axmol/core/3d/CCBillBoard.h

/****************************************************************************
 Copyright (c) 2014-2016 Chukong Technologies Inc.
 Copyright (c) 2017-2018 Xiamen Yaji Software Co., Ltd.

 https://axis-project.github.io/

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 all copies or substantial portions of the Software.

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 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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 ****************************************************************************/

#pragma once

#include "2d/CCSprite.h"

NS_AX_BEGIN
/**
 * @addtogroup _3d
 * @{
 */

/**
 * @brief Inherit from Sprite, achieve BillBoard.
 */
class AX_DLL BillBoard : public Sprite
{
public:
    enum class Mode
    {
        VIEW_POINT_ORIENTED,  // orient to the camera
        VIEW_PLANE_ORIENTED   // orient to the XOY plane of camera
    };

    /// @name Creators

    /**
     * Creates an empty BillBoard without texture. You can call setTexture method subsequently.
     *
     * @return An autoreleased BillBoard object.
     */
    static BillBoard* create(Mode mode = Mode::VIEW_POINT_ORIENTED);

    /**
     * Creates a BillBoard with an image filename.
     *
     * After creation, the rect of BillBoard will be the size of the image,
     * and the offset will be (0,0).
     *
     * @param   filename A path to image file, e.g., "scene1/monster.png"
     * @return  An autoreleased BillBoard object.
     */
    static BillBoard* create(std::string_view filename, Mode mode = Mode::VIEW_POINT_ORIENTED);

    /**
     * Creates a BillBoard with an image filename and a rect.
     *
     * @param   filename A path to image file, e.g., "scene1/monster.png"
     * @param   rect     A subrect of the image file
     * @return  An autoreleased BillBoard object
     */
    static BillBoard* create(std::string_view filename, const Rect& rect, Mode mode = Mode::VIEW_POINT_ORIENTED);

    /**
     * Creates a BillBoard with a Texture2D object.
     *
     * After creation, the rect will be the size of the texture, and the offset will be (0,0).
     *
     * @param   texture    A pointer to a Texture2D object.
     * @return  An autoreleased BillBoard object
     */
    static BillBoard* createWithTexture(Texture2D* texture, Mode mode = Mode::VIEW_POINT_ORIENTED);

    /** Set the billboard rotation mode. */
    void setMode(Mode mode);

    /** Get the billboard rotation mode. */
    Mode getMode() const;

    // override

    /** update billboard's transform and turn it towards camera */
    virtual void visit(Renderer* renderer, const Mat4& parentTransform, uint32_t parentFlags) override;

    /**
     * draw BillBoard object.
     *
     * @lua NA
     */
    virtual void draw(Renderer* renderer, const Mat4& transform, uint32_t flags) override;

    BillBoard();
    virtual ~BillBoard();

protected:
    /**
     * calculate a model matrix which keep original translate & scaling but always face to the camera
     */
    bool calculateBillboardTransform();

    Mat4 _camWorldMat;
    Mat4 _mvTransform;

    Mode _mode;
    bool _modeDirty;

private:
    AX_DISALLOW_COPY_AND_ASSIGN(BillBoard);
};

// end of 3d group
/// @}

NS_AX_END