A somewhat incomplete, pure-C implementation of a 3D Linear Algebra System with no dependencies, because none existed when I started writing video game engines. It features the functions that I've needed so far, and is debugged to the degree that I've needed so far. Work continues as the games becomes more sophisticated. Some functions have explicit wide SIMD versions for parallel processing of sets of data.

MIT licensed, see LICENSE file. I intend to release my portions of the code under Public Domain, but there are some functions which might have a 3rd-party MIT license depending on the legal disposition of a modified version of a C port of an MIT-licensed glsl function.

Compiling

Repos:
Github
Notabug (Currently down due to the Goddamn AI scrapers. Fuck Sam Altman.)
Gitlab
Codeberg

Symlink or copy the code into your project however you wish, #include "c3dlas/c3dlas.h", and add c3dlas/c3dlas.c to your build files.

Return Values

Some functions return integers corresponding to the following enums, in the format C3DLAS_*:

FALSE False.

TRUE True.

COPLANAR The respective objects are coplanar but not necessarily parallel.

FRONT Front-face of a triangle.

BACK Back-face of a triangle.

INTERSECT The two objects intersect.

DISJOINT The two objects do not intersect.

PARALLEL The respective objects are parallel.

CW Clockwise.

CCW Counter-clockwise.

UNKNOWN The situation cannot be classified by ths function.

The enum is typedefed to C3DLAS_retval_t but is not used consistently yet for historical reasons. String names of the enums can be found in extern char const * const C3DLAS_retval__names[];.

Complete Features

These will see very little change, aside from addition of the odd helper or obscure function.

[docs] Vector math in 2, 3, and 4 dimensions for floats, doubles, ints, and longs, with structs, typedefs, and helper macros. All basic math functions are implemented. There are _Generic()-based macros to automatically select the correct function based on the type of the first argument. Most functions have literal and pointer versions.
[docs] Quaternion math for floats, with structs and typedefs. All basic basic math functions are implemented. Quaternion is a typedef of Vector4 for mutual function compatibility.
[docs] Matrix math in 4 dimensions, with structs and typedefs. All basic basic math functions are implemented, as well as all the more common advanced operations used in 3D rendering.
[docs] Bezier and Catmull-Rom splines.

Essentially Complete Features

These features have a good function coverage but may not include every useful function yet.

[docs] 2D Polygon operations. Most operations are supported, but there are a lot of obscure, difficult to implement, but perfectly legitimate operations that can be done on polygons.
[docs] Matrix math in 2 and 3 dimensions.
[docs] Miscellaneous math functions.
[docs] PCG random number generation. 32-bit only.

Features with Sporadic Coverage

Function names in this category are not yet completely systematic and may change with no notice.

[docs] Line functions in 2 and 3 dimensions.
[docs] Plane functions
[docs] Triangle functions in 2 and 3 dimensions
[docs] Circle and sphere functions
[docs] Rectangle and box functions
[docs] Matrix math in 2 and 3 dimensions.
[docs] Inertia functions for a few shapes.