ItemDef/EntityDef/Block: Add method cloneTo to definition to other definition

ContentBuilder: Add method `get` to get definition or nullptr
ContentLoader: Add functionality to clone from definition specified in `parent` field in json

src/content/ContentBuilder.hpp

@@ -44,6 +44,14 @@ public:
         defs[id] = std::make_unique<T>(id);
         return *defs[id];
     }
+    // Only fetch existing definition, return null otherwise.
+    T* get(const std::string& id) {
+        auto found = defs.find(id);
+        if (found != defs.end()) {
+            return &*found->second;
+        }
+        return nullptr;
+    }
 
     auto build() {
         return std::move(defs);

src/content/ContentLoader.cpp

@@ -6,6 +6,9 @@
 #include <memory>
 #include <string>
 
+#include "Content.hpp"
+#include "ContentBuilder.hpp"
+#include "ContentPack.hpp"
 #include "coders/json.hpp"
 #include "core_defs.hpp"
 #include "data/dynamic.hpp"
@@ -18,9 +21,6 @@
 #include "util/listutil.hpp"
 #include "util/stringutil.hpp"
 #include "voxels/Block.hpp"
-#include "Content.hpp"
-#include "ContentBuilder.hpp"
-#include "ContentPack.hpp"
 
 namespace fs = std::filesystem;
 
@@ -123,6 +123,18 @@ void ContentLoader::loadBlock(
 ) {
     auto root = files::read_json(file);
 
+    if (root->has("parent")) {
+        std::string parentName;
+        root->str("parent", parentName);
+        auto parentDef = this->builder.blocks.get(parentName);
+        if (parentDef == nullptr) {
+            throw std::runtime_error(
+                "Failed to find parent(" + parentName + ") for " + name
+            );
+        }
+        parentDef->cloneTo(def);
+    }
+
     root->str("caption", def.caption);
 
     // block texturing
@@ -289,6 +301,19 @@ void ContentLoader::loadItem(
     ItemDef& def, const std::string& name, const fs::path& file
 ) {
     auto root = files::read_json(file);
+
+    if (root->has("parent")) {
+        std::string parentName;
+        root->str("parent", parentName);
+        auto parentDef = this->builder.items.get(parentName);
+        if (parentDef == nullptr) {
+            throw std::runtime_error(
+                "Failed to find parent(" + parentName + ") for " + name
+            );
+        }
+        parentDef->cloneTo(def);
+    }
+
     root->str("caption", def.caption);
 
     std::string iconTypeStr = "";
@@ -319,6 +344,19 @@ void ContentLoader::loadEntity(
     EntityDef& def, const std::string& name, const fs::path& file
 ) {
     auto root = files::read_json(file);
+
+    if (root->has("parent")) {
+        std::string parentName;
+        root->str("parent", parentName);
+        auto parentDef = this->builder.entities.get(parentName);
+        if (parentDef == nullptr) {
+            throw std::runtime_error(
+                "Failed to find parent(" + parentName + ") for " + name
+            );
+        }
+        parentDef->cloneTo(def);
+    }
+
     if (auto componentsarr = root->list("components")) {
         for (size_t i = 0; i < componentsarr->size(); i++) {
             def.components.emplace_back(componentsarr->str(i));
@@ -340,7 +378,8 @@ void ContentLoader::loadEntity(
                              sensorarr->num(3)},
                             {sensorarr->num(4),
                              sensorarr->num(5),
-                             sensorarr->num(6)}}
+                             sensorarr->num(6)}
+                        }
                     );
                 } else if (sensorType == "radius") {
                     def.radialSensors.emplace_back(i, sensorarr->num(1));

src/content/ContentLoader.hpp

@@ -42,13 +42,13 @@ class ContentLoader {
 
     static void loadCustomBlockModel(Block& def, dynamic::Map* primitives);
     static void loadBlockMaterial(BlockMaterial& def, const fs::path& file);
-    static void loadBlock(
+    void loadBlock(
         Block& def, const std::string& name, const fs::path& file
     );
-    static void loadItem(
+    void loadItem(
         ItemDef& def, const std::string& name, const fs::path& file
     );
-    static void loadEntity(
+    void loadEntity(
         EntityDef& def, const std::string& name, const fs::path& file
     );
     void loadResources(ResourceType type, dynamic::List* list);

src/items/ItemDef.cpp

@@ -5,3 +5,13 @@
 ItemDef::ItemDef(const std::string& name) : name(name) {
     caption = util::id_to_caption(name);
 }
+void ItemDef::cloneTo(ItemDef& dst) {
+    dst.caption = caption;
+    dst.stackSize = stackSize;
+    dst.generated = generated;
+    std::copy(&emission[0], &emission[3], dst.emission);
+    dst.iconType = iconType;
+    dst.icon = icon;
+    dst.placingBlock = placingBlock;
+    dst.scriptName = scriptName;
+}

src/items/ItemDef.hpp

@@ -44,4 +44,5 @@ struct ItemDef {
 
     ItemDef(const std::string& name);
     ItemDef(const ItemDef&) = delete;
+    void cloneTo(ItemDef& dst);
 };

src/objects/EntityDef.cpp

@@ -0,0 +1,12 @@
+#include "EntityDef.hpp"
+void EntityDef::cloneTo(EntityDef& dst) {
+    dst.components = components;
+    dst.bodyType = bodyType;
+    dst.hitbox = hitbox;
+    dst.boxSensors = boxSensors;
+    dst.radialSensors = radialSensors;
+    dst.skeletonName = skeletonName;
+    dst.blocking = blocking;
+    dst.save = save;
+
+}

src/objects/EntityDef.hpp

@@ -56,4 +56,6 @@ struct EntityDef {
 
     EntityDef(const std::string& name) : name(name) {}
     EntityDef(const EntityDef&) = delete;
+    void cloneTo(EntityDef& dst);
 };
+

src/voxels/Block.cpp

@@ -64,7 +64,8 @@ const BlockRotProfile BlockRotProfile::NONE {
         {{1, 0, 0}, {0, 1, 0}, {0, 0, 1}},  // West
         {{1, 0, 0}, {0, 1, 0}, {0, 0, 1}},  // Up
         {{1, 0, 0}, {0, 1, 0}, {0, 0, 1}},  // Down
-    }};
+    }
+};
 
 const BlockRotProfile BlockRotProfile::PIPE {
     "pipe",
@@ -75,7 +76,8 @@ const BlockRotProfile BlockRotProfile::PIPE {
         {{0, 0, -1}, {1, 0, 0}, {0, -1, 0}},   // West
         {{1, 0, 0}, {0, 1, 0}, {0, 0, 1}},     // Up
         {{1, 0, 0}, {0, -1, 0}, {0, 0, -1}},   // Down
-    }};
+    }
+};
 
 const BlockRotProfile BlockRotProfile::PANE {
     "pane",
@@ -84,7 +86,8 @@ const BlockRotProfile BlockRotProfile::PANE {
         {{0, 0, -1}, {0, 1, 0}, {1, 0, 0}},   // East
         {{-1, 0, 0}, {0, 1, 0}, {0, 0, -1}},  // South
         {{0, 0, 1}, {0, 1, 0}, {-1, 0, 0}},   // West
-    }};
+    }
+};
 
 Block::Block(const std::string& name)
     : name(name),
@@ -95,10 +98,43 @@ Block::Block(const std::string& name)
           TEXTURE_NOTFOUND,
           TEXTURE_NOTFOUND,
           TEXTURE_NOTFOUND,
-          TEXTURE_NOTFOUND} {
+          TEXTURE_NOTFOUND
+      } {
 }
 
 Block::Block(std::string name, const std::string& texture)
     : name(std::move(name)),
       textureFaces {texture, texture, texture, texture, texture, texture} {
 }
+void Block::cloneTo(Block& dst) {
+    dst.caption = caption;
+    for (int i = 0; i < 6; i++) {
+            dst.textureFaces[i] = textureFaces[i];
+    }
+    dst.modelTextures = modelTextures;
+    dst.modelBoxes = modelBoxes;
+    dst.modelExtraPoints = modelExtraPoints;
+    dst.modelUVs = modelUVs;
+    dst.material = material;
+    std::copy(&emission[0], &emission[3], dst.emission);
+    dst.size = size;
+    dst.model = model;
+    dst.lightPassing = lightPassing;
+    dst.skyLightPassing = skyLightPassing;
+    dst.shadeless = shadeless;
+    dst.ambientOcclusion = ambientOcclusion;
+    dst.obstacle = obstacle;
+    dst.selectable = selectable;
+    dst.replaceable = replaceable;
+    dst.breakable = breakable;
+    dst.rotatable = rotatable;
+    dst.grounded = grounded;
+    dst.hidden = hidden;
+    dst.hitboxes = hitboxes;
+    dst.rotations = rotations;
+    dst.pickingItem = pickingItem;
+    dst.scriptName = scriptName;
+    dst.uiLayout = uiLayout;
+    dst.inventorySize = inventorySize;
+    dst.tickInterval = tickInterval;
+}

src/voxels/Block.hpp

@@ -211,6 +211,8 @@ public:
     Block(const std::string& name);
     Block(std::string name, const std::string& texture);
     Block(const Block&) = delete;
+
+    void cloneTo(Block& dst);
 };
 
 inline glm::ivec3 get_ground_direction(const Block& def, int rotation) {