From f2f254f8d576b48fde9305c3d2927552d1d4c20d Mon Sep 17 00:00:00 2001
From: Daniel Karbach <daniel.karbach@localhorst.tv>
Date: Mon, 15 Jun 2015 10:13:25 +0200
Subject: [PATCH] fixed light propagation after obstacle removal

regression from 4485397d
careful with the yoda conditions!
---
 TODO                    |  2 --
 src/world/chunk.cpp     |  8 ++---
 tst/world/ChunkTest.cpp | 79 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 83 insertions(+), 6 deletions(-)

diff --git a/TODO b/TODO
index 6234fd0..8ee6ef2 100644
--- a/TODO
+++ b/TODO
@@ -43,8 +43,6 @@ entity ai
 	this could be solved by using a pre-interpolated light texture and
 	mapping light levels to coordinates on that
 
-	there seems to be a bug with adding/removing obstacles...again
-
 	also: how could block light affect entity lighting?
 	maybe get the interpolated light level at the entity's center and use
 	that as the light power for the directional lighting shader and use a
diff --git a/src/world/chunk.cpp b/src/world/chunk.cpp
index fe4f802..569bb11 100644
--- a/src/world/chunk.cpp
+++ b/src/world/chunk.cpp
@@ -169,15 +169,16 @@ void Chunk::SetBlock(int index, const Block &block) noexcept {
 	} else if (!new_type.block_light && old_type.block_light) {
 		// obstacle removed
 		int level = 0;
+		Pos pos(ToPos(index));
 		for (int face = 0; face < Block::FACE_COUNT; ++face) {
-			BlockLookup next_block(this, ToPos(index), Block::Face(face));
+			BlockLookup next_block(this, pos, Block::Face(face));
 			if (next_block) {
-				level = std::min(level, next_block.GetLight());
+				level = std::max(level, next_block.GetLight());
 			}
 		}
 		if (level > 1) {
 			SetLight(index, level - 1);
-			light_queue.emplace(this, ToPos(index));
+			light_queue.emplace(this, pos);
 			work_light();
 		}
 	}
@@ -449,7 +450,6 @@ bool Chunk::Intersection(
 	float &dist,
 	glm::vec3 &normal
 ) const noexcept {
-	// TODO: should be possible to heavily optimize this
 	int idx = 0;
 	blkid = -1;
 	dist = std::numeric_limits<float>::infinity();
diff --git a/tst/world/ChunkTest.cpp b/tst/world/ChunkTest.cpp
index 3ecf0f6..408fec3 100644
--- a/tst/world/ChunkTest.cpp
+++ b/tst/world/ChunkTest.cpp
@@ -451,6 +451,85 @@ void ChunkTest::testLightPropagation() {
 
 	// now block the light to the left
 	chunk->SetBlock(Chunk::Pos(6, 7, 7), Block(1));
+	CPPUNIT_ASSERT_EQUAL_MESSAGE(
+		"non-zero light level in solid block",
+		0, chunk->GetLight(Chunk::Pos(6, 7, 7))
+	);
+	CPPUNIT_ASSERT_EQUAL_MESSAGE(
+		"adding obstacle affected unrelated index",
+		5, chunk->GetLight(Chunk::Pos(7, 7, 7))
+	);
+	CPPUNIT_ASSERT_EQUAL_MESSAGE(
+		"adding obstacle affected unrelated index",
+		4, chunk->GetLight(Chunk::Pos(8, 7, 7))
+	);
+	CPPUNIT_ASSERT_EQUAL_MESSAGE(
+		"adding obstacle affected unrelated index",
+		4, chunk->GetLight(Chunk::Pos(7, 8, 7))
+	);
+	CPPUNIT_ASSERT_EQUAL_MESSAGE(
+		"adding obstacle affected unrelated index",
+		4, chunk->GetLight(Chunk::Pos(7, 6, 7))
+	);
+	CPPUNIT_ASSERT_EQUAL_MESSAGE(
+		"adding obstacle affected unrelated index",
+		4, chunk->GetLight(Chunk::Pos(7, 7, 8))
+	);
+	CPPUNIT_ASSERT_EQUAL_MESSAGE(
+		"adding obstacle affected unrelated index",
+		4, chunk->GetLight(Chunk::Pos(7, 7, 6))
+	);
+	CPPUNIT_ASSERT_EQUAL_MESSAGE(
+		"adding obstacle affected unrelated index",
+		3, chunk->GetLight(Chunk::Pos(6, 6, 7))
+	);
+	CPPUNIT_ASSERT_EQUAL_MESSAGE(
+		"adding obstacle affected unrelated index",
+		3, chunk->GetLight(Chunk::Pos(6, 8, 7))
+	);
+	CPPUNIT_ASSERT_EQUAL_MESSAGE(
+		"adding obstacle affected unrelated index",
+		3, chunk->GetLight(Chunk::Pos(6, 7, 6))
+	);
+	CPPUNIT_ASSERT_EQUAL_MESSAGE(
+		"adding obstacle affected unrelated index",
+		3, chunk->GetLight(Chunk::Pos(6, 7, 6))
+	);
+	CPPUNIT_ASSERT_EQUAL_MESSAGE(
+		"adding obstacle affected unrelated index",
+		2, chunk->GetLight(Chunk::Pos(5, 6, 7))
+	);
+	CPPUNIT_ASSERT_EQUAL_MESSAGE(
+		"adding obstacle affected unrelated index",
+		2, chunk->GetLight(Chunk::Pos(5, 8, 7))
+	);
+	CPPUNIT_ASSERT_EQUAL_MESSAGE(
+		"adding obstacle affected unrelated index",
+		2, chunk->GetLight(Chunk::Pos(5, 7, 6))
+	);
+	CPPUNIT_ASSERT_EQUAL_MESSAGE(
+		"adding obstacle affected unrelated index",
+		2, chunk->GetLight(Chunk::Pos(5, 7, 6))
+	);
+	CPPUNIT_ASSERT_EQUAL_MESSAGE(
+		"adding obstacle resulted in unexpected light level behind it",
+		1, chunk->GetLight(Chunk::Pos(5, 7, 7))
+	);
+
+	// and remove it again
+	chunk->SetBlock(Chunk::Pos(6, 7, 7), Block(0));
+	CPPUNIT_ASSERT_EQUAL_MESSAGE(
+		"removing obstacle did not refill light correctly",
+		4, chunk->GetLight(Chunk::Pos(6, 7, 7))
+	);
+	CPPUNIT_ASSERT_EQUAL_MESSAGE(
+		"removing obstacle did not refill light correctly",
+		3, chunk->GetLight(Chunk::Pos(5, 7, 7))
+	);
+	CPPUNIT_ASSERT_EQUAL_MESSAGE(
+		"removing obstacle did not refill light correctly",
+		2, chunk->GetLight(Chunk::Pos(4, 7, 7))
+	);
 }
 
 }
-- 
2.39.2