cglm Mathematics Library

cglm is an optimized 3D mathematics library written in C99 (and compatible with C89). It is designed as a C-compatible alternative to the original OpenGL Mathematics (glm) library.

Key technical detail: cglm stores matrices in column-major order. While row-major support is considered for future optional implementation, current usage assumes column-major layout.

The mat3x4 type represents a 3x4 matrix. In memory, it is organized by columns as follows:

Include the header cglm/mat3x4.h to use these functions.

The mat4x3 type represents a 4x3 matrix. It is stored in column-major order.

Memory Layout:

Include the header cglm/mat4x3.h to use these functions.

In cglm, a 2D Axis-Aligned Bounding Box (AABB) is represented as a two-dimensional array of vec2s.

• aabb[0] represents the min point.
• aabb[1] represents the max point.

If you are using a different data structure (like a custom struct), you must convert it to this vec2[2] format before calling AABB functions and convert it back afterward.

cglm uses the glm prefix for all functions. Types are implemented as arrays rather than structs to ensure they are homogeneous and can be passed directly to OpenGL without casting or using a value_ptr function.

Because types are arrays, you must use subscript notation (e.g., vec[0], vec[1]) to access elements instead of struct members like vec.x or vec.y. Matrices are arrays of vectors, so elements are accessed via matrix[row][column].

In cglm, an Axis-Aligned Bounding Box (AABB) is represented as a two-dimensional array of vec3.

• box[0] represents the min point.
• box[1] represents the max point.

If you are using a different data structure (like a custom struct), you must convert it to this vec3[2] format before calling cglm box functions and convert it back afterward.

The mat4x2 type represents a 4x2 matrix. It is stored in memory such that the elements are organized by rows:

Include the header cglm/mat4x2.h to use these functions.

Use Autotools for Unix-based systems. This method installs pkg-config files, allowing you to use pkg-config --cflags cglm and pkg-config --libs cglm.

Build Steps:

1. Run sh autogen.sh.
2. Run ./configure.
3. Run make.
4. (Optional) Run make check to run tests.
5. (Optional) Run sudo make install.

Note on pkg-config path: If your files are installed in a non-standard prefix, you can use ./configure --with-pkgconfigdir=/your/path or set the PKG_CONFIG_PATH environment variable.

$ sh autogen.sh
$ ./configure
$ make
$ make check # [Optional]
$ [sudo] make install # [Optional]

You can integrate cglm into your CMake project in two ways:

1. As a header-only library

This requires no building or installation of cglm. Use the cglm_headers target.

2. As a compiled library

This links against the compiled cglm library using the cglm target.

In both cases, you must use add_subdirectory pointing to the cglm source directory.

# Header-only integration
cmake_minimum_required(VERSION 3.8.2)
project(<Your Project Name>)

add_executable(${PROJECT_NAME} src/main.c)
target_link_libraries(${PROJECT_NAME} PRIVATE cglm_headers)

add_subdirectory(external/cglm/ EXCLUDE_FROM_ALL)

# --- OR ---

# Compiled library integration
cmake_minimum_required(VERSION 3.8.2)
project(<Your Project Name>)

add_executable(${PROJECT_NAME} src/main.c)
target_link_libraries(${PROJECT_NAME} PRIVATE cglm)

add_subdirectory(external/cglm/)