axmol/extensions/Particle3D/PU/CCPURibbonTrail.h

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 Copyright (c) 2015-2016 Chukong Technologies Inc.
 Copyright (c) 2017-2018 Xiamen Yaji Software Co., Ltd.

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#ifndef __AX_PU_PARTICLE_3D_RIBBON_TRAIL_H__
#define __AX_PU_PARTICLE_3D_RIBBON_TRAIL_H__

#include "base/CCRef.h"
#include "math/CCMath.h"
#include "extensions/Particle3D/PU/CCPUBillboardChain.h"
#include <vector>
#include <unordered_map>

NS_AX_BEGIN

class PURibbonTrail : public PUBillboardChain
{

public:
    /** Constructor
    @param name The name to give this object
    @param maxElements The maximum number of elements per chain
    @param numberOfChains The number of separate chain segments contained in this object,
        ie the maximum number of nodes that can have trails attached
    @param useTextureCoords If true, use texture coordinates from the chain elements
    @param useVertexColors If true, use vertex colors from the chain elements (must
        be true if you intend to use fading)
    */
    PURibbonTrail(std::string_view name,
                  std::string_view texFile = "",
                  size_t maxElements       = 20,
                  size_t numberOfChains    = 1,
                  bool useTextureCoords    = true,
                  bool useColours          = true);
    /// destructor
    virtual ~PURibbonTrail();

    typedef std::vector<Node*> NodeList;

    /** Add a node to be tracked.
    @param n The node that will be tracked.
    */
    virtual void addNode(Node* n);
    /** Remove tracking on a given node. */
    virtual void removeNode(Node* n);
    /** Get the chain index for a given Node being tracked. */
    virtual size_t getChainIndexForNode(const Node* n);

    void setAttachedNode(Node* parent) { _parentNode = parent; }

    /** Set the length of the trail.
    @remarks
        This sets the length of the trail, in world units. It also sets how
        far apart each segment will be, ie length / max_elements.
    @param len The length of the trail in world units
    */
    virtual void setTrailLength(float len);
    /** Get the length of the trail. */
    virtual float getTrailLength() const { return _trailLength; }

    /** @copydoc BillboardChain::setMaxChainElements */
    void setMaxChainElements(size_t maxElements) override;
    /** @copydoc BillboardChain::setNumberOfChains */
    virtual void setNumberOfChains(size_t numChains) override;
    /** @copydoc BillboardChain::clearChain */
    void clearChain(size_t chainIndex) override;

    /** Set the starting ribbon colour for a given segment.
    @param chainIndex The index of the chain
    @param col The initial colour
    @note
        Only used if this instance is using vertex colours.
    */
    virtual void setInitialColour(size_t chainIndex, const Vec4& col);
    /** Set the starting ribbon colour.
    @param chainIndex The index of the chain
    @param r,b,g,a The initial colour
    @note
        Only used if this instance is using vertex colours.
    */
    virtual void setInitialColour(size_t chainIndex, float r, float g, float b, float a = 1.0);
    /** Get the starting ribbon colour. */
    virtual const Vec4& getInitialColour(size_t chainIndex) const;

    /** Enables / disables fading the trail using colour.
    @param chainIndex The index of the chain
    @param valuePerSecond The amount to subtract from colour each second
    */
    virtual void setColourChange(size_t chainIndex, const Vec4& valuePerSecond);

    /** Set the starting ribbon width in world units.
    @param chainIndex The index of the chain
    @param width The initial width of the ribbon
    */
    virtual void setInitialWidth(size_t chainIndex, float width);
    /** Get the starting ribbon width in world units. */
    virtual float getInitialWidth(size_t chainIndex) const;

    /** Set the change in ribbon width per second.
    @param chainIndex The index of the chain
    @param widthDeltaPerSecond The amount the width will reduce by per second
    */
    virtual void setWidthChange(size_t chainIndex, float widthDeltaPerSecond);
    /** Get the change in ribbon width per second. */
    virtual float getWidthChange(size_t chainIndex) const;

    /** Enables / disables fading the trail using colour.
    @param chainIndex The index of the chain
    @param r,g,b,a The amount to subtract from each colour channel per second
    */
    virtual void setColourChange(size_t chainIndex, float r, float g, float b, float a);

    /** Get the per-second fading amount */
    virtual const Vec4& getColourChange(size_t chainIndex) const;

    void update(float deltaTime);

    /// @see Node::Listener::nodeUpdated
    void nodeUpdated(const Node* node);
    /// @see Node::Listener::nodeDestroyed
    void nodeDestroyed(const Node* node);

    /// Perform any fading / width delta required; internal method
    void timeUpdate(float time);

protected:
    /// Manage updates to the time controller
    void manageController();
    /// Node has changed position, update
    void updateTrail(size_t index, const Node* node);
    /// Reset the tracked chain to initial state
    void resetTrail(size_t index, const Node* node);
    /// Reset all tracked chains to initial state
    void resetAllTrails();

protected:
    /// List of nodes being trailed
    NodeList _nodeList;
    /// Mapping of nodes to chain segments
    typedef std::vector<size_t> IndexVector;
    /// Ordered like mNodeList, contains chain index
    IndexVector _nodeToChainSegment;
    // chains not in use
    IndexVector _freeChains;

    // fast lookup node->chain index
    // we use positional map too because that can be useful
    typedef std::unordered_map<const Node*, size_t> NodeToChainSegmentMap;
    NodeToChainSegmentMap _nodeToSegMap;

    /// Total length of trail in world units
    float _trailLength;
    /// length of each element
    float _elemLength;
    /// Squared length of each element
    float _squaredElemLength;
    typedef std::vector<Vec4> ColorValueList;
    typedef std::vector<float> RealList;
    /// Initial colour of the ribbon
    ColorValueList _initialColor;
    /// fade amount per second
    ColorValueList _deltaColor;
    /// Initial width of the ribbon
    RealList _initialWidth;
    /// Delta width of the ribbon
    RealList _deltaWidth;

    Node* _parentNode;
    bool _needTimeUpdate;
};

NS_AX_END
#endif