townengine/apps/lua/game.c

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2024-10-05 21:17:22 +00:00
#include "twn_game_api.h"
#include "state.h"
#include <lua.h>
#include <lualib.h>
#include <lauxlib.h>
#include <malloc.h>
/* require will go through physicsfs exclusively so that scripts can be in the data dir */
static int physfs_loader(lua_State *L) {
const char *name = luaL_checkstring(L, 1);
char *final_path = NULL;
SDL_asprintf(&final_path, "%s.lua", name);
if (!file_exists(final_path)) {
char *error_message = NULL;
SDL_asprintf(&error_message, "could not find module %s in filesystem", name);
lua_pushstring(L, error_message);
free(error_message);
free(final_path);
return 1;
}
unsigned char *buf = NULL;
int64_t buf_size = file_to_bytes(final_path, &buf);
free(final_path);
luaL_loadbuffer(L, (char *)buf, buf_size, name);
free(buf);
return 1;
}
static Rect table_to_rect(lua_State *L, int idx, const char *name) {
/* types are checked here to help prevent unexpected results */
Rect rect;
int is_num;
lua_getfield(L, idx, "x");
rect.x = (float)lua_tonumberx(L, -1, &is_num);
if (!is_num)
luaL_error(L, "bad field 'x' in '%s' (number expected, got %s)", name, luaL_typename(L, -1));
lua_pop(L, 1);
lua_getfield(L, idx, "y");
rect.y = (float)lua_tonumberx(L, -1, &is_num);
if (!is_num)
luaL_error(L, "bad field 'y' in '%s' (number expected, got %s)", name, luaL_typename(L, -1));
lua_pop(L, 1);
lua_getfield(L, idx, "w");
rect.w = (float)lua_tonumberx(L, -1, &is_num);
if (!is_num)
luaL_error(L, "bad field 'w' in '%s' (number expected, got %s)", name, luaL_typename(L, -1));
lua_pop(L, 1);
lua_getfield(L, idx, "h");
rect.h = (float)lua_tonumberx(L, -1, &is_num);
if (!is_num)
luaL_error(L, "bad field 'h' in '%s' (number expected, got %s)", name, luaL_typename(L, -1));
lua_pop(L, 1);
return rect;
}
static Color table_to_color(lua_State *L, int idx) {
Color color;
lua_getfield(L, idx, "r");
color.r = (uint8_t)lua_tointeger(L, -1);
lua_pop(L, 1);
lua_getfield(L, idx, "g");
color.g = (uint8_t)lua_tointeger(L, -1);
lua_pop(L, 1);
lua_getfield(L, idx, "b");
color.b = (uint8_t)lua_tointeger(L, -1);
lua_pop(L, 1);
lua_getfield(L, idx, "a");
color.a = (uint8_t)lua_tointeger(L, -1);
lua_pop(L, 1);
return color;
}
/* sprite(data [table]) */
/* data should contain the following fields: */
/*
* path [string]
* rect [table]
* texture_region [table], optional
* color [table], optional
* rotation [number], optional
* flip_x [boolean], optional
* flip_y [boolean], optional
* stretch [boolean], optional
*/
static int b_sprite(lua_State *L) {
luaL_checktype(L, 1, LUA_TTABLE);
PushSpriteArgs args = { 0 };
lua_getfield(L, 1, "path");
const char *field_path = lua_tostring(L, -1);
if (field_path == NULL)
luaL_error(L, "bad field 'path' in 'data' (string expected, got %s)", luaL_typename(L, -1));
args.path = field_path;
lua_getfield(L, 1, "rect");
if (!lua_istable(L, -1))
luaL_error(L, "bad field 'rect' in 'data' (table expected, got %s)", luaL_typename(L, -1));
args.rect = table_to_rect(L, -1, "data.rect");
lua_getfield(L, 1, "texture_region");
if (lua_istable(L, -1)) {
args.texture_region_opt = table_to_rect(L, -1, "data.texture_region");
args.texture_region_opt_set = true;
}
lua_getfield(L, 1, "color");
if (lua_istable(L, -1)) {
args.color_opt = table_to_color(L, -1);
args.color_opt_set = true;
}
lua_getfield(L, 1, "rotation");
if (lua_isnumber(L, -1)) {
args.rotation_opt = (float)lua_tonumber(L, -1);
args.rotation_opt_set = true;
}
lua_getfield(L, 1, "flip_x");
if (lua_isboolean(L, -1)) {
args.flip_x_opt = lua_toboolean(L, -1);
args.flip_x_opt_set = true;
}
lua_getfield(L, 1, "flip_y");
if (lua_isboolean(L, -1)) {
args.flip_y_opt = lua_toboolean(L, -1);
args.flip_y_opt_set = true;
}
lua_getfield(L, 1, "stretch");
if (lua_isboolean(L, -1)) {
args.stretch_opt = lua_toboolean(L, -1);
args.stretch_opt_set = true;
}
push_sprite(args);
return 0;
}
/* rectangle(data [table]) */
/* data should contain the following fields: */
/*
* rect [table]
* color [table], optional, defaults to white
*/
static int b_rectangle(lua_State *L) {
luaL_checktype(L, 1, LUA_TTABLE);
lua_getfield(L, 1, "rect");
if (!lua_istable(L, -1))
luaL_error(L, "bad field 'rect' in 'data' (table expected, got %s)", luaL_typename(L, -1));
Rect rect = table_to_rect(L, -1, "data.rect");
Color color = { 255, 255, 255, 255 };
lua_getfield(L, 1, "color");
if (lua_istable(L, -1))
color = table_to_color(L, -1);
push_rectangle(rect, color);
return 0;
}
/* text(data [table]) */
/* data should contain the following fields: */
/*
* string [string]
* position [table]
* height_px [number], optional, defaults to 22
* color [table], optional, defaults to black
* font_path [string]
*/
static int b_text(lua_State *L) {
luaL_checktype(L, 1, LUA_TTABLE);
lua_getfield(L, 1, "string");
const char *string = lua_tostring(L, -1);
if (string == NULL)
luaL_error(L, "bad field 'string' in 'data' (string expected, got %s)", luaL_typename(L, -1));
lua_getfield(L, 1, "position");
if (!lua_istable(L, -1))
luaL_error(L, "bad field 'position' in 'data' (table expected, got %s)", luaL_typename(L, -1));
lua_getfield(L, -1, "x");
float x = (float)lua_tonumber(L, -1);
lua_getfield(L, -2, "y");
float y = (float)lua_tonumber(L, -1);
lua_getfield(L, 1, "height_px");
int is_num;
int height_px = (int)lua_tointegerx(L, -1, &is_num);
if (!is_num)
height_px = 22;
lua_getfield(L, 1, "color");
Color color = { 0, 0, 0, 255 };
if (lua_istable(L, -1))
color = table_to_color(L, -1);
lua_getfield(L, 1, "font_path");
const char *font_path = lua_tostring(L, -1);
if (font_path == NULL)
luaL_error(L, "bad field 'font_path' in 'data' (string expected, got %s)", luaL_typename(L, -1));
push_text(string, (Vec2) { x, y }, height_px, color, font_path);
return 0;
}
void game_tick(void) {
if (ctx.initialization_needed) {
if (!ctx.udata)
ctx.udata = ccalloc(1, sizeof (State));
State *state = ctx.udata;
/* let's init lua */
/* state existed already */
if (state->L != NULL) {
lua_close(state->L);
}
state->L = luaL_newstate();
/* fakey version of luaL_openlibs() that excludes file i/o */
{
static const luaL_Reg loaded_libs[] = {
{ LUA_GNAME, luaopen_base },
{ LUA_LOADLIBNAME, luaopen_package },
{ LUA_COLIBNAME, luaopen_coroutine },
{ LUA_TABLIBNAME, luaopen_table },
{ LUA_OSLIBNAME, luaopen_os },
{ LUA_STRLIBNAME, luaopen_string },
{ LUA_MATHLIBNAME, luaopen_math },
{ LUA_UTF8LIBNAME, luaopen_utf8 },
{ LUA_DBLIBNAME, luaopen_debug },
{ NULL, NULL },
};
for (const luaL_Reg *lib = loaded_libs; lib->func; ++lib) {
luaL_requiref(state->L, lib->name, lib->func, true);
lua_pop(state->L, 1); /* already stored, don't need the copy */
}
}
/* package.searchers = { physfs_loader } */
lua_getglobal(state->L, "package");
lua_newtable(state->L);
lua_setfield(state->L, -2, "searchers");
lua_getfield(state->L, -1, "searchers");
lua_pushcfunction(state->L, physfs_loader);
lua_seti(state->L, -2, 1);
/* pop package, package.searchers */
lua_pop(state->L, 2);
/* now finally get to running the code */
unsigned char *game_buf = NULL;
int64_t game_buf_size = file_to_bytes("/scripts/game.lua", &game_buf);
if (luaL_loadbuffer(state->L, (char *)game_buf, game_buf_size, "game.lua") == LUA_OK) {
if (lua_pcall(state->L, 0, 0, 0) != LUA_OK) {
log_critical("%s", lua_tostring(state->L, -1));
lua_pop(state->L, 1);
}
}
/* from this point we have access to everything defined in lua */
/* binding */
lua_register(state->L, "sprite", b_sprite);
lua_register(state->L, "rectangle", b_rectangle);
lua_register(state->L, "text", b_text);
}
State *state = ctx.udata;
lua_getglobal(state->L, "game_tick");
if (lua_pcall(state->L, 0, 0, 0) != LUA_OK) {
log_critical("%s", lua_tostring(state->L, -1));
lua_pop(state->L, 1);
}
}
void game_end(void) {
State *state = ctx.udata;
lua_close(state->L);
free(state);
}