From: Daniel Karbach <daniel.karbach@localhorst.tv>
Date: Mon, 1 Jun 2015 15:08:45 +0000 (+0200)
Subject: slight lighting improvement
X-Git-Url: http://git.localhorst.tv/?a=commitdiff_plain;h=bee003d1d375789b6533cfd39c65f6d4478f1966;p=blank.git

slight lighting improvement

using a combination of interpolation and occlusion
---

diff --git a/TODO b/TODO
index 29fd94f..411172d 100644
--- a/TODO
+++ b/TODO
@@ -40,10 +40,9 @@ entity ai
 
 (block) lighting
 
-	light levels are roughtly implemented. the shader has to be
-	adjusted so they actually have an impact on the resulting color
-
-	there seems to be a bug with propagating light across chunk borders
+	occlusion/neighbor light mixing is implemented, but still linear
+	this could be solved by using a pre-interpolated light texture and
+	mapping light levels to coordinates on that
 
 	also: how could block light affect entity lighting?
 
diff --git a/src/block.hpp b/src/block.hpp
index 2c26ed7..84efa48 100644
--- a/src/block.hpp
+++ b/src/block.hpp
@@ -55,6 +55,21 @@ struct Block {
 		return Face(f ^ 1);
 	}
 
+	static int Axis(Face f) noexcept {
+		switch (f) {
+			case FACE_UP:
+			case FACE_DOWN:
+				return 1;
+			default:
+			case FACE_RIGHT:
+			case FACE_LEFT:
+				return 0;
+			case FACE_FRONT:
+			case FACE_BACK:
+				return 2;
+		}
+	}
+
 	static glm::tvec3<int> FaceNormal(Face face) noexcept {
 		return face2normal[face];
 	}
diff --git a/src/chunk.cpp b/src/chunk.cpp
index f172143..a0415fd 100644
--- a/src/chunk.cpp
+++ b/src/chunk.cpp
@@ -333,18 +333,81 @@ float Chunk::GetVertexLight(int index, const BlockModel::Position &vtx, const Mo
 		if (direct_light > light) {
 			light = direct_light;
 		}
+	} else {
+		return light;
+	}
+
+	if (Type(BlockAt(index)).luminosity > 0 || direct.GetType().block_light) {
+		return light;
+	}
+
+	Block::Face edge[2];
+	switch (Block::Axis(direct_face)) {
+		case 0: // X
+			edge[0] = (vtx.y - pos.y) > 0.5f ? Block::FACE_UP : Block::FACE_DOWN;
+			edge[1] = (vtx.z - pos.z) > 0.5f ? Block::FACE_FRONT : Block::FACE_BACK;
+			break;
+		case 1: // Y
+			edge[0] = (vtx.z - pos.z) > 0.5f ? Block::FACE_FRONT : Block::FACE_BACK;
+			edge[1] = (vtx.x - pos.x) > 0.5f ? Block::FACE_RIGHT : Block::FACE_LEFT;
+			break;
+		case 2: // Z
+			edge[0] = (vtx.x - pos.x) > 0.5f ? Block::FACE_RIGHT : Block::FACE_LEFT;
+			edge[1] = (vtx.y - pos.y) > 0.5f ? Block::FACE_UP : Block::FACE_DOWN;
+			break;
 	}
 
-	// cheap alternative until AO etc are implemented
-	// to tell the faces apart
+	int num = 1;
+	int occlusion = 0;
+
+	BlockLookup next[2] = {
+		direct.Next(edge[0]),
+		direct.Next(edge[1]),
+	};
 
-	if (direct_face == Block::FACE_LEFT || direct_face == Block::FACE_RIGHT) {
-		light -= 0.2;
-	} else if (direct_face == Block::FACE_FRONT || direct_face == Block::FACE_BACK) {
-		light -= 0.4;
+	if (next[0]) {
+		if (next[0].GetType().block_light) {
+			++occlusion;
+		} else {
+			light += next[0].GetLight();
+			++num;
+		}
+	}
+	if (next[1]) {
+		if (next[1].GetType().block_light) {
+			++occlusion;
+		} else {
+			light += next[1].GetLight();
+			++num;
+		}
+	}
+	if (occlusion < 2) {
+		if (next[0]) {
+			BlockLookup corner = next[0].Next(edge[1]);
+			if (corner) {
+				if (corner.GetType().block_light) {
+					++occlusion;
+				} else {
+					light += corner.GetLight();
+					++num;
+				}
+			}
+		} else if (next[1]) {
+			BlockLookup corner = next[1].Next(edge[0]);
+			if (corner) {
+				if (corner.GetType().block_light) {
+					++occlusion;
+				} else {
+					light += corner.GetLight();
+					++num;
+				}
+			}
+		}
+	} else {
+		++occlusion;
 	}
 
-	return light;
+	return (light / num) - (occlusion * 0.8f);
 }
 
 
diff --git a/src/chunk.hpp b/src/chunk.hpp
index 24024f9..040a817 100644
--- a/src/chunk.hpp
+++ b/src/chunk.hpp
@@ -172,6 +172,9 @@ public:
 	const BlockType &GetType() const noexcept { return GetChunk().Type(GetBlock()); }
 	int GetLight() const noexcept { return GetChunk().GetLight(GetBlockPos()); }
 
+	// traverse in given direction
+	BlockLookup Next(Block::Face f) const { return BlockLookup(chunk, pos, f); }
+
 private:
 	Chunk *chunk;
 	Chunk::Pos pos;