update voxel fragments lua api & replace structure.save command with fragment.save & add 'export' entry point

.gitignore

@@ -6,6 +6,8 @@ Debug/voxel_engine
 /build
 /cmake-build-**
 /screenshots
+/export
+/config
 /out
 
 /misc

res/scripts/stdcmd.lua

@@ -151,8 +151,8 @@ console.add_command(
 )
 
 console.add_command(
-    "structure.save x:int y:int z:int w:int h:int d:int name:str='untitled'",
-    "Save structure",
+    "fragment.save x:int y:int z:int w:int h:int d:int name:str='untitled' crop:bool=false",
+    "Save fragment",
     function(args, kwargs)
         local x = args[1]
         local y = args[2]
@@ -163,6 +163,14 @@ console.add_command(
         local d = args[6]
 
         local name = args[7]
-        generation.save_structure({x, y, z}, {x+w, y+h, z+d}, name..'.vox', false)
+        local crop = args[8]
+        
+        local fragment = generation.create_fragment(
+            {x, y, z}, {x + w, y + h, z + d}, crop, false
+        )
+        local filename = 'export:'..name..'.vox'
+        generation.save_fragment(fragment, filename, crop)
+        console.log("fragment with size "..vec3.tostring(fragment.size)..
+                    " has been saved as "..file.resolve(filename))
     end
 )

src/files/engine_paths.cpp

@@ -18,6 +18,7 @@ static inline auto SCREENSHOTS_FOLDER = std::filesystem::u8path("screenshots");
 static inline auto CONTENT_FOLDER = std::filesystem::u8path("content");
 static inline auto WORLDS_FOLDER = std::filesystem::u8path("worlds");
 static inline auto CONFIG_FOLDER = std::filesystem::u8path("config");
+static inline auto EXPORT_FOLDER = std::filesystem::u8path("export");
 static inline auto CONTROLS_FILE = std::filesystem::u8path("controls.toml");
 static inline auto SETTINGS_FILE = std::filesystem::u8path("settings.toml");
 
@@ -51,6 +52,10 @@ void EnginePaths::prepare() {
     if (!fs::is_directory(contentFolder)) {
         fs::create_directories(contentFolder);
     }
+    auto exportFolder = userFilesFolder / EXPORT_FOLDER;
+    if (!fs::is_directory(exportFolder)) {
+        fs::create_directories(exportFolder);
+    }
 }
 
 std::filesystem::path EnginePaths::getUserFilesFolder() const {
@@ -187,6 +192,9 @@ std::filesystem::path EnginePaths::resolve(
     if (prefix == "world") {
         return currentWorldFolder / fs::u8path(filename);
     }
+    if (prefix == "export") {
+        return userFilesFolder / EXPORT_FOLDER / fs::u8path(filename);
+    }
 
     if (contentPacks) {
         for (auto& pack : *contentPacks) {

src/logic/scripting/lua/libs/libgeneration.cpp

@@ -11,24 +11,30 @@
 
 using namespace scripting;
 
-static int l_save_structure(lua::State* L) {
-    auto pointA = lua::tovec<3>(L, 1);
-    auto pointB = lua::tovec<3>(L, 2);
-    auto filename = lua::require_string(L, 3);
-    if (!files::is_valid_name(filename)) {
-        throw std::runtime_error("invalid file name");
-    }
-    bool saveEntities = lua::toboolean(L, 4);
-    
-    auto structure = VoxelFragment::create(level, pointA, pointB, saveEntities);
-    auto map = structure->serialize();
-
-    auto bytes = json::to_binary(map);
-    files::write_bytes(fs::u8path(filename), bytes.data(), bytes.size());
+static int l_save_fragment(lua::State* L) {
+    auto paths = engine->getPaths();
+    auto fragment = lua::touserdata<lua::LuaVoxelFragment>(L, 1);
+    auto file = paths->resolve(lua::require_string(L, 2), true);
+    auto map = fragment->getFragment()->serialize();
+    auto bytes = json::to_binary(map, true);
+    files::write_bytes(file, bytes.data(), bytes.size());
     return 0;
 }
 
-static int l_load_structure(lua::State* L) {
+static int l_create_fragment(lua::State* L) {
+    auto pointA = lua::tovec<3>(L, 1);
+    auto pointB = lua::tovec<3>(L, 2);
+    bool crop = lua::toboolean(L, 3);
+    bool saveEntities = lua::toboolean(L, 4);
+
+    auto fragment =
+        VoxelFragment::create(level, pointA, pointB, crop, saveEntities);
+    return lua::newuserdata<lua::LuaVoxelFragment>(
+        L, std::shared_ptr<VoxelFragment>(std::move(fragment))
+    );
+}
+
+static int l_load_fragment(lua::State* L) {
     auto paths = engine->getPaths();
     auto [prefix, filename] = EnginePaths::parsePath(lua::require_string(L, 1));
 
@@ -38,9 +44,9 @@ static int l_load_structure(lua::State* L) {
     }
     auto map = files::read_binary_json(path);
 
-    auto structure = std::make_shared<VoxelFragment>();
-    structure->deserialize(map);
-    return lua::newuserdata<lua::LuaVoxelStructure>(L, std::move(structure));
+    auto fragment = std::make_shared<VoxelFragment>();
+    fragment->deserialize(map);
+    return lua::newuserdata<lua::LuaVoxelFragment>(L, std::move(fragment));
 }
 
 /// @brief Get a list of all world generators
@@ -72,8 +78,9 @@ static int l_get_default_generator(lua::State* L) {
 }
 
 const luaL_Reg generationlib[] = {
-    {"save_structure", lua::wrap<l_save_structure>},
-    {"load_structure", lua::wrap<l_load_structure>},
+    {"create_fragment", lua::wrap<l_create_fragment>},
+    {"save_fragment", lua::wrap<l_save_fragment>},
+    {"load_fragment", lua::wrap<l_load_fragment>},
     {"get_generators", lua::wrap<l_get_generators>},
     {"get_default_generator", lua::wrap<l_get_default_generator>},
     {NULL, NULL}};

src/logic/scripting/lua/lua_custom_types.hpp

@@ -71,15 +71,15 @@ namespace lua {
     };
     static_assert(!std::is_abstract<LuaHeightmap>());
 
-    class LuaVoxelStructure : public Userdata {
-        std::shared_ptr<VoxelFragment> structure;
+    class LuaVoxelFragment : public Userdata {
+        std::shared_ptr<VoxelFragment> fragment;
     public:
-        LuaVoxelStructure(std::shared_ptr<VoxelFragment> structure);
+        LuaVoxelFragment(std::shared_ptr<VoxelFragment> fragment);
 
-        virtual ~LuaVoxelStructure();
+        virtual ~LuaVoxelFragment();
 
-        std::shared_ptr<VoxelFragment> getStructure() const {
-            return structure;
+        std::shared_ptr<VoxelFragment> getFragment() const {
+            return fragment;
         }
 
         const std::string& getTypeName() const override {
@@ -87,7 +87,7 @@ namespace lua {
         }
 
         static int createMetatable(lua::State*);
-        inline static std::string TYPENAME = "VoxelStructure";
+        inline static std::string TYPENAME = "VoxelFragment";
     };
-    static_assert(!std::is_abstract<LuaVoxelStructure>());
+    static_assert(!std::is_abstract<LuaVoxelFragment>());
 }

src/logic/scripting/lua/lua_engine.cpp

@@ -103,7 +103,7 @@ void lua::init_state(State* L, StateType stateType) {
 
     newusertype<LuaBytearray>(L);
     newusertype<LuaHeightmap>(L);
-    newusertype<LuaVoxelStructure>(L);
+    newusertype<LuaVoxelFragment>(L);
 }
 
 void lua::initialize(const EnginePaths& paths) {

src/logic/scripting/lua/usertypes/lua_type_voxelstructure.cpp

@@ -7,20 +7,37 @@
 
 using namespace lua;
 
-LuaVoxelStructure::LuaVoxelStructure(std::shared_ptr<VoxelFragment> structure)
-    : structure(std::move(structure)) {}
+LuaVoxelFragment::LuaVoxelFragment(std::shared_ptr<VoxelFragment> fragment)
+    : fragment(std::move(fragment)) {}
 
-LuaVoxelStructure::~LuaVoxelStructure() {
+LuaVoxelFragment::~LuaVoxelFragment() {
 }
 
 static int l_meta_tostring(lua::State* L) {
-    return pushstring(L, "VoxelStructure(0x" + util::tohex(
+    return pushstring(L, "VoxelFragment(0x" + util::tohex(
         reinterpret_cast<uint64_t>(topointer(L, 1)))+")");
 }
 
-int LuaVoxelStructure::createMetatable(lua::State* L) {
-    createtable(L, 0, 1);
+static int l_meta_index(lua::State* L) {
+    auto fragment = touserdata<LuaVoxelFragment>(L, 1);
+    if (fragment == nullptr) {
+        return 0;
+    }
+    if (isstring(L, 2)) {
+        auto fieldname = tostring(L, 2);
+        if (!std::strcmp(fieldname, "size")) {
+            return pushivec(L, fragment->getFragment()->getSize());
+        }
+    }
+    return 0;
+}
+
+
+int LuaVoxelFragment::createMetatable(lua::State* L) {
+    createtable(L, 0, 2);
     pushcfunction(L, lua::wrap<l_meta_tostring>);
     setfield(L, "__tostring");
+    pushcfunction(L, lua::wrap<l_meta_index>);
+    setfield(L, "__index");
     return 1;
 }

src/world/generator/VoxelFragment.cpp

@@ -11,11 +11,41 @@
 #include "world/Level.hpp"
 
 std::unique_ptr<VoxelFragment> VoxelFragment::create(
-    Level* level, const glm::ivec3& a, const glm::ivec3& b, bool entities
+    Level* level,
+    const glm::ivec3& a,
+    const glm::ivec3& b,
+    bool crop,
+    bool entities
 ) {
     auto start = glm::min(a, b);
     auto size = glm::abs(a - b);
 
+    if (crop) {
+        VoxelsVolume volume(size.x, size.y, size.z);
+        volume.setPosition(start.x, start.y, start.z);
+        level->chunksStorage->getVoxels(&volume);
+
+        auto end = start + size;
+
+        auto min = end;
+        auto max = start;
+        
+        for (int y = start.y; y < end.y; y++) {
+            for (int z = start.z; z < end.z; z++) {
+                for (int x = start.x; x < end.x; x++) {
+                    if (volume.pickBlockId(x, y, z)) {
+                        min = glm::min(min, {x, y, z});
+                        max = glm::max(max, {x+1, y+1, z+1});
+                    }
+                }
+            }
+        }
+        if (glm::min(min, max) == min) {
+            start = min;
+            size = max - min;
+        }
+    }
+
     VoxelsVolume volume(size.x, size.y, size.z);
     volume.setPosition(start.x, start.y, start.z);
     level->chunksStorage->getVoxels(&volume);

src/world/generator/VoxelFragment.hpp

@@ -44,7 +44,12 @@ public:
     std::unique_ptr<VoxelFragment> rotated(const Content& content) const;
 
     static std::unique_ptr<VoxelFragment> create(
-        Level* level, const glm::ivec3& a, const glm::ivec3& b, bool entities);
+        Level* level,
+        const glm::ivec3& a,
+        const glm::ivec3& b,
+        bool crop,
+        bool entities
+    );
 
     const glm::ivec3& getSize() const {
         return size;