luaraylib.c

/* LuaRayLib API:
 * raylib
 * - set_fps(integer)
 * - number get_delta()
 * - number get_time()
 * - window [window control function]
 *   - init(integer, integer, string)
 *   - close()
 *   - boolean should_close()
 * - draw [drawing functions]
 *   - begin()
 *   - rend()^1
 *   - clear(integer)
 *   - rect(integer, integer, integer, integer, integer)
 *   - circle(integer, integer, number, integer)
 * - colors [color constants (is integers)]
 *   - red ... raywhite
 *
 * [1] end is keyword, because
 *     rend mean "Raylib END"
 */

#include <raylib/raylib.h>
#include <lua54/lauxlib.h>
#include <lua54/lua.h>

static inline unsigned lrl_col2int(Color col) {
    return (unsigned)col.r << 24 | (unsigned)col.g << 16
        |  (unsigned)col.b <<  8 | (unsigned)col.a;
}

static int lrl_init_window(lua_State* L) {
    int width  = luaL_checkinteger(L, 1);
    int height = luaL_checkinteger(L, 2);
    const char* title = luaL_checkstring(L, 3);
    luaL_argcheck(L, title != NULL, 3,
        "title cannot be empty");

    InitWindow(width, height, title);
    return 0;
}

static int lrl_close_window(lua_State* L) {
    CloseWindow(); (void)L; return 0;
}

static int lrl_window_should_close(lua_State* L) {
    lua_pushboolean(L, WindowShouldClose());
    return 1;
}

static int lrl_set_target_fps(lua_State* L) {
    SetTargetFPS(luaL_checkinteger(L, 1));
    return 0;
}

static int lrl_get_frame_time(lua_State* L) {
    lua_pushnumber(L, GetFrameTime());
    return 1;
}

static int lrl_get_time(lua_State* L) {
    lua_pushnumber(L, GetTime());
    return 1;
}

static int lrl_begin_drawing(lua_State* L) {
    BeginDrawing(); (void)L; return 0;
}

static int lrl_end_drawing(lua_State* L) {
    EndDrawing(); (void)L; return 0;
}

static int lrl_clear_background(lua_State* L) {
    ClearBackground(GetColor(luaL_checkinteger(L, 1)));
    return 0;
}

static int lrl_draw_rectangle(lua_State* L) {
    int x = luaL_checkinteger(L, 1);
    int y = luaL_checkinteger(L, 2);
    int width  = luaL_checkinteger(L, 3);
    int height = luaL_checkinteger(L, 4);
    int color  = luaL_checkinteger(L, 5);

    DrawRectangle(x, y, width, height, GetColor(color));
    return 0;
}

static int lrl_draw_circle(lua_State* L) {
    int x = luaL_checkinteger(L, 1);
    int y = luaL_checkinteger(L, 2);
    double radius = luaL_checknumber(L, 3);
    int color = luaL_checkinteger(L, 4);

    DrawCircle(x, y, radius, GetColor(color));
    return 0;
}

static const struct luaL_Reg lrl_window_funcs[] = {
    { "init", lrl_init_window },
    { "close", lrl_close_window },
    { "should_close", lrl_window_should_close },
    { NULL, NULL }
};

static const struct luaL_Reg lrl_draw_funcs[] = {
    { "begin", lrl_begin_drawing },
    { "rend", lrl_end_drawing },
    { "clear", lrl_clear_background },
    { "rect", lrl_draw_rectangle },
    { "circle", lrl_draw_circle },
    { NULL, NULL }
};

static const struct luaL_Reg lrl_glob_funcs[] = {
    { "set_fps", lrl_set_target_fps },
    { "get_delta", lrl_get_frame_time },
    { "get_time", lrl_get_time },
    { NULL, NULL }
};

LUA_API int luaopen_luaraylib(lua_State* L) {
    luaL_newlib(L, lrl_glob_funcs);

    luaL_newlib(L, lrl_window_funcs);
    lua_setfield(L, -2, "window");

    luaL_newlib(L, lrl_draw_funcs);
    lua_setfield(L, -2, "draw");

    lua_createtable(L, 0, 26);
#define DO(name) \
    lua_pushinteger(L, lrl_col2int(name)); \
    lua_setfield(L, -2, #name);
    DO(LIGHTGRAY) DO(GRAY) DO(DARKGRAY) DO(YELLOW)
    DO(GOLD) DO(ORANGE) DO(PINK) DO(RED) DO(MAROON)
    DO(GREEN) DO(LIME) DO(DARKGREEN) DO(SKYBLUE)
    DO(BLUE) DO(DARKBLUE) DO(PURPLE) DO(VIOLET)
    DO(DARKPURPLE) DO(BEIGE) DO(BROWN) DO(DARKBROWN)
    DO(WHITE) DO(BLACK) DO(BLANK) DO(MAGENTA) DO(RAYWHITE)
#undef DO
    lua_setfield(L, -2, "colors");

    return 1;
}