From f40aba941eaf69b52ac0fbe3d8cea1ea349b97a6 Mon Sep 17 00:00:00 2001
From: Alexander Harkness <me@bearbin.net>
Date: Wed, 8 Apr 2020 21:35:08 +0100
Subject: Add mixins for blocks that rotate based on player yaw at placement

Also add observer block handler.
---
 src/Blocks/Mixins.h | 134 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 134 insertions(+)

(limited to 'src/Blocks/Mixins.h')

diff --git a/src/Blocks/Mixins.h b/src/Blocks/Mixins.h
index a65fe7b06..2ab83a4d5 100644
--- a/src/Blocks/Mixins.h
+++ b/src/Blocks/Mixins.h
@@ -10,6 +10,7 @@ class cBlockLadder: public cMetaRotator<cClearMetaOnDrop, ...>
 #pragma once
 
 #include "../Item.h"
+#include "../Entities/Player.h"
 
 
 
@@ -164,3 +165,136 @@ public:
 		return a_Meta;
 	}
 };
+
+
+/** Mixin for rotations and reflections following the standard pattern of "apply mask, then use a switch".
+Inherit from this class providing your base class as Base, the BitMask for the direction bits in bitmask and the masked value for the directions in North, East, South, West.
+There is also an aptional parameter AssertIfNotMatched, set this if it is invalid for a block to exist in any other state. */
+template <class Base, NIBBLETYPE BitMask = 0x7, NIBBLETYPE North = 0x2, NIBBLETYPE East = 0x5, NIBBLETYPE South = 0x3, NIBBLETYPE West = 0x4, bool AssertIfNotMatched = false>
+class cYawRotator:
+	public cMetaRotator<Base, BitMask, North, East, South, West, AssertIfNotMatched>
+{
+	using super = cMetaRotator<Base, BitMask, North, East, South, West, AssertIfNotMatched>;
+public:
+
+	cYawRotator(BLOCKTYPE a_BlockType):
+		super(a_BlockType)
+	{}
+
+
+
+
+
+	virtual bool GetPlacementBlockTypeMeta(
+		cChunkInterface & a_ChunkInterface, cPlayer & a_Player,
+		int a_BlockX, int a_BlockY, int a_BlockZ, eBlockFace a_BlockFace,
+		int a_CursorX, int a_CursorY, int a_CursorZ,
+		BLOCKTYPE & a_BlockType, NIBBLETYPE & a_BlockMeta
+	) override
+	{
+		NIBBLETYPE BaseMeta;
+		super::GetPlacementBlockTypeMeta(a_ChunkInterface, a_Player, a_BlockX, a_BlockY, a_BlockZ, a_BlockFace, a_CursorX, a_CursorY, a_CursorZ, a_BlockType, BaseMeta);
+
+		a_BlockMeta = (BaseMeta & ~BitMask) | YawToMetaData(a_Player.GetYaw());
+		return true;
+	}
+
+
+
+
+
+	static NIBBLETYPE YawToMetaData(double a_Rotation)
+	{
+		a_Rotation += 90 + 45;  // So its not aligned with axis
+
+		if (a_Rotation >= 360)
+		{
+			a_Rotation -= 360;
+		}
+		if ((a_Rotation >= 0) && (a_Rotation < 90))
+		{
+			return West;
+		}
+		else if ((a_Rotation >= 90) && (a_Rotation < 180))
+		{
+			return North;
+		}
+		else if ((a_Rotation >= 180) && (a_Rotation < 270))
+		{
+			return East;
+		}
+		else  // (a_Rotation >= 270) && (a_Rotation < 360)
+		{
+			return South;
+		}
+	}
+};
+
+/** Mixin for rotations and reflections following the standard pattern of "apply mask, then use a switch".
+Inherit from this class providing your base class as Base, the BitMask for the direction bits in bitmask and the masked value for the directions in North, East, South, West.
+There is also an aptional parameter AssertIfNotMatched, set this if it is invalid for a block to exist in any other state. */
+template <class Base, NIBBLETYPE BitMask = 0x7, NIBBLETYPE North = 0x2, NIBBLETYPE East = 0x5, NIBBLETYPE South = 0x3, NIBBLETYPE West = 0x4, NIBBLETYPE Up = 0x1, NIBBLETYPE Down = 0x0>
+class cPitchYawRotator:
+	public cYawRotator<Base, BitMask, North, East, South, West>
+{
+	using super = cYawRotator<Base, BitMask, North, East, South, West>;
+public:
+
+	cPitchYawRotator(BLOCKTYPE a_BlockType):
+		super(a_BlockType)
+	{}
+
+
+
+
+
+	virtual bool GetPlacementBlockTypeMeta(
+		cChunkInterface & a_ChunkInterface, cPlayer & a_Player,
+		int a_BlockX, int a_BlockY, int a_BlockZ, eBlockFace a_BlockFace,
+		int a_CursorX, int a_CursorY, int a_CursorZ,
+		BLOCKTYPE & a_BlockType, NIBBLETYPE & a_BlockMeta
+	) override
+	{
+		NIBBLETYPE BaseMeta;
+		super::GetPlacementBlockTypeMeta(a_ChunkInterface, a_Player, a_BlockX, a_BlockY, a_BlockZ, a_BlockFace, a_CursorX, a_CursorY, a_CursorZ, a_BlockType, BaseMeta);
+
+		a_BlockMeta = (BaseMeta & ~BitMask) |  PitchYawToMetaData(a_Player.GetYaw(), a_Player.GetPitch());
+		return true;
+	}
+
+
+
+
+
+	virtual NIBBLETYPE MetaMirrorXZ(NIBBLETYPE a_Meta) override
+	{
+		// Bit 0x08 is a flag. Lowest three bits are position.
+		NIBBLETYPE OtherMeta = a_Meta & (~BitMask);
+		// Mirrors defined by a table. (Source, minecraft.gamepedia.com)
+		switch (a_Meta & BitMask)
+		{
+			case Down: return Up | OtherMeta;  // Down -> Up
+			case Up: return Down | OtherMeta;  // Up -> Down
+		}
+		// Not Facing Up or Down; No change.
+		return a_Meta;
+	}
+
+
+
+
+
+	static NIBBLETYPE PitchYawToMetaData(double a_Rotation, double a_Pitch)
+	{
+		if (a_Pitch >= 50)
+		{
+			return Up;
+		}
+		else if (a_Pitch <= -50)
+		{
+			return Down;
+		}
+
+		return super::YawToMetaData(a_Rotation);
+	}
+};
-- 
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