From 35c09fc00094a3d390732fd533b2bd03413d90c7 Mon Sep 17 00:00:00 2001
From: Daniel Karbach <daniel.karbach@localhorst.tv>
Date: Wed, 27 May 2015 18:50:52 +0200
Subject: [PATCH] added ability to get seperate information about block face
 obstruction

---
 src/block.hpp | 37 +++++++++++++++++++++++++++++++++++++
 src/chunk.cpp | 11 ++++++-----
 src/chunk.hpp |  4 ++--
 3 files changed, 45 insertions(+), 7 deletions(-)

diff --git a/src/block.hpp b/src/block.hpp
index 4fcee4c..3af80a8 100644
--- a/src/block.hpp
+++ b/src/block.hpp
@@ -87,6 +87,43 @@ struct Block {
 		}
 	}
 
+	struct FaceSet {
+
+		explicit FaceSet(unsigned char v = 0)
+		: value(v) { }
+
+		bool IsSet(Face f) const {
+			return value & Mask(f);
+		}
+		void Set(Face f) {
+			value |= Mask(f);
+		}
+		void Unset(Face f) {
+			value |= ~Mask(f);
+		}
+
+		void Clear() {
+			value = 0;
+		}
+		void Fill() {
+			value = Mask(FACE_COUNT) - 1;
+		}
+
+		bool Empty() const {
+			return value == 0;
+		}
+		bool All() const {
+			return value == Mask(FACE_COUNT) - 1;
+		}
+
+		unsigned char Mask(Face f) const {
+			return 1 << f;
+		}
+
+		unsigned char value;
+
+	};
+
 };
 
 
diff --git a/src/chunk.cpp b/src/chunk.cpp
index 74ca1bc..23d5a13 100644
--- a/src/chunk.cpp
+++ b/src/chunk.cpp
@@ -445,7 +445,7 @@ void Chunk::Update() {
 	for (size_t i = 0; i < Size(); ++i) {
 		const BlockType &type = Type(blocks[i]);
 
-		if (!type.visible || Obstructed(i)) continue;
+		if (!type.visible || Obstructed(i).All()) continue;
 
 		type.FillBlockModel(buf, ToTransform(i), vtx_counter);
 		size_t vtx_begin = vtx_counter;
@@ -464,18 +464,19 @@ void Chunk::Update() {
 	dirty = false;
 }
 
-bool Chunk::Obstructed(int idx) const {
+Block::FaceSet Chunk::Obstructed(int idx) const {
 	Chunk::Pos pos(ToPos(idx));
+	Block::FaceSet result;
 
 	for (int f = 0; f < Block::FACE_COUNT; ++f) {
 		Block::Face face = Block::Face(f);
 		BlockLookup next(const_cast<Chunk *>(this), pos, face);
-		if (!next || !next.GetType().FaceFilled(next.GetBlock(), Block::Opposite(face))) {
-			return false;
+		if (next && next.GetType().FaceFilled(next.GetBlock(), Block::Opposite(face))) {
+			result.Set(face);
 		}
 	}
 
-	return true;
+	return result;
 }
 
 glm::mat4 Chunk::ToTransform(int idx) const {
diff --git a/src/chunk.hpp b/src/chunk.hpp
index 4addb56..06dc98b 100644
--- a/src/chunk.hpp
+++ b/src/chunk.hpp
@@ -88,8 +88,8 @@ public:
 	void Unlink();
 	void Relink();
 
-	// check if block at given index is completely enclosed (and therefore invisible)
-	bool Obstructed(int idx) const;
+	// check which faces of a block at given index are obstructed (and therefore invisible)
+	Block::FaceSet Obstructed(int idx) const;
 
 	void Invalidate() { dirty = true; }
 
-- 
2.39.2