From 1d1fa914012125126d1a3656edc428859696f54f Mon Sep 17 00:00:00 2001
From: KingCol13 <48412633+KingCol13@users.noreply.github.com>
Date: Sat, 10 Jul 2021 21:05:00 +0100
Subject: Chorus fruit teleport (#5259)

* Outline function for teleporting.

* Created new handler for chorus fruit.

* Fixed AttemptTeleport failing.

* Better names, working sound effect.

* Corrected naming.

* Remove stray LOGD.

* Offset teleport to middle of block.

* Style Fixes

Co-authored-by: x12xx12x <44411062+12xx12@users.noreply.github.com>

* Style Fixes 2

Co-authored-by: x12xx12x <44411062+12xx12@users.noreply.github.com>

* Move FindTeleportDestination to static cPawn method.

* cBoundingBox interface.

* Cleanup includes.

* Maybe exported to API?

* Change a_World to reference, add to APIDesc.

Co-authored-by: x12xx12x <44411062+12xx12@users.noreply.github.com>
---
 src/Entities/Pawn.cpp | 78 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 78 insertions(+)

(limited to 'src/Entities/Pawn.cpp')

diff --git a/src/Entities/Pawn.cpp b/src/Entities/Pawn.cpp
index 5476db468..ed26a080b 100644
--- a/src/Entities/Pawn.cpp
+++ b/src/Entities/Pawn.cpp
@@ -547,3 +547,81 @@ bool cPawn::DeductTotem(const eDamageType a_DamageType)
 	}
 	return false;
 }
+
+
+
+
+
+bool cPawn::FindTeleportDestination(cWorld & a_World, const int a_HeightRequired, const unsigned int a_NumTries, Vector3d & a_Destination, const Vector3i a_MinBoxCorner, const Vector3i a_MaxBoxCorner)
+{
+	/*
+	Algorithm:
+	Choose random destination.
+	Seek downwards, regardless of distance until the block is made of movement-blocking material: https://minecraft.fandom.com/wiki/Materials
+	Succeeds if no liquid or solid blocks prevents from standing at destination.
+	*/
+	auto & Random = GetRandomProvider();
+
+	for (unsigned int i = 0; i < a_NumTries; i++)
+	{
+		const int DestX = Random.RandInt(a_MinBoxCorner.x, a_MaxBoxCorner.x);
+		int DestY = Random.RandInt(a_MinBoxCorner.y, a_MaxBoxCorner.y);
+		const int DestZ = Random.RandInt(a_MinBoxCorner.z, a_MaxBoxCorner.z);
+
+		// Seek downwards from initial destination until we find a solid block or go into the void
+		BLOCKTYPE DestBlock = a_World.GetBlock({DestX, DestY, DestZ});
+		while ((DestY >= 0) && !cBlockInfo::IsSolid(DestBlock))
+		{
+			DestBlock = a_World.GetBlock({DestX, DestY, DestZ});
+			DestY--;
+		}
+
+		// Couldn't find a solid block so move to next attempt
+		if (DestY < 0)
+		{
+			continue;
+		}
+
+		// Succeed if blocks above destination are empty
+		bool Success = true;
+		for (int j = 1; j <= a_HeightRequired; j++)
+		{
+			BLOCKTYPE TestBlock = a_World.GetBlock({DestX, DestY + j, DestZ});
+			if (cBlockInfo::IsSolid(TestBlock) || IsBlockLiquid(TestBlock))
+			{
+				Success = false;
+				break;
+			}
+		}
+
+		if (!Success)
+		{
+			continue;
+		}
+
+		// Offsets for entity to be centred and standing on solid block
+		a_Destination = Vector3d(DestX + 0.5, DestY + 1, DestZ + 0.5);
+		return true;
+	}
+	return false;
+}
+
+
+
+
+
+bool cPawn::FindTeleportDestination(cWorld & a_World, const int a_HeightRequired, const unsigned int a_NumTries, Vector3d & a_Destination, const cBoundingBox a_BoundingBox)
+{
+	return FindTeleportDestination(a_World, a_HeightRequired, a_NumTries, a_Destination, a_BoundingBox.GetMin(), a_BoundingBox.GetMax());
+}
+
+
+
+
+
+bool cPawn::FindTeleportDestination(cWorld & a_World, const int a_HeightRequired, const unsigned int a_NumTries, Vector3d & a_Destination, Vector3i a_Centre, const int a_HalfCubeWidth)
+{
+	Vector3i MinCorner(a_Centre.x - a_HalfCubeWidth, a_Centre.y - a_HalfCubeWidth, a_Centre.z - a_HalfCubeWidth);
+	Vector3i MaxCorner(a_Centre.x + a_HalfCubeWidth, a_Centre.y + a_HalfCubeWidth, a_Centre.z + a_HalfCubeWidth);
+	return FindTeleportDestination(a_World, a_HeightRequired, a_NumTries, a_Destination, MinCorner, MaxCorner);
+}
-- 
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