4.2.2 vec4 - 4d vector

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 vec4 can be used just like a list with 4 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]
1.0
>>> print v.y
2.0
>>> print v.w
1.0
>>> print v.t   # this is the same as v.w
1.0

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 % vec4      # component wise
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()

Methods

length( ): Returns the length of the vector ( $\sqrt{x^2+y^2+z^2}$ ). This is equivalent to calling abs(self).

normalize( ): Returns normalized vector. If the method is called on the null vector (where each component is zero) a ZeroDivisionError is raised.

min( ): Returns the minimum value of the components.

max( ): Returns the maximum value of the components.

minIndex( ): Return the index of the component with the minimum value.

maxIndex( ): Return the index of the component with the maximum value.

minAbs( ): Returns the minimum absolute value of the components.

maxAbs( ): Returns the maximum absolute value of the components.

minAbsIndex( ): Return the index of the component with the minimum absolute value.

maxAbsIndex( ): Return the index of the component with the maximum absolute value.