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/** @file  IRRLoader.cpp
 *  @brief Implementation of the Irr importer class
 */

#include "assimp/Exceptional.h"
#include "assimp/StringComparison.h"
#ifndef ASSIMP_BUILD_NO_IRR_IMPORTER

#include "AssetLib/Irr/IRRLoader.h"
#include "Common/Importer.h"

#include <assimp/GenericProperty.h>
#include <assimp/MathFunctions.h>
#include <assimp/ParsingUtils.h>
#include <assimp/SceneCombiner.h>
#include <assimp/StandardShapes.h>
#include <assimp/fast_atof.h>
#include <assimp/importerdesc.h>
#include <assimp/material.h>
#include <assimp/mesh.h>
#include <assimp/postprocess.h>
#include <assimp/scene.h>
#include <assimp/DefaultLogger.hpp>
#include <assimp/IOSystem.hpp>

using namespace Assimp;

static constexpr aiImporterDesc desc = {
    "Irrlicht Scene Reader",
    "",
    "",
    "http://irrlicht.sourceforge.net/",
    aiImporterFlags_SupportTextFlavour,
    0,
    0,
    0,
    0,
    "irr xml"
};

// ------------------------------------------------------------------------------------------------
// Constructor to be privately used by Importer
IRRImporter::IRRImporter() :
        fps(), configSpeedFlag() {
    // empty
}

// ------------------------------------------------------------------------------------------------
// Destructor, private as well
IRRImporter::~IRRImporter() = default;

// ------------------------------------------------------------------------------------------------
// Returns whether the class can handle the format of the given file.
bool IRRImporter::CanRead(const std::string &pFile, IOSystem *pIOHandler, bool /*checkSig*/) const {
    static const char *tokens[] = { "irr_scene" };
    return SearchFileHeaderForToken(pIOHandler, pFile, tokens, AI_COUNT_OF(tokens));
}

// ------------------------------------------------------------------------------------------------
const aiImporterDesc *IRRImporter::GetInfo() const {
    return &desc;
}

// ------------------------------------------------------------------------------------------------
void IRRImporter::SetupProperties(const Importer *pImp) {
    // read the output frame rate of all node animation channels
    fps = pImp->GetPropertyInteger(AI_CONFIG_IMPORT_IRR_ANIM_FPS, 100);
    if (fps < 10.) {
        ASSIMP_LOG_ERROR("IRR: Invalid FPS configuration");
        fps = 100;
    }

    // AI_CONFIG_FAVOUR_SPEED
    configSpeedFlag = (0 != pImp->GetPropertyInteger(AI_CONFIG_FAVOUR_SPEED, 0));
}

// ------------------------------------------------------------------------------------------------
// Build a mesh that consists of a single squad (a side of a skybox)
aiMesh *IRRImporter::BuildSingleQuadMesh(const SkyboxVertex &v1,
        const SkyboxVertex &v2,
        const SkyboxVertex &v3,
        const SkyboxVertex &v4) {
    // allocate and prepare the mesh
    aiMesh *out = new aiMesh();

    out->mPrimitiveTypes = aiPrimitiveType_POLYGON;
    out->mNumFaces = 1;

    // build the face
    out->mFaces = new aiFace[1];
    aiFace &face = out->mFaces[0];

    face.mNumIndices = 4;
    face.mIndices = new unsigned int[4];
    for (unsigned int i = 0; i < 4; ++i)
        face.mIndices[i] = i;

    out->mNumVertices = 4;

    // copy vertex positions
    aiVector3D *vec = out->mVertices = new aiVector3D[4];
    *vec++ = v1.position;
    *vec++ = v2.position;
    *vec++ = v3.position;
    *vec = v4.position;

    // copy vertex normals
    vec = out->mNormals = new aiVector3D[4];
    *vec++ = v1.normal;
    *vec++ = v2.normal;
    *vec++ = v3.normal;
    *vec = v4.normal;

    // copy texture coordinates
    vec = out->mTextureCoords[0] = new aiVector3D[4];
    *vec++ = v1.uv;
    *vec++ = v2.uv;
    *vec++ = v3.uv;
    *vec = v4.uv;
    return out;
}

// ------------------------------------------------------------------------------------------------
void IRRImporter::BuildSkybox(std::vector<aiMesh *> &meshes, std::vector<aiMaterial *> materials) {
    // Update the material of the skybox - replace the name and disable shading for skyboxes.
    for (unsigned int i = 0; i < 6; ++i) {
        aiMaterial *out = (aiMaterial *)(*(materials.end() - (6 - i)));

        aiString s;
        s.length = ::ai_snprintf(s.data, AI_MAXLEN, "SkyboxSide_%u", i);
        out->AddProperty(&s, AI_MATKEY_NAME);

        int shading = aiShadingMode_NoShading;
        out->AddProperty(&shading, 1, AI_MATKEY_SHADING_MODEL);
    }

    // Skyboxes are much more difficult. They are represented
    // by six single planes with different textures, so we'll
    // need to build six meshes.

    const ai_real l = 10.0; // the size used by Irrlicht

    // FRONT SIDE
    meshes.push_back(BuildSingleQuadMesh(
            SkyboxVertex(-l, -l, -l, 0, 0, 1, 1.0, 1.0),
            SkyboxVertex(l, -l, -l, 0, 0, 1, 0.0, 1.0),
            SkyboxVertex(l, l, -l, 0, 0, 1, 0.0, 0.0),
            SkyboxVertex(-l, l, -l, 0, 0, 1, 1.0, 0.0)));
    meshes.back()->mMaterialIndex = static_cast<unsigned int>(materials.size() - 6u);

    // LEFT SIDE
    meshes.push_back(BuildSingleQuadMesh(
            SkyboxVertex(l, -l, -l, -1, 0, 0, 1.0, 1.0),
            SkyboxVertex(l, -l, l, -1, 0, 0, 0.0, 1.0),
            SkyboxVertex(l, l, l, -1, 0, 0, 0.0, 0.0),
            SkyboxVertex(l, l, -l, -1, 0, 0, 1.0, 0.0)));
    meshes.back()->mMaterialIndex = static_cast<unsigned int>(materials.size() - 5u);

    // BACK SIDE
    meshes.push_back(BuildSingleQuadMesh(
            SkyboxVertex(l, -l, l, 0, 0, -1, 1.0, 1.0),
            SkyboxVertex(-l, -l, l, 0, 0, -1, 0.0, 1.0),
            SkyboxVertex(-l, l, l, 0, 0, -1, 0.0, 0.0),
            SkyboxVertex(l, l, l, 0, 0, -1, 1.0, 0.0)));
    meshes.back()->mMaterialIndex = static_cast<unsigned int>(materials.size() - 4u);

    // RIGHT SIDE
    meshes.push_back(BuildSingleQuadMesh(
            SkyboxVertex(-l, -l, l, 1, 0, 0, 1.0, 1.0),
            SkyboxVertex(-l, -l, -l, 1, 0, 0, 0.0, 1.0),
            SkyboxVertex(-l, l, -l, 1, 0, 0, 0.0, 0.0),
            SkyboxVertex(-l, l, l, 1, 0, 0, 1.0, 0.0)));
    meshes.back()->mMaterialIndex = static_cast<unsigned int>(materials.size() - 3u);

    // TOP SIDE
    meshes.push_back(BuildSingleQuadMesh(
            SkyboxVertex(l, l, -l, 0, -1, 0, 1.0, 1.0),
            SkyboxVertex(l, l, l, 0, -1, 0, 0.0, 1.0),
            SkyboxVertex(-l, l, l, 0, -1, 0, 0.0, 0.0),
            SkyboxVertex(-l, l, -l, 0, -1, 0, 1.0, 0.0)));
    meshes.back()->mMaterialIndex = static_cast<unsigned int>(materials.size() - 2u);

    // BOTTOM SIDE
    meshes.push_back(BuildSingleQuadMesh(
            SkyboxVertex(l, -l, l, 0, 1, 0, 0.0, 0.0),
            SkyboxVertex(l, -l, -l, 0, 1, 0, 1.0, 0.0),
            SkyboxVertex(-l, -l, -l, 0, 1, 0, 1.0, 1.0),
            SkyboxVertex(-l, -l, l, 0, 1, 0, 0.0, 1.0)));
    meshes.back()->mMaterialIndex = static_cast<unsigned int>(materials.size() - 1u);
}

// ------------------------------------------------------------------------------------------------
void IRRImporter::CopyMaterial(std::vector<aiMaterial *> &materials,
        std::vector<std::pair<aiMaterial *, unsigned int>> &inmaterials,
        unsigned int &defMatIdx,
        aiMesh *mesh) {
    if (inmaterials.empty()) {
        // Do we have a default material? If not we need to create one
        if (UINT_MAX == defMatIdx) {
            defMatIdx = (unsigned int)materials.size();
            // TODO: add this materials to someone?
            /*aiMaterial* mat = new aiMaterial();

            aiString s;
            s.Set(AI_DEFAULT_MATERIAL_NAME);
            mat->AddProperty(&s,AI_MATKEY_NAME);

            aiColor3D c(0.6f,0.6f,0.6f);
            mat->AddProperty(&c,1,AI_MATKEY_COLOR_DIFFUSE);*/
        }
        mesh->mMaterialIndex = defMatIdx;
        return;
    } else if (inmaterials.size() > 1) {
        ASSIMP_LOG_INFO("IRR: Skipping additional materials");
    }

    mesh->mMaterialIndex = (unsigned int)materials.size();
    materials.push_back(inmaterials[0].first);
}

// ------------------------------------------------------------------------------------------------
inline int ClampSpline(int idx, int size) {
    return (idx < 0 ? size + idx : (idx >= size ? idx - size : idx));
}

// ------------------------------------------------------------------------------------------------
inline void FindSuitableMultiple(int &angle) {
    if (angle < 3)
        angle = 3;
    else if (angle < 10)
        angle = 10;
    else if (angle < 20)
        angle = 20;
    else if (angle < 30)
        angle = 30;
}

// ------------------------------------------------------------------------------------------------
void IRRImporter::ComputeAnimations(Node *root, aiNode *real, std::vector<aiNodeAnim *> &anims) {
    ai_assert(nullptr != root && nullptr != real);

    // XXX totally WIP - doesn't produce proper results, need to evaluate
    // whether there's any use for Irrlicht's proprietary scene format
    // outside Irrlicht ...
    // This also applies to the above function of FindSuitableMultiple and ClampSpline which are
    // solely used in this function

    if (root->animators.empty()) {
        return;
    }
    unsigned int total(0);
    for (std::list<Animator>::iterator it = root->animators.begin(); it != root->animators.end(); ++it) {
        if ((*it).type == Animator::UNKNOWN || (*it).type == Animator::OTHER) {
            ASSIMP_LOG_WARN("IRR: Skipping unknown or unsupported animator");
            continue;
        }
        ++total;
    }
    if (!total) {
        return;
    } else if (1 == total) {
        ASSIMP_LOG_WARN("IRR: Adding dummy nodes to simulate multiple animators");
    }

    // NOTE: 1 tick == i millisecond

    unsigned int cur = 0;
    for (std::list<Animator>::iterator it = root->animators.begin();
            it != root->animators.end(); ++it) {
        if ((*it).type == Animator::UNKNOWN || (*it).type == Animator::OTHER) continue;

        Animator &in = *it;
        aiNodeAnim *anim = new aiNodeAnim();

        if (cur != total - 1) {
            // Build a new name - a prefix instead of a suffix because it is
            // easier to check against
            anim->mNodeName.length = ::ai_snprintf(anim->mNodeName.data, AI_MAXLEN,
                    "$INST_DUMMY_%i_%s", total - 1,
                    (root->name.length() ? root->name.c_str() : ""));

            // we'll also need to insert a dummy in the node hierarchy.
            aiNode *dummy = new aiNode();

            for (unsigned int i = 0; i < real->mParent->mNumChildren; ++i)
                if (real->mParent->mChildren[i] == real)
                    real->mParent->mChildren[i] = dummy;

            dummy->mParent = real->mParent;
            dummy->mName = anim->mNodeName;

            dummy->mNumChildren = 1;
            dummy->mChildren = new aiNode *[dummy->mNumChildren];
            dummy->mChildren[0] = real;

            // the transformation matrix of the dummy node is the identity

            real->mParent = dummy;
        } else
            anim->mNodeName.Set(root->name);
        ++cur;

        switch (in.type) {
        case Animator::ROTATION: {
            // -----------------------------------------------------
            // find out how long a full rotation will take
            // This is the least common multiple of 360.f and all
            // three euler angles. Although we'll surely find a
            // possible multiple (haha) it could be somewhat large
            // for our purposes. So we need to modify the angles
            // here in order to get good results.
            // -----------------------------------------------------
            int angles[3];
            angles[0] = (int)(in.direction.x * 100);
            angles[1] = (int)(in.direction.y * 100);
            angles[2] = (int)(in.direction.z * 100);

            angles[0] %= 360;
            angles[1] %= 360;
            angles[2] %= 360;

            if ((angles[0] * angles[1]) != 0 && (angles[1] * angles[2]) != 0) {
                FindSuitableMultiple(angles[0]);
                FindSuitableMultiple(angles[1]);
                FindSuitableMultiple(angles[2]);
            }

            int lcm = 360;

            if (angles[0])
                lcm = Math::lcm(lcm, angles[0]);

            if (angles[1])
                lcm = Math::lcm(lcm, angles[1]);

            if (angles[2])
                lcm = Math::lcm(lcm, angles[2]);

            if (360 == lcm)
                break;

            // find out how many time units we'll need for the finest
            // track (in seconds) - this defines the number of output
            // keys (fps * seconds)
            float max = 0.f;
            if (angles[0])
                max = (float)lcm / angles[0];
            if (angles[1])
                max = std::max(max, (float)lcm / angles[1]);
            if (angles[2])
                max = std::max(max, (float)lcm / angles[2]);

            anim->mNumRotationKeys = (unsigned int)(max * fps);
            anim->mRotationKeys = new aiQuatKey[anim->mNumRotationKeys];

            // begin with a zero angle
            aiVector3D angle;
            for (unsigned int i = 0; i < anim->mNumRotationKeys; ++i) {
                // build the quaternion for the given euler angles
                aiQuatKey &q = anim->mRotationKeys[i];

                q.mValue = aiQuaternion(angle.x, angle.y, angle.z);
                q.mTime = (double)i;

                // increase the angle
                angle += in.direction;
            }

            // This animation is repeated and repeated ...
            anim->mPostState = anim->mPreState = aiAnimBehaviour_REPEAT;
        } break;

        case Animator::FLY_CIRCLE: {
            // -----------------------------------------------------
            // Find out how much time we'll need to perform a
            // full circle.
            // -----------------------------------------------------
            const double seconds = (1. / in.speed) / 1000.;
            const double tdelta = 1000. / fps;

            anim->mNumPositionKeys = (unsigned int)(fps * seconds);
            anim->mPositionKeys = new aiVectorKey[anim->mNumPositionKeys];

            // from Irrlicht, what else should we do than copying it?
            aiVector3D vecU, vecV;
            if (in.direction.y) {
                vecV = aiVector3D(50, 0, 0) ^ in.direction;
            } else
                vecV = aiVector3D(0, 50, 00) ^ in.direction;
            vecV.Normalize();
            vecU = (vecV ^ in.direction).Normalize();

            // build the output keys
            for (unsigned int i = 0; i < anim->mNumPositionKeys; ++i) {
                aiVectorKey &key = anim->mPositionKeys[i];
                key.mTime = i * tdelta;

                const ai_real t = (ai_real)(in.speed * key.mTime);
                key.mValue = in.circleCenter + in.circleRadius * ((vecU * std::cos(t)) + (vecV * std::sin(t)));
            }

            // This animation is repeated and repeated ...
            anim->mPostState = anim->mPreState = aiAnimBehaviour_REPEAT;
        } break;

        case Animator::FLY_STRAIGHT: {
            anim->mPostState = anim->mPreState = (in.loop ? aiAnimBehaviour_REPEAT : aiAnimBehaviour_CONSTANT);
            const double seconds = in.timeForWay / 1000.;
            const double tdelta = 1000. / fps;

            anim->mNumPositionKeys = (unsigned int)(fps * seconds);
            anim->mPositionKeys = new aiVectorKey[anim->mNumPositionKeys];

            aiVector3D diff = in.direction - in.circleCenter;
            const ai_real lengthOfWay = diff.Length();
            diff.Normalize();

            const double timeFactor = lengthOfWay / in.timeForWay;

            // build the output keys
            for (unsigned int i = 0; i < anim->mNumPositionKeys; ++i) {
                aiVectorKey &key = anim->mPositionKeys[i];
                key.mTime = i * tdelta;
                key.mValue = in.circleCenter + diff * ai_real(timeFactor * key.mTime);
            }
        } break;

        case Animator::FOLLOW_SPLINE: {
            // repeat outside the defined time range
            anim->mPostState = anim->mPreState = aiAnimBehaviour_REPEAT;
            const int size = (int)in.splineKeys.size();
            if (!size) {
                // We have no point in the spline. That's bad. Really bad.
                ASSIMP_LOG_WARN("IRR: Spline animators with no points defined");

                delete anim;
                anim = nullptr;
                break;
            } else if (size == 1) {
                // We have just one point in the spline so we don't need the full calculation
                anim->mNumPositionKeys = 1;
                anim->mPositionKeys = new aiVectorKey[anim->mNumPositionKeys];

                anim->mPositionKeys[0].mValue = in.splineKeys[0].mValue;
                anim->mPositionKeys[0].mTime = 0.f;
                break;
            }

            unsigned int ticksPerFull = 15;
            anim->mNumPositionKeys = (unsigned int)(ticksPerFull * fps);
            anim->mPositionKeys = new aiVectorKey[anim->mNumPositionKeys];

            for (unsigned int i = 0; i < anim->mNumPositionKeys; ++i) {
                aiVectorKey &key = anim->mPositionKeys[i];

                const ai_real dt = (i * in.speed * ai_real(0.001));
                const ai_real u = dt - std::floor(dt);
                const int idx = (int)std::floor(dt) % size;

                // get the 4 current points to evaluate the spline
                const aiVector3D &p0 = in.splineKeys[ClampSpline(idx - 1, size)].mValue;
                const aiVector3D &p1 = in.splineKeys[ClampSpline(idx + 0, size)].mValue;
                const aiVector3D &p2 = in.splineKeys[ClampSpline(idx + 1, size)].mValue;
                const aiVector3D &p3 = in.splineKeys[ClampSpline(idx + 2, size)].mValue;

                // compute polynomials
                const ai_real u2 = u * u;
                const ai_real u3 = u2 * 2;

                const ai_real h1 = ai_real(2.0) * u3 - ai_real(3.0) * u2 + ai_real(1.0);
                const ai_real h2 = ai_real(-2.0) * u3 + ai_real(3.0) * u3;
                const ai_real h3 = u3 - ai_real(2.0) * u3;
                const ai_real h4 = u3 - u2;

                // compute the spline tangents
                const aiVector3D t1 = (p2 - p0) * in.tightness;
                aiVector3D t2 = (p3 - p1) * in.tightness;

                // and use them to get the interpolated point
                t2 = (h1 * p1 + p2 * h2 + t1 * h3 + h4 * t2);

                // build a simple translation matrix from it
                key.mValue = t2;
                key.mTime = (double)i;
            }
        } break;
        default:
            // UNKNOWN , OTHER
            break;
        };
        if (anim) {
            anims.push_back(anim);
            ++total;
        }
    }
}

// ------------------------------------------------------------------------------------------------
// This function is maybe more generic than we'd need it here
void SetupMapping(aiMaterial *mat, aiTextureMapping mode, const aiVector3D &axis = aiVector3D(0.f, 0.f, -1.f)) {
    if (nullptr == mat) {
        return;
    }

    // Check whether there are texture properties defined - setup
    // the desired texture mapping mode for all of them and ignore
    // all UV settings we might encounter. WE HAVE NO UVS!

    std::vector<aiMaterialProperty *> p;
    p.reserve(mat->mNumProperties + 1);

    for (unsigned int i = 0; i < mat->mNumProperties; ++i) {
        aiMaterialProperty *prop = mat->mProperties[i];
        if (!::strcmp(prop->mKey.data, "$tex.file")) {
            // Setup the mapping key
            aiMaterialProperty *m = new aiMaterialProperty();
            m->mKey.Set("$tex.mapping");
            m->mIndex = prop->mIndex;
            m->mSemantic = prop->mSemantic;
            m->mType = aiPTI_Integer;

            m->mDataLength = 4;
            m->mData = new char[4];
            *((int *)m->mData) = mode;

            p.push_back(prop);
            p.push_back(m);

            // Setup the mapping axis
            if (mode == aiTextureMapping_CYLINDER || mode == aiTextureMapping_PLANE || mode == aiTextureMapping_SPHERE) {
                m = new aiMaterialProperty();
                m->mKey.Set("$tex.mapaxis");
                m->mIndex = prop->mIndex;
                m->mSemantic = prop->mSemantic;
                m->mType = aiPTI_Float;

                m->mDataLength = sizeof(aiVector3D);
                m->mData = new char[m->mDataLength];
                *((aiVector3D *)m->mData) = axis;
                p.push_back(m);
            }
        } else if (!::strcmp(prop->mKey.data, "$tex.uvwsrc")) {
            delete mat->mProperties[i];
        } else
            p.push_back(prop);
    }

    if (p.empty()) return;

    // rebuild the output array
    if (p.size() > mat->mNumAllocated) {
        delete[] mat->mProperties;
        mat->mProperties = new aiMaterialProperty *[p.size() * 2];

        mat->mNumAllocated = static_cast<unsigned int>(p.size() * 2);
    }
    mat->mNumProperties = (unsigned int)p.size();
    ::memcpy(mat->mProperties, &p[0], sizeof(void *) * mat->mNumProperties);
}

// ------------------------------------------------------------------------------------------------
void IRRImporter::GenerateGraph(Node *root, aiNode *rootOut, aiScene *scene,
        BatchLoader &batch,
        std::vector<aiMesh *> &meshes,
        std::vector<aiNodeAnim *> &anims,
        std::vector<AttachmentInfo> &attach,
        std::vector<aiMaterial *> &materials,
        unsigned int &defMatIdx) {
    unsigned int oldMeshSize = (unsigned int)meshes.size();
    // unsigned int meshTrafoAssign = 0;

    // Now determine the type of the node
    switch (root->type) {
    case Node::ANIMMESH:
    case Node::MESH: {
        if (!root->meshPath.length())
            break;

        // Get the loaded mesh from the scene and add it to
        // the list of all scenes to be attached to the
        // graph we're currently building
        aiScene *localScene = batch.GetImport(root->id);
        if (!localScene) {
            ASSIMP_LOG_ERROR("IRR: Unable to load external file: ", root->meshPath);
            break;
        }
        attach.emplace_back(localScene, rootOut);

        // Now combine the material we've loaded for this mesh
        // with the real materials we got from the file. As we
        // don't execute any pp-steps on the file, the numbers
        // should be equal. If they are not, we can impossibly
        // do this  ...
        if (root->materials.size() != (unsigned int)localScene->mNumMaterials) {
            ASSIMP_LOG_WARN("IRR: Failed to match imported materials "
                            "with the materials found in the IRR scene file");

            break;
        }
        for (unsigned int i = 0; i < localScene->mNumMaterials; ++i) {
            // Delete the old material, we don't need it anymore
            delete localScene->mMaterials[i];

            std::pair<aiMaterial *, unsigned int> &src = root->materials[i];
            localScene->mMaterials[i] = src.first;
        }

        // NOTE: Each mesh should have exactly one material assigned,
        // but we do it in a separate loop if this behavior changes
        // in future.
        for (unsigned int i = 0; i < localScene->mNumMeshes; ++i) {
            // Process material flags
            aiMesh *mesh = localScene->mMeshes[i];

            // If "trans_vertex_alpha" mode is enabled, search all vertex colors
            // and check whether they have a common alpha value. This is quite
            // often the case so we can simply extract it to a shared oacity
            // value.
            std::pair<aiMaterial *, unsigned int> &src = root->materials[mesh->mMaterialIndex];
            aiMaterial *mat = (aiMaterial *)src.first;

            if (mesh->HasVertexColors(0) && src.second & AI_IRRMESH_MAT_trans_vertex_alpha) {
                bool bdo = true;
                for (unsigned int a = 1; a < mesh->mNumVertices; ++a) {

                    if (mesh->mColors[0][a].a != mesh->mColors[0][a - 1].a) {
                        bdo = false;
                        break;
                    }
                }
                if (bdo) {
                    ASSIMP_LOG_INFO("IRR: Replacing mesh vertex alpha with common opacity");

                    for (unsigned int a = 0; a < mesh->mNumVertices; ++a)
                        mesh->mColors[0][a].a = 1.f;

                    mat->AddProperty(&mesh->mColors[0][0].a, 1, AI_MATKEY_OPACITY);
                }
            }

            // If we have a second texture coordinate set and a second texture
            // (either light-map, normal-map, 2layered material) we need to
            // setup the correct UV index for it. The texture can either
            // be diffuse (light-map & 2layer) or a normal map (normal & parallax)
            if (mesh->HasTextureCoords(1)) {

                int idx = 1;
                if (src.second & (AI_IRRMESH_MAT_solid_2layer | AI_IRRMESH_MAT_lightmap)) {
                    mat->AddProperty(&idx, 1, AI_MATKEY_UVWSRC_DIFFUSE(0));
                } else if (src.second & AI_IRRMESH_MAT_normalmap_solid) {
                    mat->AddProperty(&idx, 1, AI_MATKEY_UVWSRC_NORMALS(0));
                }
            }
        }
    } break;

    case Node::LIGHT:
    case Node::CAMERA:

        // We're already finished with lights and cameras
        break;

    case Node::SPHERE: {
        // Generate the sphere model. Our input parameter to
        // the sphere generation algorithm is the number of
        // subdivisions of each triangle - but here we have
        // the number of polygons on a specific axis. Just
        // use some hard-coded limits to approximate this ...
        unsigned int mul = root->spherePolyCountX * root->spherePolyCountY;
        if (mul < 100)
            mul = 2;
        else if (mul < 300)
            mul = 3;
        else
            mul = 4;

        meshes.push_back(StandardShapes::MakeMesh(mul,
                &StandardShapes::MakeSphere));

        // Adjust scaling
        root->scaling *= root->sphereRadius / 2;

        // Copy one output material
        CopyMaterial(materials, root->materials, defMatIdx, meshes.back());

        // Now adjust this output material - if there is a first texture
        // set, setup spherical UV mapping around the Y axis.
        SetupMapping((aiMaterial *)materials.back(), aiTextureMapping_SPHERE);
    } break;

    case Node::CUBE: {
        // Generate an unit cube first
        meshes.push_back(StandardShapes::MakeMesh(
                &StandardShapes::MakeHexahedron));

        // Adjust scaling
        root->scaling *= root->sphereRadius;

        // Copy one output material
        CopyMaterial(materials, root->materials, defMatIdx, meshes.back());

        // Now adjust this output material - if there is a first texture
        // set, setup cubic UV mapping
        SetupMapping((aiMaterial *)materials.back(), aiTextureMapping_BOX);
    } break;

    case Node::SKYBOX: {
        // A sky-box is defined by six materials
        if (root->materials.size() < 6) {
            ASSIMP_LOG_ERROR("IRR: There should be six materials for a skybox");
            break;
        }

        // copy those materials and generate 6 meshes for our new sky-box
        materials.reserve(materials.size() + 6);
        for (unsigned int i = 0; i < 6; ++i)
            materials.insert(materials.end(), root->materials[i].first);

        BuildSkybox(meshes, materials);

        // *************************************************************
        // Skyboxes will require a different code path for rendering,
        // so there must be a way for the user to add special support
        // for IRR skyboxes. We add a 'IRR.SkyBox_' prefix to the node.
        // *************************************************************
        root->name = "IRR.SkyBox_" + root->name;
        ASSIMP_LOG_INFO("IRR: Loading skybox, this will "
                        "require special handling to be displayed correctly");
    } break;

    case Node::TERRAIN: {
        // to support terrains, we'd need to have a texture decoder
        ASSIMP_LOG_ERROR("IRR: Unsupported node - TERRAIN");
    } break;
    default:
        // DUMMY
        break;
    };

    // Check whether we added a mesh (or more than one ...). In this case
    // we'll also need to attach it to the node
    if (oldMeshSize != (unsigned int)meshes.size()) {

        rootOut->mNumMeshes = (unsigned int)meshes.size() - oldMeshSize;
        rootOut->mMeshes = new unsigned int[rootOut->mNumMeshes];

        for (unsigned int a = 0; a < rootOut->mNumMeshes; ++a) {
            rootOut->mMeshes[a] = oldMeshSize + a;
        }
    }

    // Setup the name of this node
    rootOut->mName.Set(root->name);

    // Now compute the final local transformation matrix of the
    // node from the given translation, rotation and scaling values.
    // (the rotation is given in Euler angles, XYZ order)
    // std::swap((float&)root->rotation.z,(float&)root->rotation.y);
    rootOut->mTransformation.FromEulerAnglesXYZ(AI_DEG_TO_RAD(root->rotation));

    // apply scaling
    aiMatrix4x4 &mat = rootOut->mTransformation;
    mat.a1 *= root->scaling.x;
    mat.b1 *= root->scaling.x;
    mat.c1 *= root->scaling.x;
    mat.a2 *= root->scaling.y;
    mat.b2 *= root->scaling.y;
    mat.c2 *= root->scaling.y;
    mat.a3 *= root->scaling.z;
    mat.b3 *= root->scaling.z;
    mat.c3 *= root->scaling.z;

    // apply translation
    mat.a4 += root->position.x;
    mat.b4 += root->position.y;
    mat.c4 += root->position.z;

    // now compute animations for the node
    ComputeAnimations(root, rootOut, anims);

    // Add all children recursively. First allocate enough storage
    // for them, then call us again
    rootOut->mNumChildren = (unsigned int)root->children.size();
    if (rootOut->mNumChildren) {

        rootOut->mChildren = new aiNode *[rootOut->mNumChildren];
        for (unsigned int i = 0; i < rootOut->mNumChildren; ++i) {

            aiNode *node = rootOut->mChildren[i] = new aiNode();
            node->mParent = rootOut;
            GenerateGraph(root->children[i], node, scene, batch, meshes,
                    anims, attach, materials, defMatIdx);
        }
    }
}

void IRRImporter::ParseNodeAttributes(pugi::xml_node &attributesNode, IRRImporter::Node *nd, BatchLoader &batch) {
    ai_assert(!ASSIMP_stricmp(attributesNode.name(), "attributes")); // Node must be <attributes>
    ai_assert(nd != nullptr); // dude

    // Big switch statement that tests for various tags inside <attributes>
    // and applies them to nd
    // I don't believe nodes have boolean attributes
    for (pugi::xml_node &attribute : attributesNode.children()) {
        if (attribute.type() != pugi::node_element) continue;
        if (!ASSIMP_stricmp(attribute.name(), "vector3d")) { // <vector3d />
            VectorProperty prop;
            ReadVectorProperty(prop, attribute);
            if (prop.name == "Position") {
                nd->position = prop.value;
            } else if (prop.name == "Rotation") {
                nd->rotation = prop.value;
            } else if (prop.name == "Scale") {
                nd->scaling = prop.value;
            } else if (Node::CAMERA == nd->type) {
                aiCamera *cam = cameras.back();
                if (prop.name == "Target") {
                    cam->mLookAt = prop.value;
                } else if (prop.name == "UpVector") {
                    cam->mUp = prop.value;
                }
            }
        } else if (!ASSIMP_stricmp(attribute.name(), "float")) { // <float />
            FloatProperty prop;
            ReadFloatProperty(prop, attribute);
            if (prop.name == "FramesPerSecond" && Node::ANIMMESH == nd->type) {
                nd->framesPerSecond = prop.value;
            } else if (Node::CAMERA == nd->type) {
                /*  This is the vertical, not the horizontal FOV.
                 *  We need to compute the right FOV from the
                 *  screen aspect which we don't know yet.
                 */
                if (prop.name == "Fovy") {
                    cameras.back()->mHorizontalFOV = prop.value;
                } else if (prop.name == "Aspect") {
                    cameras.back()->mAspect = prop.value;
                } else if (prop.name == "ZNear") {
                    cameras.back()->mClipPlaneNear = prop.value;
                } else if (prop.name == "ZFar") {
                    cameras.back()->mClipPlaneFar = prop.value;
                }
            } else if (Node::LIGHT == nd->type) {
                /*  Additional light information
                 */
                if (prop.name == "Attenuation") {
                    lights.back()->mAttenuationLinear = prop.value;
                } else if (prop.name == "OuterCone") {
                    lights.back()->mAngleOuterCone = AI_DEG_TO_RAD(prop.value);
                } else if (prop.name == "InnerCone") {
                    lights.back()->mAngleInnerCone = AI_DEG_TO_RAD(prop.value);
                }
            }
            // radius of the sphere to be generated -
            // or alternatively, size of the cube
            else if ((Node::SPHERE == nd->type && prop.name == "Radius") ||
                     (Node::CUBE == nd->type && prop.name == "Size")) {
                nd->sphereRadius = prop.value;
            }
        } else if (!ASSIMP_stricmp(attribute.name(), "int")) { // <int />
            // Only sphere nodes make use of integer attributes
            if (Node::SPHERE == nd->type) {
                IntProperty prop;
                ReadIntProperty(prop, attribute);
                if (prop.name == "PolyCountX") {
                    nd->spherePolyCountX = prop.value;
                } else if (prop.name == "PolyCountY") {
                    nd->spherePolyCountY = prop.value;
                }
            }
        } else if (!ASSIMP_stricmp(attribute.name(), "string") || !ASSIMP_stricmp(attribute.name(), "enum")) { // <string /> or < enum />
            StringProperty prop;
            ReadStringProperty(prop, attribute);
            if (prop.value.length() == 0) continue; // skip empty strings
            if (prop.name == "Name") {
                nd->name = prop.value;

                /*  If we're either a camera or a light source
                 *  we need to update the name in the aiLight/
                 *  aiCamera structure, too.
                 */
                if (Node::CAMERA == nd->type) {
                    cameras.back()->mName.Set(prop.value);
                } else if (Node::LIGHT == nd->type) {
                    lights.back()->mName.Set(prop.value);
                }
            } else if (Node::LIGHT == nd->type && "LightType" == prop.name) {
                if (prop.value == "Spot")
                    lights.back()->mType = aiLightSource_SPOT;
                else if (prop.value == "Point")
                    lights.back()->mType = aiLightSource_POINT;
                else if (prop.value == "Directional")
                    lights.back()->mType = aiLightSource_DIRECTIONAL;
                else {
                    // We won't pass the validation with aiLightSourceType_UNDEFINED,
                    // so we remove the light and replace it with a silly dummy node
                    delete lights.back();
                    lights.pop_back();
                    nd->type = Node::DUMMY;

                    ASSIMP_LOG_ERROR("Ignoring light of unknown type: ", prop.value);
                }
            } else if ((prop.name == "Mesh" && Node::MESH == nd->type) ||
                       Node::ANIMMESH == nd->type) {
                /*  This is the file name of the mesh - either
                 *  animated or not. We need to make sure we setup
                 *  the correct post-processing settings here.
                 */
                unsigned int pp = 0;
                BatchLoader::PropertyMap map;

                /* If the mesh is a static one remove all animations from the impor data
                 */
                if (Node::ANIMMESH != nd->type) {
                    pp |= aiProcess_RemoveComponent;
                    SetGenericProperty<int>(map.ints, AI_CONFIG_PP_RVC_FLAGS,
                            aiComponent_ANIMATIONS | aiComponent_BONEWEIGHTS);
                }

                /*  TODO: maybe implement the protection against recursive
                 *  loading calls directly in BatchLoader? The current
                 *  implementation is not absolutely safe. A LWS and an IRR
                 *  file referencing each other *could* cause the system to
                 *  recurse forever.
                 */

                const std::string extension = GetExtension(prop.value);
                if ("irr" == extension) {
                    ASSIMP_LOG_ERROR("IRR: Can't load another IRR file recursively");
                } else {
                    nd->id = batch.AddLoadRequest(prop.value, pp, &map);
                    nd->meshPath = prop.value;
                }
            }
        }
    }
}

void IRRImporter::ParseAnimators(pugi::xml_node &animatorNode, IRRImporter::Node *nd) {
    Animator *curAnim = nullptr;
    // Make empty animator
    nd->animators.emplace_back();
    curAnim = &nd->animators.back(); // Push it back
    pugi::xml_node attributes = animatorNode.child("attributes");
    if (!attributes) {
        ASSIMP_LOG_WARN("Animator node does not contain attributes. ");
        return;
    }

    for (pugi::xml_node attrib : attributes.children()) {
        // XML may contain useless noes like CDATA
        if (!ASSIMP_stricmp(attrib.name(), "vector3d")) {
            VectorProperty prop;
            ReadVectorProperty(prop, attrib);

            if (curAnim->type == Animator::ROTATION && prop.name == "Rotation") {
                // We store the rotation euler angles in 'direction'
                curAnim->direction = prop.value;
            } else if (curAnim->type == Animator::FOLLOW_SPLINE) {
                // Check whether the vector follows the PointN naming scheme,
                // here N is the ONE-based index of the point
                if (prop.name.length() >= 6 && prop.name.substr(0, 5) == "Point") {
                    // Add a new key to the list
                    curAnim->splineKeys.emplace_back();
                    aiVectorKey &key = curAnim->splineKeys.back();

                    // and parse its properties
                    key.mValue = prop.value;
                    key.mTime = strtoul10(&prop.name[5]);
                }
            } else if (curAnim->type == Animator::FLY_CIRCLE) {
                if (prop.name == "Center") {
                    curAnim->circleCenter = prop.value;
                } else if (prop.name == "Direction") {
                    curAnim->direction = prop.value;

                    // From Irrlicht's source - a workaround for backward compatibility with Irrlicht 1.1
                    if (curAnim->direction == aiVector3D()) {
                        curAnim->direction = aiVector3D(0.f, 1.f, 0.f);
                    } else
                        curAnim->direction.Normalize();
                }
            } else if (curAnim->type == Animator::FLY_STRAIGHT) {
                if (prop.name == "Start") {
                    // We reuse the field here
                    curAnim->circleCenter = prop.value;
                } else if (prop.name == "End") {
                    // We reuse the field here
                    curAnim->direction = prop.value;
                }
            }

            //} else if (!ASSIMP_stricmp(reader->getNodeName(), "bool")) {
        } else if (!ASSIMP_stricmp(attrib.name(), "bool")) {
            BoolProperty prop;
            ReadBoolProperty(prop, attrib);

            if (curAnim->type == Animator::FLY_CIRCLE && prop.name == "Loop") {
                curAnim->loop = prop.value;
            }
            //} else if (!ASSIMP_stricmp(reader->getNodeName(), "float")) {
        } else if (!ASSIMP_stricmp(attrib.name(), "float")) {
            FloatProperty prop;
            ReadFloatProperty(prop, attrib);

            // The speed property exists for several animators
            if (prop.name == "Speed") {
                curAnim->speed = prop.value;
            } else if (curAnim->type == Animator::FLY_CIRCLE && prop.name == "Radius") {
                curAnim->circleRadius = prop.value;
            } else if (curAnim->type == Animator::FOLLOW_SPLINE && prop.name == "Tightness") {
                curAnim->tightness = prop.value;
            }
            //} else if (!ASSIMP_stricmp(reader->getNodeName(), "int")) {
        } else if (!ASSIMP_stricmp(attrib.name(), "int")) {
            IntProperty prop;
            ReadIntProperty(prop, attrib);

            if (curAnim->type == Animator::FLY_STRAIGHT && prop.name == "TimeForWay") {
                curAnim->timeForWay = prop.value;
            }
            //} else if (!ASSIMP_stricmp(reader->getNodeName(), "string") || !ASSIMP_stricmp(reader->getNodeName(), "enum")) {
        } else if (!ASSIMP_stricmp(attrib.name(), "string") || !ASSIMP_stricmp(attrib.name(), "enum")) {
            StringProperty prop;
            ReadStringProperty(prop, attrib);

            if (prop.name == "Type") {
                // type of the animator
                if (prop.value == "rotation") {
                    curAnim->type = Animator::ROTATION;
                } else if (prop.value == "flyCircle") {
                    curAnim->type = Animator::FLY_CIRCLE;
                } else if (prop.value == "flyStraight") {
                    curAnim->type = Animator::FLY_CIRCLE;
                } else if (prop.value == "followSpline") {
                    curAnim->type = Animator::FOLLOW_SPLINE;
                } else {
                    ASSIMP_LOG_WARN("IRR: Ignoring unknown animator: ", prop.value);

                    curAnim->type = Animator::UNKNOWN;
                }
            }
        }
    }
}

IRRImporter::Node *IRRImporter::ParseNode(pugi::xml_node &node, BatchLoader &batch) {
    // Parse <node> tags.
    // <node> tags have various types
    // <node> tags can contain <attribute>, <material>
    // they can also contain other <node> tags, (and can reference other files as well?)
    // ***********************************************************************
    /*  What we're going to do with the node depends
     *  on its type:
     *
     *  "mesh" - Load a mesh from an external file
     *  "cube" - Generate a cube
     *  "skybox" - Generate a skybox
     *  "light" - A light source
     *  "sphere" - Generate a sphere mesh
     *  "animatedMesh" - Load an animated mesh from an external file
     *    and join its animation channels with ours.
     *  "empty" - A dummy node
     *  "camera" - A camera
     *  "terrain" - a terrain node (data comes from a heightmap)
     *  "billboard", ""
     *
     *  Each of these nodes can be animated and all can have multiple
     *  materials assigned (except lights, cameras and dummies, of course).
     *  Said materials and animators are all collected at the bottom
     */
    // ***********************************************************************
    Node *nd;
    pugi::xml_attribute nodeTypeAttrib = node.attribute("type");
    if (!ASSIMP_stricmp(nodeTypeAttrib.value(), "mesh") || !ASSIMP_stricmp(nodeTypeAttrib.value(), "octTree")) {
        // OctTree's and meshes are treated equally
        nd = new Node(Node::MESH);
    } else if (!ASSIMP_stricmp(nodeTypeAttrib.value(), "cube")) {
        nd = new Node(Node::CUBE);
        guessedMeshCnt += 1; // Cube is only one mesh
    } else if (!ASSIMP_stricmp(nodeTypeAttrib.value(), "skybox")) {
        nd = new Node(Node::SKYBOX);
        guessedMeshCnt += 6; // Skybox is a box, with 6 meshes?
    } else if (!ASSIMP_stricmp(nodeTypeAttrib.value(), "camera")) {
        nd = new Node(Node::CAMERA);
        // Setup a temporary name for the camera
        aiCamera *cam = new aiCamera();
        cam->mName.Set(nd->name);
        cameras.push_back(cam);
    } else if (!ASSIMP_stricmp(nodeTypeAttrib.value(), "light")) {
        nd = new Node(Node::LIGHT);
        // Setup a temporary name for the light
        aiLight *cam = new aiLight();
        cam->mName.Set(nd->name);
        lights.push_back(cam);
    } else if (!ASSIMP_stricmp(nodeTypeAttrib.value(), "sphere")) {
        nd = new Node(Node::SPHERE);
        guessedMeshCnt += 1;
    } else if (!ASSIMP_stricmp(nodeTypeAttrib.value(), "animatedMesh")) {
        nd = new Node(Node::ANIMMESH);
    } else if (!ASSIMP_stricmp(nodeTypeAttrib.value(), "empty")) {
        nd = new Node(Node::DUMMY);
    } else if (!ASSIMP_stricmp(nodeTypeAttrib.value(), "terrain")) {
        nd = new Node(Node::TERRAIN);
    } else if (!ASSIMP_stricmp(nodeTypeAttrib.value(), "billBoard")) {
        // We don't support billboards, so ignore them
        ASSIMP_LOG_ERROR("IRR: Billboards are not supported by Assimp");
        nd = new Node(Node::DUMMY);
    } else {
        ASSIMP_LOG_WARN("IRR: Found unknown node: ", nodeTypeAttrib.value());

        /*  We skip the contents of nodes we don't know.
         *  We parse the transformation and all animators
         *  and skip the rest.
         */
        nd = new Node(Node::DUMMY);
    }

    // TODO: consolidate all into one loop
    for (pugi::xml_node subNode : node.children()) {
        // Collect node attributes first
        if (!ASSIMP_stricmp(subNode.name(), "attributes")) {
            ParseNodeAttributes(subNode, nd, batch); // Parse attributes into this node
        } else if (!ASSIMP_stricmp(subNode.name(), "animators")) {
            // Then parse any animators
            // All animators should contain an <attributes> tag

            //  This is an animation path - add a new animator
            //  to the list.
            ParseAnimators(subNode, nd); // Function modifies nd's animator vector
            guessedAnimCnt += 1;
        }

        // Then parse any materials
        // Materials are available to almost all node types
        if (nd->type != Node::DUMMY) {
            if (!ASSIMP_stricmp(subNode.name(), "materials")) {
                // Parse material description directly
                // Each material should contain an <attributes> node
                // with everything specified
                nd->materials.emplace_back();
                std::pair<aiMaterial *, unsigned int> &p = nd->materials.back();
                p.first = ParseMaterial(subNode, p.second);
                guessedMatCnt += 1;
            }
        }
    }

    // Then parse any child nodes
    // Attach the newly created node to the scene-graph
    for (pugi::xml_node child : node.children()) {
        if (!ASSIMP_stricmp(child.name(), "node")) { // Is a child node
            Node *childNd = ParseNode(child, batch); // Repeat this function for all children
            nd->children.push_back(childNd);
        };
    }

    // Return fully specified node
    return nd;
}

// ------------------------------------------------------------------------------------------------
// Imports the given file into the given scene structure.
void IRRImporter::InternReadFile(const std::string &pFile, aiScene *pScene, IOSystem *pIOHandler) {
    std::unique_ptr<IOStream> file(pIOHandler->Open(pFile));
    // Check whether we can read from the file
    if (file == nullptr) {
        throw DeadlyImportError("Failed to open IRR file ", pFile);
    }

    // Construct the irrXML parser
    XmlParser st;
    if (!st.parse(file.get())) {
        throw DeadlyImportError("XML parse error while loading IRR file ", pFile);
    }
    pugi::xml_node documentRoot = st.getRootNode();

    // The root node of the scene
    Node *root = new Node(Node::DUMMY);
    root->parent = nullptr;
    root->name = "<IRRSceneRoot>";

    // Batch loader used to load external models
    BatchLoader batch(pIOHandler);
    // batch.SetBasePath(pFile);

    cameras.reserve(1); // Probably only one camera in entire scene
    lights.reserve(5);

    this->guessedAnimCnt = 0;
    this->guessedMeshCnt = 0;
    this->guessedMatCnt = 0;

    // Parse the XML
    // Find the scene root from document root.
    const pugi::xml_node &sceneRoot = documentRoot.child("irr_scene");
    if (!sceneRoot) {
        delete root;
        throw new DeadlyImportError("IRR: <irr_scene> not found in file");
    }
    for (pugi::xml_node &child : sceneRoot.children()) {
        // XML elements are either nodes, animators, attributes, or materials
        if (!ASSIMP_stricmp(child.name(), "node")) {
            // Recursive collect subtree children
            Node *nd = ParseNode(child, batch);
            // Attach to root
            root->children.push_back(nd);
        }
    }

    //  Now iterate through all cameras and compute their final (horizontal) FOV
    for (aiCamera *cam : cameras) {
        // screen aspect could be missing
        if (cam->mAspect) {
            cam->mHorizontalFOV *= cam->mAspect;
        } else {
            ASSIMP_LOG_WARN("IRR: Camera aspect is not given, can't compute horizontal FOV");
        }
    }

    batch.LoadAll();

    // Allocate a temporary scene data structure
    aiScene *tempScene = new aiScene();
    tempScene->mRootNode = new aiNode();
    tempScene->mRootNode->mName.Set("<IRRRoot>");

    // Copy the cameras to the output array
    if (!cameras.empty()) {
        tempScene->mNumCameras = (unsigned int)cameras.size();
        tempScene->mCameras = new aiCamera *[tempScene->mNumCameras];
        ::memcpy(tempScene->mCameras, &cameras[0], sizeof(void *) * tempScene->mNumCameras);
    }

    // Copy the light sources to the output array
    if (!lights.empty()) {
        tempScene->mNumLights = (unsigned int)lights.size();
        tempScene->mLights = new aiLight *[tempScene->mNumLights];
        ::memcpy(tempScene->mLights, &lights[0], sizeof(void *) * tempScene->mNumLights);
    }

    // temporary data
    std::vector<aiNodeAnim *> anims;
    std::vector<aiMaterial *> materials;
    std::vector<AttachmentInfo> attach;
    std::vector<aiMesh *> meshes;

    // try to guess how much storage we'll need
    anims.reserve(guessedAnimCnt + (guessedAnimCnt >> 2));
    meshes.reserve(guessedMeshCnt + (guessedMeshCnt >> 2));
    materials.reserve(guessedMatCnt + (guessedMatCnt >> 2));

    // Now process our scene-graph recursively: generate final
    // meshes and generate animation channels for all nodes.
    unsigned int defMatIdx = UINT_MAX;
    GenerateGraph(root, tempScene->mRootNode, tempScene,
            batch, meshes, anims, attach, materials, defMatIdx);

    if (!anims.empty()) {
        tempScene->mNumAnimations = 1;
        tempScene->mAnimations = new aiAnimation *[tempScene->mNumAnimations];
        aiAnimation *an = tempScene->mAnimations[0] = new aiAnimation();

        // ***********************************************************
        // This is only the global animation channel of the scene.
        // If there are animated models, they will have separate
        // animation channels in the scene. To display IRR scenes
        // correctly, users will need to combine the global anim
        // channel with all the local animations they want to play
        // ***********************************************************
        an->mName.Set("Irr_GlobalAnimChannel");

        // copy all node animation channels to the global channel
        an->mNumChannels = (unsigned int)anims.size();
        an->mChannels = new aiNodeAnim *[an->mNumChannels];
        ::memcpy(an->mChannels, &anims[0], sizeof(void *) * an->mNumChannels);
    }
    if (!meshes.empty()) {
        // copy all meshes to the temporary scene
        tempScene->mNumMeshes = (unsigned int)meshes.size();
        tempScene->mMeshes = new aiMesh *[tempScene->mNumMeshes];
        ::memcpy(tempScene->mMeshes, &meshes[0], tempScene->mNumMeshes * sizeof(void *));
    }

    // Copy all materials to the output array
    if (!materials.empty()) {
        tempScene->mNumMaterials = (unsigned int)materials.size();
        tempScene->mMaterials = new aiMaterial *[tempScene->mNumMaterials];
        ::memcpy(tempScene->mMaterials, &materials[0], sizeof(void *) * tempScene->mNumMaterials);
    }

    //  Now merge all sub scenes and attach them to the correct
    //  attachment points in the scenegraph.
    SceneCombiner::MergeScenes(&pScene, tempScene, attach,
            AI_INT_MERGE_SCENE_GEN_UNIQUE_NAMES | (!configSpeedFlag ? (AI_INT_MERGE_SCENE_GEN_UNIQUE_NAMES_IF_NECESSARY | AI_INT_MERGE_SCENE_GEN_UNIQUE_MATNAMES) :
                                                                      0));

    // If we have no meshes | no materials now set the INCOMPLETE
    // scene flag. This is necessary if we failed to load all
    // models from external files
    if (!pScene->mNumMeshes || !pScene->mNumMaterials) {
        ASSIMP_LOG_WARN("IRR: No meshes loaded, setting AI_SCENE_FLAGS_INCOMPLETE");
        pScene->mFlags |= AI_SCENE_FLAGS_INCOMPLETE;
    }

    // Finished ... everything destructs automatically and all
    // temporary scenes have already been deleted by MergeScenes()
    delete root;
}

#endif // !! ASSIMP_BUILD_NO_IRR_IMPORTER
