t;
}
else
{
// Gradually decrease the throttle
if (_throttle > 0.0f)
{
_throttle *= 1.0f - t;
}
}
// Clamp the throttle
_throttle = CLAMP(_throttle, 0.0f, 1.0f);
// Update acceleration (a = F/m)
_acceleration.set(_force.x / MASS, _force.y / MASS);
// Update velocity (v1 = v0 + at)
_velocity.x += _acceleration.x * t;
_velocity.y += _acceleration.y * t;
// Clamp velocity to its maximum range
_velocity.x = CLAMP(_velocity.x, -VELOCITY_MAX, VELOCITY_MAX);
_velocity.y = CLAMP(_velocity.y, -VELOCITY_MAX, VELOCITY_MAX);
// Move the spaceship based on its current velocity (x1 = x0 + vt)
_shipGroupNode->translate(_velocity.x * t, _velocity.y * t, 0);
// Check for collisions
handleCollisions(t);
// Update camera
updateCamera();
// Reset ship rotation
_shipGroupNode->setRotation(_initialShipRot);
// Apply ship tilt
if (_force.x != 0 && fabs(_velocity.x) > 0.1f)
{
// Compute an angle based on the dot product between the force vector and the Y axis
Vector2 fn;
_force.normalize(&fn);
float angle = MATH_RAD_TO_DEG(acos(Vector2::dot(Vector2(0, 1), fn)));
if (_force.x > 0)
angle = -angle;
angle *= _throttle * t;
_shipTilt += angle;
_shipTilt = _shipTilt < -SHIP_TILT_MAX ? -SHIP_TILT_MAX : (_shipTilt > SHIP_TILT_MAX ? SHIP_TILT_MAX : _shipTilt);
}
else
{
// Interpolate tilt back towards zero when no force is applied
_shipTilt = (_shipTilt + ((0 - _shipTilt) * t * 2.0f));
}
_shipGroupNode->rotateZ(MATH_DEG_TO_RAD(_shipTilt));
if (_throttle > MATH_EPSILON)
{
// Apply ship spin
_shipNode->rotateY(MATH_DEG_TO_RAD(SHIP_ROTATE_SPEED_MAX * t * _throttle));
// Play sound effect
if (_spaceshipSound->getState() != AudioSource::PLAYING)
_spaceshipSound->play();
// Set the pitch based on the throttle
_spaceshipSound->setPitch(_throttle * SOUND_PITCH_SCALE);
}
else
{
// Stop sound effect
_spaceshipSound->stop();
}
// Modify ship glow effect based on the throttle
_glowDiffuseParameter->setValue(Vector4(1, 1, 1, _throttle * ENGINE_POWER));
_shipSpecularParameter->setValue(SPECULAR - ((SPECULAR-2.0f) * _throttle));
}
void EntityManager::update()
{
m_isUpdating = true;
handleCollisions();
// Update existing entities.
for(std::list<Entity *>::iterator iter = m_entities.begin();
iter != m_entities.end();
iter++)
{
(*iter)->update();
if((*iter)->isExpired())
{
*iter = NULL;
}
}
m_isUpdating = false;
// Add new entities.
for(std::list<Entity *>::iterator iter = m_addedEntities.begin();
iter != m_addedEntities.end();
iter++)
{
addEntity(*iter);
}
// Clear new entities list.
m_addedEntities.clear();
// Remove all NULL elements.
m_entities.remove(NULL);
// Walk the bullet list.
for(std::list<Bullet *>::iterator iter = m_bullets.begin();
iter != m_bullets.end();
iter++)
{
if((*iter)->isExpired())
{
delete *iter;
*iter = NULL;
}
}
m_bullets.remove(NULL);
// Walk the enemies list.
for(std::list<Enemy *>::iterator iter = m_enemies.begin();
iter != m_enemies.end();
iter++)
{
if((*iter)->isExpired())
{
delete *iter;
*iter = NULL;
}
}
m_enemies.remove(NULL);
// Walk the enemies list.
for(std::list<BlackHole *>::iterator iter = m_blackHoles.begin();
iter != m_blackHoles.end();
iter++)
{
if((*iter)->isExpired())
{
delete *iter;
*iter = NULL;
}
}
m_blackHoles.remove(NULL);
}
