Fix loading files on pico builds

lua-bindings/surface.cpp

@@ -1,5 +1,7 @@
 #include "../luablitlib.hpp"
 
+extern std::string base_path;
+
 using namespace blit;
 
 static Surface *to_surface(lua_State *L, int arg) {
@@ -237,7 +239,7 @@ static int surface_load_sprites(lua_State *L, Surface *surface, int first_arg) {
         delete surface->sprites;
         surface->sprites = nullptr;
     }
-    surface->sprites = Surface::load(filename);
+    surface->sprites = Surface::load(base_path + "/" + filename);
     return 0;
 }
 

lua/CMakeLists.txt

@@ -34,11 +34,14 @@ add_library(lua STATIC
     ldblib.c
     liolib.c
     loslib.c
-    wrap/stdio.cpp
 )
 
 target_include_directories(lua PRIVATE ${32BLIT_DIR}/32blit)
 
-if(32BLIT_HW)
+set(LUA_PATH "\"/lib/?.lua\;/lib/?/init.lua\;./?.lua\;./?/init.lua\"")
+target_compile_definitions(lua PRIVATE "LUA_PATH_DEFAULT=${LUA_PATH}")
+
+if(32BLIT_HW OR CMAKE_SYSTEM_NAME STREQUAL "PICO")
     target_include_directories(lua SYSTEM PUBLIC wrap)
+    target_sources(lua PRIVATE wrap/stdio.cpp)
 endif()

lua/wrap/stdio.cpp

@@ -1,11 +1,11 @@
-#ifdef TARGET_32BLIT_HW
-
 #include <cstdarg>
 #include <stdio.h>
 #include <cstring>
 
 #include "engine/file.hpp"
 
+extern std::string base_path;
+
 // wrap stdio funcs around blit:: funcs
 wrap_FILE *wrap_stdin = nullptr;
 wrap_FILE *wrap_stdout = nullptr;
@@ -46,8 +46,14 @@ wrap_FILE *wrap_fopen(const char *filename, const char *mode)
             blit_mode |= blit::OpenMode::read;
     }
 
+    std::string filename_str = filename;
+
+    // adjust relative filenames to root
+    if(filename[0] == '.' && filename[1] == '/')
+        filename_str = base_path + (filename + 1);
+
     auto ret = new wrap_FILE;
-    ret->file.open(filename, blit_mode);
+    ret->file.open(filename_str, blit_mode);
     ret->offset = 0;
 
     ret->getc_buf_len = ret->getc_buf_off = 0;
@@ -213,4 +219,7 @@ int wrap_fflush(wrap_FILE *file)
     return 0;
 }
 
-#endif
+wrap_FILE *wrap_tmpfile()
+{
+    return nullptr;
+}

lua/wrap/stdio.h

@@ -29,6 +29,8 @@ int wrap_ferror(wrap_FILE *file);
 int wrap_clearerr(wrap_FILE *file);
 int wrap_fflush(wrap_FILE *file);
 
+wrap_FILE *wrap_tmpfile();
+
 extern wrap_FILE *wrap_stdin;
 extern wrap_FILE *wrap_stdout;
 extern wrap_FILE *wrap_stderr;
@@ -54,6 +56,7 @@ extern wrap_FILE *wrap_stderr;
 #define ferror wrap_ferror
 #define clearerr wrap_clearerr
 #define fflush wrap_fflush
+#define tmpfile wrap_tmpfile
 
 #ifdef __cplusplus
 }

main.cpp

@@ -8,6 +8,8 @@ lua_State *L;
 bool has_update = true;
 bool has_render = true;
 
+std::string base_path;
+
 void init() {
     set_screen_mode(ScreenMode::lores);
     screen.pen = Pen(0, 0, 0, 255);
@@ -20,9 +22,18 @@ void init() {
     lua_blit_update_state(L);
 
     auto launchPath = blit::get_launch_path();
+
     if(!launchPath) {
         launchPath = "main.lua";
     }
+
+
+    // set base path from dir of main script
+    auto pos = std::string_view(launchPath).find_last_of('/');
+    if(pos != std::string_view::npos)
+        base_path = std::string_view(launchPath).substr(0, pos);
+
+    // load the script
     auto err = luaL_loadfile(L, launchPath);
 
     if(err) {