From 31a11a6df4922b590a50a5ff3d3c00d42a45599d Mon Sep 17 00:00:00 2001
From: peterbell10 <peterbell10@live.co.uk>
Date: Mon, 23 Jul 2018 19:12:51 +0100
Subject: Optimise chunk set (#4260)

Closes #1244

Initially I was just going to add the cChunkData to cSetChunkData but profiling revealed
that the copying wasn't even the biggest slowdown. Much more time was being spent in
cChunk::CreateBlockEntities and cChunk::WakeUpSimulators than was in memcpy so I've made
those significantly faster as well.

Optimisations performed:
 * cSetChunkData now stores blocks in a cChunkData object
 * cChunkData objects can now perform moves even if they are using different pools
 * cChunk::CreateBlockEntities now iterates in the correct order and only over present chunk sections
 * Similarly for cChunk::WakeUpSimulators
 * cSetChunkData::CalculateHeightMap now shortcuts to the highest present chunk section before checking blocks directly
---
 src/SetChunkData.cpp | 56 +++++++++++++++++++++++++++++++---------------------
 1 file changed, 33 insertions(+), 23 deletions(-)

(limited to 'src/SetChunkData.cpp')

diff --git a/src/SetChunkData.cpp b/src/SetChunkData.cpp
index c218c361c..1fdc2e775 100644
--- a/src/SetChunkData.cpp
+++ b/src/SetChunkData.cpp
@@ -8,6 +8,17 @@
 #include "BlockEntities/BlockEntity.h"
 #include "Entities/Entity.h"
 
+namespace
+{
+struct sMemCallbacks:
+	cAllocationPool<cChunkData::sChunkSection>::cStarvationCallbacks
+{
+	virtual void OnStartUsingReserve() override {}
+	virtual void OnEndUsingReserve() override {}
+	virtual void OnOutOfReserve() override {}
+};
+}  // namespace (anonymous)
+
 
 
 
@@ -15,6 +26,8 @@
 cSetChunkData::cSetChunkData(int a_ChunkX, int a_ChunkZ, bool a_ShouldMarkDirty) :
 	m_ChunkX(a_ChunkX),
 	m_ChunkZ(a_ChunkZ),
+	m_Pool(cpp14::make_unique<sMemCallbacks>(), cChunkData::NumSections),
+	m_ChunkData(m_Pool),
 	m_IsLightValid(false),
 	m_IsHeightMapValid(false),
 	m_AreBiomesValid(false),
@@ -38,29 +51,23 @@ cSetChunkData::cSetChunkData(
 	cBlockEntities && a_BlockEntities,
 	bool a_ShouldMarkDirty
 ) :
-	m_ChunkX(a_ChunkX),
-	m_ChunkZ(a_ChunkZ),
-	m_ShouldMarkDirty(a_ShouldMarkDirty)
+	cSetChunkData(a_ChunkX, a_ChunkZ, a_ShouldMarkDirty)
 {
 	// Check the params' validity:
 	ASSERT(a_BlockTypes != nullptr);
 	ASSERT(a_BlockMetas != nullptr);
 
 	// Copy block types and metas:
-	memcpy(m_BlockTypes, a_BlockTypes, sizeof(cChunkDef::BlockTypes));
-	memcpy(m_BlockMetas, a_BlockMetas, sizeof(cChunkDef::BlockNibbles));
+	m_ChunkData.SetBlockTypes(a_BlockTypes);
+	m_ChunkData.SetMetas(a_BlockMetas);
 
 	// Copy lights, if both given:
 	if ((a_BlockLight != nullptr) && (a_SkyLight != nullptr))
 	{
-		memcpy(m_BlockLight, a_BlockLight, sizeof(m_BlockLight));
-		memcpy(m_SkyLight,   a_SkyLight,   sizeof(m_SkyLight));
+		m_ChunkData.SetBlockLight(a_BlockLight);
+		m_ChunkData.SetSkyLight(a_SkyLight);
 		m_IsLightValid = true;
 	}
-	else
-	{
-		m_IsLightValid = false;
-	}
 
 	// Copy the heightmap, if available:
 	if (a_HeightMap != nullptr)
@@ -68,10 +75,6 @@ cSetChunkData::cSetChunkData(
 		memcpy(m_HeightMap, a_HeightMap, sizeof(m_HeightMap));
 		m_IsHeightMapValid = true;
 	}
-	else
-	{
-		m_IsHeightMapValid = false;
-	}
 
 	// Copy biomes, if available:
 	if (a_Biomes != nullptr)
@@ -79,10 +82,6 @@ cSetChunkData::cSetChunkData(
 		memcpy(m_Biomes, a_Biomes, sizeof(m_Biomes));
 		m_AreBiomesValid = true;
 	}
-	else
-	{
-		m_AreBiomesValid = false;
-	}
 
 	// Move entities and blockentities:
 	m_Entities = std::move(a_Entities);
@@ -95,14 +94,25 @@ cSetChunkData::cSetChunkData(
 
 void cSetChunkData::CalculateHeightMap(void)
 {
+	// Find the heighest present section in the chunk
+	size_t MaxSection = 0;
+	for (size_t i = cChunkData::NumSections - 1; i != 0; --i)
+	{
+		if (m_ChunkData.GetSection(i) != nullptr)
+		{
+			MaxSection = i;
+			break;
+		}
+	}
+	const int MaxHeight = static_cast<int>(MaxSection + 1) * cChunkData::SectionHeight - 1;
+
 	for (int x = 0; x < cChunkDef::Width; x++)
 	{
 		for (int z = 0; z < cChunkDef::Width; z++)
 		{
-			for (int y = cChunkDef::Height - 1; y > -1; y--)
+			for (int y = MaxHeight; y > -1; y--)
 			{
-				int index = cChunkDef::MakeIndexNoCheck(x, y, z);
-				if (m_BlockTypes[index] != E_BLOCK_AIR)
+				if (m_ChunkData.GetBlock({x, y, z}) != E_BLOCK_AIR)
 				{
 					m_HeightMap[x + z * cChunkDef::Width] = static_cast<HEIGHTTYPE>(y);
 					break;
@@ -124,7 +134,7 @@ void cSetChunkData::RemoveInvalidBlockEntities(void)
 	{
 		cBlockEntity * BlockEntity = itr->second;
 		BLOCKTYPE EntityBlockType = BlockEntity->GetBlockType();
-		BLOCKTYPE WorldBlockType = cChunkDef::GetBlock(m_BlockTypes, BlockEntity->GetRelX(), BlockEntity->GetPosY(), BlockEntity->GetRelZ());
+		BLOCKTYPE WorldBlockType = m_ChunkData.GetBlock({BlockEntity->GetRelX(), BlockEntity->GetPosY(), BlockEntity->GetRelZ()});
 		if (EntityBlockType != WorldBlockType)
 		{
 			// Bad blocktype, remove the block entity:
-- 
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