RE: [pygame] 2D Vector Class

[Chris Ashurst <CAshurst@xxxxxxxx>]

I'm a little lost on this... Someone wants a 2D vector class?

I use the following I built after wrestling with the NeHe particle tutorial:

class Vector2D(object):
    def __init__(self, x, y):
        self.x = x
        self.y = y

    def __add__(self, v):
        return Vector2D(float(self.x + v.x), float(self.y + v.y))
        
    def __sub__(self, v):
        return Vector2D(float(self.x - v.x), float(self.y - v.y))

class Vector3D(Vector2D):
    def __init__(self, x, y, z):
        super(Vector3D, self).__init__(x, y)
        self.z = z

    def __add__(self, v):
        return Vector3D(float(self.x + v.x), float(self.y + v.y),
float(self.z + v.z))
        
    def __sub__(self, v):
        return Vector3D(float(self.x - v.x), float(self.y - v.y),
float(self.z - v.z))

---snip---

v1 = Vector3D(1.0, 1.0, 1.0)
v2 = Vector3D(2.0, 2.0, 2.0)
v3 = v1 - v2

print v3.x, v3.y, v3.z
>>> -1.0, -1.0, -1.0

---snip---

These allow me to add/subtract instances of a Vector3D class and get a
Vector3D class in return. I only have add and subtract on these methods, but
I could easily extend them by using the information at
http://docs.python.org/ref/customization.html and
http://docs.python.org/lib/module-operator.html to add more math methods.

As I say, I'm a little lost and confused... I put this down to Delta/Atlanta
airport yesterday and a funtastic trip from Oregon to Florida. Ignore me.

-----Original Message-----
From: owner-pygame-users@xxxxxxxx [mailto:owner-pygame-users@xxxxxxxx]On
Behalf Of Greg Ewing
Sent: Wednesday, May 16, 2007 23:41
To: pygame-users@xxxxxxxx
Subject: Re: [pygame] 2D Vector Class


Ulf Ekström wrote:

> > That [complex number trick] seems very smart, and I imagine it is very
fast...
> 
> Yes, and you get fast rotations with just a multiply.

Only for 2D, though... unless we can persuade Guido
to put quaternions in the core... :-)

-- 
Greg Ewing, Computer Science Dept, +--------------------------------------+
University of Canterbury,	   | Carpe post meridiem!          	  |
Christchurch, New Zealand	   | (I'm not a morning person.)          |
greg.ewing@xxxxxxxxxxxxxxxx	   +--------------------------------------+




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