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Core / vec4

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FunctionIconType-Small.png vec4() function


The 'Vector' chapter of Codea's in-app reference documents most of the vec4() function. The function is similar to the vec3() function, except that it returns a userdata value that is a vector in four dimensions rather than three.

Returning a four dimensional vector

The vec4() function is used to return a new four-dimensional vector value as in the following examples:

v1 = vec4(x1, y1, z1, w1)         -- x1, y1, z1, w1 contain numbers for the respective co-ordinates
print(vec4() == vec4(0, 0, 0, 1)) -- Output: true

If vec4() is called without arguments it returns the origin in three-dimensional space, but in homogeneous co-ordinates (with the w co-ordinate equal to 1).

Setting and getting individual coordinates

Indexing can be used to set and get individual coordinates, either by ordinal number or by letter - (x, y, z, w) or (r, g, b, a), as summarised in the table below:

Co-ordinateIndex schemeIndex schemeIndex scheme
Firstv1[1]v1.x or v1["x"]v1.r or v1["r"]
Secondv1[2]v1.y or v1["y"]v1.g or v1["g"]
Thirdv1[3]v1.z or v1["z"]v1.b or v1["b"]
Fourthv1[4]v1.w or v1["w"]v1.a or v1["a"]


As in the case of vec3(), the result of the vec4() function supports the - (uniary), *, /, +, -, and == operators, where the second operand is a number value in the case of * (multiplication by a scalar) and / (division by a scalar).


The result also supports tostring() to produce nicely-formatted output. Consequently, print() also generates nicely-formatted output.

Also as in the case of vec3(), the result of the vec4() function supports the indexed functions dot(), cross(), len(), lenSqr(), dist() and distSqr(). For example:

v1 = vec4(1, -1, 3, 4)
v2 = vec4(-2, 5, -3, 0)

-- Calculate the dot (scalar) product of two vectors
d =, v2)       -- This syntax is equivalent ...
d = v1:dot(v2)           -- ... to this syntax, using Lua's colon notation.

-- Calculate the length (magnitude) of first vector
l = v1.len(v1)           -- This syntax is equivalent ...
l = v1:len()             -- ... to this syntax, using Lua's colon notation.


The cross() function returns a four dimensional vector where the first three co-ordinates are the cross product of the three dimensional vectors corresponding to the first three co-ordinates of the two vectors and the fourth co-ordinate is 0.