Initial revision

[lsystem3d.git] / lsystem3d / src / vector.cpp

// Copyright (C) 2006 Erik Dahlberg
// 
// This file is part of LSystem3d.
// 
// LSystem3D is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License
// as published by the Free Software Foundation; either version 2
// of the License, or (at your option) any later version.
// 
// LSystem3D is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
// 
// You should have received a copy of the GNU General Public License
// along with LSystem3D; if not, write to the Free Software
// Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA




#include <cmath>

#include "vector.h"



/**
 * Constructor
 * @param x the x-coordinate
 * @param y the y-coordinate
 * @param z the z-coordinate
 */
Vector::Vector(double x, double y, double z)
{
    setXYZ(x, y, z);
}



/**
 * Destructor
 */
Vector::~Vector()
{
}



/**
 * Rotate around another vector
 * @param angle rotation angle
 * @param vector arbitrary vector to rotate around
 */
void Vector::rotate(double angle, Vector vector)
{
    double c = cos(angle);
    double s = sin(angle);
    
    double x =
    _x * (vector._x * vector._x * (1.0 - c) + c) +
    _y * (vector._x * vector._y * (1.0 - c) + vector._z * s) +
    _z * (vector._x * vector._z * (1.0 - c) - vector._y * s);
    
    double y =
    _x * (vector._y * vector._x * (1.0 - c) - vector._z * s) +
    _y * (vector._y * vector._y * (1.0 - c) + c) +
    _z * (vector._y * vector._z * (1.0 - c) + vector._x * s);
    
    double z =
    _x * (vector._z * vector._x * (1.0 - c) + vector._y * s) +
    _y * (vector._z * vector._y * (1.0 - c) - vector._x * s) +
    _z * (vector._z * vector._z * (1.0 - c) + c);
    
    _x = x;
    _y = y;
    _z = z;
    
    // TODO: call it from outside?
    normalize();
}



/**
 * Normalize vector
 */
void Vector::normalize()
{
    double length = sqrt(_x * _x + _y * _y + _z * _z);
    
    if (length != 0)
    {
        _x /= length;
        _y /= length;
        _z /= length;
    }
}



/**
 * Get scalar product of the vectors
 * @param vector arbitrary vector
 * @return the scalar product
 */
double Vector::getScalarProduct(Vector vector)
{
    double scalarProduct = getX() * vector.getX() +
                           getY() * vector.getY() +
                           getZ() * vector.getZ();
    
    return scalarProduct;
}



/**
 * Get cross product of the vectors
 * @param vector arbitrary vector
 * @return the cross product
 */
Vector Vector::getCrossProduct(Vector vector)
{
    Vector crossProduct(getY() * vector.getZ() - getZ() * vector.getY(),
                        getZ() * vector.getX() - getX() * vector.getZ(),
                        getX() * vector.getY() - getY() * vector.getX());

    return crossProduct;
}



/**
 * Get angle between the vectors
 * @param vector the second (normalized) vector
 * @return the angle, in degrees
 */
double Vector::getAngle(Vector vector)
{
    double scalarProduct = getScalarProduct(vector);
    double angle = (acos(scalarProduct) / (M_PIl * 2.0)) * 360.0;
    
    return angle;
}