add generator layers

src/world/generator/GeneratorDef.hpp

@@ -6,12 +6,30 @@
 #include "typedefs.hpp"
 #include "maths/Heightmap.hpp"
 
+class Content;
+
+struct BlocksLayer {
+    std::string block;
+    int height;
+
+    struct {
+        blockid_t id;
+    } rt;
+};
+
 class GeneratorScript {
 public:
     virtual ~GeneratorScript() = default;
 
     virtual std::shared_ptr<Heightmap> generateHeightmap(
         const glm::ivec2& offset, const glm::ivec2& size) = 0;
+
+    virtual const std::vector<BlocksLayer>& getLayers() const = 0;
+
+    /// @brief Total height of all layers after resizeable one
+    virtual uint getLastLayersHeight() const = 0;
+
+    virtual void prepare(const Content* content) = 0;
 };
 
 struct GeneratorDef {