/** Helper structures for the Collada loader */

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*/

#ifndef AI_COLLADAHELPER_H_INC
#define AI_COLLADAHELPER_H_INC

#include <string>
#include <map>
#include <vector>
#include <stdint.h>
#include <assimp/light.h>
#include <assimp/mesh.h>
#include <assimp/material.h>

struct aiMaterial;

namespace Assimp    {
namespace Collada       {

/** Collada file versions which evolved during the years ... */
enum FormatVersion
{
    FV_1_5_n,
    FV_1_4_n,
    FV_1_3_n
};


/** Transformation types that can be applied to a node */
enum TransformType
{
    TF_LOOKAT,
    TF_ROTATE,
    TF_TRANSLATE,
    TF_SCALE,
    TF_SKEW,
    TF_MATRIX
};

/** Different types of input data to a vertex or face */
enum InputType
{
    IT_Invalid,
    IT_Vertex,  // special type for per-index data referring to the <vertices> element carrying the per-vertex data.
    IT_Position,
    IT_Normal,
    IT_Texcoord,
    IT_Color,
    IT_Tangent,
    IT_Bitangent
};

/** Supported controller types */
enum ControllerType
{
    Skin,
    Morph
};

/** Supported morph methods */
enum MorphMethod
{
    Normalized,
    Relative
};


/** Contains all data for one of the different transformation types */
struct Transform
{
    std::string mID;  ///< SID of the transform step, by which anim channels address their target node
    TransformType mType;
    ai_real f[16]; ///< Interpretation of data depends on the type of the transformation
};

/** A collada camera. */
struct Camera
{
    Camera()
        :   mOrtho  (false)
        ,   mHorFov (10e10f)
        ,   mVerFov (10e10f)
        ,   mAspect (10e10f)
        ,   mZNear  (0.1f)
        ,   mZFar   (1000.f)
    {}

    // Name of camera
    std::string mName;

    // True if it is an orthografic camera
    bool mOrtho;

    //! Horizontal field of view in degrees
    ai_real mHorFov;

    //! Vertical field of view in degrees
    ai_real mVerFov;

    //! Screen aspect
    ai_real mAspect;

    //! Near& far z
    ai_real mZNear, mZFar;
};

#define ASSIMP_COLLADA_LIGHT_ANGLE_NOT_SET 1e9f

/** A collada light source. */
struct Light
{
    Light()
        :   mType            (aiLightSource_UNDEFINED)
        ,   mAttConstant     (1.f)
        ,   mAttLinear       (0.f)
        ,   mAttQuadratic    (0.f)
        ,   mFalloffAngle    (180.f)
        ,   mFalloffExponent (0.f)
        ,   mPenumbraAngle   (ASSIMP_COLLADA_LIGHT_ANGLE_NOT_SET)
        ,   mOuterAngle      (ASSIMP_COLLADA_LIGHT_ANGLE_NOT_SET)
        ,   mIntensity       (1.f)
    {}

    //! Type of the light source aiLightSourceType + ambient
    unsigned int mType;

    //! Color of the light
    aiColor3D mColor;

    //! Light attenuation
    ai_real mAttConstant,mAttLinear,mAttQuadratic;

    //! Spot light falloff
    ai_real mFalloffAngle;
    ai_real mFalloffExponent;

    // -----------------------------------------------------
    // FCOLLADA extension from here

    //! ... related stuff from maja and max extensions
    ai_real mPenumbraAngle;
    ai_real mOuterAngle;

    //! Common light intensity
    ai_real mIntensity;
};

/** Short vertex index description */
struct InputSemanticMapEntry
{
    InputSemanticMapEntry()
        :   mSet(0)
        ,   mType(IT_Invalid)
    {}

    //! Index of set, optional
    unsigned int mSet;

    //! Type of referenced vertex input
    InputType mType;
};

/** Table to map from effect to vertex input semantics */
struct SemanticMappingTable
{
    //! Name of material
    std::string mMatName;

    //! List of semantic map commands, grouped by effect semantic name
    std::map<std::string, InputSemanticMapEntry> mMap;

    //! For std::find
    bool operator == (const std::string& s) const {
        return s == mMatName;
    }
};

/** A reference to a mesh inside a node, including materials assigned to the various subgroups.
 * The ID refers to either a mesh or a controller which specifies the mesh
 */
struct MeshInstance
{
    ///< ID of the mesh or controller to be instanced
    std::string mMeshOrController;

    ///< Map of materials by the subgroup ID they're applied to
    std::map<std::string, SemanticMappingTable> mMaterials;
};

/** A reference to a camera inside a node*/
struct CameraInstance
{
     ///< ID of the camera
    std::string mCamera;
};

/** A reference to a light inside a node*/
struct LightInstance
{
     ///< ID of the camera
    std::string mLight;
};

/** A reference to a node inside a node*/
struct NodeInstance
{
     ///< ID of the node
    std::string mNode;
};

/** A node in a scene hierarchy */
struct Node
{
    std::string mName;
    std::string mID;
    std::string mSID;
    Node* mParent;
    std::vector<Node*> mChildren;

    /** Operations in order to calculate the resulting transformation to parent. */
    std::vector<Transform> mTransforms;

    /** Meshes at this node */
    std::vector<MeshInstance> mMeshes;

    /** Lights at this node */
    std::vector<LightInstance> mLights;

    /** Cameras at this node */
    std::vector<CameraInstance> mCameras;

    /** Node instances at this node */
    std::vector<NodeInstance> mNodeInstances;

    /** Rootnodes: Name of primary camera, if any */
    std::string mPrimaryCamera;

    //! Constructor. Begin with a zero parent
    Node() {
        mParent = NULL;
    }

    //! Destructor: delete all children subsequently
    ~Node() {
        for( std::vector<Node*>::iterator it = mChildren.begin(); it != mChildren.end(); ++it)
            delete *it;
    }
};

/** Data source array: either floats or strings */
struct Data
{
    bool mIsStringArray;
    std::vector<ai_real> mValues;
    std::vector<std::string> mStrings;
};

/** Accessor to a data array */
struct Accessor
{
    size_t mCount;   // in number of objects
    size_t mSize;    // size of an object, in elements (floats or strings, mostly 1)
    size_t mOffset;  // in number of values
    size_t mStride;  // Stride in number of values
    std::vector<std::string> mParams; // names of the data streams in the accessors. Empty string tells to ignore.
    size_t mSubOffset[4]; // Suboffset inside the object for the common 4 elements. For a vector, thats XYZ, for a color RGBA and so on.
                          // For example, SubOffset[0] denotes which of the values inside the object is the vector X component.
    std::string mSource;   // URL of the source array
    mutable const Data* mData; // Pointer to the source array, if resolved. NULL else

    Accessor()
    {
        mCount = 0; mSize = 0; mOffset = 0; mStride = 0; mData = NULL;
        mSubOffset[0] = mSubOffset[1] = mSubOffset[2] = mSubOffset[3] = 0;
    }
};

/** A single face in a mesh */
struct Face
{
    std::vector<size_t> mIndices;
};

/** An input channel for mesh data, referring to a single accessor */
struct InputChannel
{
    InputType mType;      // Type of the data
    size_t mIndex;        // Optional index, if multiple sets of the same data type are given
    size_t mOffset;       // Index offset in the indices array of per-face indices. Don't ask, can't explain that any better.
    std::string mAccessor; // ID of the accessor where to read the actual values from.
    mutable const Accessor* mResolved; // Pointer to the accessor, if resolved. NULL else

    InputChannel() { mType = IT_Invalid; mIndex = 0; mOffset = 0; mResolved = NULL; }
};

/** Subset of a mesh with a certain material */
struct SubMesh
{
    std::string mMaterial; ///< subgroup identifier
    size_t mNumFaces; ///< number of faces in this submesh
};

/** Contains data for a single mesh */
struct Mesh
{
    Mesh()
    {
        for (unsigned int i = 0; i < AI_MAX_NUMBER_OF_TEXTURECOORDS;++i)
            mNumUVComponents[i] = 2;
    }

    std::string mName;

    // just to check if there's some sophisticated addressing involved...
    // which we don't support, and therefore should warn about.
    std::string mVertexID;

    // Vertex data addressed by vertex indices
    std::vector<InputChannel> mPerVertexData;

    // actual mesh data, assembled on encounter of a <p> element. Verbose format, not indexed
    std::vector<aiVector3D> mPositions;
    std::vector<aiVector3D> mNormals;
    std::vector<aiVector3D> mTangents;
    std::vector<aiVector3D> mBitangents;
    std::vector<aiVector3D> mTexCoords[AI_MAX_NUMBER_OF_TEXTURECOORDS];
    std::vector<aiColor4D>  mColors[AI_MAX_NUMBER_OF_COLOR_SETS];

    unsigned int mNumUVComponents[AI_MAX_NUMBER_OF_TEXTURECOORDS];

    // Faces. Stored are only the number of vertices for each face.
    // 1 == point, 2 == line, 3 == triangle, 4+ == poly
    std::vector<size_t> mFaceSize;

    // Position indices for all faces in the sequence given in mFaceSize -
    // necessary for bone weight assignment
    std::vector<size_t> mFacePosIndices;

    // Submeshes in this mesh, each with a given material
    std::vector<SubMesh> mSubMeshes;
};

/** Which type of primitives the ReadPrimitives() function is going to read */
enum PrimitiveType
{
    Prim_Invalid,
    Prim_Lines,
    Prim_LineStrip,
    Prim_Triangles,
    Prim_TriStrips,
    Prim_TriFans,
    Prim_Polylist,
    Prim_Polygon
};

/** A skeleton controller to deform a mesh with the use of joints */
struct Controller
{
    // controller type
    ControllerType mType;

    // Morphing method if type is Morph
    MorphMethod mMethod;

    // the URL of the mesh deformed by the controller.
    std::string mMeshId;

    // accessor URL of the joint names
    std::string mJointNameSource;

    ///< The bind shape matrix, as array of floats. I'm not sure what this matrix actually describes, but it can't be ignored in all cases
    ai_real mBindShapeMatrix[16];

    // accessor URL of the joint inverse bind matrices
    std::string mJointOffsetMatrixSource;

    // input channel: joint names.
    InputChannel mWeightInputJoints;
    // input channel: joint weights
    InputChannel mWeightInputWeights;

    // Number of weights per vertex.
    std::vector<size_t> mWeightCounts;

    // JointIndex-WeightIndex pairs for all vertices
    std::vector< std::pair<size_t, size_t> > mWeights;

    std::string mMorphTarget;
    std::string mMorphWeight;
};

/** A collada material. Pretty much the only member is a reference to an effect. */
struct Material
{
    std::string mName;
    std::string mEffect;
};

/** Type of the effect param */
enum ParamType
{
    Param_Sampler,
    Param_Surface
};

/** A param for an effect. Might be of several types, but they all just refer to each other, so I summarize them */
struct EffectParam
{
    ParamType mType;
    std::string mReference; // to which other thing the param is referring to.
};

/** Shading type supported by the standard effect spec of Collada */
enum ShadeType
{
    Shade_Invalid,
    Shade_Constant,
    Shade_Lambert,
    Shade_Phong,
    Shade_Blinn
};

/** Represents a texture sampler in collada */
struct Sampler
{
    Sampler()
        :   mWrapU      (true)
        ,   mWrapV      (true)
        ,   mMirrorU    ()
        ,   mMirrorV    ()
        ,   mOp         (aiTextureOp_Multiply)
        ,   mUVId       (UINT_MAX)
        ,   mWeighting  (1.f)
        ,   mMixWithPrevious (1.f)
    {}

    /** Name of image reference
     */
    std::string mName;

    /** Wrap U?
     */
    bool mWrapU;

    /** Wrap V?
     */
    bool mWrapV;

    /** Mirror U?
     */
    bool mMirrorU;

    /** Mirror V?
     */
    bool mMirrorV;

    /** Blend mode
     */
    aiTextureOp mOp;

    /** UV transformation
     */
    aiUVTransform mTransform;

    /** Name of source UV channel
     */
    std::string mUVChannel;

    /** Resolved UV channel index or UINT_MAX if not known
     */
    unsigned int mUVId;

    // OKINO/MAX3D extensions from here
    // -------------------------------------------------------

    /** Weighting factor
     */
    ai_real mWeighting;

    /** Mixing factor from OKINO
     */
    ai_real mMixWithPrevious;
};

/** A collada effect. Can contain about anything according to the Collada spec,
    but we limit our version to a reasonable subset. */
struct Effect
{
    // Shading mode
    ShadeType mShadeType;

    // Colors
    aiColor4D mEmissive, mAmbient, mDiffuse, mSpecular,
        mTransparent, mReflective;

    // Textures
    Sampler mTexEmissive, mTexAmbient, mTexDiffuse, mTexSpecular,
        mTexTransparent, mTexBump, mTexReflective;

    // Scalar factory
    ai_real mShininess, mRefractIndex, mReflectivity;
    ai_real mTransparency;
    bool mHasTransparency;
    bool mRGBTransparency;
    bool mInvertTransparency;

    // local params referring to each other by their SID
    typedef std::map<std::string, Collada::EffectParam> ParamLibrary;
    ParamLibrary mParams;

    // MAX3D extensions
    // ---------------------------------------------------------
    // Double-sided?
    bool mDoubleSided, mWireframe, mFaceted;

    Effect()
        : mShadeType    (Shade_Phong)
        , mEmissive     ( 0, 0, 0, 1)
        , mAmbient      ( 0.1f, 0.1f, 0.1f, 1)
        , mDiffuse      ( 0.6f, 0.6f, 0.6f, 1)
        , mSpecular     ( 0.4f, 0.4f, 0.4f, 1)
        , mTransparent  ( 0, 0, 0, 1)
        , mShininess    (10.0f)
        , mRefractIndex (1.f)
        , mReflectivity (0.f)
        , mTransparency (1.f)
        , mHasTransparency (false)
        , mRGBTransparency(false)
        , mInvertTransparency(false)
        , mDoubleSided  (false)
        , mWireframe    (false)
        , mFaceted      (false)
    {
    }
};

/** An image, meaning texture */
struct Image
{
    std::string mFileName;

    /** If image file name is zero, embedded image data
     */
    std::vector<uint8_t> mImageData;

    /** If image file name is zero, file format of
     *  embedded image data.
     */
    std::string mEmbeddedFormat;

};

/** An animation channel. */
struct AnimationChannel
{
    /** URL of the data to animate. Could be about anything, but we support only the
     * "NodeID/TransformID.SubElement" notation
     */
    std::string mTarget;

    /** Source URL of the time values. Collada calls them "input". Meh. */
    std::string mSourceTimes;
    /** Source URL of the value values. Collada calls them "output". */
    std::string mSourceValues;
    /** Source URL of the IN_TANGENT semantic values. */
    std::string mInTanValues;
    /** Source URL of the OUT_TANGENT semantic values. */
    std::string mOutTanValues;
    /** Source URL of the INTERPOLATION semantic values. */
    std::string mInterpolationValues;
};

/** An animation. Container for 0-x animation channels or 0-x animations */
struct Animation
{
    /** Anim name */
    std::string mName;

    /** the animation channels, if any */
    std::vector<AnimationChannel> mChannels;

    /** the sub-animations, if any */
    std::vector<Animation*> mSubAnims;

    /** Destructor */
    ~Animation()
    {
        for( std::vector<Animation*>::iterator it = mSubAnims.begin(); it != mSubAnims.end(); ++it)
            delete *it;
    }

	/** Collect all channels in the animation hierarchy into a single channel list. */
	void CollectChannelsRecursively(std::vector<AnimationChannel> &channels)
	{
		channels.insert(channels.end(), mChannels.begin(), mChannels.end());

		for (std::vector<Animation*>::iterator it = mSubAnims.begin(); it != mSubAnims.end(); ++it)
		{
			Animation *pAnim = (*it);

			pAnim->CollectChannelsRecursively(channels);
		}
	}

	/** Combine all single-channel animations' channel into the same (parent) animation channel list. */
	void CombineSingleChannelAnimations()
	{
		CombineSingleChannelAnimationsRecursively(this);
	}

	void CombineSingleChannelAnimationsRecursively(Animation *pParent)
	{
		for (std::vector<Animation*>::iterator it = pParent->mSubAnims.begin(); it != pParent->mSubAnims.end();)
		{
			Animation *anim = *it;

			CombineSingleChannelAnimationsRecursively(anim);

			if (anim->mChannels.size() == 1)
			{
				pParent->mChannels.push_back(anim->mChannels[0]);

				it = pParent->mSubAnims.erase(it);

				delete anim;
			}
			else
			{
				++it;
			}
		}
	}
};

/** Description of a collada animation channel which has been determined to affect the current node */
struct ChannelEntry
{
    const Collada::AnimationChannel* mChannel; ///> the source channel
    std::string mTargetId;
    std::string mTransformId;   // the ID of the transformation step of the node which is influenced
    size_t mTransformIndex; // Index into the node's transform chain to apply the channel to
    size_t mSubElement; // starting index inside the transform data

    // resolved data references
    const Collada::Accessor* mTimeAccessor; ///> Collada accessor to the time values
    const Collada::Data* mTimeData; ///> Source data array for the time values
    const Collada::Accessor* mValueAccessor; ///> Collada accessor to the key value values
    const Collada::Data* mValueData; ///> Source datat array for the key value values

    ChannelEntry()
      : mChannel()
      , mTransformIndex()
      , mSubElement()
      , mTimeAccessor()
      , mTimeData()
      , mValueAccessor()
      , mValueData()
   {}
};

} // end of namespace Collada
} // end of namespace Assimp

#endif // AI_COLLADAHELPER_H_INC