baseline: OpenMU upstream b5a0961 (fresh source)

docs/Packets/C1-46-ChangeTerrainAttributes_by-server.md

@@ -0,0 +1,47 @@
+# C1 46 - ChangeTerrainAttributes (by server)
+
+## Is sent when
+
+The server wants to alter the terrain attributes of a map at runtime.
+
+## Causes the following actions on the client side
+
+The client updates the terrain attributes on its side.
+
+## Structure
+
+| Index | Length | Data Type | Value | Description |
+|-------|--------|-----------|-------|-------------|
+| 0 | 1 |   Byte   | 0xC1  | [Packet type](PacketTypes.md) |
+| 1 | 1 |    Byte   |      | Packet header - length of the packet |
+| 2 | 1 |    Byte   | 0x46  | Packet header - packet type identifier |
+| 3 | 1 | Boolean | false | Type |
+| 4 | 1 | TerrainAttributeType |  | Attribute |
+| 5 | 1 | Boolean |  | RemoveAttribute; When this is true, the attribute is removed on the client side. If it's false, then the attribute is added. |
+| 6 | 1 | Byte |  | AreaCount |
+| 7 | TerrainArea.Length * AreaCount | Array of TerrainArea |  | Areas |
+
+### TerrainArea Structure
+
+Defines the area which should be changed.
+
+Length: 4 Bytes
+
+| Index | Length | Data Type | Value | Description |
+|-------|--------|-----------|-------|-------------|
+| 0 | 1 | Byte |  | StartX |
+| 1 | 1 | Byte |  | StartY |
+| 2 | 1 | Byte |  | EndX |
+| 3 | 1 | Byte |  | EndY |
+
+### TerrainAttributeType Enum
+
+Defines the attribute which should be set/unset. It's a Flags enumeration.
+
+| Value | Name | Description |
+|-------|------|-------------|
+| 1 | Safezone | The coordinate is a safezone. |
+| 2 | Character | The coordinate is occupied by a character. |
+| 4 | Blocked | The coordinate is blocked and can't be passed by a character. |
+| 8 | NoGround | The coordinate is blocked, because there is no ground and can't be passed by a character. |
+| 16 | Water | The coordinate is blocked by water and can't be passed by a character. |