From 2263d599391cce82735f16f43b7907e8846cbb2a Mon Sep 17 00:00:00 2001
From: Kevin Chabowski <kevin@kch42.de>
Date: Mon, 12 Aug 2013 21:40:02 +0200
Subject: Implemented height map recalculation

---
 mcmap/chunk.go | 20 +++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)

(limited to 'mcmap')

diff --git a/mcmap/chunk.go b/mcmap/chunk.go
index 9cf2dc7..d11d24b 100644
--- a/mcmap/chunk.go
+++ b/mcmap/chunk.go
@@ -110,4 +110,22 @@ func (c *Chunk) SetBiome(x, z int, bio Biome) { c.biomes[x*ChunkSizeXZ+z] = bio
 // If the chunk was modified, call MarkModified BEFORE.
 func (c *Chunk) MarkUnused() error { return c.reg.unloadChunk(int(c.x), int(c.z)) }
 
-// TODO: func (c *Chunk) RecalcHeightMap()
+// RecalcHeightMap recalculates the internal height map.
+//
+// You should use this function before marking the chunk as unused, if you modified the chunk
+// (unless you know, your changes wouldn't affect the height map).
+func (c *Chunk) RecalcHeightMap() {
+	i := 0
+	for z := 0; z < ChunkSizeXZ; z++ {
+		for x := 0; x < ChunkSizeXZ; x++ {
+			for y := ChunkSizeY; y >= 0; y-- {
+				blkid := c.blocks[calcBlockOffset(x, y, z)].ID
+				if (blkid != BlkAir) && (blkid != BlkGlass) && (blkid != BlkGlassPane) {
+					c.heightMap[i] = int32(y)
+					break
+				}
+			}
+			i++
+		}
+	}
+}
-- 
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