public void setOrigin(final int win_x, final int win_y) {
final float[] in = {
win_x * m_delta.get(0) + m_constant.get(0), win_y * m_delta.get(1) + m_constant.get(1)
};
final float[] center = {
m_inverse.get(0, 0) * in[0] + m_inverse.get(0, 1) * in[1] + m_inverse.get(0, 3),
m_inverse.get(1, 0) * in[0] + m_inverse.get(1, 1) * in[1] + m_inverse.get(1, 3),
m_inverse.get(2, 0) * in[0] + m_inverse.get(2, 1) * in[1] + m_inverse.get(2, 3),
m_inverse.get(3, 0) * in[0] + m_inverse.get(3, 1) * in[1] + m_inverse.get(3, 3)
};
float[] front = {
center[0] - m_inverse.get(0, 2),
center[1] - m_inverse.get(1, 2),
center[2] - m_inverse.get(2, 2),
center[3] - m_inverse.get(3, 2)
};
final float front_inv = 1.0f / front[3];
front[0] *= front_inv;
front[1] *= front_inv;
front[2] *= front_inv;
float[] back = {
center[0] + m_inverse.get(0, 2),
center[1] + m_inverse.get(1, 2),
center[2] + m_inverse.get(2, 2),
center[3] + m_inverse.get(3, 2)
};
final float back_inv = 1.0f / back[3];
back[0] *= back_inv;
back[1] *= back_inv;
back[2] *= back_inv;
m_t = 0.0f;
m_from = new Vector3f(front[0], front[1], front[2]);
Vector3f direction = new Vector3f(back[0] - front[0], back[1] - front[1], back[2] - front[2]);
m_direction = direction.normalize();
}
