AngleDirection creates a unit vector based on theta and phi.

Identity creates a new identity matrix.

LookMatrix creates a matrix looking from `from` towards `to` http://www.cs.virginia.edu/~gfx/courses/1999/intro.fall99.html/lookat.html https://www.3dgep.com/understanding-the-view-matrix/#Look_At_Camera http://www.codinglabs.net/article_world_view_projection_matrix.aspx https://fgiesen.wordpress.com/2012/02/12/row-major-vs-column-major-row-vectors-vs-column-vectors/.

NewMat constructs a new matrix.

RandDirection returns a random unit vector (a point on the edge of a unit sphere).

RandPointInCircle returns a random x, y point within a circle of radius r.

Rotate creates a rotation matrix from an angle-axis Vector representation http://www.euclideanspace.com/maths/geometry/rotations/conversions/angleToMatrix/.

Scale creates a new scaling matrix.

Shift creates a new translation matrix.

Tangent creates a matrix that translates from world space to tangent space and a corresponding matrix that translates from tangent space to world space.

Up is the positive Direction on the vertical (Y) axis.

Mtx handles matrix data and operations Column-major (as in math and Direct3D) https://fgiesen.wordpress.com/2012/02/12/row-major-vs-column-major-row-vectors-vs-column-vectors/.

Ray describes a 3-dimensional ray with an origin and a unit direction Vector3.

Vec holds x, y, z values.

Dir is a unit vector that specifies a direction in 3D space.