/**
* Calculates the product of this transform with the given "transformBy" transform (P = this * T)
* and stores this in store.
*
* @param transformBy
* @return the product
* @throws NullPointerException if transformBy is null.
*/
public CCTransform multiply(final CCTransform transformBy, CCTransform theStore) {
if (theStore == null) theStore = new CCTransform();
if (_myIsIdentity) {
return theStore.set(transformBy);
}
if (transformBy.isIdentity()) {
return theStore.set(this);
}
if (_myIsRotationMatrix && transformBy.isRotationMatrix() && _myIsUniformScale) {
theStore._myIsRotationMatrix = true;
theStore._myMatrix.set(_myMatrix).multiplyLocal(transformBy.getMatrix());
theStore._myTranslation.set(transformBy.translation());
theStore._myTranslation.set(_myMatrix.applyPost(theStore._myTranslation));
// uniform scale, so just use X.
theStore._myTranslation.multiplyLocal(_myScale.x);
theStore._myTranslation.addLocal(_myTranslation);
if (transformBy.isUniformScale()) {
theStore.scale(_myScale.x * transformBy.scale().x);
} else {
final CCVector3 scale = theStore._myScale.set(transformBy.scale());
scale.multiplyLocal(_myScale.x);
}
// update our flags in one place.
theStore.updateFlags(true);
return theStore;
}
// In all remaining cases, the matrix cannot be written as R*S*X+T.
final CCMatrix3x3 matrixA =
isRotationMatrix() ? _myMatrix.multiplyDiagonalPost(_myScale) : _myMatrix;
final CCMatrix3x3 matrixB =
transformBy.isRotationMatrix()
? transformBy.getMatrix().multiplyDiagonalPost(transformBy.scale())
: transformBy.getMatrix();
final CCMatrix3x3 newMatrix = theStore._myMatrix;
newMatrix.set(matrixA).multiplyLocal(matrixB);
theStore._myTranslation.set(
matrixA.applyPost(transformBy.translation()).addLocal(translation()));
// prevent scale bleeding since we don't set it.
theStore._myScale.set(1.0f, 1.0f, 1.0f);
// update our flags in one place.
theStore.updateFlags(false);
return theStore;
}
