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Open Asset Import Library (assimp)
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/** @file ColladaExporter.h
 * Declares the exporter class to write a scene to a Collada file
 */
#ifndef AI_COLLADAEXPORTER_H_INC
#define AI_COLLADAEXPORTER_H_INC

#include <assimp/ai_assert.h>
#include <assimp/material.h>

#include <array>
#include <map>
#include <sstream>
#include <unordered_set>
#include <vector>

struct aiScene;
struct aiNode;
struct aiLight;
struct aiBone;

namespace Assimp {

class IOSystem;

/// Helper class to export a given scene to a Collada file. Just for my personal
/// comfort when implementing it.
class ColladaExporter {
public:
    /// Constructor for a specific scene to export
    ColladaExporter(const aiScene *pScene, IOSystem *pIOSystem, const std::string &path, const std::string &file);

    /// Destructor
    virtual ~ColladaExporter();

protected:
    /// Starts writing the contents
    void WriteFile();

    /// Writes the asset header
    void WriteHeader();

    /// Writes the embedded textures
    void WriteTextures();

    /// Writes the material setup
    void WriteMaterials();

    /// Writes the cameras library
    void WriteCamerasLibrary();

    // Write a camera entry
    void WriteCamera(size_t pIndex);

    /// Writes the cameras library
    void WriteLightsLibrary();

    // Write a camera entry
    void WriteLight(size_t pIndex);
    void WritePointLight(const aiLight *const light);
    void WriteDirectionalLight(const aiLight *const light);
    void WriteSpotLight(const aiLight *const light);
    void WriteAmbienttLight(const aiLight *const light);

    /// Writes the controller library
    void WriteControllerLibrary();

    /// Writes a skin controller of the given mesh
    void WriteController(size_t pIndex);

    /// Writes the geometry library
    void WriteGeometryLibrary();

    /// Writes the given mesh
    void WriteGeometry(size_t pIndex);

    //enum FloatDataType { FloatType_Vector, FloatType_TexCoord2, FloatType_TexCoord3, FloatType_Color, FloatType_Mat4x4, FloatType_Weight };
    // customized to add animation related type
    enum FloatDataType { FloatType_Vector,
        FloatType_TexCoord2,
        FloatType_TexCoord3,
        FloatType_Color,
        FloatType_Mat4x4,
        FloatType_Weight,
        FloatType_Time };

    /// Writes a float array of the given type
    void WriteFloatArray(const std::string &pIdString, FloatDataType pType, const ai_real *pData, size_t pElementCount);

    /// Writes the scene library
    void WriteSceneLibrary();

    // customized, Writes the animation library
    void WriteAnimationsLibrary();
    void WriteAnimationLibrary(size_t pIndex);
    std::string mFoundSkeletonRootNodeID = "skeleton_root"; // will be replaced by found node id in the WriteNode call.

    /// Recursively writes the given node
    void WriteNode(const aiNode *pNode);

    /// Enters a new xml element, which increases the indentation
    void PushTag() { startstr.append("  "); }
    /// Leaves an element, decreasing the indentation
    void PopTag() {
        ai_assert(startstr.length() > 1);
        startstr.erase(startstr.length() - 2);
    }

    void CreateNodeIds(const aiNode *node);

    /// Get or Create a unique Node ID string for the given Node
    std::string GetNodeUniqueId(const aiNode *node);
    std::string GetNodeName(const aiNode *node);

    std::string GetBoneUniqueId(const aiBone *bone);

    enum class AiObjectType {
        Mesh,
        Material,
        Animation,
        Light,
        Camera,
        Count,
    };
    /// Get or Create a unique ID string for the given scene object index
    std::string GetObjectUniqueId(AiObjectType type, size_t pIndex);
    /// Get or Create a name string for the given scene object index
    std::string GetObjectName(AiObjectType type, size_t pIndex);

    typedef std::map<size_t, std::string> IndexIdMap;
    typedef std::pair<std::string, std::string> NameIdPair;
    NameIdPair AddObjectIndexToMaps(AiObjectType type, size_t pIndex);

    // Helpers
    inline IndexIdMap &GetObjectIdMap(AiObjectType type) { return mObjectIdMap[static_cast<size_t>(type)]; }
    inline IndexIdMap &GetObjectNameMap(AiObjectType type) { return mObjectNameMap[static_cast<size_t>(type)]; }

private:
    std::unordered_set<std::string> mUniqueIds; // Cache of used unique ids
    std::map<const void *, std::string> mNodeIdMap; // Cache of encoded node and bone ids
    std::array<IndexIdMap, static_cast<size_t>(AiObjectType::Count)> mObjectIdMap; // Cache of encoded unique IDs
    std::array<IndexIdMap, static_cast<size_t>(AiObjectType::Count)> mObjectNameMap; // Cache of encoded names

public:
    /// Stringstream to write all output into
    std::stringstream mOutput;

    /// The IOSystem for output
    IOSystem *mIOSystem;

    /// Path of the directory where the scene will be exported
    const std::string mPath;

    /// Name of the file (without extension) where the scene will be exported
    const std::string mFile;

    /// The scene to be written
    const aiScene *const mScene;
    std::string mSceneId;
    bool mAdd_root_node = false;

    /// current line start string, contains the current indentation for simple stream insertion
    std::string startstr;
    /// current line end string for simple stream insertion
    const std::string endstr;

    // pair of color and texture - texture precedences color
    struct Surface {
        bool exist;
        aiColor4D color;
        std::string texture;
        size_t channel;
        Surface() {
            exist = false;
            channel = 0;
        }
    };

    struct Property {
        bool exist;
        ai_real value;
        Property() :
                exist(false),
                value(0.0) {}
    };

    // summarize a material in an convenient way.
    struct Material {
        std::string id;
        std::string name;
        std::string shading_model;
        Surface ambient, diffuse, specular, emissive, reflective, transparent, normal;
        Property shininess, transparency, index_refraction;

        Material() {}
    };

    std::map<unsigned int, std::string> textures;

public:
    /// Dammit C++ - y u no compile two-pass? No I have to add all methods below the struct definitions
    /// Reads a single surface entry from the given material keys
    bool ReadMaterialSurface(Surface &poSurface, const aiMaterial &pSrcMat, aiTextureType pTexture, const char *pKey, size_t pType, size_t pIndex);
    /// Writes an image entry for the given surface
    void WriteImageEntry(const Surface &pSurface, const std::string &imageId);
    /// Writes the two parameters necessary for referencing a texture in an effect entry
    void WriteTextureParamEntry(const Surface &pSurface, const std::string &pTypeName, const std::string &materialId);
    /// Writes a color-or-texture entry into an effect definition
    void WriteTextureColorEntry(const Surface &pSurface, const std::string &pTypeName, const std::string &imageId);
    /// Writes a scalar property
    void WriteFloatEntry(const Property &pProperty, const std::string &pTypeName);
};

} // namespace Assimp

#endif // !! AI_COLLADAEXPORTER_H_INC
