vec4 - a four-dimensional vector type

A vec4 represents a 4D vector type. You can construct a vec4 by several ways:

# all components are set to zero
v = vec4()

(0.0000, 0.0000, 0.0000, 0.0000)

# set all components to one value
v = vec4(2.5)

(2.5000, 2.5000, 2.5000, 2.5000)

# set a 2d vector, the ramaining components will be zero
v = vec4(1.5, 0.8)

(1.5000, 0.8000, 0.0000, 0.0000)

# set a 3d vector, the ramaining component will be zero
v = vec4(1.5, 0.8, -0.5)

(1.5000, 0.8000, -0.5000, 0.0000)

# set all components
v = vec4(1.5, 0.8, -0.5, 0.2)

(1.5000, 0.8000, -0.5000, 0.2000)
Additionally you can use all of the above, but store the values inside a tuple, a list or a string:
v = vec4([1.5, 0.8, -0.5])
w = vec4("1.5, 0.8")
Finally, you can initialize a vector with a copy of another vector:
v = vec4(w)

A vec3 can be used just like a list with 3 elements, so you can read and write components using the index operator or by accessing the components by name:

>>> v=vec4(1,2,3,1)
>>> print v[0]
>>> print v.y
>>> print v.w
>>> print v.t   # this is the same as v.w
The 4th component can be accessed either by the name "w" or "t". You might prefer the former name when using the vector as a homogenous coordinate while the latter might be preferable when the 4th component shall represent a time value.

Mathematical operations:

The mathematical operators are supported with the following combination of types:
vec4  =  vec4 + vec4
vec4  =  vec4 - vec4
float =  vec4 * vec4      # dot product
vec4  = float * vec4
vec4  =  vec4 * float
vec4  =  vec4 / float
vec4  =  vec4 % float     # each component
vec4  = -vec4
float =  vec4[i]          # get or set element
Additionally, you can compare vectors with ==, !=, <, <=, >, >=. Each comparison (except < and >) takes an epsilon environment into account, this means two values are considered to be equal if their absolute difference is less than or equal to a threshold value epsilon. You can read and write this threshold value using the functions getEpsilon() and setEpsilon().

Taking the absolute value of a vector will return the length of the vector:

float = abs(v)            # this is equivalent to v.length()


Returns the length of the vector (=sqrt(x*x+y*y+z*z)). This is equivalent to calling abs(self).
Returns normalized vector. If the method is called on the null vector (where each component is zero) a ZeroDivisionError is raised.

Copyright © 2002 Matthias Baas (