From 5402b214b31af60bc96cd4e47e9211715c3e99f5 Mon Sep 17 00:00:00 2001
From: Lane Kolbly <lane@rscheme.org>
Date: Fri, 28 Jul 2017 11:59:21 -0500
Subject: Check for intersection between placed blocks and entities. (#3850)

* Check for intersection between placed blocks and entities.

+ Implemented GetPlacementCollisionBox, to permit custom placement collision boxes for blocks.

* Factored block-entity placement checking into another function in cPlayer.

- Removed vector min/max functions

* Use GetWorld to get the world in DoesPlacingBlocksIntersectEntity.

+ Added block height checks, allow different cEntity subclasses to decide whether they will prevent block placement.
---
 src/Blocks/BlockFence.h | 80 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 80 insertions(+)
 create mode 100644 src/Blocks/BlockFence.h

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

diff --git a/src/Blocks/BlockFence.h b/src/Blocks/BlockFence.h
new file mode 100644
index 000000000..92f52cbbe
--- /dev/null
+++ b/src/Blocks/BlockFence.h
@@ -0,0 +1,80 @@
+
+#pragma once
+
+#include "BlockHandler.h"
+#include "BlockID.h"
+#include "../BoundingBox.h"
+
+
+
+
+class cBlockFenceHandler :
+	public cBlockHandler
+{
+public:
+	// These are the min and max coordinates (X and Z) for a straight fence.
+	// 0.4 and 0.6 are really just guesses, but they seem pretty good.
+	// (0.4 to 0.6 is a fence that's 0.2 wide, down the center of the block)
+	const double MIN_COORD = 0.4;
+	const double MAX_COORD = 0.6;
+
+	cBlockFenceHandler(BLOCKTYPE a_BlockType)
+		: cBlockHandler(a_BlockType)
+	{
+	}
+
+	virtual cBoundingBox GetPlacementCollisionBox(BLOCKTYPE a_XM, BLOCKTYPE a_XP, BLOCKTYPE a_YM, BLOCKTYPE a_YP, BLOCKTYPE a_ZM, BLOCKTYPE a_ZP) override
+	{
+		bool XMSolid = cBlockInfo::IsSolid(a_XM);
+		bool XPSolid = cBlockInfo::IsSolid(a_XP);
+		bool ZMSolid = cBlockInfo::IsSolid(a_ZM);
+		bool ZPSolid = cBlockInfo::IsSolid(a_ZP);
+
+		double FENCE_HEIGHT = cBlockInfo::GetBlockHeight(m_BlockType);
+
+		// Entities can never be in the center
+		cBoundingBox PlacementBox(MIN_COORD, MAX_COORD, 0, FENCE_HEIGHT, MIN_COORD, MAX_COORD);
+
+		// For each solid neighbor, the hitbox extends that way
+		if (XMSolid)
+		{
+			PlacementBox = PlacementBox.Union(cBoundingBox(0, 0.5, 0, FENCE_HEIGHT, MIN_COORD, MAX_COORD));
+		}
+		if (XPSolid)
+		{
+			PlacementBox = PlacementBox.Union(cBoundingBox(0.5, 1.0, 0, FENCE_HEIGHT, MIN_COORD, MAX_COORD));
+		}
+		if (ZMSolid)
+		{
+			PlacementBox = PlacementBox.Union(cBoundingBox(MIN_COORD, MAX_COORD, 0, FENCE_HEIGHT, 0.0, 0.5));
+		}
+		if (ZPSolid)
+		{
+			PlacementBox = PlacementBox.Union(cBoundingBox(MIN_COORD, MAX_COORD, 0, FENCE_HEIGHT, 0.5, 1.0));
+		}
+
+		// For each corner, fill in the corner
+		if (XMSolid && ZMSolid)
+		{
+			PlacementBox = PlacementBox.Union(cBoundingBox(0, 0.5, 0, FENCE_HEIGHT, 0, 0.5));
+		}
+		if (XPSolid && ZMSolid)
+		{
+			PlacementBox = PlacementBox.Union(cBoundingBox(0.5, 1.0, 0, FENCE_HEIGHT, 0, 0.5));
+		}
+		if (XPSolid && ZPSolid)
+		{
+			PlacementBox = PlacementBox.Union(cBoundingBox(0.5, 1.0, 0, FENCE_HEIGHT, 0.5, 1.0));
+		}
+		if (XMSolid && ZPSolid)
+		{
+			PlacementBox = PlacementBox.Union(cBoundingBox(0, 0.5, 0, FENCE_HEIGHT, 0.5, 1.0));
+		}
+
+		return PlacementBox;
+	}
+};
+
+
+
+
-- 
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