//see http://nehe.gamedev.net/data/lessons/lesson.asp?lesson=Quaternion_Camera_Class
void SimpleCamera::getLookAt(MATRIX &look)
{
MATRIX m1, m2, m3, translation;
QUATERNION q;
// Make the Quaternions that will represent our rotations
MatrixQuaternionRotationAxis(_qPitch, Vec3(1.0f, 0.0f, 0.0f), _pitchRadians);
MatrixQuaternionRotationAxis(_qHeading, Vec3(0.0f, 1.0f, 0.0f), _headingRadians);
// Combine the pitch and heading rotations and store the results in q
MatrixQuaternionMultiply(q, _qHeading, _qPitch);
MatrixRotationQuaternion(m1, q);
// Create a matrix from the pitch Quaternion and get the j vector
// for our direction.
MatrixRotationQuaternion(m3, _qPitch);
_direction.y = m3.f[9];
// Combine the heading and pitch rotations and make a matrix to get
// the i and j vectors for our direction.
MatrixQuaternionMultiply(q, _qPitch, _qHeading);
MatrixRotationQuaternion(m2, q);
_direction.x = m2.f[8];
_direction.z = -m2.f[10];
// Increment our position by the vector
_position += (_direction * _forwardVelocity);
// Translate to our new position.
MatrixTranslation(translation, -_position.x, -_position.y, -_position.z);
MatrixMultiply(look, translation, m1);
}
const MATRIX &TransformInterpolator::current() const
{
btScalar progress(1.0);
if (d->totalSteps) {
progress = (float)d->currentStep / (float)d->totalSteps;
}
QUATERNION qOut;
MatrixQuaternionSlerp(qOut, d->startRotation, d->endRotation, progress);
MatrixRotationQuaternion(d->currentTransform, qOut);
MatrixTranslationLerp(d->currentTransform, d->startTransform, d->endTransform, progress);
return d->currentTransform;
}
