Tag: research

Chicken-Scheme FFI Examples

I'm currently working on refactoring the FFI implementation for the Rebel Game Engine. It was previously written using the Bind chicken egg but I wanted to have more control over the implementation by using the low level foreign functions.

To help me better understand I made some examples that has the basic FFI implementations that I'll be needing for my project.


foreign-lambda example

Let's say we have a structure Vec3 and a function Vec3Create that we want to access from chicken-scheme.

typedef struct Vec3 {
    float x;
    float y;
    float z;
} Vec3;

Vec3* Vec3Create(float x, float y, float z)
{
    Vec3* v = (Vec3*)malloc(sizeof(Vec3));
    v->x = x;
    v->y = y;
    v->z = z;
    return v;
}

We could use foreign-lambda to bind to the function:

(define vec3_create
  (foreign-lambda
    (c-pointer (struct "Vec3"))   ; Return type, a pointer to a struct object of Vec3
    "Vec3Create"                  ; Name fo the function
    float float float))           ; The …