forked from 0ad/0ad
Split pathfinder into multiple files, to make it more manageable.
This was SVN commit r8055.
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f80ee08f5f
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248
source/simulation2/components/CCmpPathfinder_Common.h
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248
source/simulation2/components/CCmpPathfinder_Common.h
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@ -0,0 +1,248 @@
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/* Copyright (C) 2010 Wildfire Games.
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* This file is part of 0 A.D.
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*
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* 0 A.D. is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 2 of the License, or
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* (at your option) any later version.
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*
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* 0 A.D. is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with 0 A.D. If not, see <http://www.gnu.org/licenses/>.
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*/
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#ifndef INCLUDED_CCMPPATHFINDER_COMMON
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#define INCLUDED_CCMPPATHFINDER_COMMON
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/**
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* @file
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* Declares CCmpPathfinder, whose implementation is split into multiple source files,
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* and provides common code needed for more than one of those files.
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* CCmpPathfinder includes two pathfinding algorithms (one tile-based, one vertex-based)
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* with some shared state and functionality, so the code is split into
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* CCmpPathfinder_Vertex.cpp, CCmpPathfinder_Tile.cpp and CCmpPathfinder.cpp
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*/
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#include "simulation2/system/Component.h"
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#include "ICmpPathfinder.h"
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#include "graphics/Overlay.h"
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#include "graphics/Terrain.h"
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#include "maths/MathUtil.h"
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#include "simulation2/helpers/Geometry.h"
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#include "simulation2/helpers/Grid.h"
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class PathfinderOverlay;
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class SceneCollector;
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struct PathfindTile;
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#ifdef NDEBUG
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#define PATHFIND_DEBUG 0
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#else
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#define PATHFIND_DEBUG 1
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#endif
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/*
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* For efficient pathfinding we want to try hard to minimise the per-tile search cost,
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* so we precompute the tile passability flags and movement costs for the various different
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* types of unit.
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* We also want to minimise memory usage (there can easily be 100K tiles so we don't want
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* to store many bytes for each).
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*
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* To handle passability efficiently, we have a small number of passability classes
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* (e.g. "infantry", "ship"). Each unit belongs to a single passability class, and
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* uses that for all its pathfinding.
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* Passability is determined by water depth, terrain slope, forestness, buildingness.
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* We need at least one bit per class per tile to represent passability.
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*
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* We use a separate bit to indicate building obstructions (instead of folding it into
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* the class passabilities) so that it can be ignored when doing the accurate short paths.
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*
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* To handle movement costs, we have an arbitrary number of unit cost classes (e.g. "infantry", "camel"),
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* and a small number of terrain cost classes (e.g. "grass", "steep grass", "road", "sand"),
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* and a cost mapping table between the classes (e.g. camels are fast on sand).
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* We need log2(|terrain cost classes|) bits per tile to represent costs.
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*
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* We could have one passability bitmap per class, and another array for cost classes,
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* but instead (for no particular reason) we'll pack them all into a single u8 array.
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* Space is a bit tight so maybe this should be changed to a u16 in the future.
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*
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* We handle dynamic updates currently by recomputing the entire array, which is stupid;
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* it should only bother updating the region that has changed.
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*/
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class PathfinderPassability
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{
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public:
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PathfinderPassability(u8 mask, const CParamNode& node) :
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m_Mask(mask)
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{
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if (node.GetChild("MinWaterDepth").IsOk())
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m_MinDepth = node.GetChild("MinWaterDepth").ToFixed();
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else
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m_MinDepth = std::numeric_limits<fixed>::min();
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if (node.GetChild("MaxWaterDepth").IsOk())
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m_MaxDepth = node.GetChild("MaxWaterDepth").ToFixed();
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else
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m_MaxDepth = std::numeric_limits<fixed>::max();
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if (node.GetChild("MaxTerrainSlope").IsOk())
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m_MaxSlope = node.GetChild("MaxTerrainSlope").ToFixed();
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else
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m_MaxSlope = std::numeric_limits<fixed>::max();
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}
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bool IsPassable(fixed waterdepth, fixed steepness)
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{
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return ((m_MinDepth <= waterdepth && waterdepth <= m_MaxDepth) && (steepness < m_MaxSlope));
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}
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u8 m_Mask;
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private:
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fixed m_MinDepth;
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fixed m_MaxDepth;
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fixed m_MaxSlope;
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};
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typedef u8 TerrainTile; // 1 bit for obstructions, PASS_CLASS_BITS for terrain passability, COST_CLASS_BITS for movement costs
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const int PASS_CLASS_BITS = 4;
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const int COST_CLASS_BITS = 8 - (PASS_CLASS_BITS + 1);
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#define IS_TERRAIN_PASSABLE(item, classmask) (((item) & (classmask)) == 0)
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#define IS_PASSABLE(item, classmask) (((item) & ((classmask) | 1)) == 0)
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#define GET_COST_CLASS(item) ((item) >> (PASS_CLASS_BITS + 1))
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#define COST_CLASS_TAG(id) ((id) << (PASS_CLASS_BITS + 1))
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/**
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* Implementation of ICmpPathfinder
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*/
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class CCmpPathfinder : public ICmpPathfinder
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{
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public:
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static void ClassInit(CComponentManager& componentManager)
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{
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componentManager.SubscribeToMessageType(MT_RenderSubmit); // for debug overlays
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componentManager.SubscribeToMessageType(MT_TerrainChanged);
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}
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DEFAULT_COMPONENT_ALLOCATOR(Pathfinder)
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std::map<std::string, u8> m_PassClassMasks;
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std::vector<PathfinderPassability> m_PassClasses;
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std::map<std::string, u8> m_TerrainCostClassTags;
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std::map<std::string, u8> m_UnitCostClassTags;
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std::vector<std::vector<u32> > m_MoveCosts; // costs[unitClass][terrainClass]
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std::vector<std::vector<fixed> > m_MoveSpeeds; // speeds[unitClass][terrainClass]
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u16 m_MapSize; // tiles per side
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Grid<TerrainTile>* m_Grid; // terrain/passability information
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Grid<u8>* m_ObstructionGrid; // cached obstruction information (TODO: we shouldn't bother storing this, it's redundant with LSBs of m_Grid)
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bool m_TerrainDirty; // indicates if m_Grid has been updated since terrain changed
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// Debugging - output from last pathfind operation:
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Grid<PathfindTile>* m_DebugGrid;
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u32 m_DebugSteps;
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Path* m_DebugPath;
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PathfinderOverlay* m_DebugOverlay;
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u8 m_DebugPassClass;
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std::vector<SOverlayLine> m_DebugOverlayShortPathLines;
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static std::string GetSchema()
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{
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return "<a:component type='system'/><empty/>";
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}
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virtual void Init(const CSimContext& UNUSED(context), const CParamNode& paramNode);
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virtual void Deinit(const CSimContext& UNUSED(context));
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virtual void Serialize(ISerializer& UNUSED(serialize))
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{
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// TODO: do something here
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// (Do we need to serialise the pathfinder state, or is it fine to regenerate it from
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// the original entities after deserialisation?)
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}
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virtual void Deserialize(const CSimContext& context, const CParamNode& paramNode, IDeserializer& UNUSED(deserialize))
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{
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Init(context, paramNode);
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// TODO
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}
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virtual void HandleMessage(const CSimContext& context, const CMessage& msg, bool UNUSED(global));
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virtual u8 GetPassabilityClass(const std::string& name);
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virtual std::vector<std::string> GetPassabilityClasses();
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virtual u8 GetCostClass(const std::string& name);
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virtual void ComputePath(entity_pos_t x0, entity_pos_t z0, const Goal& goal, u8 passClass, u8 costClass, Path& ret);
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virtual void ComputeShortPath(const IObstructionTestFilter& filter, entity_pos_t x0, entity_pos_t z0, entity_pos_t r, entity_pos_t range, const Goal& goal, u8 passClass, Path& ret);
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virtual void SetDebugPath(entity_pos_t x0, entity_pos_t z0, const Goal& goal, u8 passClass, u8 costClass);
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virtual void ResetDebugPath();
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virtual void SetDebugOverlay(bool enabled);
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virtual fixed GetMovementSpeed(entity_pos_t x0, entity_pos_t z0, u8 costClass);
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/**
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* Returns the tile containing the given position
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*/
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void NearestTile(entity_pos_t x, entity_pos_t z, u16& i, u16& j)
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{
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i = clamp((x / (int)CELL_SIZE).ToInt_RoundToZero(), 0, m_MapSize-1);
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j = clamp((z / (int)CELL_SIZE).ToInt_RoundToZero(), 0, m_MapSize-1);
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}
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/**
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* Returns the position of the center of the given tile
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*/
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static void TileCenter(u16 i, u16 j, entity_pos_t& x, entity_pos_t& z)
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{
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x = entity_pos_t::FromInt(i*(int)CELL_SIZE + CELL_SIZE/2);
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z = entity_pos_t::FromInt(j*(int)CELL_SIZE + CELL_SIZE/2);
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}
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/**
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* Regenerates the grid based on the current obstruction list, if necessary
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*/
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void UpdateGrid();
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void RenderSubmit(const CSimContext& context, SceneCollector& collector);
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};
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static fixed DistanceToGoal(CFixedVector2D pos, const CCmpPathfinder::Goal& goal)
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{
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switch (goal.type)
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{
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case CCmpPathfinder::Goal::POINT:
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return (pos - CFixedVector2D(goal.x, goal.z)).Length();
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case CCmpPathfinder::Goal::CIRCLE:
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return ((pos - CFixedVector2D(goal.x, goal.z)).Length() - goal.hw).Absolute();
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case CCmpPathfinder::Goal::SQUARE:
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{
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CFixedVector2D halfSize(goal.hw, goal.hh);
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CFixedVector2D d(pos.X - goal.x, pos.Y - goal.z);
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return Geometry::DistanceToSquare(d, goal.u, goal.v, halfSize);
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}
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default:
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debug_warn(L"invalid type");
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return fixed::Zero();
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}
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}
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#endif // INCLUDED_CCMPPATHFINDER_COMMON
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471
source/simulation2/components/CCmpPathfinder_Tile.cpp
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471
source/simulation2/components/CCmpPathfinder_Tile.cpp
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@ -0,0 +1,471 @@
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/* Copyright (C) 2010 Wildfire Games.
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* This file is part of 0 A.D.
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*
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* 0 A.D. is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 2 of the License, or
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* (at your option) any later version.
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*
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* 0 A.D. is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with 0 A.D. If not, see <http://www.gnu.org/licenses/>.
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*/
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/**
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* @file
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* Tile-based algorithm for CCmpPathfinder.
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* This is a fairly naive algorithm and could probably be improved substantially
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* (hopefully without needing to change the interface much).
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*/
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#include "precompiled.h"
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#include "CCmpPathfinder_Common.h"
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#include "ps/Profile.h"
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#include "renderer/TerrainOverlay.h"
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#include "simulation2/helpers/PriorityQueue.h"
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typedef PriorityQueueList<std::pair<u16, u16>, u32> PriorityQueue;
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#define PATHFIND_STATS 0
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#define USE_DIAGONAL_MOVEMENT 1
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// Heuristic cost to move between adjacent tiles.
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// This should be similar to DEFAULT_MOVE_COST.
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const u32 g_CostPerTile = 256;
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/**
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* Tile data for A* computation.
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* (We store an array of one of these per terrain tile, so it ought to be optimised for size)
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*/
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struct PathfindTile
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{
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public:
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enum {
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STATUS_UNEXPLORED = 0,
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STATUS_OPEN = 1,
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STATUS_CLOSED = 2
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};
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bool IsUnexplored() { return status == STATUS_UNEXPLORED; }
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bool IsOpen() { return status == STATUS_OPEN; }
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bool IsClosed() { return status == STATUS_CLOSED; }
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void SetStatusOpen() { status = STATUS_OPEN; }
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void SetStatusClosed() { status = STATUS_CLOSED; }
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// Get pi,pj coords of predecessor to this tile on best path, given i,j coords of this tile
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u16 GetPredI(u16 i) { return i+dpi; }
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u16 GetPredJ(u16 j) { return j+dpj; }
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// Set the pi,pj coords of predecessor, given i,j coords of this tile
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void SetPred(u16 pi_, u16 pj_, u16 i, u16 j)
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{
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dpi = pi_-i;
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dpj = pj_-j;
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#if PATHFIND_DEBUG
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// predecessor must be adjacent
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debug_assert(pi_-i == -1 || pi_-i == 0 || pi_-i == 1);
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debug_assert(pj_-j == -1 || pj_-j == 0 || pj_-j == 1);
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#endif
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}
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private:
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u8 status; // this only needs 2 bits
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i8 dpi, dpj; // these only really need 2 bits in total
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public:
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u32 cost; // g (cost to this tile)
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u32 h; // h (heuristic cost to goal) (TODO: is it really better for performance to store this instead of recomputing?)
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#if PATHFIND_DEBUG
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u32 GetStep() { return step; }
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void SetStep(u32 s) { step = s; }
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private:
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u32 step; // step at which this tile was last processed (for debug rendering)
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#else
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u32 GetStep() { return 0; }
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void SetStep(u32) { }
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#endif
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};
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/**
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* Terrain overlay for pathfinder debugging.
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* Renders a representation of the most recent pathfinding operation.
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*/
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class PathfinderOverlay : public TerrainOverlay
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{
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NONCOPYABLE(PathfinderOverlay);
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public:
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CCmpPathfinder& m_Pathfinder;
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PathfinderOverlay(CCmpPathfinder& pathfinder) : m_Pathfinder(pathfinder)
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{
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}
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virtual void ProcessTile(ssize_t i, ssize_t j)
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{
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if (m_Pathfinder.m_Grid && !IS_PASSABLE(m_Pathfinder.m_Grid->get(i, j), m_Pathfinder.m_DebugPassClass))
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RenderTile(CColor(1, 0, 0, 0.6f), false);
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if (m_Pathfinder.m_DebugGrid)
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{
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PathfindTile& n = m_Pathfinder.m_DebugGrid->get(i, j);
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float c = clamp(n.GetStep() / (float)m_Pathfinder.m_DebugSteps, 0.f, 1.f);
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if (n.IsOpen())
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RenderTile(CColor(1, 1, c, 0.6f), false);
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||||
else if (n.IsClosed())
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RenderTile(CColor(0, 1, c, 0.6f), false);
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||||
}
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||||
}
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||||
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virtual void EndRender()
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{
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if (m_Pathfinder.m_DebugPath)
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{
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std::vector<ICmpPathfinder::Waypoint>& wp = m_Pathfinder.m_DebugPath->m_Waypoints;
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for (size_t n = 0; n < wp.size(); ++n)
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{
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u16 i, j;
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m_Pathfinder.NearestTile(wp[n].x, wp[n].z, i, j);
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RenderTileOutline(CColor(1, 1, 1, 1), 2, false, i, j);
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||||
}
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||||
}
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||||
}
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||||
};
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||||
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||||
void CCmpPathfinder::SetDebugOverlay(bool enabled)
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||||
{
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||||
if (enabled && !m_DebugOverlay)
|
||||
{
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||||
m_DebugOverlay = new PathfinderOverlay(*this);
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||||
}
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||||
else if (!enabled && m_DebugOverlay)
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||||
{
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||||
delete m_DebugOverlay;
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||||
m_DebugOverlay = NULL;
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||||
}
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}
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||||
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||||
void CCmpPathfinder::SetDebugPath(entity_pos_t x0, entity_pos_t z0, const Goal& goal, u8 passClass, u8 costClass)
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||||
{
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||||
if (!m_DebugOverlay)
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||||
return;
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||||
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||||
delete m_DebugGrid;
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||||
m_DebugGrid = NULL;
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||||
delete m_DebugPath;
|
||||
m_DebugPath = new Path();
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ComputePath(x0, z0, goal, passClass, costClass, *m_DebugPath);
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m_DebugPassClass = passClass;
|
||||
}
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||||
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||||
void CCmpPathfinder::ResetDebugPath()
|
||||
{
|
||||
delete m_DebugGrid;
|
||||
m_DebugGrid = NULL;
|
||||
delete m_DebugPath;
|
||||
m_DebugPath = NULL;
|
||||
}
|
||||
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||||
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||||
//////////////////////////////////////////////////////////
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||||
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||||
|
||||
struct PathfinderState
|
||||
{
|
||||
u32 steps; // number of algorithm iterations
|
||||
|
||||
u16 iGoal, jGoal; // goal tile
|
||||
u16 rGoal; // radius of goal (around tile center)
|
||||
|
||||
u8 passClass;
|
||||
std::vector<u32> moveCosts;
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||||
|
||||
PriorityQueue open;
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||||
// (there's no explicit closed list; it's encoded in PathfindTile)
|
||||
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||||
Grid<PathfindTile>* tiles;
|
||||
Grid<TerrainTile>* terrain;
|
||||
|
||||
u32 hBest; // heuristic of closest discovered tile to goal
|
||||
u16 iBest, jBest; // closest tile
|
||||
|
||||
#if PATHFIND_STATS
|
||||
// Performance debug counters
|
||||
size_t numProcessed;
|
||||
size_t numImproveOpen;
|
||||
size_t numImproveClosed;
|
||||
size_t numAddToOpen;
|
||||
size_t sumOpenSize;
|
||||
#endif
|
||||
};
|
||||
|
||||
static bool AtGoal(u16 i, u16 j, const ICmpPathfinder::Goal& goal)
|
||||
{
|
||||
// Allow tiles slightly more than sqrt(2) from the actual goal,
|
||||
// i.e. adjacent diagonally to the target tile
|
||||
fixed tolerance = entity_pos_t::FromInt(CELL_SIZE*3/2);
|
||||
|
||||
entity_pos_t x, z;
|
||||
CCmpPathfinder::TileCenter(i, j, x, z);
|
||||
fixed dist = DistanceToGoal(CFixedVector2D(x, z), goal);
|
||||
return (dist < tolerance);
|
||||
}
|
||||
|
||||
// Calculate heuristic cost from tile i,j to destination
|
||||
// (This ought to be an underestimate for correctness)
|
||||
static u32 CalculateHeuristic(u16 i, u16 j, u16 iGoal, u16 jGoal, u16 rGoal)
|
||||
{
|
||||
#if USE_DIAGONAL_MOVEMENT
|
||||
CFixedVector2D pos (fixed::FromInt(i), fixed::FromInt(j));
|
||||
CFixedVector2D goal (fixed::FromInt(iGoal), fixed::FromInt(jGoal));
|
||||
fixed dist = (pos - goal).Length();
|
||||
// TODO: the heuristic could match the costs better - it's not really Euclidean movement
|
||||
|
||||
fixed rdist = dist - fixed::FromInt(rGoal);
|
||||
rdist = rdist.Absolute();
|
||||
|
||||
// To avoid overflows on large distances we have to convert to int before multiplying
|
||||
// by the full tile cost, which means we lose some accuracy over short distances,
|
||||
// so do a partial multiplication here.
|
||||
// (This will overflow if sqrt(2)*tilesPerSide*premul >= 32768, so
|
||||
// premul=32 means max tilesPerSide=724)
|
||||
const int premul = 32;
|
||||
cassert(g_CostPerTile % premul == 0);
|
||||
return (rdist * premul).ToInt_RoundToZero() * (g_CostPerTile / premul);
|
||||
|
||||
#else
|
||||
return (abs((int)i - (int)iGoal) + abs((int)j - (int)jGoal)) * g_CostPerTile;
|
||||
#endif
|
||||
}
|
||||
|
||||
// Calculate movement cost from predecessor tile pi,pj to tile i,j
|
||||
static u32 CalculateCostDelta(u16 pi, u16 pj, u16 i, u16 j, Grid<PathfindTile>* tempGrid, u32 tileCost)
|
||||
{
|
||||
u32 dg = tileCost;
|
||||
|
||||
#if USE_DIAGONAL_MOVEMENT
|
||||
// XXX: Probably a terrible hack:
|
||||
// For simplicity, we only consider horizontally/vertically adjacent neighbours, but
|
||||
// units can move along arbitrary lines. That results in ugly square paths, so we want
|
||||
// to prefer diagonal paths.
|
||||
// Instead of solving this nicely, I'll just special-case 45-degree and 30-degree lines
|
||||
// by checking the three predecessor tiles (which'll be in the closed set and therefore
|
||||
// likely to be reasonably stable) and reducing the cost, and use a Euclidean heuristic.
|
||||
// At least this makes paths look a bit nicer for now...
|
||||
|
||||
PathfindTile& p = tempGrid->get(pi, pj);
|
||||
u16 ppi = p.GetPredI(pi);
|
||||
u16 ppj = p.GetPredJ(pj);
|
||||
if (ppi != i && ppj != j)
|
||||
dg = (dg << 16) / 92682; // dg*sqrt(2)/2
|
||||
else
|
||||
{
|
||||
PathfindTile& pp = tempGrid->get(ppi, ppj);
|
||||
int di = abs(i - pp.GetPredI(ppi));
|
||||
int dj = abs(j - pp.GetPredJ(ppj));
|
||||
if ((di == 1 && dj == 2) || (di == 2 && dj == 1))
|
||||
dg = (dg << 16) / 79742; // dg*(sqrt(5)-sqrt(2))
|
||||
}
|
||||
#endif
|
||||
|
||||
return dg;
|
||||
}
|
||||
|
||||
// Do the A* processing for a neighbour tile i,j.
|
||||
static void ProcessNeighbour(u16 pi, u16 pj, u16 i, u16 j, u32 pg, PathfinderState& state)
|
||||
{
|
||||
#if PATHFIND_STATS
|
||||
state.numProcessed++;
|
||||
#endif
|
||||
|
||||
// Reject impassable tiles
|
||||
TerrainTile tileTag = state.terrain->get(i, j);
|
||||
if (!IS_PASSABLE(tileTag, state.passClass))
|
||||
return;
|
||||
|
||||
u32 dg = CalculateCostDelta(pi, pj, i, j, state.tiles, state.moveCosts.at(GET_COST_CLASS(tileTag)));
|
||||
|
||||
u32 g = pg + dg; // cost to this tile = cost to predecessor + delta from predecessor
|
||||
|
||||
PathfindTile& n = state.tiles->get(i, j);
|
||||
|
||||
// If this is a new tile, compute the heuristic distance
|
||||
if (n.IsUnexplored())
|
||||
{
|
||||
n.h = CalculateHeuristic(i, j, state.iGoal, state.jGoal, state.rGoal);
|
||||
// Remember the best tile we've seen so far, in case we never actually reach the target
|
||||
if (n.h < state.hBest)
|
||||
{
|
||||
state.hBest = n.h;
|
||||
state.iBest = i;
|
||||
state.jBest = j;
|
||||
}
|
||||
}
|
||||
else
|
||||
{
|
||||
// If we've already seen this tile, and the new path to this tile does not have a
|
||||
// better cost, then stop now
|
||||
if (g >= n.cost)
|
||||
return;
|
||||
|
||||
// Otherwise, we have a better path.
|
||||
|
||||
// If we've already added this tile to the open list:
|
||||
if (n.IsOpen())
|
||||
{
|
||||
// This is a better path, so replace the old one with the new cost/parent
|
||||
n.cost = g;
|
||||
n.SetPred(pi, pj, i, j);
|
||||
n.SetStep(state.steps);
|
||||
state.open.promote(std::make_pair(i, j), g + n.h);
|
||||
#if PATHFIND_STATS
|
||||
state.numImproveOpen++;
|
||||
#endif
|
||||
return;
|
||||
}
|
||||
|
||||
// If we've already found the 'best' path to this tile:
|
||||
if (n.IsClosed())
|
||||
{
|
||||
// This is a better path (possible when we use inadmissible heuristics), so reopen it
|
||||
#if PATHFIND_STATS
|
||||
state.numImproveClosed++;
|
||||
#endif
|
||||
// (fall through)
|
||||
}
|
||||
}
|
||||
|
||||
// Add it to the open list:
|
||||
n.SetStatusOpen();
|
||||
n.cost = g;
|
||||
n.SetPred(pi, pj, i, j);
|
||||
n.SetStep(state.steps);
|
||||
PriorityQueue::Item t = { std::make_pair(i, j), g + n.h };
|
||||
state.open.push(t);
|
||||
#if PATHFIND_STATS
|
||||
state.numAddToOpen++;
|
||||
#endif
|
||||
}
|
||||
|
||||
void CCmpPathfinder::ComputePath(entity_pos_t x0, entity_pos_t z0, const Goal& goal, u8 passClass, u8 costClass, Path& path)
|
||||
{
|
||||
UpdateGrid();
|
||||
|
||||
PROFILE("ComputePath");
|
||||
|
||||
PathfinderState state = { 0 };
|
||||
|
||||
// Convert the start/end coordinates to tile indexes
|
||||
u16 i0, j0;
|
||||
NearestTile(x0, z0, i0, j0);
|
||||
NearestTile(goal.x, goal.z, state.iGoal, state.jGoal);
|
||||
|
||||
// If we're already at the goal tile, then move directly to the exact goal coordinates
|
||||
if (AtGoal(i0, j0, goal))
|
||||
{
|
||||
Waypoint w = { goal.x, goal.z };
|
||||
path.m_Waypoints.push_back(w);
|
||||
return;
|
||||
}
|
||||
|
||||
// If the target is a circle, we want to aim for the edge of it (so e.g. if we're inside
|
||||
// a large circle then the heuristics will aim us directly outwards);
|
||||
// otherwise just aim at the center point. (We'll never try moving outwards to a square shape.)
|
||||
if (goal.type == Goal::CIRCLE)
|
||||
state.rGoal = (goal.hw / (int)CELL_SIZE).ToInt_RoundToZero();
|
||||
else
|
||||
state.rGoal = 0;
|
||||
|
||||
state.passClass = passClass;
|
||||
state.moveCosts = m_MoveCosts.at(costClass);
|
||||
|
||||
state.steps = 0;
|
||||
|
||||
state.tiles = new Grid<PathfindTile>(m_MapSize, m_MapSize);
|
||||
state.terrain = m_Grid;
|
||||
|
||||
state.iBest = i0;
|
||||
state.jBest = j0;
|
||||
state.hBest = CalculateHeuristic(i0, j0, state.iGoal, state.jGoal, state.rGoal);
|
||||
|
||||
PriorityQueue::Item start = { std::make_pair(i0, j0), 0 };
|
||||
state.open.push(start);
|
||||
state.tiles->get(i0, j0).SetStatusOpen();
|
||||
state.tiles->get(i0, j0).SetPred(i0, j0, i0, j0);
|
||||
state.tiles->get(i0, j0).cost = 0;
|
||||
|
||||
while (1)
|
||||
{
|
||||
++state.steps;
|
||||
|
||||
// Hack to avoid spending ages computing giant paths, particularly when
|
||||
// the destination is unreachable
|
||||
if (state.steps > 10000)
|
||||
break;
|
||||
|
||||
// If we ran out of tiles to examine, give up
|
||||
if (state.open.empty())
|
||||
break;
|
||||
|
||||
#if PATHFIND_STATS
|
||||
state.sumOpenSize += state.open.size();
|
||||
#endif
|
||||
|
||||
// Move best tile from open to closed
|
||||
PriorityQueue::Item curr = state.open.pop();
|
||||
u16 i = curr.id.first;
|
||||
u16 j = curr.id.second;
|
||||
state.tiles->get(i, j).SetStatusClosed();
|
||||
|
||||
// If we've reached the destination, stop
|
||||
if (AtGoal(i, j, goal))
|
||||
{
|
||||
state.iBest = i;
|
||||
state.jBest = j;
|
||||
state.hBest = 0;
|
||||
break;
|
||||
}
|
||||
|
||||
u32 g = state.tiles->get(i, j).cost;
|
||||
if (i > 0)
|
||||
ProcessNeighbour(i, j, i-1, j, g, state);
|
||||
if (i < m_MapSize-1)
|
||||
ProcessNeighbour(i, j, i+1, j, g, state);
|
||||
if (j > 0)
|
||||
ProcessNeighbour(i, j, i, j-1, g, state);
|
||||
if (j < m_MapSize-1)
|
||||
ProcessNeighbour(i, j, i, j+1, g, state);
|
||||
}
|
||||
|
||||
// Reconstruct the path (in reverse)
|
||||
u16 ip = state.iBest, jp = state.jBest;
|
||||
while (ip != i0 || jp != j0)
|
||||
{
|
||||
PathfindTile& n = state.tiles->get(ip, jp);
|
||||
entity_pos_t x, z;
|
||||
TileCenter(ip, jp, x, z);
|
||||
Waypoint w = { x, z };
|
||||
path.m_Waypoints.push_back(w);
|
||||
|
||||
// Follow the predecessor link
|
||||
ip = n.GetPredI(ip);
|
||||
jp = n.GetPredJ(jp);
|
||||
}
|
||||
|
||||
// Save this grid for debug display
|
||||
delete m_DebugGrid;
|
||||
m_DebugGrid = state.tiles;
|
||||
m_DebugSteps = state.steps;
|
||||
|
||||
#if PATHFIND_STATS
|
||||
printf("PATHFINDER: steps=%d avgo=%d proc=%d impc=%d impo=%d addo=%d\n", state.steps, state.sumOpenSize/state.steps, state.numProcessed, state.numImproveClosed, state.numImproveOpen, state.numAddToOpen);
|
||||
#endif
|
||||
}
|
||||
494
source/simulation2/components/CCmpPathfinder_Vertex.cpp
Normal file
494
source/simulation2/components/CCmpPathfinder_Vertex.cpp
Normal file
@ -0,0 +1,494 @@
|
||||
/* Copyright (C) 2010 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/>.
|
||||
*/
|
||||
|
||||
/**
|
||||
* @file
|
||||
* Vertex-based algorithm for CCmpPathfinder.
|
||||
*/
|
||||
|
||||
#include "precompiled.h"
|
||||
|
||||
#include "CCmpPathfinder_Common.h"
|
||||
|
||||
#include "ps/Profile.h"
|
||||
#include "simulation2/components/ICmpObstructionManager.h"
|
||||
#include "simulation2/helpers/PriorityQueue.h"
|
||||
#include "simulation2/helpers/Render.h"
|
||||
|
||||
struct Vertex
|
||||
{
|
||||
enum
|
||||
{
|
||||
UNEXPLORED,
|
||||
OPEN,
|
||||
CLOSED,
|
||||
};
|
||||
|
||||
CFixedVector2D p;
|
||||
fixed g, h;
|
||||
u16 pred;
|
||||
u8 status;
|
||||
};
|
||||
|
||||
struct Edge
|
||||
{
|
||||
CFixedVector2D p0, p1;
|
||||
};
|
||||
|
||||
// When computing vertexes to insert into the search graph,
|
||||
// add a small delta so that the vertexes of an edge don't get interpreted
|
||||
// as crossing the edge (given minor numerical inaccuracies)
|
||||
static const entity_pos_t EDGE_EXPAND_DELTA = entity_pos_t::FromInt(1)/4;
|
||||
|
||||
/**
|
||||
* Check whether a ray from 'a' to 'b' crosses any of the edges.
|
||||
* (Edges are one-sided so it's only considered a cross if going from front to back.)
|
||||
*/
|
||||
static bool CheckVisibility(CFixedVector2D a, CFixedVector2D b, const std::vector<Edge>& edges)
|
||||
{
|
||||
CFixedVector2D abn = (b - a).Perpendicular();
|
||||
|
||||
for (size_t i = 0; i < edges.size(); ++i)
|
||||
{
|
||||
CFixedVector2D d = (edges[i].p1 - edges[i].p0).Perpendicular();
|
||||
|
||||
// If 'a' is behind the edge, we can't cross
|
||||
fixed q = (a - edges[i].p0).Dot(d);
|
||||
if (q < fixed::Zero())
|
||||
continue;
|
||||
|
||||
// If 'b' is in front of the edge, we can't cross
|
||||
fixed r = (b - edges[i].p0).Dot(d);
|
||||
if (r > fixed::Zero())
|
||||
continue;
|
||||
|
||||
// The ray is crossing the infinitely-extended edge from in front to behind.
|
||||
// Check the finite edge is crossing the infinitely-extended ray too.
|
||||
// (Given the previous tests, it can only be crossing in one direction.)
|
||||
fixed s = (edges[i].p0 - a).Dot(abn);
|
||||
fixed t = (edges[i].p1 - a).Dot(abn);
|
||||
if (s <= fixed::Zero() && t >= fixed::Zero())
|
||||
return false;
|
||||
}
|
||||
|
||||
return true;
|
||||
}
|
||||
|
||||
static CFixedVector2D NearestPointOnGoal(CFixedVector2D pos, const CCmpPathfinder::Goal& goal)
|
||||
{
|
||||
CFixedVector2D g(goal.x, goal.z);
|
||||
|
||||
switch (goal.type)
|
||||
{
|
||||
case CCmpPathfinder::Goal::POINT:
|
||||
{
|
||||
return g;
|
||||
}
|
||||
|
||||
case CCmpPathfinder::Goal::CIRCLE:
|
||||
{
|
||||
CFixedVector2D d = pos - g;
|
||||
if (d.IsZero())
|
||||
d = CFixedVector2D(fixed::FromInt(1), fixed::Zero()); // some arbitrary direction
|
||||
d.Normalize(goal.hw);
|
||||
return g + d;
|
||||
}
|
||||
|
||||
case CCmpPathfinder::Goal::SQUARE:
|
||||
{
|
||||
CFixedVector2D halfSize(goal.hw, goal.hh);
|
||||
CFixedVector2D d = pos - g;
|
||||
return g + Geometry::NearestPointOnSquare(d, goal.u, goal.v, halfSize);
|
||||
}
|
||||
|
||||
default:
|
||||
debug_warn(L"invalid type");
|
||||
return CFixedVector2D();
|
||||
}
|
||||
}
|
||||
|
||||
typedef PriorityQueueList<u16, fixed> PriorityQueue;
|
||||
|
||||
struct TileEdge
|
||||
{
|
||||
u16 i, j;
|
||||
enum { TOP, BOTTOM, LEFT, RIGHT } dir;
|
||||
};
|
||||
|
||||
static void AddTerrainEdges(std::vector<Edge>& edges, std::vector<Vertex>& vertexes, u16 i0, u16 j0, u16 i1, u16 j1, fixed r, u8 passClass, const Grid<TerrainTile>& terrain)
|
||||
{
|
||||
PROFILE("AddTerrainEdges");
|
||||
|
||||
std::vector<TileEdge> tileEdges;
|
||||
|
||||
// Find all edges between tiles of differently passability statuses
|
||||
for (u16 j = j0; j <= j1; ++j)
|
||||
{
|
||||
for (u16 i = i0; i <= i1; ++i)
|
||||
{
|
||||
if (!IS_TERRAIN_PASSABLE(terrain.get(i, j), passClass))
|
||||
{
|
||||
if (j > 0 && IS_TERRAIN_PASSABLE(terrain.get(i, j-1), passClass))
|
||||
{
|
||||
TileEdge e = { i, j, TileEdge::BOTTOM };
|
||||
tileEdges.push_back(e);
|
||||
}
|
||||
|
||||
if (j < terrain.m_H-1 && IS_TERRAIN_PASSABLE(terrain.get(i, j+1), passClass))
|
||||
{
|
||||
TileEdge e = { i, j, TileEdge::TOP };
|
||||
tileEdges.push_back(e);
|
||||
}
|
||||
|
||||
if (i > 0 && IS_TERRAIN_PASSABLE(terrain.get(i-1, j), passClass))
|
||||
{
|
||||
TileEdge e = { i, j, TileEdge::LEFT };
|
||||
tileEdges.push_back(e);
|
||||
}
|
||||
|
||||
if (i < terrain.m_W-1 && IS_TERRAIN_PASSABLE(terrain.get(i+1, j), passClass))
|
||||
{
|
||||
TileEdge e = { i, j, TileEdge::RIGHT };
|
||||
tileEdges.push_back(e);
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
// TODO: maybe we should precompute these terrain edges since they'll rarely change?
|
||||
|
||||
// TODO: for efficiency (minimising the A* search space), we should coalesce adjoining edges
|
||||
|
||||
// Add all the tile edges to the search edge/vertex lists
|
||||
for (size_t n = 0; n < tileEdges.size(); ++n)
|
||||
{
|
||||
u16 i = tileEdges[n].i;
|
||||
u16 j = tileEdges[n].j;
|
||||
CFixedVector2D v0, v1;
|
||||
Vertex vert;
|
||||
vert.status = Vertex::UNEXPLORED;
|
||||
|
||||
switch (tileEdges[n].dir)
|
||||
{
|
||||
case TileEdge::BOTTOM:
|
||||
{
|
||||
v0 = CFixedVector2D(fixed::FromInt(i * CELL_SIZE) - r, fixed::FromInt(j * CELL_SIZE) - r);
|
||||
v1 = CFixedVector2D(fixed::FromInt((i+1) * CELL_SIZE) + r, fixed::FromInt(j * CELL_SIZE) - r);
|
||||
Edge e = { v0, v1 };
|
||||
edges.push_back(e);
|
||||
vert.p.X = v0.X - EDGE_EXPAND_DELTA; vert.p.Y = v0.Y - EDGE_EXPAND_DELTA; vertexes.push_back(vert);
|
||||
vert.p.X = v1.X + EDGE_EXPAND_DELTA; vert.p.Y = v1.Y - EDGE_EXPAND_DELTA; vertexes.push_back(vert);
|
||||
break;
|
||||
}
|
||||
case TileEdge::TOP:
|
||||
{
|
||||
v0 = CFixedVector2D(fixed::FromInt((i+1) * CELL_SIZE) + r, fixed::FromInt((j+1) * CELL_SIZE) + r);
|
||||
v1 = CFixedVector2D(fixed::FromInt(i * CELL_SIZE) - r, fixed::FromInt((j+1) * CELL_SIZE) + r);
|
||||
Edge e = { v0, v1 };
|
||||
edges.push_back(e);
|
||||
vert.p.X = v0.X + EDGE_EXPAND_DELTA; vert.p.Y = v0.Y + EDGE_EXPAND_DELTA; vertexes.push_back(vert);
|
||||
vert.p.X = v1.X - EDGE_EXPAND_DELTA; vert.p.Y = v1.Y + EDGE_EXPAND_DELTA; vertexes.push_back(vert);
|
||||
break;
|
||||
}
|
||||
case TileEdge::LEFT:
|
||||
{
|
||||
v0 = CFixedVector2D(fixed::FromInt(i * CELL_SIZE) - r, fixed::FromInt((j+1) * CELL_SIZE) + r);
|
||||
v1 = CFixedVector2D(fixed::FromInt(i * CELL_SIZE) - r, fixed::FromInt(j * CELL_SIZE) - r);
|
||||
Edge e = { v0, v1 };
|
||||
edges.push_back(e);
|
||||
vert.p.X = v0.X - EDGE_EXPAND_DELTA; vert.p.Y = v0.Y + EDGE_EXPAND_DELTA; vertexes.push_back(vert);
|
||||
vert.p.X = v1.X - EDGE_EXPAND_DELTA; vert.p.Y = v1.Y - EDGE_EXPAND_DELTA; vertexes.push_back(vert);
|
||||
break;
|
||||
}
|
||||
case TileEdge::RIGHT:
|
||||
{
|
||||
v0 = CFixedVector2D(fixed::FromInt((i+1) * CELL_SIZE) + r, fixed::FromInt(j * CELL_SIZE) - r);
|
||||
v1 = CFixedVector2D(fixed::FromInt((i+1) * CELL_SIZE) + r, fixed::FromInt((j+1) * CELL_SIZE) + r);
|
||||
Edge e = { v0, v1 };
|
||||
edges.push_back(e);
|
||||
vert.p.X = v0.X + EDGE_EXPAND_DELTA; vert.p.Y = v0.Y - EDGE_EXPAND_DELTA; vertexes.push_back(vert);
|
||||
vert.p.X = v1.X + EDGE_EXPAND_DELTA; vert.p.Y = v1.Y + EDGE_EXPAND_DELTA; vertexes.push_back(vert);
|
||||
break;
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
void CCmpPathfinder::ComputeShortPath(const IObstructionTestFilter& filter, entity_pos_t x0, entity_pos_t z0, entity_pos_t r, entity_pos_t range, const Goal& goal, u8 passClass, Path& path)
|
||||
{
|
||||
UpdateGrid(); // TODO: only need to bother updating if the terrain changed
|
||||
|
||||
PROFILE("ComputeShortPath");
|
||||
|
||||
m_DebugOverlayShortPathLines.clear();
|
||||
|
||||
if (m_DebugOverlay)
|
||||
{
|
||||
// Render the goal shape
|
||||
m_DebugOverlayShortPathLines.push_back(SOverlayLine());
|
||||
m_DebugOverlayShortPathLines.back().m_Color = CColor(1, 0, 0, 1);
|
||||
switch (goal.type)
|
||||
{
|
||||
case CCmpPathfinder::Goal::POINT:
|
||||
{
|
||||
SimRender::ConstructCircleOnGround(GetSimContext(), goal.x.ToFloat(), goal.z.ToFloat(), 0.2f, m_DebugOverlayShortPathLines.back(), true);
|
||||
break;
|
||||
}
|
||||
case CCmpPathfinder::Goal::CIRCLE:
|
||||
{
|
||||
SimRender::ConstructCircleOnGround(GetSimContext(), goal.x.ToFloat(), goal.z.ToFloat(), goal.hw.ToFloat(), m_DebugOverlayShortPathLines.back(), true);
|
||||
break;
|
||||
}
|
||||
case CCmpPathfinder::Goal::SQUARE:
|
||||
{
|
||||
float a = atan2(goal.v.X.ToFloat(), goal.v.Y.ToFloat());
|
||||
SimRender::ConstructSquareOnGround(GetSimContext(), goal.x.ToFloat(), goal.z.ToFloat(), goal.hw.ToFloat()*2, goal.hh.ToFloat()*2, a, m_DebugOverlayShortPathLines.back(), true);
|
||||
break;
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
// List of collision edges - paths must never cross these.
|
||||
// (Edges are one-sided so intersections are fine in one direction, but not the other direction.)
|
||||
std::vector<Edge> edges;
|
||||
|
||||
// Create impassable edges at the max-range boundary, so we can't escape the region
|
||||
// where we're meant to be searching
|
||||
fixed rangeXMin = x0 - range;
|
||||
fixed rangeXMax = x0 + range;
|
||||
fixed rangeZMin = z0 - range;
|
||||
fixed rangeZMax = z0 + range;
|
||||
{
|
||||
// (The edges are the opposite direction to usual, so it's an inside-out square)
|
||||
Edge e0 = { CFixedVector2D(rangeXMin, rangeZMin), CFixedVector2D(rangeXMin, rangeZMax) };
|
||||
Edge e1 = { CFixedVector2D(rangeXMin, rangeZMax), CFixedVector2D(rangeXMax, rangeZMax) };
|
||||
Edge e2 = { CFixedVector2D(rangeXMax, rangeZMax), CFixedVector2D(rangeXMax, rangeZMin) };
|
||||
Edge e3 = { CFixedVector2D(rangeXMax, rangeZMin), CFixedVector2D(rangeXMin, rangeZMin) };
|
||||
edges.push_back(e0);
|
||||
edges.push_back(e1);
|
||||
edges.push_back(e2);
|
||||
edges.push_back(e3);
|
||||
}
|
||||
|
||||
CFixedVector2D goalVec(goal.x, goal.z);
|
||||
|
||||
// List of obstruction vertexes (plus start/end points); we'll try to find paths through
|
||||
// the graph defined by these vertexes
|
||||
std::vector<Vertex> vertexes;
|
||||
|
||||
// Add the start point to the graph
|
||||
Vertex start = { CFixedVector2D(x0, z0), fixed::Zero(), (CFixedVector2D(x0, z0) - goalVec).Length(), 0, Vertex::OPEN };
|
||||
vertexes.push_back(start);
|
||||
const size_t START_VERTEX_ID = 0;
|
||||
|
||||
// Add the goal vertex to the graph.
|
||||
// Since the goal isn't always a point, this a special magic virtual vertex which moves around - whenever
|
||||
// we look at it from another vertex, it is moved to be the closest point on the goal shape to that vertex.
|
||||
Vertex end = { CFixedVector2D(goal.x, goal.z), fixed::Zero(), fixed::Zero(), 0, Vertex::UNEXPLORED };
|
||||
vertexes.push_back(end);
|
||||
const size_t GOAL_VERTEX_ID = 1;
|
||||
|
||||
// Add terrain obstructions
|
||||
{
|
||||
u16 i0, j0, i1, j1;
|
||||
NearestTile(rangeXMin, rangeZMin, i0, j0);
|
||||
NearestTile(rangeXMax, rangeZMax, i1, j1);
|
||||
AddTerrainEdges(edges, vertexes, i0, j0, i1, j1, r, passClass, *m_Grid);
|
||||
}
|
||||
|
||||
// Find all the obstruction squares that might affect us
|
||||
CmpPtr<ICmpObstructionManager> cmpObstructionManager(GetSimContext(), SYSTEM_ENTITY);
|
||||
std::vector<ICmpObstructionManager::ObstructionSquare> squares;
|
||||
cmpObstructionManager->GetObstructionsInRange(filter, rangeXMin - r, rangeZMin - r, rangeXMax + r, rangeZMax + r, squares);
|
||||
|
||||
// Resize arrays to reduce reallocations
|
||||
vertexes.reserve(vertexes.size() + squares.size()*4);
|
||||
edges.reserve(edges.size() + squares.size()*4);
|
||||
|
||||
// Convert each obstruction square into collision edges and search graph vertexes
|
||||
for (size_t i = 0; i < squares.size(); ++i)
|
||||
{
|
||||
CFixedVector2D center(squares[i].x, squares[i].z);
|
||||
CFixedVector2D u = squares[i].u;
|
||||
CFixedVector2D v = squares[i].v;
|
||||
|
||||
// Expand the vertexes by the moving unit's collision radius, to find the
|
||||
// closest we can get to it
|
||||
|
||||
CFixedVector2D hd0(squares[i].hw + r + EDGE_EXPAND_DELTA, squares[i].hh + r + EDGE_EXPAND_DELTA);
|
||||
CFixedVector2D hd1(squares[i].hw + r + EDGE_EXPAND_DELTA, -(squares[i].hh + r + EDGE_EXPAND_DELTA));
|
||||
|
||||
Vertex vert;
|
||||
vert.status = Vertex::UNEXPLORED;
|
||||
vert.p.X = center.X - hd0.Dot(u); vert.p.Y = center.Y + hd0.Dot(v); vertexes.push_back(vert);
|
||||
vert.p.X = center.X - hd1.Dot(u); vert.p.Y = center.Y + hd1.Dot(v); vertexes.push_back(vert);
|
||||
vert.p.X = center.X + hd0.Dot(u); vert.p.Y = center.Y - hd0.Dot(v); vertexes.push_back(vert);
|
||||
vert.p.X = center.X + hd1.Dot(u); vert.p.Y = center.Y - hd1.Dot(v); vertexes.push_back(vert);
|
||||
|
||||
// Add the four edges
|
||||
|
||||
CFixedVector2D h0(squares[i].hw + r, squares[i].hh + r);
|
||||
CFixedVector2D h1(squares[i].hw + r, -(squares[i].hh + r));
|
||||
|
||||
CFixedVector2D ev0(center.X - h0.Dot(u), center.Y + h0.Dot(v));
|
||||
CFixedVector2D ev1(center.X - h1.Dot(u), center.Y + h1.Dot(v));
|
||||
CFixedVector2D ev2(center.X + h0.Dot(u), center.Y - h0.Dot(v));
|
||||
CFixedVector2D ev3(center.X + h1.Dot(u), center.Y - h1.Dot(v));
|
||||
Edge e0 = { ev0, ev1 };
|
||||
Edge e1 = { ev1, ev2 };
|
||||
Edge e2 = { ev2, ev3 };
|
||||
Edge e3 = { ev3, ev0 };
|
||||
edges.push_back(e0);
|
||||
edges.push_back(e1);
|
||||
edges.push_back(e2);
|
||||
edges.push_back(e3);
|
||||
|
||||
// TODO: should clip out vertexes and edges that are outside the range,
|
||||
// to reduce the search space
|
||||
}
|
||||
|
||||
debug_assert(vertexes.size() < 65536); // we store array indexes as u16
|
||||
|
||||
if (m_DebugOverlay)
|
||||
{
|
||||
// Render the obstruction edges
|
||||
for (size_t i = 0; i < edges.size(); ++i)
|
||||
{
|
||||
m_DebugOverlayShortPathLines.push_back(SOverlayLine());
|
||||
m_DebugOverlayShortPathLines.back().m_Color = CColor(0, 1, 1, 1);
|
||||
std::vector<float> xz;
|
||||
xz.push_back(edges[i].p0.X.ToFloat());
|
||||
xz.push_back(edges[i].p0.Y.ToFloat());
|
||||
xz.push_back(edges[i].p1.X.ToFloat());
|
||||
xz.push_back(edges[i].p1.Y.ToFloat());
|
||||
SimRender::ConstructLineOnGround(GetSimContext(), xz, m_DebugOverlayShortPathLines.back(), true);
|
||||
}
|
||||
}
|
||||
|
||||
// Do an A* search over the vertex/visibility graph:
|
||||
|
||||
// Since we are just measuring Euclidean distance the heuristic is admissible,
|
||||
// so we never have to re-examine a node once it's been moved to the closed set.
|
||||
|
||||
// To save time in common cases, we don't precompute a graph of valid edges between vertexes;
|
||||
// we do it lazily instead. When the search algorithm reaches a vertex, we examine every other
|
||||
// vertex and see if we can reach it without hitting any collision edges, and ignore the ones
|
||||
// we can't reach. Since the algorithm can only reach a vertex once (and then it'll be marked
|
||||
// as closed), we won't be doing any redundant visibility computations.
|
||||
|
||||
PROFILE_START("A*");
|
||||
|
||||
PriorityQueue open;
|
||||
PriorityQueue::Item qiStart = { START_VERTEX_ID, start.h };
|
||||
open.push(qiStart);
|
||||
|
||||
u16 idBest = START_VERTEX_ID;
|
||||
fixed hBest = start.h;
|
||||
|
||||
while (!open.empty())
|
||||
{
|
||||
// Move best tile from open to closed
|
||||
PriorityQueue::Item curr = open.pop();
|
||||
vertexes[curr.id].status = Vertex::CLOSED;
|
||||
|
||||
// If we've reached the destination, stop
|
||||
if (curr.id == GOAL_VERTEX_ID)
|
||||
{
|
||||
idBest = curr.id;
|
||||
break;
|
||||
}
|
||||
|
||||
// Check the lines to every other vertex
|
||||
for (size_t n = 0; n < vertexes.size(); ++n)
|
||||
{
|
||||
if (vertexes[n].status == Vertex::CLOSED)
|
||||
continue;
|
||||
|
||||
// If this is the magical goal vertex, move it to near the current vertex
|
||||
CFixedVector2D npos;
|
||||
if (n == GOAL_VERTEX_ID)
|
||||
npos = NearestPointOnGoal(vertexes[curr.id].p, goal);
|
||||
else
|
||||
npos = vertexes[n].p;
|
||||
|
||||
bool visible = CheckVisibility(vertexes[curr.id].p, npos, edges);
|
||||
|
||||
/*
|
||||
// Render the edges that we examine
|
||||
m_DebugOverlayShortPathLines.push_back(SOverlayLine());
|
||||
m_DebugOverlayShortPathLines.back().m_Color = visible ? CColor(0, 1, 0, 0.5) : CColor(1, 0, 0, 0.5);
|
||||
std::vector<float> xz;
|
||||
xz.push_back(vertexes[curr.id].p.X.ToFloat());
|
||||
xz.push_back(vertexes[curr.id].p.Y.ToFloat());
|
||||
xz.push_back(npos.X.ToFloat());
|
||||
xz.push_back(npos.Y.ToFloat());
|
||||
SimRender::ConstructLineOnGround(GetSimContext(), xz, m_DebugOverlayShortPathLines.back(), false);
|
||||
//*/
|
||||
|
||||
if (visible)
|
||||
{
|
||||
fixed g = vertexes[curr.id].g + (vertexes[curr.id].p - npos).Length();
|
||||
|
||||
// If this is a new tile, compute the heuristic distance
|
||||
if (vertexes[n].status == Vertex::UNEXPLORED)
|
||||
{
|
||||
// Add it to the open list:
|
||||
vertexes[n].status = Vertex::OPEN;
|
||||
vertexes[n].g = g;
|
||||
vertexes[n].h = DistanceToGoal(npos, goal);
|
||||
vertexes[n].pred = curr.id;
|
||||
if (n == GOAL_VERTEX_ID)
|
||||
vertexes[n].p = npos; // remember the new best goal position
|
||||
PriorityQueue::Item t = { (u16)n, g + vertexes[n].h };
|
||||
open.push(t);
|
||||
|
||||
// Remember the heuristically best vertex we've seen so far, in case we never actually reach the target
|
||||
if (vertexes[n].h < hBest)
|
||||
{
|
||||
idBest = n;
|
||||
hBest = vertexes[n].h;
|
||||
}
|
||||
}
|
||||
else // must be OPEN
|
||||
{
|
||||
// If we've already seen this tile, and the new path to this tile does not have a
|
||||
// better cost, then stop now
|
||||
if (g >= vertexes[n].g)
|
||||
continue;
|
||||
|
||||
// Otherwise, we have a better path, so replace the old one with the new cost/parent
|
||||
vertexes[n].g = g;
|
||||
vertexes[n].pred = curr.id;
|
||||
if (n == GOAL_VERTEX_ID)
|
||||
vertexes[n].p = npos; // remember the new best goal position
|
||||
open.promote((u16)n, g + vertexes[n].h);
|
||||
continue;
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
// Reconstruct the path (in reverse)
|
||||
for (u16 id = idBest; id != START_VERTEX_ID; id = vertexes[id].pred)
|
||||
{
|
||||
Waypoint w = { vertexes[id].p.X, vertexes[id].p.Y };
|
||||
path.m_Waypoints.push_back(w);
|
||||
}
|
||||
|
||||
PROFILE_END("A*");
|
||||
}
|
||||
|
||||
199
source/simulation2/helpers/PriorityQueue.h
Normal file
199
source/simulation2/helpers/PriorityQueue.h
Normal file
@ -0,0 +1,199 @@
|
||||
/* Copyright (C) 2010 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/>.
|
||||
*/
|
||||
|
||||
#ifndef INCLUDED_PRIORITYQUEUE
|
||||
#define INCLUDED_PRIORITYQUEUE
|
||||
|
||||
/*
|
||||
* Priority queues for pathfinder.
|
||||
* (These probably aren't suitable for more general uses.)
|
||||
*/
|
||||
|
||||
#ifdef NDEBUG
|
||||
#define PRIORITYQUEUE_DEBUG 0
|
||||
#else
|
||||
#define PRIORITYQUEUE_DEBUG 1
|
||||
#endif
|
||||
|
||||
template <typename Item>
|
||||
struct QueueItemPriority
|
||||
{
|
||||
bool operator()(const Item& a, const Item& b)
|
||||
{
|
||||
if (a.rank > b.rank) // higher costs are lower priority
|
||||
return true;
|
||||
if (a.rank < b.rank)
|
||||
return false;
|
||||
// Need to tie-break to get a consistent ordering
|
||||
// TODO: Should probably tie-break on g or h or something, but don't bother for now
|
||||
if (a.id < b.id)
|
||||
return true;
|
||||
if (b.id < a.id)
|
||||
return false;
|
||||
#if PRIORITYQUEUE_DEBUG
|
||||
debug_warn(L"duplicate tiles in queue");
|
||||
#endif
|
||||
return false;
|
||||
}
|
||||
};
|
||||
|
||||
|
||||
/**
|
||||
* Priority queue implemented as a binary heap.
|
||||
* This is quite dreadfully slow in MSVC's debug STL implementation,
|
||||
* so we shouldn't use it unless we reimplement the heap functions more efficiently.
|
||||
*/
|
||||
template <typename ID, typename R>
|
||||
class PriorityQueueHeap
|
||||
{
|
||||
public:
|
||||
struct Item
|
||||
{
|
||||
ID id;
|
||||
R rank; // f = g+h (estimated total cost of path through here)
|
||||
};
|
||||
|
||||
void push(const Item& item)
|
||||
{
|
||||
m_Heap.push_back(item);
|
||||
push_heap(m_Heap.begin(), m_Heap.end(), QueueItemPriority<Item>());
|
||||
}
|
||||
|
||||
Item* find(ID id)
|
||||
{
|
||||
for (size_t n = 0; n < m_Heap.size(); ++n)
|
||||
{
|
||||
if (m_Heap[n].id == id)
|
||||
return &m_Heap[n];
|
||||
}
|
||||
return NULL;
|
||||
}
|
||||
|
||||
void promote(ID id, u32 newrank)
|
||||
{
|
||||
for (size_t n = 0; n < m_Heap.size(); ++n)
|
||||
{
|
||||
if (m_Heap[n].id == id)
|
||||
{
|
||||
#if PRIORITYQUEUE_DEBUG
|
||||
debug_assert(m_Heap[n].rank > newrank);
|
||||
#endif
|
||||
m_Heap[n].rank = newrank;
|
||||
push_heap(m_Heap.begin(), m_Heap.begin()+n+1, QueueItemPriority<Item>());
|
||||
return;
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
Item pop()
|
||||
{
|
||||
#if PRIORITYQUEUE_DEBUG
|
||||
debug_assert(m_Heap.size());
|
||||
#endif
|
||||
Item r = m_Heap.front();
|
||||
pop_heap(m_Heap.begin(), m_Heap.end(), QueueItemPriority<Item>());
|
||||
m_Heap.pop_back();
|
||||
return r;
|
||||
}
|
||||
|
||||
bool empty()
|
||||
{
|
||||
return m_Heap.empty();
|
||||
}
|
||||
|
||||
size_t size()
|
||||
{
|
||||
return m_Heap.size();
|
||||
}
|
||||
|
||||
std::vector<Item> m_Heap;
|
||||
};
|
||||
|
||||
/**
|
||||
* Priority queue implemented as an unsorted array.
|
||||
* This means pop() is O(n), but push and promote are O(1), and n is typically small
|
||||
* (average around 50-100 in some rough tests).
|
||||
* It seems fractionally slower than a binary heap in optimised builds, but is
|
||||
* much simpler and less susceptible to MSVC's painfully slow debug STL.
|
||||
*/
|
||||
template <typename ID, typename R>
|
||||
class PriorityQueueList
|
||||
{
|
||||
public:
|
||||
struct Item
|
||||
{
|
||||
ID id;
|
||||
R rank; // f = g+h (estimated total cost of path through here)
|
||||
};
|
||||
|
||||
void push(const Item& item)
|
||||
{
|
||||
m_List.push_back(item);
|
||||
}
|
||||
|
||||
Item* find(ID id)
|
||||
{
|
||||
for (size_t n = 0; n < m_List.size(); ++n)
|
||||
{
|
||||
if (m_List[n].id == id)
|
||||
return &m_List[n];
|
||||
}
|
||||
return NULL;
|
||||
}
|
||||
|
||||
void promote(ID id, R newrank)
|
||||
{
|
||||
find(id)->rank = newrank;
|
||||
}
|
||||
|
||||
Item pop()
|
||||
{
|
||||
#if PRIORITYQUEUE_DEBUG
|
||||
debug_assert(m_List.size());
|
||||
#endif
|
||||
// Loop backwards looking for the best (it's most likely to be one
|
||||
// we've recently pushed, so going backwards saves a bit of copying)
|
||||
Item best = m_List.back();
|
||||
size_t bestidx = m_List.size()-1;
|
||||
for (ssize_t i = (ssize_t)bestidx-1; i >= 0; --i)
|
||||
{
|
||||
if (QueueItemPriority<Item>()(best, m_List[i]))
|
||||
{
|
||||
bestidx = i;
|
||||
best = m_List[i];
|
||||
}
|
||||
}
|
||||
// Swap the matched element with the last in the list, then pop the new last
|
||||
m_List[bestidx] = m_List[m_List.size()-1];
|
||||
m_List.pop_back();
|
||||
return best;
|
||||
}
|
||||
|
||||
bool empty()
|
||||
{
|
||||
return m_List.empty();
|
||||
}
|
||||
|
||||
size_t size()
|
||||
{
|
||||
return m_List.size();
|
||||
}
|
||||
|
||||
std::vector<Item> m_List;
|
||||
};
|
||||
|
||||
#endif // INCLUDED_PRIORITYQUEUE
|
||||
Loading…
Reference in New Issue
Block a user