h-a-how-to-use-raymath-single-alone-header.org

How to use raymath as a stand-alone header

If you want to use any raymatch.h related function (e.g. Vector3Normalize), then you might try to do something like below:

const rl = @cImport({
    @cInclude("raylib.h");
    @cInclude("raymath.h");
});

But it won’t work, as it will cause duplicate struct definition!!!

That’s because raylib.h has the following macros to prevent duplicate struct definition:

// NOTE: We set some defines with some data types declared by raylib
// Other modules (raymath, rlgl) also require some of those types, so,
// to be able to use those other modules as standalone (not depending on raylib)
// this defines are very useful for internal check and avoid type (re)definitions
#define RL_COLOR_TYPE
#define RL_RECTANGLE_TYPE
#define RL_VECTOR2_TYPE
#define RL_VECTOR3_TYPE
#define RL_VECTOR4_TYPE
#define RL_QUATERNION_TYPE
#define RL_MATRIX_TYPE

And raymath.h designs to be able to use a stand alone header without raylib.h or work with raylib.h, that’s why it has the following conditional complination restrictions:

#if !defined(RL_XXXXXXX)
// ... struct type definition here
#define RL_XXXXXXX
#endif

That said if you try include raylib.h and raymath.h together, raymath. doesn’t re-define all those struct types!!!

But the problem is that zig translate-c can’t handle those RL_XXXXXX macro, there is no way to define them before @cInclude("raymath.h"); be executed!!! That’s the reason to cause duplicate struct definition.

So, how to solve it???

1. Use clang to expand raymath.h with those macros

clang -E \
    -D RL_COLOR_TYPE \
    -D RL_RECTANGLE_TYPE \
    -D RL_VECTOR2_TYPE \
    -D RL_VECTOR3_TYPE \
    -D RL_VECTOR4_TYPE \
    -D RL_QUATERNION_TYPE
    -D RL_MATRIX_TYPE \
    raylib/zig-out/include/raymath.h > raylib/zig-out/include/raymath_2.h

After that, raylib/zig-out/include/raymath_2.h removes all struct definitions exists inside raylib.h:)

2. Add extra include statement

You have to add the following include statement at the begining of raylib/zig-out/include/raymath_2.h:

#include "raylib.h"

That’s because all struct definitions don’t exists in raylib/zig-out/include/raymath_2.h.

3. Translate header file into zig

zig translate-c raylib/zig-out/include/raymath_2.h > ../src/raymath_2.zig

So, that raymatch_2.zig includes everything in raylib.h and raymath.h. You should only import it like below without using @cImport:

const rl = @import("raymath.zig");

// rl.LoadFont (from `raylib.h`)
// ......
// rl.Vector3Normalize (from `raymath.h`)

That’s it;)