ICmpPathfinder.h

Go to the documentation of this file.

/* 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/>.
 */

#ifndef INCLUDED_ICMPPATHFINDER
#define INCLUDED_ICMPPATHFINDER

#include "simulation2/system/Interface.h"

#include "simulation2/components/ICmpObstruction.h"
#include "simulation2/helpers/Pathfinding.h"

#include <map>

class IObstructionTestFilter;
class PathGoal;

template<typename T> class Grid;

// Returned by asynchronous workers, used to send messages in the main thread.
struct WaypointPath;

struct PathResult
{
    PathResult() = default;
    PathResult(u32 t, entity_id_t n, WaypointPath p) : ticket(t), notify(n), path(p) {};

    u32 ticket;
    entity_id_t notify;
    WaypointPath path;
};

/**
 * Pathfinder algorithms.
 *
 * There are two different modes: a tile-based pathfinder that works over long distances and
 * accounts for terrain costs but ignore units, and a 'short' vertex-based pathfinder that
 * provides precise paths and avoids other units.
 *
 * Both use the same concept of a PathGoal: either a point, circle or square.
 * (If the starting point is inside the goal shape then the path will move outwards
 * to reach the shape's outline.)
 *
 * The output is a list of waypoints.
 */
class ICmpPathfinder : public IComponent
{
public:

    /**
     * Get the list of all known passability classes.
     */
    virtual void GetPassabilityClasses(std::map<std::string, pass_class_t>& passClasses) const = 0;

    /**
    * Get the list of passability classes, separating pathfinding classes and others.
    */
    virtual void GetPassabilityClasses(
        std::map<std::string, pass_class_t>& nonPathfindingPassClasses,
        std::map<std::string, pass_class_t>& pathfindingPassClasses) const = 0;

    /**
     * Get the tag for a given passability class name.
     * Logs an error and returns something acceptable if the name is unrecognised.
     */
    virtual pass_class_t GetPassabilityClass(const std::string& name) const = 0;

    virtual entity_pos_t GetClearance(pass_class_t passClass) const = 0;

    /**
     * Get the larger clearance in all passability classes.
     */
    virtual entity_pos_t GetMaximumClearance() const = 0;

    virtual const Grid<NavcellData>& GetPassabilityGrid() = 0;

    /**
     * Get the accumulated dirtiness information since the last time the AI accessed and flushed it.
     */
    virtual const GridUpdateInformation& GetAIPathfinderDirtinessInformation() const = 0;
    virtual void FlushAIPathfinderDirtinessInformation() = 0;

    /**
     * Get a grid representing the distance to the shore of the terrain tile.
     */
    virtual Grid<u16> ComputeShoreGrid(bool expandOnWater = false) = 0;

    /**
     * Asynchronous version of ComputePath.
     * Request a long path computation, asynchronously.
     * The result will be sent as CMessagePathResult to 'notify'.
     * Returns a unique non-zero number, which will match the 'ticket' in the result,
     * so callers can recognise each individual request they make.
     */
    virtual u32 ComputePathAsync(entity_pos_t x0, entity_pos_t z0, const PathGoal& goal, pass_class_t passClass, entity_id_t notify) = 0;

    /*
     * Request a long-path computation immediately
     */
    virtual void ComputePathImmediate(entity_pos_t x0, entity_pos_t z0, const PathGoal& goal, pass_class_t passClass, WaypointPath& ret) const = 0;

    /**
     * Request a short path computation, asynchronously.
     * The result will be sent as CMessagePathResult to 'notify'.
     * Returns a unique non-zero number, which will match the 'ticket' in the result,
     * so callers can recognise each individual request they make.
     */
    virtual u32 ComputeShortPathAsync(entity_pos_t x0, entity_pos_t z0, entity_pos_t clearance, entity_pos_t range, const PathGoal& goal, pass_class_t passClass, bool avoidMovingUnits, entity_id_t controller, entity_id_t notify) = 0;

    /*
     * Request a short-path computation immediately.
     */
    virtual WaypointPath ComputeShortPathImmediate(const ShortPathRequest& request) const = 0;

    /**
     * If the debug overlay is enabled, render the path that will computed by ComputePath.
     */
    virtual void SetDebugPath(entity_pos_t x0, entity_pos_t z0, const PathGoal& goal, pass_class_t passClass) = 0;

    /**
     * @return true if the goal is reachable from (x0, z0) for the given passClass, false otherwise.
     * Warning: this is synchronous, somewhat expensive and not should not be called too liberally.
     */
    virtual bool IsGoalReachable(entity_pos_t x0, entity_pos_t z0, const PathGoal& goal, pass_class_t passClass) = 0;

    /**
     * Check whether the given movement line is valid and doesn't hit any obstructions
     * or impassable terrain.
     * Returns true if the movement is okay.
     */
    virtual bool CheckMovement(const IObstructionTestFilter& filter, entity_pos_t x0, entity_pos_t z0, entity_pos_t x1, entity_pos_t z1, entity_pos_t r, pass_class_t passClass) const = 0;

    /**
     * Check whether a unit placed here is valid and doesn't hit any obstructions
     * or impassable terrain.
     * When onlyCenterPoint = true, only check the center tile of the unit
     * @return ICmpObstruction::FOUNDATION_CHECK_SUCCESS if the placement is okay, else
     *  a value describing the type of failure.
     */
    virtual ICmpObstruction::EFoundationCheck CheckUnitPlacement(const IObstructionTestFilter& filter, entity_pos_t x, entity_pos_t z, entity_pos_t r, pass_class_t passClass, bool onlyCenterPoint = false) const = 0;

    /**
     * Check whether a building placed here is valid and doesn't hit any obstructions
     * or impassable terrain.
     * @return ICmpObstruction::FOUNDATION_CHECK_SUCCESS if the placement is okay, else
     *  a value describing the type of failure.
     */
    virtual ICmpObstruction::EFoundationCheck CheckBuildingPlacement(const IObstructionTestFilter& filter, entity_pos_t x, entity_pos_t z, entity_pos_t a, entity_pos_t w, entity_pos_t h, entity_id_t id, pass_class_t passClass) const = 0;

    /**
     * Check whether a building placed here is valid and doesn't hit any obstructions
     * or impassable terrain.
     * when onlyCenterPoint = true, only check the center tile of the building
     * @return ICmpObstruction::FOUNDATION_CHECK_SUCCESS if the placement is okay, else
     *  a value describing the type of failure.
     */
    virtual ICmpObstruction::EFoundationCheck CheckBuildingPlacement(const IObstructionTestFilter& filter, entity_pos_t x, entity_pos_t z, entity_pos_t a, entity_pos_t w, entity_pos_t h, entity_id_t id, pass_class_t passClass, bool onlyCenterPoint) const = 0;


    /**
     * Toggle the storage and rendering of debug info.
     */
    virtual void SetDebugOverlay(bool enabled) = 0;

    /**
     * Toggle the storage and rendering of debug info for the hierarchical pathfinder.
     */
    virtual void SetHierDebugOverlay(bool enabled) = 0;

    /**
     * Finish computing asynchronous path requests and send the CMessagePathResult messages.
     */
    virtual void SendRequestedPaths() = 0;

    /**
     * Tell asynchronous pathfinder threads that they can begin computing paths.
     */
    virtual void StartProcessingMoves(bool useMax) = 0;

    /**
     * Regenerates the grid based on the current obstruction list, if necessary
     */
    virtual void UpdateGrid() = 0;

    /**
     * Returns some stats about the last ComputePath.
     */
    virtual void GetDebugData(u32& steps, double& time, Grid<u8>& grid) const = 0;

    /**
     * Sets up the pathfinder passability overlay in Atlas.
     */
    virtual void SetAtlasOverlay(bool enable, pass_class_t passClass = 0) = 0;

    DECLARE_INTERFACE_TYPE(Pathfinder)
};

#endif // INCLUDED_ICMPPATHFINDER