CCmpRallyPointRenderer.h

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/* Copyright (C) 2022 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_CCMPRALLYPOINTRENDERER
#define INCLUDED_CCMPRALLYPOINTRENDERER

#include "ICmpRallyPointRenderer.h"

#include "graphics/Overlay.h"
#include "graphics/TextureManager.h"
#include "ps/CLogger.h"
#include "renderer/Renderer.h"
#include "simulation2/MessageTypes.h"
#include "simulation2/components/ICmpFootprint.h"
#include "simulation2/components/ICmpIdentity.h"
#include "simulation2/components/ICmpObstructionManager.h"
#include "simulation2/components/ICmpOwnership.h"
#include "simulation2/components/ICmpPathfinder.h"
#include "simulation2/components/ICmpPlayer.h"
#include "simulation2/components/ICmpPlayerManager.h"
#include "simulation2/components/ICmpPosition.h"
#include "simulation2/components/ICmpTerrain.h"
#include "simulation2/components/ICmpVisual.h"
#include "simulation2/components/ICmpWaterManager.h"
#include "simulation2/helpers/Render.h"
#include "simulation2/helpers/Geometry.h"
#include "simulation2/system/Component.h"

struct SVisibilitySegment
{
    bool m_Visible;
    size_t m_StartIndex;
    size_t m_EndIndex; // Inclusive

    SVisibilitySegment(bool visible, size_t startIndex, size_t endIndex)
        : m_Visible(visible), m_StartIndex(startIndex), m_EndIndex(endIndex)
    {}

    bool operator==(const SVisibilitySegment& other) const
    {
        return m_Visible == other.m_Visible && m_StartIndex == other.m_StartIndex && m_EndIndex == other.m_EndIndex;
    }

    bool operator!=(const SVisibilitySegment& other) const
    {
        return !(*this == other);
    }

    bool IsSinglePoint() const
    {
        return m_StartIndex == m_EndIndex;
    }
};

class CCmpRallyPointRenderer final : public ICmpRallyPointRenderer
{
public:
    static std::string GetSchema();
    static void ClassInit(CComponentManager& componentManager);

    void Init(const CParamNode& paramNode) override;
    void Deinit() override;

    void Serialize(ISerializer& UNUSED(serialize)) override;
    void Deserialize(const CParamNode& paramNode, IDeserializer& UNUSED(deserialize)) override;

    void HandleMessage(const CMessage& msg, bool UNUSED(global)) override;

    /*
     * Must be called whenever m_Displayed or the size of m_RallyPoints change,
     * to determine whether we need to respond to render messages.
     */
    virtual void UpdateMessageSubscriptions();

    void AddPosition_wrapper(const CFixedVector2D& pos) override;

    void SetPosition(const CFixedVector2D& pos) override;

    void UpdatePosition(u32 rallyPointId, const CFixedVector2D& pos) override;

    void SetDisplayed(bool displayed) override;

    void Reset() override;

    void UpdateColor() override;

    /**
     * Returns true if at least one display rally point is set; i.e., if we have a point to render our marker/line at.
     */
    bool IsSet() const override;

    DEFAULT_COMPONENT_ALLOCATOR(RallyPointRenderer)

protected:
    /**
     * Display position of the rally points. Note that this are merely the display positions; they not necessarily the same as the
     * actual positions used in the simulation at any given time. In particular, we need this separate copy to support
     * instantaneously rendering the rally point markers/lines when the user sets one in-game (instead of waiting until the
     * network-synchronization code sets it on the RallyPoint component, which might take up to half a second).
     */
    std::vector<CFixedVector2D> m_RallyPoints;
    /**
     * Full path to the rally points as returned by the pathfinder, with some post-processing applied to reduce zig/zagging.
     */
    std::vector<std::vector<CVector2D> > m_Path;
    /**
     * Visibility segments of the rally point paths; splits the path into SoD/non-SoD segments.
     */
    std::vector<std::vector<SVisibilitySegment> > m_VisibilitySegments;
    /**
     * Should we render the rally points and the path lines? (set from JS when e.g. the unit is selected/deselected)
     */
    bool m_Displayed;
    /**
     * Smooth the path before rendering?
     */
    bool m_SmoothPath;
    /**
     * Entity IDs of the rally point markers.
     */
    std::vector<entity_id_t> m_MarkerEntityIds;

    size_t m_LastMarkerCount;
    /**
     * Last seen owner of this entity (used to keep track of ownership changes).
     */
    player_id_t m_LastOwner;
    /**
     * Template name of the rally point markers.
     */
    std::wstring m_MarkerTemplate;

    /**
     * Marker connector line settings (loaded from XML)
     */
    float m_LineThickness;
    CColor m_LineColor;
    CColor m_LineDashColor;
    SOverlayTexturedLine::LineCapType m_LineStartCapType;
    SOverlayTexturedLine::LineCapType m_LineEndCapType;
    std::wstring m_LineTexturePath;
    std::wstring m_LineTextureMaskPath;
    /**
     * Pathfinder passability class to use for computing the (long-range) marker line path.
     */
    std::string m_LinePassabilityClass;

    CTexturePtr m_Texture;
    CTexturePtr m_TextureMask;

    /**
     * Textured overlay lines to be used for rendering the marker line. There can be multiple because we may need to render
     * dashes for segments that are inside the SoD.
     */
    std::vector<std::vector<SOverlayTexturedLine> > m_TexturedOverlayLines;

    /**
     * Draw little overlay circles to indicate where the exact path points are.
     */
    bool m_EnableDebugNodeOverlay;
    std::vector<std::vector<SOverlayLine> > m_DebugNodeOverlays;

private:
    /**
     * Helper function for AddPosition_wrapper and SetPosition.
     */
    void AddPosition(CFixedVector2D pos, bool recompute);

    /**
    * Helper function to set the line color to its owner's color.
    */
    void UpdateLineColor();

    /**
     * Repositions the rally point markers; moves them outside of the world (ie. hides them), or positions them at the currently
     * set rally points. Also updates the actor's variation according to the entity's current owning player's civilization.
     *
     * Should be called whenever either the position of a rally point changes (including whether it is set or not), or the display
     * flag changes, or the ownership of the entity changes.
     */
    void UpdateMarkers();

    /**
     * Recomputes all the full paths from this entity to the rally point and from the rally point to the next, and does all the necessary
     * post-processing to make them prettier.
     *
     * Should be called whenever all rally points' position changes.
     */
    void RecomputeAllRallyPointPaths();

    /**
     * Recomputes the full path for m_Path[ @p index], and does all the necessary post-processing to make it prettier.
     *
     * Should be called whenever either the starting position or the rally point's position changes.
     */
    void RecomputeRallyPointPath_wrapper(size_t index);

    /**
     * Recomputes the full path from this entity/the previous rally point to the next rally point, and does all the necessary
     * post-processing to make it prettier. This doesn't check if we have a valid position or if a rally point is set.
     *
     * You shouldn't need to call this method directly.
     */
    void RecomputeRallyPointPath(size_t index, CmpPtr<ICmpPosition>& cmpPosition, CmpPtr<ICmpFootprint>& cmpFootprint, CmpPtr<ICmpPathfinder> cmpPathfinder);

    /**
     * Checks for changes to the SoD to the previously saved state, and reconstructs the visibility segments and overlay lines to
     * match if necessary. Does nothing if the rally point lines are not currently set to be displayed, or if no rally point is set.
     */
    void UpdateOverlayLines();

    /**
     * Sets up all overlay lines for rendering according to the current full path and visibility segments. Splits the line into solid
     * and dashed pieces (for the SoD). Should be called whenever the SoD has changed. If no full path is currently set, this method
     * does nothing.
     */
    void ConstructAllOverlayLines();

    /**
     * Sets up the overlay lines for rendering according to the full path and visibility segments at @p index. Splits the line into
     * solid and dashed pieces (for the SoD). Should be called whenever the SoD of the path at @p index has changed.
     */
    void ConstructOverlayLines(size_t index);

    /**
     * Get the point on the footprint edge that's as close from "start" as possible.
     */
    void GetClosestsEdgePointFrom(CFixedVector2D& result, CFixedVector2D& start, CmpPtr<ICmpPosition> cmpPosition, CmpPtr<ICmpFootprint> cmpFootprint) const;

    /**
     * Returns a list of indices of waypoints in the current path (m_Path[index]) where the LOS visibility changes, ordered from
     * building/previous rally point to rally point. Used to construct the overlay line segments and track changes to the SoD.
     */
    void GetVisibilitySegments(std::vector<SVisibilitySegment>& out, size_t index) const;

    /**
     * Simplifies the path by removing waypoints that lie between two points that are visible from one another. This is primarily
     * intended to reduce some unnecessary curviness of the path; the pathfinder returns a mathematically (near-)optimal path, which
     * will happily curve and bend to reduce costs. Visually, it doesn't make sense for a rally point path to curve and bend when it
     * could just as well have gone in a straight line; that's why we have this, to make it look more natural.
     *
     * @p coords array of path coordinates to simplify
     * @p maxSegmentLinks if non-zero, indicates the maximum amount of consecutive node-to-node links that can be joined into a
     *                    single link. If this value is set to e.g. 1, then no reductions will be performed. A value of 3 means that
     *                    at most 3 consecutive node links will be joined into a single link.
     * @p floating whether to consider nodes who are under the water level as floating on top of the water
     */
    void ReduceSegmentsByVisibility(std::vector<CVector2D>& coords, unsigned maxSegmentLinks = 0, bool floating = true) const;

    /**
     * Helper function to GetVisibilitySegments, factored out for testing. Merges single-point segments with its neighbouring
     * segments. You should not have to call this method directly.
     */
    static void MergeVisibilitySegments(std::vector<SVisibilitySegment>& segments);

    void RenderSubmit(SceneCollector& collector, const CFrustum& frustum, bool culling);
};

REGISTER_COMPONENT_TYPE(RallyPointRenderer)

#endif // INCLUDED_CCMPRALLYPOINTRENDERER