Index: ps/trunk/source/renderer/PatchRData.cpp
===================================================================
--- ps/trunk/source/renderer/PatchRData.cpp	(revision 24825)
+++ ps/trunk/source/renderer/PatchRData.cpp	(revision 24826)
@@ -1,1458 +1,1464 @@
 /* Copyright (C) 2021 Wildfire Games.
  * This file is part of 0 A.D.
  *
  * 0 A.D. is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation, either version 2 of the License, or
  * (at your option) any later version.
  *
  * 0 A.D. is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with 0 A.D.  If not, see <http://www.gnu.org/licenses/>.
  */
 
 #include "precompiled.h"
 
 #include "renderer/PatchRData.h"
 
 #include "graphics/GameView.h"
 #include "graphics/LightEnv.h"
 #include "graphics/LOSTexture.h"
 #include "graphics/Patch.h"
 #include "graphics/ShaderManager.h"
 #include "graphics/Terrain.h"
 #include "graphics/TerrainTextureEntry.h"
 #include "graphics/TextRenderer.h"
 #include "lib/allocators/DynamicArena.h"
 #include "lib/allocators/STLAllocators.h"
 #include "maths/MathUtil.h"
 #include "ps/CLogger.h"
 #include "ps/Game.h"
 #include "ps/GameSetup/Config.h"
 #include "ps/Profile.h"
 #include "ps/Pyrogenesis.h"
 #include "ps/World.h"
 #include "renderer/AlphaMapCalculator.h"
 #include "renderer/Renderer.h"
 #include "renderer/TerrainRenderer.h"
 #include "renderer/WaterManager.h"
 #include "simulation2/components/ICmpWaterManager.h"
 #include "simulation2/Simulation2.h"
 
 #include <algorithm>
 #include <numeric>
 #include <set>
 
 const ssize_t BlendOffsets[9][2] = {
 	{  0, -1 },
 	{ -1, -1 },
 	{ -1,  0 },
 	{ -1,  1 },
 	{  0,  1 },
 	{  1,  1 },
 	{  1,  0 },
 	{  1, -1 },
 	{  0,  0 }
 };
 
 ///////////////////////////////////////////////////////////////////
 // CPatchRData constructor
 CPatchRData::CPatchRData(CPatch* patch, CSimulation2* simulation) :
 	m_Patch(patch), m_VBSides(0),
 	m_VBBase(0), m_VBBaseIndices(0),
 	m_VBBlends(0), m_VBBlendIndices(0),
 	m_VBWater(0), m_VBWaterIndices(0),
 	m_VBWaterShore(0), m_VBWaterIndicesShore(0),
 	m_Simulation(simulation)
 {
 	ENSURE(patch);
 	Build();
 }
 
 ///////////////////////////////////////////////////////////////////
 // CPatchRData destructor
 CPatchRData::~CPatchRData()
 {
 	// release vertex buffer chunks
 	if (m_VBSides) g_VBMan.Release(m_VBSides);
 	if (m_VBBase) g_VBMan.Release(m_VBBase);
 	if (m_VBBaseIndices) g_VBMan.Release(m_VBBaseIndices);
 	if (m_VBBlends) g_VBMan.Release(m_VBBlends);
 	if (m_VBBlendIndices) g_VBMan.Release(m_VBBlendIndices);
 	if (m_VBWater) g_VBMan.Release(m_VBWater);
 	if (m_VBWaterIndices) g_VBMan.Release(m_VBWaterIndices);
 	if (m_VBWaterShore) g_VBMan.Release(m_VBWaterShore);
 	if (m_VBWaterIndicesShore) g_VBMan.Release(m_VBWaterIndicesShore);
 }
 
 /**
  * Represents a blend for a single tile, texture and shape.
  */
 struct STileBlend
 {
 	CTerrainTextureEntry* m_Texture;
 	int m_Priority;
 	u16 m_TileMask; // bit n set if this blend contains neighbour tile BlendOffsets[n]
 
 	struct DecreasingPriority
 	{
 		bool operator()(const STileBlend& a, const STileBlend& b) const
 		{
 			if (a.m_Priority > b.m_Priority)
 				return true;
 			if (a.m_Priority < b.m_Priority)
 				return false;
 			if (a.m_Texture && b.m_Texture)
 				return a.m_Texture->GetTag() > b.m_Texture->GetTag();
 			return false;
 		}
 	};
 
 	struct CurrentTile
 	{
 		bool operator()(const STileBlend& a) const
 		{
 			return (a.m_TileMask & (1 << 8)) != 0;
 		}
 	};
 };
 
 /**
  * Represents the ordered collection of blends drawn on a particular tile.
  */
 struct STileBlendStack
 {
 	u8 i, j;
 	std::vector<STileBlend> blends; // back of vector is lowest-priority texture
 };
 
 /**
  * Represents a batched collection of blends using the same texture.
  */
 struct SBlendLayer
 {
 	struct Tile
 	{
 		u8 i, j;
 		u8 shape;
 	};
 
 	CTerrainTextureEntry* m_Texture;
 	std::vector<Tile> m_Tiles;
 };
 
 void CPatchRData::BuildBlends()
 {
 	PROFILE3("build blends");
 
 	m_BlendSplats.clear();
 
 	std::vector<SBlendVertex> blendVertices;
 	std::vector<u16> blendIndices;
 
 	CTerrain* terrain = m_Patch->m_Parent;
 
 	std::vector<STileBlendStack> blendStacks;
 	blendStacks.reserve(PATCH_SIZE*PATCH_SIZE);
 
 	// For each tile in patch ..
 	for (ssize_t j = 0; j < PATCH_SIZE; ++j)
 	{
 		for (ssize_t i = 0; i < PATCH_SIZE; ++i)
 		{
 			ssize_t gx = m_Patch->m_X * PATCH_SIZE + i;
 			ssize_t gz = m_Patch->m_Z * PATCH_SIZE + j;
 
 			std::vector<STileBlend> blends;
 			blends.reserve(9);
 
 			// Compute a blend for every tile in the 3x3 square around this tile
 			for (size_t n = 0; n < 9; ++n)
 			{
 				ssize_t ox = gx + BlendOffsets[n][1];
 				ssize_t oz = gz + BlendOffsets[n][0];
 
 				CMiniPatch* nmp = terrain->GetTile(ox, oz);
 				if (!nmp)
 					continue;
 
 				STileBlend blend;
 				blend.m_Texture = nmp->GetTextureEntry();
 				blend.m_Priority = nmp->GetPriority();
 				blend.m_TileMask = 1 << n;
 				blends.push_back(blend);
 			}
 
 			// Sort the blends, highest priority first
 			std::sort(blends.begin(), blends.end(), STileBlend::DecreasingPriority());
 
 			STileBlendStack blendStack;
 			blendStack.i = i;
 			blendStack.j = j;
 
 			// Put the blends into the tile's stack, merging any adjacent blends with the same texture
 			for (size_t k = 0; k < blends.size(); ++k)
 			{
 				if (!blendStack.blends.empty() && blendStack.blends.back().m_Texture == blends[k].m_Texture)
 					blendStack.blends.back().m_TileMask |= blends[k].m_TileMask;
 				else
 					blendStack.blends.push_back(blends[k]);
 			}
 
 			// Remove blends that are after (i.e. lower priority than) the current tile
 			// (including the current tile), since we don't want to render them on top of
 			// the tile's base texture
 			blendStack.blends.erase(
 				std::find_if(blendStack.blends.begin(), blendStack.blends.end(), STileBlend::CurrentTile()),
 				blendStack.blends.end());
 
 			blendStacks.push_back(blendStack);
 		}
 	}
 
 	// Given the blend stack per tile, we want to batch together as many blends as possible.
 	// Group them into a series of layers (each of which has a single texture):
 	// (This is effectively a topological sort / linearisation of the partial order induced
 	// by the per-tile stacks, preferring to make tiles with equal textures adjacent.)
 
 	std::vector<SBlendLayer> blendLayers;
 
 	while (true)
 	{
 		if (!blendLayers.empty())
 		{
 			// Try to grab as many tiles as possible that match our current layer,
 			// from off the blend stacks of all the tiles
 
 			CTerrainTextureEntry* tex = blendLayers.back().m_Texture;
 
 			for (size_t k = 0; k < blendStacks.size(); ++k)
 			{
 				if (!blendStacks[k].blends.empty() && blendStacks[k].blends.back().m_Texture == tex)
 				{
 					SBlendLayer::Tile t = { blendStacks[k].i, blendStacks[k].j, (u8)blendStacks[k].blends.back().m_TileMask };
 					blendLayers.back().m_Tiles.push_back(t);
 					blendStacks[k].blends.pop_back();
 				}
 				// (We've already merged adjacent entries of the same texture in each stack,
 				// so we don't need to bother looping to check the next entry in this stack again)
 			}
 		}
 
 		// We've grabbed as many tiles as possible; now we need to start a new layer.
 		// The new layer's texture could come from the back of any non-empty stack;
 		// choose the longest stack as a heuristic to reduce the number of layers
 		CTerrainTextureEntry* bestTex = NULL;
 		size_t bestStackSize = 0;
 
 		for (size_t k = 0; k < blendStacks.size(); ++k)
 		{
 			if (blendStacks[k].blends.size() > bestStackSize)
 			{
 				bestStackSize = blendStacks[k].blends.size();
 				bestTex = blendStacks[k].blends.back().m_Texture;
 			}
 		}
 
 		// If all our stacks were empty, we're done
 		if (bestStackSize == 0)
 			break;
 
 		// Otherwise add the new layer, then loop back and start filling it in
 
 		SBlendLayer layer;
 		layer.m_Texture = bestTex;
 		blendLayers.push_back(layer);
 	}
 
 	// Now build outgoing splats
 	m_BlendSplats.resize(blendLayers.size());
 
 	for (size_t k = 0; k < blendLayers.size(); ++k)
 	{
 		SSplat& splat = m_BlendSplats[k];
 		splat.m_IndexStart = blendIndices.size();
 		splat.m_Texture = blendLayers[k].m_Texture;
 
 		for (size_t t = 0; t < blendLayers[k].m_Tiles.size(); ++t)
 		{
 			SBlendLayer::Tile& tile = blendLayers[k].m_Tiles[t];
 			AddBlend(blendVertices, blendIndices, tile.i, tile.j, tile.shape, splat.m_Texture);
 		}
 
 		splat.m_IndexCount = blendIndices.size() - splat.m_IndexStart;
 	}
 
 	// Release existing vertex buffer chunks
 	if (m_VBBlends)
 	{
 		g_VBMan.Release(m_VBBlends);
 		m_VBBlends = 0;
 	}
 
 	if (m_VBBlendIndices)
 	{
 		g_VBMan.Release(m_VBBlendIndices);
 		m_VBBlendIndices = 0;
 	}
 
 	if (blendVertices.size())
 	{
 		// Construct vertex buffer
 
 		m_VBBlends = g_VBMan.Allocate(sizeof(SBlendVertex), blendVertices.size(), GL_STATIC_DRAW, GL_ARRAY_BUFFER);
 		m_VBBlends->m_Owner->UpdateChunkVertices(m_VBBlends, &blendVertices[0]);
 
 		// Update the indices to include the base offset of the vertex data
 		for (size_t k = 0; k < blendIndices.size(); ++k)
 			blendIndices[k] += static_cast<u16>(m_VBBlends->m_Index);
 
 		m_VBBlendIndices = g_VBMan.Allocate(sizeof(u16), blendIndices.size(), GL_STATIC_DRAW, GL_ELEMENT_ARRAY_BUFFER);
 		m_VBBlendIndices->m_Owner->UpdateChunkVertices(m_VBBlendIndices, &blendIndices[0]);
 	}
 }
 
 void CPatchRData::AddBlend(std::vector<SBlendVertex>& blendVertices, std::vector<u16>& blendIndices,
 			   u16 i, u16 j, u8 shape, CTerrainTextureEntry* texture)
 {
 	CTerrain* terrain = m_Patch->m_Parent;
 
 	ssize_t gx = m_Patch->m_X * PATCH_SIZE + i;
 	ssize_t gz = m_Patch->m_Z * PATCH_SIZE + j;
 
 	// uses the current neighbour texture
 	BlendShape8 shape8;
 	for (size_t m = 0; m < 8; ++m)
 		shape8[m] = (shape & (1 << m)) ? 0 : 1;
 
 	// calculate the required alphamap and the required rotation of the alphamap from blendshape
 	unsigned int alphamapflags;
 	int alphamap = CAlphaMapCalculator::Calculate(shape8, alphamapflags);
 
 	// now actually render the blend tile (if we need one)
 	if (alphamap == -1)
 		return;
 
 	float u0 = texture->m_TerrainAlpha->second.m_AlphaMapCoords[alphamap].u0;
 	float u1 = texture->m_TerrainAlpha->second.m_AlphaMapCoords[alphamap].u1;
 	float v0 = texture->m_TerrainAlpha->second.m_AlphaMapCoords[alphamap].v0;
 	float v1 = texture->m_TerrainAlpha->second.m_AlphaMapCoords[alphamap].v1;
 
 	if (alphamapflags & BLENDMAP_FLIPU)
 		std::swap(u0, u1);
 
 	if (alphamapflags & BLENDMAP_FLIPV)
 		std::swap(v0, v1);
 
 	int base = 0;
 	if (alphamapflags & BLENDMAP_ROTATE90)
 		base = 1;
 	else if (alphamapflags & BLENDMAP_ROTATE180)
 		base = 2;
 	else if (alphamapflags & BLENDMAP_ROTATE270)
 		base = 3;
 
 	SBlendVertex vtx[4];
 	vtx[(base + 0) % 4].m_AlphaUVs[0] = u0;
 	vtx[(base + 0) % 4].m_AlphaUVs[1] = v0;
 	vtx[(base + 1) % 4].m_AlphaUVs[0] = u1;
 	vtx[(base + 1) % 4].m_AlphaUVs[1] = v0;
 	vtx[(base + 2) % 4].m_AlphaUVs[0] = u1;
 	vtx[(base + 2) % 4].m_AlphaUVs[1] = v1;
 	vtx[(base + 3) % 4].m_AlphaUVs[0] = u0;
 	vtx[(base + 3) % 4].m_AlphaUVs[1] = v1;
 
 	SBlendVertex dst;
 
 	CVector3D normal;
 
 	u16 index = static_cast<u16>(blendVertices.size());
 
 	terrain->CalcPosition(gx, gz, dst.m_Position);
 	terrain->CalcNormal(gx, gz, normal);
 	dst.m_Normal = normal;
 	dst.m_AlphaUVs[0] = vtx[0].m_AlphaUVs[0];
 	dst.m_AlphaUVs[1] = vtx[0].m_AlphaUVs[1];
 	blendVertices.push_back(dst);
 
 	terrain->CalcPosition(gx + 1, gz, dst.m_Position);
 	terrain->CalcNormal(gx + 1, gz, normal);
 	dst.m_Normal = normal;
 	dst.m_AlphaUVs[0] = vtx[1].m_AlphaUVs[0];
 	dst.m_AlphaUVs[1] = vtx[1].m_AlphaUVs[1];
 	blendVertices.push_back(dst);
 
 	terrain->CalcPosition(gx + 1, gz + 1, dst.m_Position);
 	terrain->CalcNormal(gx + 1, gz + 1, normal);
 	dst.m_Normal = normal;
 	dst.m_AlphaUVs[0] = vtx[2].m_AlphaUVs[0];
 	dst.m_AlphaUVs[1] = vtx[2].m_AlphaUVs[1];
 	blendVertices.push_back(dst);
 
 	terrain->CalcPosition(gx, gz + 1, dst.m_Position);
 	terrain->CalcNormal(gx, gz + 1, normal);
 	dst.m_Normal = normal;
 	dst.m_AlphaUVs[0] = vtx[3].m_AlphaUVs[0];
 	dst.m_AlphaUVs[1] = vtx[3].m_AlphaUVs[1];
 	blendVertices.push_back(dst);
 
 	bool dir = terrain->GetTriangulationDir(gx, gz);
 	if (dir)
 	{
 		blendIndices.push_back(index+0);
 		blendIndices.push_back(index+1);
 		blendIndices.push_back(index+3);
 
 		blendIndices.push_back(index+1);
 		blendIndices.push_back(index+2);
 		blendIndices.push_back(index+3);
 	}
 	else
 	{
 		blendIndices.push_back(index+0);
 		blendIndices.push_back(index+1);
 		blendIndices.push_back(index+2);
 
 		blendIndices.push_back(index+2);
 		blendIndices.push_back(index+3);
 		blendIndices.push_back(index+0);
 	}
 }
 
 void CPatchRData::BuildIndices()
 {
 	PROFILE3("build indices");
 
 	CTerrain* terrain = m_Patch->m_Parent;
 
 	ssize_t px = m_Patch->m_X * PATCH_SIZE;
 	ssize_t pz = m_Patch->m_Z * PATCH_SIZE;
 
 	// must have allocated some vertices before trying to build corresponding indices
 	ENSURE(m_VBBase);
 
 	// number of vertices in each direction in each patch
 	ssize_t vsize=PATCH_SIZE+1;
 
 	// PATCH_SIZE must be 2^8-2 or less to not overflow u16 indices buffer. Thankfully this is always true.
 	ENSURE(vsize*vsize < 65536);
 
 	std::vector<unsigned short> indices;
 	indices.reserve(PATCH_SIZE * PATCH_SIZE * 4);
 
 	// release existing splats
 	m_Splats.clear();
 
 	// build grid of textures on this patch
 	std::vector<CTerrainTextureEntry*> textures;
 	CTerrainTextureEntry* texgrid[PATCH_SIZE][PATCH_SIZE];
 	for (ssize_t j=0;j<PATCH_SIZE;j++) {
 		for (ssize_t i=0;i<PATCH_SIZE;i++) {
 			CTerrainTextureEntry* tex=m_Patch->m_MiniPatches[j][i].GetTextureEntry();
 			texgrid[j][i]=tex;
 			if (std::find(textures.begin(),textures.end(),tex)==textures.end()) {
 				textures.push_back(tex);
 			}
 		}
 	}
 
 	// now build base splats from interior textures
 	m_Splats.resize(textures.size());
 	// build indices for base splats
 	size_t base=m_VBBase->m_Index;
 
 	for (size_t k = 0; k < m_Splats.size(); ++k)
 	{
 		CTerrainTextureEntry* tex = textures[k];
 
 		SSplat& splat=m_Splats[k];
 		splat.m_Texture=tex;
 		splat.m_IndexStart=indices.size();
 
 		for (ssize_t j = 0; j < PATCH_SIZE; j++)
 		{
 			for (ssize_t i = 0; i < PATCH_SIZE; i++)
 			{
 				if (texgrid[j][i] == tex)
 				{
 					bool dir = terrain->GetTriangulationDir(px+i, pz+j);
 					if (dir)
 					{
 						indices.push_back(u16(((j+0)*vsize+(i+0))+base));
 						indices.push_back(u16(((j+0)*vsize+(i+1))+base));
 						indices.push_back(u16(((j+1)*vsize+(i+0))+base));
 
 						indices.push_back(u16(((j+0)*vsize+(i+1))+base));
 						indices.push_back(u16(((j+1)*vsize+(i+1))+base));
 						indices.push_back(u16(((j+1)*vsize+(i+0))+base));
 					}
 					else
 					{
 						indices.push_back(u16(((j+0)*vsize+(i+0))+base));
 						indices.push_back(u16(((j+0)*vsize+(i+1))+base));
 						indices.push_back(u16(((j+1)*vsize+(i+1))+base));
 
 						indices.push_back(u16(((j+1)*vsize+(i+1))+base));
 						indices.push_back(u16(((j+1)*vsize+(i+0))+base));
 						indices.push_back(u16(((j+0)*vsize+(i+0))+base));
 					}
 				}
 			}
 		}
 		splat.m_IndexCount=indices.size()-splat.m_IndexStart;
 	}
 
 	// Release existing vertex buffer chunk
 	if (m_VBBaseIndices)
 	{
 		g_VBMan.Release(m_VBBaseIndices);
 		m_VBBaseIndices = 0;
 	}
 
 	ENSURE(indices.size());
 
 	// Construct vertex buffer
 	m_VBBaseIndices = g_VBMan.Allocate(sizeof(u16), indices.size(), GL_STATIC_DRAW, GL_ELEMENT_ARRAY_BUFFER);
 	m_VBBaseIndices->m_Owner->UpdateChunkVertices(m_VBBaseIndices, &indices[0]);
 }
 
 
 void CPatchRData::BuildVertices()
 {
 	PROFILE3("build vertices");
 
 	// create both vertices and lighting colors
 
 	// number of vertices in each direction in each patch
 	ssize_t vsize = PATCH_SIZE + 1;
 
 	std::vector<SBaseVertex> vertices;
 	vertices.resize(vsize * vsize);
 
 	// get index of this patch
 	ssize_t px = m_Patch->m_X;
 	ssize_t pz = m_Patch->m_Z;
 
 	CTerrain* terrain = m_Patch->m_Parent;
 
 	// build vertices
 	for (ssize_t j = 0; j < vsize; ++j)
 	{
 		for (ssize_t i = 0; i < vsize; ++i)
 		{
 			ssize_t ix = px * PATCH_SIZE + i;
 			ssize_t iz = pz * PATCH_SIZE + j;
 			ssize_t v = j * vsize + i;
 
 			// calculate vertex data
 			terrain->CalcPosition(ix, iz, vertices[v].m_Position);
 
 			CVector3D normal;
 			terrain->CalcNormal(ix, iz, normal);
 			vertices[v].m_Normal = normal;
 		}
 	}
 
 	// upload to vertex buffer
 	if (!m_VBBase)
 		m_VBBase = g_VBMan.Allocate(sizeof(SBaseVertex), vsize * vsize, GL_STATIC_DRAW, GL_ARRAY_BUFFER);
 
 	m_VBBase->m_Owner->UpdateChunkVertices(m_VBBase, &vertices[0]);
 }
 
 void CPatchRData::BuildSide(std::vector<SSideVertex>& vertices, CPatchSideFlags side)
 {
 	ssize_t vsize = PATCH_SIZE + 1;
 	CTerrain* terrain = m_Patch->m_Parent;
 	CmpPtr<ICmpWaterManager> cmpWaterManager(*m_Simulation, SYSTEM_ENTITY);
 
 	for (ssize_t k = 0; k < vsize; k++)
 	{
 		ssize_t gx = m_Patch->m_X * PATCH_SIZE;
 		ssize_t gz = m_Patch->m_Z * PATCH_SIZE;
 		switch (side)
 		{
 		case CPATCH_SIDE_NEGX: gz += k; break;
 		case CPATCH_SIDE_POSX: gx += PATCH_SIZE; gz += PATCH_SIZE-k; break;
 		case CPATCH_SIDE_NEGZ: gx += PATCH_SIZE-k; break;
 		case CPATCH_SIDE_POSZ: gz += PATCH_SIZE; gx += k; break;
 		}
 
 		CVector3D pos;
 		terrain->CalcPosition(gx, gz, pos);
 
 		// Clamp the height to the water level
 		float waterHeight = 0.f;
 		if (cmpWaterManager)
 			waterHeight = cmpWaterManager->GetExactWaterLevel(pos.X, pos.Z);
 		pos.Y = std::max(pos.Y, waterHeight);
 
 		SSideVertex v0, v1;
 		v0.m_Position = pos;
 		v1.m_Position = pos;
 		v1.m_Position.Y = 0;
 
 		// If this is the start of this tristrip, but we've already got a partial
 		// tristrip, add a couple of degenerate triangles to join the strips properly
 		if (k == 0 && !vertices.empty())
 		{
 			vertices.push_back(vertices.back());
 			vertices.push_back(v1);
 		}
 
 		// Now add the new triangles
 		vertices.push_back(v1);
 		vertices.push_back(v0);
 	}
 }
 
 void CPatchRData::BuildSides()
 {
 	PROFILE3("build sides");
 
 	std::vector<SSideVertex> sideVertices;
 
 	int sideFlags = m_Patch->GetSideFlags();
 
 	// If no sides are enabled, we don't need to do anything
 	if (!sideFlags)
 		return;
 
 	// For each side, generate a tristrip by adding a vertex at ground/water
 	// level and a vertex underneath at height 0.
 
 	if (sideFlags & CPATCH_SIDE_NEGX)
 		BuildSide(sideVertices, CPATCH_SIDE_NEGX);
 
 	if (sideFlags & CPATCH_SIDE_POSX)
 		BuildSide(sideVertices, CPATCH_SIDE_POSX);
 
 	if (sideFlags & CPATCH_SIDE_NEGZ)
 		BuildSide(sideVertices, CPATCH_SIDE_NEGZ);
 
 	if (sideFlags & CPATCH_SIDE_POSZ)
 		BuildSide(sideVertices, CPATCH_SIDE_POSZ);
 
 	if (sideVertices.empty())
 		return;
 
 	if (!m_VBSides)
 		m_VBSides = g_VBMan.Allocate(sizeof(SSideVertex), sideVertices.size(), GL_STATIC_DRAW, GL_ARRAY_BUFFER);
 	m_VBSides->m_Owner->UpdateChunkVertices(m_VBSides, &sideVertices[0]);
 }
 
 void CPatchRData::Build()
 {
 	BuildVertices();
 	BuildSides();
 	BuildIndices();
 	BuildBlends();
 	BuildWater();
 }
 
 void CPatchRData::Update(CSimulation2* simulation)
 {
 	m_Simulation = simulation;
 	if (m_UpdateFlags!=0) {
 		// TODO,RC 11/04/04 - need to only rebuild necessary bits of renderdata rather
 		// than everything; it's complicated slightly because the blends are dependent
 		// on both vertex and index data
 		BuildVertices();
 		BuildSides();
 		BuildIndices();
 		BuildBlends();
 		BuildWater();
 
 		m_UpdateFlags=0;
 	}
 }
 
 // Types used for glMultiDrawElements batching:
 
 // To minimise the cost of memory allocations, everything used for computing
 // batches uses a arena allocator. (All allocations are short-lived so we can
 // just throw away the whole arena at the end of each frame.)
 
 using Arena = Allocators::DynamicArena<1 * MiB>;
 
 // std::map types with appropriate arena allocators and default comparison operator
 template<class Key, class Value>
 using PooledBatchMap = std::map<Key, Value, std::less<Key>, ProxyAllocator<std::pair<Key const, Value>, Arena>>;
 
 // Equivalent to "m[k]", when it returns a arena-allocated std::map (since we can't
 // use the default constructor in that case)
 template<typename M>
 typename M::mapped_type& PooledMapGet(M& m, const typename M::key_type& k, Arena& arena)
 {
 	return m.insert(std::make_pair(k,
 		typename M::mapped_type(typename M::mapped_type::key_compare(), typename M::mapped_type::allocator_type(arena))
 	)).first->second;
 }
 
 // Equivalent to "m[k]", when it returns a std::pair of arena-allocated std::vectors
 template<typename M>
 typename M::mapped_type& PooledPairGet(M& m, const typename M::key_type& k, Arena& arena)
 {
 	return m.insert(std::make_pair(k, std::make_pair(
 			typename M::mapped_type::first_type(typename M::mapped_type::first_type::allocator_type(arena)),
 			typename M::mapped_type::second_type(typename M::mapped_type::second_type::allocator_type(arena))
 	))).first->second;
 }
 
 // Each multidraw batch has a list of index counts, and a list of pointers-to-first-indexes
 using BatchElements = std::pair<std::vector<GLint, ProxyAllocator<GLint, Arena>>, std::vector<void*, ProxyAllocator<void*, Arena>>>;
 
 // Group batches by index buffer
 using IndexBufferBatches = PooledBatchMap<CVertexBuffer*, BatchElements>;
 
 // Group batches by vertex buffer
 using VertexBufferBatches = PooledBatchMap<CVertexBuffer*, IndexBufferBatches>;
 
 // Group batches by texture
 using TextureBatches = PooledBatchMap<CTerrainTextureEntry*, VertexBufferBatches>;
 
+// Group batches by shaders.
+using ShaderTechniqueBatches = PooledBatchMap<CShaderTechniquePtr, TextureBatches>;
+
 void CPatchRData::RenderBases(
 	const std::vector<CPatchRData*>& patches, const CShaderDefines& context, ShadowMap* shadow)
 {
 	Arena arena;
 
-	TextureBatches batches(TextureBatches::key_compare(), (TextureBatches::allocator_type(arena)));
+	ShaderTechniqueBatches batches(ShaderTechniqueBatches::key_compare(), (ShaderTechniqueBatches::allocator_type(arena)));
 
- 	PROFILE_START("compute batches");
+	PROFILE_START("compute batches");
 
- 	// Collect all the patches' base splats into their appropriate batches
- 	for (size_t i = 0; i < patches.size(); ++i)
- 	{
- 		CPatchRData* patch = patches[i];
- 		for (size_t j = 0; j < patch->m_Splats.size(); ++j)
- 		{
- 			SSplat& splat = patch->m_Splats[j];
+	// Collect all the patches' base splats into their appropriate batches
+	for (size_t i = 0; i < patches.size(); ++i)
+	{
+		CPatchRData* patch = patches[i];
+		for (size_t j = 0; j < patch->m_Splats.size(); ++j)
+		{
+			SSplat& splat = patch->m_Splats[j];
+			const CMaterial& material = splat.m_Texture->GetMaterial();
+			if (material.GetShaderEffect().empty())
+			{
+				LOGERROR("Terrain renderer failed to load shader effect.\n");
+				continue;
+			}
+			CShaderTechniquePtr techBase = g_Renderer.GetShaderManager().LoadEffect(
+				material.GetShaderEffect(), context, material.GetShaderDefines(0));
 
- 			BatchElements& batch = PooledPairGet(
+			BatchElements& batch = PooledPairGet(
 				PooledMapGet(
- 					PooledMapGet(batches, splat.m_Texture, arena),
- 					patch->m_VBBase->m_Owner, arena
+					PooledMapGet(
+						PooledMapGet(batches, techBase, arena),
+						splat.m_Texture, arena
+					),
+					patch->m_VBBase->m_Owner, arena
 				),
 				patch->m_VBBaseIndices->m_Owner, arena
 			);
 
- 			batch.first.push_back(splat.m_IndexCount);
+			batch.first.push_back(splat.m_IndexCount);
 
- 			u8* indexBase = patch->m_VBBaseIndices->m_Owner->GetBindAddress();
- 			batch.second.push_back(indexBase + sizeof(u16)*(patch->m_VBBaseIndices->m_Index + splat.m_IndexStart));
+			u8* indexBase = patch->m_VBBaseIndices->m_Owner->GetBindAddress();
+			batch.second.push_back(indexBase + sizeof(u16)*(patch->m_VBBaseIndices->m_Index + splat.m_IndexStart));
 		}
- 	}
+	}
 
- 	PROFILE_END("compute batches");
+	PROFILE_END("compute batches");
 
- 	// Render each batch
- 	for (TextureBatches::iterator itt = batches.begin(); itt != batches.end(); ++itt)
+	// Render each batch
+	for (ShaderTechniqueBatches::iterator itTech = batches.begin(); itTech != batches.end(); ++itTech)
 	{
-		if (itt->first->GetMaterial().GetShaderEffect().empty())
-		{
-			LOGERROR("Terrain renderer failed to load shader effect.\n");
-			continue;
-		}
-
-		CShaderTechniquePtr techBase = g_Renderer.GetShaderManager().LoadEffect(itt->first->GetMaterial().GetShaderEffect(),
-					context, itt->first->GetMaterial().GetShaderDefines(0));
-
+		const CShaderTechniquePtr& techBase = itTech->first;
 		const int numPasses = techBase->GetNumPasses();
-
 		for (int pass = 0; pass < numPasses; ++pass)
 		{
 			techBase->BeginPass(pass);
-			TerrainRenderer::PrepareShader(techBase->GetShader(), shadow);
-
 			const CShaderProgramPtr& shader = techBase->GetShader(pass);
+			TerrainRenderer::PrepareShader(shader, shadow);
 
-			if (itt->first->GetMaterial().GetSamplers().size() != 0)
+			TextureBatches& textureBatches = itTech->second;
+			for (TextureBatches::iterator itt = textureBatches.begin(); itt != textureBatches.end(); ++itt)
 			{
-				const CMaterial::SamplersVector& samplers = itt->first->GetMaterial().GetSamplers();
-				size_t samplersNum = samplers.size();
-
-				for (size_t s = 0; s < samplersNum; ++s)
+				if (itt->first->GetMaterial().GetSamplers().size() != 0)
 				{
-					const CMaterial::TextureSampler& samp = samplers[s];
-					shader->BindTexture(samp.Name, samp.Sampler);
+					const CMaterial::SamplersVector& samplers = itt->first->GetMaterial().GetSamplers();
+					for(const CMaterial::TextureSampler& samp : samplers)
+						shader->BindTexture(samp.Name, samp.Sampler);
+
+					itt->first->GetMaterial().GetStaticUniforms().BindUniforms(shader);
+
+					float c = itt->first->GetTextureMatrix()[0];
+					float ms = itt->first->GetTextureMatrix()[8];
+					shader->Uniform(str_textureTransform, c, ms, -ms, 0.f);
+				}
+				else
+				{
+					shader->BindTexture(str_baseTex, g_Renderer.GetTextureManager().GetErrorTexture());
 				}
 
-				itt->first->GetMaterial().GetStaticUniforms().BindUniforms(shader);
-
-				float c = itt->first->GetTextureMatrix()[0];
-				float ms = itt->first->GetTextureMatrix()[8];
-				shader->Uniform(str_textureTransform, c, ms, -ms, 0.f);
-			}
-			else
-			{
-				shader->BindTexture(str_baseTex, g_Renderer.GetTextureManager().GetErrorTexture());
-			}
+				for (VertexBufferBatches::iterator itv = itt->second.begin(); itv != itt->second.end(); ++itv)
+				{
+					GLsizei stride = sizeof(SBaseVertex);
+					SBaseVertex *base = (SBaseVertex *)itv->first->Bind();
+					shader->VertexPointer(3, GL_FLOAT, stride, &base->m_Position[0]);
+					shader->NormalPointer(GL_FLOAT, stride, &base->m_Normal[0]);
+					shader->TexCoordPointer(GL_TEXTURE0, 3, GL_FLOAT, stride, &base->m_Position[0]);
 
-			for (VertexBufferBatches::iterator itv = itt->second.begin(); itv != itt->second.end(); ++itv)
-			{
-				GLsizei stride = sizeof(SBaseVertex);
-				SBaseVertex *base = (SBaseVertex *)itv->first->Bind();
-				shader->VertexPointer(3, GL_FLOAT, stride, &base->m_Position[0]);
-				shader->NormalPointer(GL_FLOAT, stride, &base->m_Normal[0]);
-				shader->TexCoordPointer(GL_TEXTURE0, 3, GL_FLOAT, stride, &base->m_Position[0]);
+					shader->AssertPointersBound();
 
-				shader->AssertPointersBound();
+					for (IndexBufferBatches::iterator it = itv->second.begin(); it != itv->second.end(); ++it)
+					{
+						it->first->Bind();
 
-				for (IndexBufferBatches::iterator it = itv->second.begin(); it != itv->second.end(); ++it)
-				{
-					it->first->Bind();
+						BatchElements& batch = it->second;
 
-					BatchElements& batch = it->second;
+						if (!g_Renderer.m_SkipSubmit)
+						{
+							// Don't use glMultiDrawElements here since it doesn't have a significant
+							// performance impact and it suffers from various driver bugs (e.g. it breaks
+							// in Mesa 7.10 swrast with index VBOs)
+							for (size_t i = 0; i < batch.first.size(); ++i)
+								glDrawElements(GL_TRIANGLES, batch.first[i], GL_UNSIGNED_SHORT, batch.second[i]);
+						}
 
-					if (!g_Renderer.m_SkipSubmit)
-					{
-						// Don't use glMultiDrawElements here since it doesn't have a significant
-						// performance impact and it suffers from various driver bugs (e.g. it breaks
-						// in Mesa 7.10 swrast with index VBOs)
-						for (size_t i = 0; i < batch.first.size(); ++i)
-							glDrawElements(GL_TRIANGLES, batch.first[i], GL_UNSIGNED_SHORT, batch.second[i]);
+						g_Renderer.m_Stats.m_DrawCalls++;
+						g_Renderer.m_Stats.m_TerrainTris += std::accumulate(batch.first.begin(), batch.first.end(), 0) / 3;
 					}
-
-					g_Renderer.m_Stats.m_DrawCalls++;
-					g_Renderer.m_Stats.m_TerrainTris += std::accumulate(batch.first.begin(), batch.first.end(), 0) / 3;
 				}
 			}
-
 			techBase->EndPass();
 		}
 	}
 
 	CVertexBuffer::Unbind();
 }
 
 /**
  * Helper structure for RenderBlends.
  */
 struct SBlendBatch
 {
 	SBlendBatch(Arena& arena) :
 		m_Batches(VertexBufferBatches::key_compare(), VertexBufferBatches::allocator_type(arena))
 	{
 	}
 
 	CTerrainTextureEntry* m_Texture;
- 	VertexBufferBatches m_Batches;
+	CShaderTechniquePtr m_ShaderTech;
+	VertexBufferBatches m_Batches;
 };
 
 /**
  * Helper structure for RenderBlends.
  */
 struct SBlendStackItem
 {
 	SBlendStackItem(CVertexBuffer::VBChunk* v, CVertexBuffer::VBChunk* i,
 			const std::vector<CPatchRData::SSplat>& s, Arena& arena) :
 		vertices(v), indices(i), splats(s.begin(), s.end(), SplatStack::allocator_type(arena))
 	{
 	}
 
 	using SplatStack = std::vector<CPatchRData::SSplat, ProxyAllocator<CPatchRData::SSplat, Arena>>;
 	CVertexBuffer::VBChunk* vertices;
 	CVertexBuffer::VBChunk* indices;
 	SplatStack splats;
 };
 
 void CPatchRData::RenderBlends(
 	const std::vector<CPatchRData*>& patches, const CShaderDefines& context, ShadowMap* shadow)
 {
 	Arena arena;
 
 	using BatchesStack = std::vector<SBlendBatch, ProxyAllocator<SBlendBatch, Arena>>;
 	BatchesStack batches((BatchesStack::allocator_type(arena)));
 
 	CShaderDefines contextBlend = context;
 	contextBlend.Add(str_BLEND, str_1);
 
  	PROFILE_START("compute batches");
 
  	// Reserve an arbitrary size that's probably big enough in most cases,
  	// to avoid heavy reallocations
  	batches.reserve(256);
 
 	using BlendStacks = std::vector<SBlendStackItem, ProxyAllocator<SBlendStackItem, Arena>>;
 	BlendStacks blendStacks((BlendStacks::allocator_type(arena)));
 	blendStacks.reserve(patches.size());
 
 	// Extract all the blend splats from each patch
  	for (size_t i = 0; i < patches.size(); ++i)
  	{
  		CPatchRData* patch = patches[i];
  		if (!patch->m_BlendSplats.empty())
  		{
 
  			blendStacks.push_back(SBlendStackItem(patch->m_VBBlends, patch->m_VBBlendIndices, patch->m_BlendSplats, arena));
  			// Reverse the splats so the first to be rendered is at the back of the list
  			std::reverse(blendStacks.back().splats.begin(), blendStacks.back().splats.end());
  		}
  	}
 
  	// Rearrange the collection of splats to be grouped by texture, preserving
  	// order of splats within each patch:
  	// (This is exactly the same algorithm used in CPatchRData::BuildBlends,
  	// but applied to patch-sized splats rather than to tile-sized splats;
  	// see that function for comments on the algorithm.)
 	while (true)
 	{
 		if (!batches.empty())
 		{
 			CTerrainTextureEntry* tex = batches.back().m_Texture;
 
 			for (size_t k = 0; k < blendStacks.size(); ++k)
 			{
 				SBlendStackItem::SplatStack& splats = blendStacks[k].splats;
 				if (!splats.empty() && splats.back().m_Texture == tex)
 				{
 					CVertexBuffer::VBChunk* vertices = blendStacks[k].vertices;
 					CVertexBuffer::VBChunk* indices = blendStacks[k].indices;
 
 					BatchElements& batch = PooledPairGet(PooledMapGet(batches.back().m_Batches, vertices->m_Owner, arena), indices->m_Owner, arena);
 					batch.first.push_back(splats.back().m_IndexCount);
 
 		 			u8* indexBase = indices->m_Owner->GetBindAddress();
 		 			batch.second.push_back(indexBase + sizeof(u16)*(indices->m_Index + splats.back().m_IndexStart));
 
 					splats.pop_back();
 				}
 			}
 		}
 
 		CTerrainTextureEntry* bestTex = NULL;
 		size_t bestStackSize = 0;
 
 		for (size_t k = 0; k < blendStacks.size(); ++k)
 		{
 			SBlendStackItem::SplatStack& splats = blendStacks[k].splats;
 			if (splats.size() > bestStackSize)
 			{
 				bestStackSize = splats.size();
 				bestTex = splats.back().m_Texture;
 			}
 		}
 
 		if (bestStackSize == 0)
 			break;
 
 		SBlendBatch layer(arena);
 		layer.m_Texture = bestTex;
+		if (!bestTex->GetMaterial().GetSamplers().empty())
+		{
+			layer.m_ShaderTech = g_Renderer.GetShaderManager().LoadEffect(
+				bestTex->GetMaterial().GetShaderEffect(), contextBlend, bestTex->GetMaterial().GetShaderDefines(0));
+		}
 		batches.push_back(layer);
 	}
 
- 	PROFILE_END("compute batches");
+	PROFILE_END("compute batches");
 
- 	CVertexBuffer* lastVB = NULL;
+	glEnable(GL_BLEND);
+	glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
 
- 	for (BatchesStack::iterator itt = batches.begin(); itt != batches.end(); ++itt)
+	CVertexBuffer* lastVB = nullptr;
+	CShaderProgramPtr previousShader;
+	for (BatchesStack::iterator itTechBegin = batches.begin(), itTechEnd = batches.begin(); itTechBegin != batches.end(); itTechBegin = itTechEnd)
 	{
-		if (itt->m_Texture->GetMaterial().GetSamplers().size() == 0)
-			continue;
+		while (itTechEnd != batches.end() && itTechEnd->m_ShaderTech == itTechBegin->m_ShaderTech)
+			++itTechEnd;
 
-		CShaderTechniquePtr techBase = g_Renderer.GetShaderManager().LoadEffect(itt->m_Texture->GetMaterial().GetShaderEffect(), contextBlend, itt->m_Texture->GetMaterial().GetShaderDefines(0));
+		const CShaderTechniquePtr& techBase = itTechBegin->m_ShaderTech;
 		const int numPasses = techBase->GetNumPasses();
-
-		CShaderProgramPtr previousShader;
 		for (int pass = 0; pass < numPasses; ++pass)
 		{
 			techBase->BeginPass(pass);
-			TerrainRenderer::PrepareShader(techBase->GetShader(), shadow);
-
-			glEnable(GL_BLEND);
-			glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
-
 			const CShaderProgramPtr& shader = techBase->GetShader(pass);
+			TerrainRenderer::PrepareShader(shader, shadow);
 
-			if (itt->m_Texture)
+			for (BatchesStack::iterator itt = itTechBegin; itt != itTechEnd; ++itt)
 			{
-				const CMaterial::SamplersVector& samplers = itt->m_Texture->GetMaterial().GetSamplers();
-				size_t samplersNum = samplers.size();
+				if (itt->m_Texture->GetMaterial().GetSamplers().empty())
+					continue;
 
-				for (size_t s = 0; s < samplersNum; ++s)
+				if (itt->m_Texture)
 				{
-					const CMaterial::TextureSampler& samp = samplers[s];
-					shader->BindTexture(samp.Name, samp.Sampler);
-				}
-
-				shader->BindTexture(str_blendTex, itt->m_Texture->m_TerrainAlpha->second.m_hCompositeAlphaMap);
+					const CMaterial::SamplersVector& samplers = itt->m_Texture->GetMaterial().GetSamplers();
+					for (const CMaterial::TextureSampler& samp : samplers)
+						shader->BindTexture(samp.Name, samp.Sampler);
 
-				itt->m_Texture->GetMaterial().GetStaticUniforms().BindUniforms(shader);
+					shader->BindTexture(str_blendTex, itt->m_Texture->m_TerrainAlpha->second.m_hCompositeAlphaMap);
 
-				float c = itt->m_Texture->GetTextureMatrix()[0];
-				float ms = itt->m_Texture->GetTextureMatrix()[8];
-				shader->Uniform(str_textureTransform, c, ms, -ms, 0.f);
-			}
-			else
-			{
-				shader->BindTexture(str_baseTex, g_Renderer.GetTextureManager().GetErrorTexture());
-			}
+					itt->m_Texture->GetMaterial().GetStaticUniforms().BindUniforms(shader);
 
-			for (VertexBufferBatches::iterator itv = itt->m_Batches.begin(); itv != itt->m_Batches.end(); ++itv)
-			{
-				// Rebind the VB only if it changed since the last batch
-				if (itv->first != lastVB || shader != previousShader)
+					float c = itt->m_Texture->GetTextureMatrix()[0];
+					float ms = itt->m_Texture->GetTextureMatrix()[8];
+					shader->Uniform(str_textureTransform, c, ms, -ms, 0.f);
+				}
+				else
 				{
-					lastVB = itv->first;
-					previousShader = shader;
-					GLsizei stride = sizeof(SBlendVertex);
-					SBlendVertex *base = (SBlendVertex *)itv->first->Bind();
-
-					shader->VertexPointer(3, GL_FLOAT, stride, &base->m_Position[0]);
-					shader->NormalPointer(GL_FLOAT, stride, &base->m_Normal[0]);
-					shader->TexCoordPointer(GL_TEXTURE0, 3, GL_FLOAT, stride, &base->m_Position[0]);
-					shader->TexCoordPointer(GL_TEXTURE1, 2, GL_FLOAT, stride, &base->m_AlphaUVs[0]);
+					shader->BindTexture(str_baseTex, g_Renderer.GetTextureManager().GetErrorTexture());
 				}
 
-				shader->AssertPointersBound();
-
-				for (IndexBufferBatches::iterator it = itv->second.begin(); it != itv->second.end(); ++it)
+				for (VertexBufferBatches::iterator itv = itt->m_Batches.begin(); itv != itt->m_Batches.end(); ++itv)
 				{
-					it->first->Bind();
+					// Rebind the VB only if it changed since the last batch
+					if (itv->first != lastVB || shader != previousShader)
+					{
+						lastVB = itv->first;
+						previousShader = shader;
+						GLsizei stride = sizeof(SBlendVertex);
+						SBlendVertex *base = (SBlendVertex *)itv->first->Bind();
+
+						shader->VertexPointer(3, GL_FLOAT, stride, &base->m_Position[0]);
+						shader->NormalPointer(GL_FLOAT, stride, &base->m_Normal[0]);
+						shader->TexCoordPointer(GL_TEXTURE0, 3, GL_FLOAT, stride, &base->m_Position[0]);
+						shader->TexCoordPointer(GL_TEXTURE1, 2, GL_FLOAT, stride, &base->m_AlphaUVs[0]);
+					}
 
-					BatchElements& batch = it->second;
+					shader->AssertPointersBound();
 
-					if (!g_Renderer.m_SkipSubmit)
+					for (IndexBufferBatches::iterator it = itv->second.begin(); it != itv->second.end(); ++it)
 					{
-						for (size_t i = 0; i < batch.first.size(); ++i)
-							glDrawElements(GL_TRIANGLES, batch.first[i], GL_UNSIGNED_SHORT, batch.second[i]);
-					}
+						it->first->Bind();
 
-					g_Renderer.m_Stats.m_DrawCalls++;
-					g_Renderer.m_Stats.m_BlendSplats++;
-					g_Renderer.m_Stats.m_TerrainTris += std::accumulate(batch.first.begin(), batch.first.end(), 0) / 3;
+						BatchElements& batch = it->second;
+
+						if (!g_Renderer.m_SkipSubmit)
+						{
+							for (size_t i = 0; i < batch.first.size(); ++i)
+								glDrawElements(GL_TRIANGLES, batch.first[i], GL_UNSIGNED_SHORT, batch.second[i]);
+						}
+
+						g_Renderer.m_Stats.m_DrawCalls++;
+						g_Renderer.m_Stats.m_BlendSplats++;
+						g_Renderer.m_Stats.m_TerrainTris += std::accumulate(batch.first.begin(), batch.first.end(), 0) / 3;
+					}
 				}
 			}
-
-			glDisable(GL_BLEND);
 			techBase->EndPass();
 		}
 	}
 
+	glDisable(GL_BLEND);
+
 	CVertexBuffer::Unbind();
 }
 
 void CPatchRData::RenderStreams(const std::vector<CPatchRData*>& patches, const CShaderProgramPtr& shader, int streamflags)
 {
 	// Each batch has a list of index counts, and a list of pointers-to-first-indexes
 	using StreamBatchElements = std::pair<std::vector<GLint>, std::vector<void*> > ;
 
 	// Group batches by index buffer
 	using StreamIndexBufferBatches = std::map<CVertexBuffer*, StreamBatchElements> ;
 
 	// Group batches by vertex buffer
 	using StreamVertexBufferBatches = std::map<CVertexBuffer*, StreamIndexBufferBatches> ;
 
 	StreamVertexBufferBatches batches;
 
  	PROFILE_START("compute batches");
 
  	// Collect all the patches into their appropriate batches
 	for (const CPatchRData* patch : patches)
 	{
 		StreamBatchElements& batch = batches[patch->m_VBBase->m_Owner][patch->m_VBBaseIndices->m_Owner];
 
 		batch.first.push_back(patch->m_VBBaseIndices->m_Count);
 
 		u8* indexBase = patch->m_VBBaseIndices->m_Owner->GetBindAddress();
  		batch.second.push_back(indexBase + sizeof(u16)*(patch->m_VBBaseIndices->m_Index));
  	}
 
  	PROFILE_END("compute batches");
 
 	ENSURE(!(streamflags & ~(STREAM_POS|STREAM_POSTOUV0|STREAM_POSTOUV1)));
 
  	// Render each batch
 	for (const std::pair<CVertexBuffer* const, StreamIndexBufferBatches>& streamBatch : batches)
 	{
 		GLsizei stride = sizeof(SBaseVertex);
 		SBaseVertex *base = (SBaseVertex *)streamBatch.first->Bind();
 
 		shader->VertexPointer(3, GL_FLOAT, stride, &base->m_Position);
 		if (streamflags & STREAM_POSTOUV0)
 			shader->TexCoordPointer(GL_TEXTURE0, 3, GL_FLOAT, stride, &base->m_Position);
 		if (streamflags & STREAM_POSTOUV1)
 			shader->TexCoordPointer(GL_TEXTURE1, 3, GL_FLOAT, stride, &base->m_Position);
 
 		shader->AssertPointersBound();
 
 		for (const std::pair<CVertexBuffer* const, StreamBatchElements>& batchIndexBuffer : streamBatch.second)
 		{
 			batchIndexBuffer.first->Bind();
 
 			const StreamBatchElements& batch = batchIndexBuffer.second;
 
 			if (!g_Renderer.m_SkipSubmit)
 			{
 				for (size_t i = 0; i < batch.first.size(); ++i)
 					glDrawElements(GL_TRIANGLES, batch.first[i], GL_UNSIGNED_SHORT, batch.second[i]);
 			}
 
 			g_Renderer.m_Stats.m_DrawCalls++;
 			g_Renderer.m_Stats.m_TerrainTris += std::accumulate(batch.first.begin(), batch.first.end(), 0) / 3;
 		}
 	}
 
 	CVertexBuffer::Unbind();
 }
 
 void CPatchRData::RenderOutline()
 {
 	CTerrain* terrain = m_Patch->m_Parent;
 	ssize_t gx = m_Patch->m_X * PATCH_SIZE;
 	ssize_t gz = m_Patch->m_Z * PATCH_SIZE;
 
 	CVector3D pos;
 	std::vector<CVector3D> line;
 	for (ssize_t i = 0, j = 0; i <= PATCH_SIZE; ++i)
 	{
 		terrain->CalcPosition(gx + i, gz + j, pos);
 		line.push_back(pos);
 	}
 	for (ssize_t i = PATCH_SIZE, j = 1; j <= PATCH_SIZE; ++j)
 	{
 		terrain->CalcPosition(gx + i, gz + j, pos);
 		line.push_back(pos);
 	}
 	for (ssize_t i = PATCH_SIZE-1, j = PATCH_SIZE; i >= 0; --i)
 	{
 		terrain->CalcPosition(gx + i, gz + j, pos);
 		line.push_back(pos);
 	}
 	for (ssize_t i = 0, j = PATCH_SIZE-1; j >= 0; --j)
 	{
 		terrain->CalcPosition(gx + i, gz + j, pos);
 		line.push_back(pos);
 	}
 
 #if CONFIG2_GLES
 #warning TODO: implement CPatchRData::RenderOutlines for GLES
 #else
 	glVertexPointer(3, GL_FLOAT, sizeof(CVector3D), &line[0]);
 	glDrawArrays(GL_LINE_STRIP, 0, line.size());
 #endif
 }
 
 void CPatchRData::RenderSides(CShaderProgramPtr& shader)
 {
 	ENSURE(m_UpdateFlags==0);
 
 	if (!m_VBSides)
 		return;
 
 	glDisable(GL_CULL_FACE);
 
 	SSideVertex *base = (SSideVertex *)m_VBSides->m_Owner->Bind();
 
 	// setup data pointers
 	GLsizei stride = sizeof(SSideVertex);
 	shader->VertexPointer(3, GL_FLOAT, stride, &base->m_Position);
 
 	shader->AssertPointersBound();
 
 	if (!g_Renderer.m_SkipSubmit)
 		glDrawArrays(GL_TRIANGLE_STRIP, m_VBSides->m_Index, (GLsizei)m_VBSides->m_Count);
 
 	// bump stats
 	g_Renderer.m_Stats.m_DrawCalls++;
 	g_Renderer.m_Stats.m_TerrainTris += m_VBSides->m_Count - 2;
 
 	CVertexBuffer::Unbind();
 
 	glEnable(GL_CULL_FACE);
 }
 
 void CPatchRData::RenderPriorities(CTextRenderer& textRenderer)
 {
 	CTerrain* terrain = m_Patch->m_Parent;
 	const CCamera& camera = *(g_Game->GetView()->GetCamera());
 
 	for (ssize_t j = 0; j < PATCH_SIZE; ++j)
 	{
 		for (ssize_t i = 0; i < PATCH_SIZE; ++i)
 		{
 			ssize_t gx = m_Patch->m_X * PATCH_SIZE + i;
 			ssize_t gz = m_Patch->m_Z * PATCH_SIZE + j;
 
 			CVector3D pos;
 			terrain->CalcPosition(gx, gz, pos);
 
 			// Move a bit towards the center of the tile
 			pos.X += TERRAIN_TILE_SIZE/4.f;
 			pos.Z += TERRAIN_TILE_SIZE/4.f;
 
 			float x, y;
 			camera.GetScreenCoordinates(pos, x, y);
 
 			textRenderer.PrintfAt(x, y, L"%d", m_Patch->m_MiniPatches[j][i].Priority);
 		}
 	}
 }
 
 //
 // Water build and rendering
 //
 
 // Build vertex buffer for water vertices over our patch
 void CPatchRData::BuildWater()
 {
 	PROFILE3("build water");
 
 	// Number of vertices in each direction in each patch
 	ENSURE(PATCH_SIZE % water_cell_size == 0);
 
 	if (m_VBWater)
 	{
 		g_VBMan.Release(m_VBWater);
 		m_VBWater = nullptr;
 	}
 	if (m_VBWaterIndices)
 	{
 		g_VBMan.Release(m_VBWaterIndices);
 		m_VBWaterIndices = nullptr;
 	}
 	if (m_VBWaterShore)
 	{
 		g_VBMan.Release(m_VBWaterShore);
 		m_VBWaterShore = nullptr;
 	}
 	if (m_VBWaterIndicesShore)
 	{
 		g_VBMan.Release(m_VBWaterIndicesShore);
 		m_VBWaterIndicesShore = nullptr;
 	}
 	m_WaterBounds.SetEmpty();
 
 	// We need to use this to access the water manager or we may not have the
 	// actual values but some compiled-in defaults
 	CmpPtr<ICmpWaterManager> cmpWaterManager(*m_Simulation, SYSTEM_ENTITY);
 	if (!cmpWaterManager)
 		return;
 
 	// Build data for water
 	std::vector<SWaterVertex> water_vertex_data;
 	std::vector<GLushort> water_indices;
 	u16 water_index_map[PATCH_SIZE+1][PATCH_SIZE+1];
 	memset(water_index_map, 0xFF, sizeof(water_index_map));
 
 	// Build data for shore
 	std::vector<SWaterVertex> water_vertex_data_shore;
 	std::vector<GLushort> water_indices_shore;
 	u16 water_shore_index_map[PATCH_SIZE+1][PATCH_SIZE+1];
 	memset(water_shore_index_map, 0xFF, sizeof(water_shore_index_map));
 
 	WaterManager* WaterMgr = g_Renderer.GetWaterManager();
 
 	CPatch* patch = m_Patch;
 	CTerrain* terrain = patch->m_Parent;
 
 	ssize_t mapSize = terrain->GetVerticesPerSide();
 
 	// Top-left coordinates of our patch.
 	ssize_t px = m_Patch->m_X * PATCH_SIZE;
 	ssize_t pz = m_Patch->m_Z * PATCH_SIZE;
 
 	// To whoever implements different water heights, this is a TODO: water height)
 	float waterHeight = cmpWaterManager->GetExactWaterLevel(0.0f,0.0f);
 
 	// The 4 points making a water tile.
 	int moves[4][2] = {
 		{0, 0},
 		{water_cell_size, 0},
 		{0, water_cell_size},
 		{water_cell_size, water_cell_size}
 	};
 	// Where to look for when checking for water for shore tiles.
 	int check[10][2] = {
 		{0, 0},
 		{water_cell_size, 0},
 		{water_cell_size*2, 0},
 		{0, water_cell_size},
 		{0, water_cell_size*2},
 		{water_cell_size, water_cell_size},
 		{water_cell_size*2, water_cell_size*2},
 		{-water_cell_size, 0},
 		{0, -water_cell_size},
 		{-water_cell_size, -water_cell_size}
 	};
 
 	// build vertices, uv, and shader varying
 	for (ssize_t z = 0; z < PATCH_SIZE; z += water_cell_size)
 	{
 		for (ssize_t x = 0; x < PATCH_SIZE; x += water_cell_size)
 		{
 			// Check that this tile is close to water
 			bool nearWater = false;
 			for (size_t test = 0; test < 10; ++test)
 				if (terrain->GetVertexGroundLevel(x + px + check[test][0], z + pz + check[test][1]) < waterHeight)
 					nearWater = true;
 			if (!nearWater)
 				continue;
 
 			// This is actually lying and I should call CcmpTerrain
 			/*if (!terrain->IsOnMap(x+x1, z+z1)
 			 && !terrain->IsOnMap(x+x1, z+z1 + water_cell_size)
 			 && !terrain->IsOnMap(x+x1 + water_cell_size, z+z1)
 			 && !terrain->IsOnMap(x+x1 + water_cell_size, z+z1 + water_cell_size))
 			 continue;*/
 
 			for (int i = 0; i < 4; ++i)
 			{
 				if (water_index_map[z+moves[i][1]][x+moves[i][0]] != 0xFFFF)
 					continue;
 
 				ssize_t xx = x + px + moves[i][0];
 				ssize_t zz = z + pz + moves[i][1];
 
 				SWaterVertex vertex;
 				terrain->CalcPosition(xx,zz, vertex.m_Position);
 				float depth = waterHeight - vertex.m_Position.Y;
 
 				vertex.m_Position.Y = waterHeight;
 
 				m_WaterBounds += vertex.m_Position;
 
 				vertex.m_WaterData = CVector2D(WaterMgr->m_WindStrength[xx + zz*mapSize], depth);
 
 				water_index_map[z+moves[i][1]][x+moves[i][0]] = static_cast<u16>(water_vertex_data.size());
 				water_vertex_data.push_back(vertex);
 			}
 			water_indices.push_back(water_index_map[z + moves[2][1]][x + moves[2][0]]);
 			water_indices.push_back(water_index_map[z + moves[0][1]][x + moves[0][0]]);
 			water_indices.push_back(water_index_map[z + moves[1][1]][x + moves[1][0]]);
 			water_indices.push_back(water_index_map[z + moves[1][1]][x + moves[1][0]]);
 			water_indices.push_back(water_index_map[z + moves[3][1]][x + moves[3][0]]);
 			water_indices.push_back(water_index_map[z + moves[2][1]][x + moves[2][0]]);
 
 			// Check id this tile is partly over land.
 			// If so add a square over the terrain. This is necessary to render waves that go on shore.
 			if (terrain->GetVertexGroundLevel(x+px, z+pz) < waterHeight &&
 				terrain->GetVertexGroundLevel(x+px + water_cell_size, z+pz) < waterHeight &&
 				terrain->GetVertexGroundLevel(x+px, z+pz+water_cell_size) < waterHeight &&
 				terrain->GetVertexGroundLevel(x+px + water_cell_size, z+pz+water_cell_size) < waterHeight)
 				continue;
 
 			for (int i = 0; i < 4; ++i)
 			{
 				if (water_shore_index_map[z+moves[i][1]][x+moves[i][0]] != 0xFFFF)
 					continue;
 				ssize_t xx = x + px + moves[i][0];
 				ssize_t zz = z + pz + moves[i][1];
 
 				SWaterVertex vertex;
 				terrain->CalcPosition(xx,zz, vertex.m_Position);
 
 				vertex.m_Position.Y += 0.02f;
 				m_WaterBounds += vertex.m_Position;
 
 				vertex.m_WaterData = CVector2D(0.0f, -5.0f);
 
 				water_shore_index_map[z+moves[i][1]][x+moves[i][0]] = static_cast<u16>(water_vertex_data_shore.size());
 				water_vertex_data_shore.push_back(vertex);
 			}
 			if (terrain->GetTriangulationDir(x + px, z + pz))
 			{
 				water_indices_shore.push_back(water_shore_index_map[z + moves[2][1]][x + moves[2][0]]);
 				water_indices_shore.push_back(water_shore_index_map[z + moves[0][1]][x + moves[0][0]]);
 				water_indices_shore.push_back(water_shore_index_map[z + moves[1][1]][x + moves[1][0]]);
 				water_indices_shore.push_back(water_shore_index_map[z + moves[1][1]][x + moves[1][0]]);
 				water_indices_shore.push_back(water_shore_index_map[z + moves[3][1]][x + moves[3][0]]);
 				water_indices_shore.push_back(water_shore_index_map[z + moves[2][1]][x + moves[2][0]]);
 			}
 			else
 			{
 				water_indices_shore.push_back(water_shore_index_map[z + moves[3][1]][x + moves[3][0]]);
 				water_indices_shore.push_back(water_shore_index_map[z + moves[2][1]][x + moves[2][0]]);
 				water_indices_shore.push_back(water_shore_index_map[z + moves[0][1]][x + moves[0][0]]);
 				water_indices_shore.push_back(water_shore_index_map[z + moves[3][1]][x + moves[3][0]]);
 				water_indices_shore.push_back(water_shore_index_map[z + moves[0][1]][x + moves[0][0]]);
 				water_indices_shore.push_back(water_shore_index_map[z + moves[1][1]][x + moves[1][0]]);
 			}
 		}
 	}
 
 	// No vertex buffers if no data generated
 	if (!water_indices.empty())
 	{
 		m_VBWater = g_VBMan.Allocate(sizeof(SWaterVertex), water_vertex_data.size(), GL_STATIC_DRAW, GL_ARRAY_BUFFER);
 		m_VBWater->m_Owner->UpdateChunkVertices(m_VBWater, &water_vertex_data[0]);
 
 		m_VBWaterIndices = g_VBMan.Allocate(sizeof(GLushort), water_indices.size(), GL_STATIC_DRAW, GL_ELEMENT_ARRAY_BUFFER);
 		m_VBWaterIndices->m_Owner->UpdateChunkVertices(m_VBWaterIndices, &water_indices[0]);
 	}
 
 	if (!water_indices_shore.empty())
 	{
 		m_VBWaterShore = g_VBMan.Allocate(sizeof(SWaterVertex), water_vertex_data_shore.size(), GL_STATIC_DRAW, GL_ARRAY_BUFFER);
 		m_VBWaterShore->m_Owner->UpdateChunkVertices(m_VBWaterShore, &water_vertex_data_shore[0]);
 
 		// Construct indices buffer
 		m_VBWaterIndicesShore = g_VBMan.Allocate(sizeof(GLushort), water_indices_shore.size(), GL_STATIC_DRAW, GL_ELEMENT_ARRAY_BUFFER);
 		m_VBWaterIndicesShore->m_Owner->UpdateChunkVertices(m_VBWaterIndicesShore, &water_indices_shore[0]);
 	}
 }
 
 void CPatchRData::RenderWater(CShaderProgramPtr& shader, bool onlyShore, bool fixedPipeline)
 {
 	ASSERT(m_UpdateFlags==0);
 
 	if (g_Renderer.m_SkipSubmit || (!m_VBWater && !m_VBWaterShore))
 		return;
 
 #if !CONFIG2_GLES
 	if (g_Renderer.GetWaterRenderMode() == WIREFRAME)
 		glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
 #endif
 
 	if (m_VBWater != 0x0 && !onlyShore)
 	{
 		SWaterVertex *base=(SWaterVertex *)m_VBWater->m_Owner->Bind();
 
 		// setup data pointers
 		GLsizei stride = sizeof(SWaterVertex);
 		shader->VertexPointer(3, GL_FLOAT, stride, &base[m_VBWater->m_Index].m_Position);
 		if (!fixedPipeline)
 			shader->VertexAttribPointer(str_a_waterInfo, 2, GL_FLOAT, false, stride, &base[m_VBWater->m_Index].m_WaterData);
 
 		shader->AssertPointersBound();
 
 		u8* indexBase = m_VBWaterIndices->m_Owner->Bind();
 		glDrawElements(GL_TRIANGLES, (GLsizei) m_VBWaterIndices->m_Count,
 					   GL_UNSIGNED_SHORT, indexBase + sizeof(u16)*(m_VBWaterIndices->m_Index));
 
 		g_Renderer.m_Stats.m_DrawCalls++;
 		g_Renderer.m_Stats.m_WaterTris += m_VBWaterIndices->m_Count / 3;
 	}
 
 	if (m_VBWaterShore != 0x0 &&
 	    g_Renderer.GetWaterManager()->m_WaterEffects &&
 	    g_Renderer.GetWaterManager()->m_WaterFancyEffects)
 	{
 		SWaterVertex *base=(SWaterVertex *)m_VBWaterShore->m_Owner->Bind();
 
 		GLsizei stride = sizeof(SWaterVertex);
 		shader->VertexPointer(3, GL_FLOAT, stride, &base[m_VBWaterShore->m_Index].m_Position);
 		if (!fixedPipeline)
 			shader->VertexAttribPointer(str_a_waterInfo, 2, GL_FLOAT, false, stride, &base[m_VBWaterShore->m_Index].m_WaterData);
 
 		shader->AssertPointersBound();
 
 		u8* indexBase = m_VBWaterIndicesShore->m_Owner->Bind();
 		glDrawElements(GL_TRIANGLES, (GLsizei) m_VBWaterIndicesShore->m_Count,
 					   GL_UNSIGNED_SHORT, indexBase + sizeof(u16)*(m_VBWaterIndicesShore->m_Index));
 
 		g_Renderer.m_Stats.m_DrawCalls++;
 		g_Renderer.m_Stats.m_WaterTris += m_VBWaterIndicesShore->m_Count / 3;
 	}
 
 	CVertexBuffer::Unbind();
 
 #if !CONFIG2_GLES
 	if (g_Renderer.GetWaterRenderMode() == WIREFRAME)
 		glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
 #endif
 }