New block properties and lua functions

src/voxels/Block.h

@@ -80,6 +80,7 @@ public:
 	bool breakable = true;
 	bool rotatable = false;
     bool grounded = false;
+    bool hidden = false;
 	AABB hitbox;
 	BlockRotProfile rotations;
 

src/voxels/Chunks.cpp

@@ -97,6 +97,13 @@ bool Chunks::isSolid(int x, int y, int z) {
     return contentIds->getBlockDef(v->id)->rt.solid;
 }
 
+bool Chunks::isReplaceable(int x, int y, int z) {
+    voxel* v = get(x, y, z);
+    if (v == nullptr)
+        return false;
+    return contentIds->getBlockDef(v->id)->replaceable;
+}
+
 ubyte Chunks::getLight(int x, int y, int z, int channel){
 	x -= ox * CHUNK_W;
 	z -= oz * CHUNK_D;

src/voxels/Chunks.h

@@ -55,6 +55,7 @@ public:
 
 	const AABB* isObstacle(float x, float y, float z);
     bool isSolid(int x, int y, int z);
+    bool isReplaceable(int x, int y, int z);
 
 	// does not move chunks inside
 	void _setOffset(int x, int z);