add assimp submodule

1 files changed, 889 insertions, 0 deletions

diff --git a/src/mesh/assimp-master/code/AssetLib/SIB/SIBImporter.cpp b/src/mesh/assimp-master/code/AssetLib/SIB/SIBImporter.cpp
new file mode 100644
index 0000000..7b66afa
--- /dev/null
+++ b/src/mesh/assimp-master/code/AssetLib/SIB/SIBImporter.cpp
@@ -0,0 +1,889 @@
+/*
+---------------------------------------------------------------------------
+Open Asset Import Library (assimp)
+---------------------------------------------------------------------------
+
+Copyright (c) 2006-2022, assimp team
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the following
+conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+---------------------------------------------------------------------------
+*/
+
+/** @file  SIBImporter.cpp
+ *  @brief Implementation of the SIB importer class.
+ *
+ *  The Nevercenter Silo SIB format is undocumented.
+ *  All details here have been reverse engineered from
+ *  studying the binary files output by Silo.
+ *
+ *  Nevertheless, this implementation is reasonably complete.
+ */
+
+#ifndef ASSIMP_BUILD_NO_SIB_IMPORTER
+
+// internal headers
+#include "SIBImporter.h"
+#include <assimp/ByteSwapper.h>
+#include <assimp/StreamReader.h>
+#include <assimp/TinyFormatter.h>
+#ifdef ASSIMP_USE_HUNTER
+#include <utf8.h>
+#else
+#include "../contrib/utf8cpp/source/utf8.h"
+#endif
+#include <assimp/importerdesc.h>
+#include <assimp/scene.h>
+#include <assimp/DefaultLogger.hpp>
+#include <assimp/IOSystem.hpp>
+#include <assimp/StringUtils.h>
+
+#include <map>
+
+using namespace Assimp;
+
+static const aiImporterDesc desc = {
+    "Silo SIB Importer",
+    "Richard Mitton (http://www.codersnotes.com/about)",
+    "",
+    "Does not apply subdivision.",
+    aiImporterFlags_SupportBinaryFlavour,
+    0, 0,
+    0, 0,
+    "sib"
+};
+
+struct SIBChunk {
+    uint32_t Tag;
+    uint32_t Size;
+} PACK_STRUCT;
+
+enum {
+    POS,
+    NRM,
+    UV,
+    N
+};
+
+typedef std::pair<uint32_t, uint32_t> SIBPair;
+
+struct SIBEdge {
+    uint32_t faceA, faceB;
+    bool creased;
+};
+
+struct SIBMesh {
+    aiMatrix4x4 axis;
+    uint32_t numPts;
+    std::vector<aiVector3D> pos, nrm, uv;
+    std::vector<uint32_t> idx;
+    std::vector<uint32_t> faceStart;
+    std::vector<uint32_t> mtls;
+    std::vector<SIBEdge> edges;
+    std::map<SIBPair, uint32_t> edgeMap;
+};
+
+struct SIBObject {
+    aiString name;
+    aiMatrix4x4 axis;
+    size_t meshIdx, meshCount;
+};
+
+struct SIB {
+    std::vector<aiMaterial *> mtls;
+    std::vector<aiMesh *> meshes;
+    std::vector<aiLight *> lights;
+    std::vector<SIBObject> objs, insts;
+};
+
+// ------------------------------------------------------------------------------------------------
+static SIBEdge &GetEdge(SIBMesh *mesh, uint32_t posA, uint32_t posB) {
+    SIBPair pair = (posA < posB) ? SIBPair(posA, posB) : SIBPair(posB, posA);
+    std::map<SIBPair, uint32_t>::iterator it = mesh->edgeMap.find(pair);
+    if (it != mesh->edgeMap.end())
+        return mesh->edges[it->second];
+
+    SIBEdge edge;
+    edge.creased = false;
+    edge.faceA = edge.faceB = 0xffffffff;
+    mesh->edgeMap[pair] = static_cast<uint32_t>(mesh->edges.size());
+    mesh->edges.push_back(edge);
+    return mesh->edges.back();
+}
+
+// ------------------------------------------------------------------------------------------------
+// Helpers for reading chunked data.
+
+#define TAG(A, B, C, D) ((A << 24) | (B << 16) | (C << 8) | D)
+
+static SIBChunk ReadChunk(StreamReaderLE *stream) {
+    SIBChunk chunk;
+    chunk.Tag = stream->GetU4();
+    chunk.Size = stream->GetU4();
+    if (chunk.Size > stream->GetRemainingSizeToLimit())
+        ASSIMP_LOG_ERROR("SIB: Chunk overflow");
+    ByteSwap::Swap4(&chunk.Tag);
+    return chunk;
+}
+
+static aiColor3D ReadColor(StreamReaderLE *stream) {
+    float r = stream->GetF4();
+    float g = stream->GetF4();
+    float b = stream->GetF4();
+    stream->GetU4(); // Colors have an unused(?) 4th component.
+    return aiColor3D(r, g, b);
+}
+
+static void UnknownChunk(StreamReaderLE * /*stream*/, const SIBChunk &chunk) {
+    char temp[4] = {
+        static_cast<char>((chunk.Tag >> 24) & 0xff),
+        static_cast<char>((chunk.Tag >> 16) & 0xff),
+        static_cast<char>((chunk.Tag >> 8) & 0xff),
+        static_cast<char>(chunk.Tag & 0xff)
+    };
+
+    ASSIMP_LOG_WARN("SIB: Skipping unknown '", ai_str_toprintable(temp, 4), "' chunk.");
+}
+
+// Reads a UTF-16LE string and returns it at UTF-8.
+static aiString ReadString(StreamReaderLE *stream, uint32_t numWChars) {
+    if (nullptr == stream || 0 == numWChars) {
+        return aiString();
+    }
+
+    // Allocate buffers (max expansion is 1 byte -> 4 bytes for UTF-8)
+    std::vector<unsigned char> str;
+    str.reserve(numWChars * 4 + 1);
+    uint16_t *temp = new uint16_t[numWChars];
+    for (uint32_t n = 0; n < numWChars; ++n) {
+        temp[n] = stream->GetU2();
+    }
+
+    // Convert it and NUL-terminate.
+    const uint16_t *start(temp), *end(temp + numWChars);
+    utf8::utf16to8(start, end, back_inserter(str));
+    str[str.size() - 1] = '\0';
+
+    // Return the final string.
+    aiString result = aiString((const char *)&str[0]);
+    delete[] temp;
+
+    return result;
+}
+
+// ------------------------------------------------------------------------------------------------
+// Constructor to be privately used by Importer
+SIBImporter::SIBImporter() {
+    // empty
+}
+
+// ------------------------------------------------------------------------------------------------
+// Destructor, private as well
+SIBImporter::~SIBImporter() {
+    // empty
+}
+
+// ------------------------------------------------------------------------------------------------
+// Returns whether the class can handle the format of the given file.
+bool SIBImporter::CanRead(const std::string &filename, IOSystem * /*pIOHandler*/, bool /*checkSig*/) const {
+    return SimpleExtensionCheck(filename, "sib");
+}
+
+// ------------------------------------------------------------------------------------------------
+const aiImporterDesc *SIBImporter::GetInfo() const {
+    return &desc;
+}
+
+// ------------------------------------------------------------------------------------------------
+static void ReadVerts(SIBMesh *mesh, StreamReaderLE *stream, uint32_t count) {
+    if (nullptr == mesh || nullptr == stream) {
+        return;
+    }
+
+    mesh->pos.resize(count);
+    for (uint32_t n = 0; n < count; ++n) {
+        mesh->pos[n].x = stream->GetF4();
+        mesh->pos[n].y = stream->GetF4();
+        mesh->pos[n].z = stream->GetF4();
+    }
+}
+
+// ------------------------------------------------------------------------------------------------
+static void ReadFaces(SIBMesh *mesh, StreamReaderLE *stream) {
+    uint32_t ptIdx = 0;
+    while (stream->GetRemainingSizeToLimit() > 0) {
+        uint32_t numPoints = stream->GetU4();
+
+        // Store room for the N index channels, plus the point count.
+        size_t pos = mesh->idx.size() + 1;
+        mesh->idx.resize(pos + numPoints * N);
+        mesh->idx[pos - 1] = numPoints;
+        uint32_t *idx = &mesh->idx[pos];
+
+        mesh->faceStart.push_back(static_cast<uint32_t>(pos - 1));
+        mesh->mtls.push_back(0);
+
+        // Read all the position data.
+        // UV/normals will be supplied later.
+        // Positions are supplied indexed already, so we preserve that
+        // mapping. UVs are supplied uniquely, so we allocate unique indices.
+        for (uint32_t n = 0; n < numPoints; n++, idx += N, ptIdx++) {
+            uint32_t p = stream->GetU4();
+            if (p >= mesh->pos.size())
+                throw DeadlyImportError("Vertex index is out of range.");
+            idx[POS] = p;
+            idx[NRM] = ptIdx;
+            idx[UV] = ptIdx;
+        }
+    }
+
+    // Allocate data channels for normals/UVs.
+    mesh->nrm.resize(ptIdx, aiVector3D(0, 0, 0));
+    mesh->uv.resize(ptIdx, aiVector3D(0, 0, 0));
+
+    mesh->numPts = ptIdx;
+}
+
+// ------------------------------------------------------------------------------------------------
+static void ReadUVs(SIBMesh *mesh, StreamReaderLE *stream) {
+    while (stream->GetRemainingSizeToLimit() > 0) {
+        uint32_t faceIdx = stream->GetU4();
+        uint32_t numPoints = stream->GetU4();
+
+        if (faceIdx >= mesh->faceStart.size())
+            throw DeadlyImportError("Invalid face index.");
+
+        uint32_t pos = mesh->faceStart[faceIdx];
+        uint32_t *idx = &mesh->idx[pos + 1];
+
+        for (uint32_t n = 0; n < numPoints; n++, idx += N) {
+            uint32_t id = idx[UV];
+            mesh->uv[id].x = stream->GetF4();
+            mesh->uv[id].y = stream->GetF4();
+        }
+    }
+}
+
+// ------------------------------------------------------------------------------------------------
+static void ReadMtls(SIBMesh *mesh, StreamReaderLE *stream) {
+    // Material assignments are stored run-length encoded.
+    // Also, we add 1 to each material so that we can use mtl #0
+    // as the default material.
+    uint32_t prevFace = stream->GetU4();
+    uint32_t prevMtl = stream->GetU4() + 1;
+    while (stream->GetRemainingSizeToLimit() > 0) {
+        uint32_t face = stream->GetU4();
+        uint32_t mtl = stream->GetU4() + 1;
+        while (prevFace < face) {
+            if (prevFace >= mesh->mtls.size())
+                throw DeadlyImportError("Invalid face index.");
+            mesh->mtls[prevFace++] = prevMtl;
+        }
+
+        prevFace = face;
+        prevMtl = mtl;
+    }
+
+    while (prevFace < mesh->mtls.size())
+        mesh->mtls[prevFace++] = prevMtl;
+}
+
+// ------------------------------------------------------------------------------------------------
+static void ReadAxis(aiMatrix4x4 &axis, StreamReaderLE *stream) {
+    axis.a4 = stream->GetF4();
+    axis.b4 = stream->GetF4();
+    axis.c4 = stream->GetF4();
+    axis.d4 = 1;
+    axis.a1 = stream->GetF4();
+    axis.b1 = stream->GetF4();
+    axis.c1 = stream->GetF4();
+    axis.d1 = 0;
+    axis.a2 = stream->GetF4();
+    axis.b2 = stream->GetF4();
+    axis.c2 = stream->GetF4();
+    axis.d2 = 0;
+    axis.a3 = stream->GetF4();
+    axis.b3 = stream->GetF4();
+    axis.c3 = stream->GetF4();
+    axis.d3 = 0;
+}
+
+// ------------------------------------------------------------------------------------------------
+static void ReadEdges(SIBMesh *mesh, StreamReaderLE *stream) {
+    while (stream->GetRemainingSizeToLimit() > 0) {
+        uint32_t posA = stream->GetU4();
+        uint32_t posB = stream->GetU4();
+        GetEdge(mesh, posA, posB);
+    }
+}
+
+// ------------------------------------------------------------------------------------------------
+static void ReadCreases(SIBMesh *mesh, StreamReaderLE *stream) {
+    while (stream->GetRemainingSizeToLimit() > 0) {
+        uint32_t edge = stream->GetU4();
+        if (edge >= mesh->edges.size())
+            throw DeadlyImportError("SIB: Invalid edge index.");
+        mesh->edges[edge].creased = true;
+    }
+}
+
+// ------------------------------------------------------------------------------------------------
+static void ConnectFaces(SIBMesh *mesh) {
+    // Find faces connected to each edge.
+    size_t numFaces = mesh->faceStart.size();
+    for (size_t faceIdx = 0; faceIdx < numFaces; faceIdx++) {
+        uint32_t *idx = &mesh->idx[mesh->faceStart[faceIdx]];
+        uint32_t numPoints = *idx++;
+        uint32_t prev = idx[(numPoints - 1) * N + POS];
+
+        for (uint32_t i = 0; i < numPoints; i++, idx += N) {
+            uint32_t next = idx[POS];
+
+            // Find this edge.
+            SIBEdge &edge = GetEdge(mesh, prev, next);
+
+            // Link this face onto it.
+            // This gives potentially undesirable normals when used
+            // with non-2-manifold surfaces, but then so does Silo to begin with.
+            if (edge.faceA == 0xffffffff)
+                edge.faceA = static_cast<uint32_t>(faceIdx);
+            else if (edge.faceB == 0xffffffff)
+                edge.faceB = static_cast<uint32_t>(faceIdx);
+
+            prev = next;
+        }
+    }
+}
+
+// ------------------------------------------------------------------------------------------------
+static aiVector3D CalculateVertexNormal(SIBMesh *mesh, uint32_t faceIdx, uint32_t pos,
+        const std::vector<aiVector3D> &faceNormals) {
+    // Creased edges complicate this. We need to find the start/end range of the
+    // ring of faces that touch this position.
+    // We do this in two passes. The first pass is to find the end of the range,
+    // the second is to work backwards to the start and calculate the final normal.
+    aiVector3D vtxNormal;
+    for (int pass = 0; pass < 2; pass++) {
+        vtxNormal = aiVector3D(0, 0, 0);
+        uint32_t startFaceIdx = faceIdx;
+        uint32_t prevFaceIdx = faceIdx;
+
+        // Process each connected face.
+        while (true) {
+            // Accumulate the face normal.
+            vtxNormal += faceNormals[faceIdx];
+
+            uint32_t nextFaceIdx = 0xffffffff;
+
+            // Move to the next edge sharing this position.
+            uint32_t *idx = &mesh->idx[mesh->faceStart[faceIdx]];
+            uint32_t numPoints = *idx++;
+            uint32_t posA = idx[(numPoints - 1) * N + POS];
+            for (uint32_t n = 0; n < numPoints; n++, idx += N) {
+                uint32_t posB = idx[POS];
+
+                // Test if this edge shares our target position.
+                if (posA == pos || posB == pos) {
+                    SIBEdge &edge = GetEdge(mesh, posA, posB);
+
+                    // Non-manifold meshes can produce faces which share
+                    // positions but have no edge entry, so check it.
+                    if (edge.faceA == faceIdx || edge.faceB == faceIdx) {
+                        // Move to whichever side we didn't just come from.
+                        if (!edge.creased) {
+                            if (edge.faceA != prevFaceIdx && edge.faceA != faceIdx && edge.faceA != 0xffffffff)
+                                nextFaceIdx = edge.faceA;
+                            else if (edge.faceB != prevFaceIdx && edge.faceB != faceIdx && edge.faceB != 0xffffffff)
+                                nextFaceIdx = edge.faceB;
+                        }
+                    }
+                }
+
+                posA = posB;
+            }
+
+            // Stop once we hit either an creased/unconnected edge, or we
+            // wrapped around and hit our start point.
+            if (nextFaceIdx == 0xffffffff || nextFaceIdx == startFaceIdx)
+                break;
+
+            prevFaceIdx = faceIdx;
+            faceIdx = nextFaceIdx;
+        }
+    }
+
+    // Normalize it.
+    float len = vtxNormal.Length();
+    if (len > 0.000000001f)
+        vtxNormal /= len;
+    return vtxNormal;
+}
+
+// ------------------------------------------------------------------------------------------------
+static void CalculateNormals(SIBMesh *mesh) {
+    size_t numFaces = mesh->faceStart.size();
+
+    // Calculate face normals.
+    std::vector<aiVector3D> faceNormals(numFaces);
+    for (size_t faceIdx = 0; faceIdx < numFaces; faceIdx++) {
+        uint32_t *idx = &mesh->idx[mesh->faceStart[faceIdx]];
+        uint32_t numPoints = *idx++;
+
+        aiVector3D faceNormal(0, 0, 0);
+
+        uint32_t *prev = &idx[(numPoints - 1) * N];
+
+        for (uint32_t i = 0; i < numPoints; i++) {
+            uint32_t *next = &idx[i * N];
+
+            faceNormal += mesh->pos[prev[POS]] ^ mesh->pos[next[POS]];
+            prev = next;
+        }
+
+        faceNormals[faceIdx] = faceNormal;
+    }
+
+    // Calculate vertex normals.
+    for (size_t faceIdx = 0; faceIdx < numFaces; faceIdx++) {
+        uint32_t *idx = &mesh->idx[mesh->faceStart[faceIdx]];
+        uint32_t numPoints = *idx++;
+
+        for (uint32_t i = 0; i < numPoints; i++) {
+            uint32_t pos = idx[i * N + POS];
+            uint32_t nrm = idx[i * N + NRM];
+            aiVector3D vtxNorm = CalculateVertexNormal(mesh, static_cast<uint32_t>(faceIdx), pos, faceNormals);
+            mesh->nrm[nrm] = vtxNorm;
+        }
+    }
+}
+
+// ------------------------------------------------------------------------------------------------
+struct TempMesh {
+    std::vector<aiVector3D> vtx;
+    std::vector<aiVector3D> nrm;
+    std::vector<aiVector3D> uv;
+    std::vector<aiFace> faces;
+};
+
+static void ReadShape(SIB *sib, StreamReaderLE *stream) {
+    SIBMesh smesh;
+    aiString name;
+
+    while (stream->GetRemainingSizeToLimit() >= sizeof(SIBChunk)) {
+        SIBChunk chunk = ReadChunk(stream);
+        unsigned oldLimit = stream->SetReadLimit(stream->GetCurrentPos() + chunk.Size);
+
+        switch (chunk.Tag) {
+        case TAG('M', 'I', 'R', 'P'): break; // mirror plane maybe?
+        case TAG('I', 'M', 'R', 'P'): break; // instance mirror? (not supported here yet)
+        case TAG('D', 'I', 'N', 'F'): break; // display info, not needed
+        case TAG('P', 'I', 'N', 'F'): break; // ?
+        case TAG('V', 'M', 'I', 'R'): break; // ?
+        case TAG('F', 'M', 'I', 'R'): break; // ?
+        case TAG('T', 'X', 'S', 'M'): break; // ?
+        case TAG('F', 'A', 'H', 'S'): break; // ?
+        case TAG('V', 'R', 'T', 'S'): ReadVerts(&smesh, stream, chunk.Size / 12); break;
+        case TAG('F', 'A', 'C', 'S'): ReadFaces(&smesh, stream); break;
+        case TAG('F', 'T', 'V', 'S'): ReadUVs(&smesh, stream); break;
+        case TAG('S', 'N', 'A', 'M'): name = ReadString(stream, chunk.Size / 2); break;
+        case TAG('F', 'A', 'M', 'A'): ReadMtls(&smesh, stream); break;
+        case TAG('A', 'X', 'I', 'S'): ReadAxis(smesh.axis, stream); break;
+        case TAG('E', 'D', 'G', 'S'): ReadEdges(&smesh, stream); break;
+        case TAG('E', 'C', 'R', 'S'): ReadCreases(&smesh, stream); break;
+        default: UnknownChunk(stream, chunk); break;
+        }
+
+        stream->SetCurrentPos(stream->GetReadLimit());
+        stream->SetReadLimit(oldLimit);
+    }
+
+    ai_assert(smesh.faceStart.size() == smesh.mtls.size()); // sanity check
+
+    // Silo doesn't store any normals in the file - we need to compute
+    // them ourselves. We can't let AssImp handle it as AssImp doesn't
+    // know about our creased edges.
+    ConnectFaces(&smesh);
+    CalculateNormals(&smesh);
+
+    // Construct the transforms.
+    aiMatrix4x4 worldToLocal = smesh.axis;
+    worldToLocal.Inverse();
+    aiMatrix4x4 worldToLocalN = worldToLocal;
+    worldToLocalN.a4 = worldToLocalN.b4 = worldToLocalN.c4 = 0.0f;
+    worldToLocalN.Inverse().Transpose();
+
+    // Allocate final mesh data.
+    // We'll allocate one mesh for each material. (we'll strip unused ones after)
+    std::vector<TempMesh> meshes(sib->mtls.size());
+
+    // Un-index the source data and apply to each vertex.
+    for (unsigned fi = 0; fi < smesh.faceStart.size(); fi++) {
+        uint32_t start = smesh.faceStart[fi];
+        uint32_t mtl = smesh.mtls[fi];
+        uint32_t *idx = &smesh.idx[start];
+
+        if (mtl >= meshes.size()) {
+            ASSIMP_LOG_ERROR("SIB: Face material index is invalid.");
+            mtl = 0;
+        }
+
+        TempMesh &dest = meshes[mtl];
+
+        aiFace face;
+        face.mNumIndices = *idx++;
+        face.mIndices = new unsigned[face.mNumIndices];
+        for (unsigned pt = 0; pt < face.mNumIndices; pt++, idx += N) {
+            size_t vtxIdx = dest.vtx.size();
+            face.mIndices[pt] = static_cast<unsigned int>(vtxIdx);
+
+            // De-index it. We don't need to validate here as
+            // we did it when creating the data.
+            aiVector3D pos = smesh.pos[idx[POS]];
+            aiVector3D nrm = smesh.nrm[idx[NRM]];
+            aiVector3D uv = smesh.uv[idx[UV]];
+
+            // The verts are supplied in world-space, so let's
+            // transform them back into the local space of this mesh:
+            pos = worldToLocal * pos;
+            nrm = worldToLocalN * nrm;
+
+            dest.vtx.push_back(pos);
+            dest.nrm.push_back(nrm);
+            dest.uv.push_back(uv);
+        }
+        dest.faces.push_back(face);
+    }
+
+    SIBObject obj;
+    obj.name = name;
+    obj.axis = smesh.axis;
+    obj.meshIdx = sib->meshes.size();
+
+    // Now that we know the size of everything,
+    // we can build the final one-material-per-mesh data.
+    for (size_t n = 0; n < meshes.size(); n++) {
+        TempMesh &src = meshes[n];
+        if (src.faces.empty())
+            continue;
+
+        aiMesh *mesh = new aiMesh;
+        mesh->mName = name;
+        mesh->mNumFaces = static_cast<unsigned int>(src.faces.size());
+        mesh->mFaces = new aiFace[mesh->mNumFaces];
+        mesh->mNumVertices = static_cast<unsigned int>(src.vtx.size());
+        mesh->mVertices = new aiVector3D[mesh->mNumVertices];
+        mesh->mNormals = new aiVector3D[mesh->mNumVertices];
+        mesh->mTextureCoords[0] = new aiVector3D[mesh->mNumVertices];
+        mesh->mNumUVComponents[0] = 2;
+        mesh->mMaterialIndex = static_cast<unsigned int>(n);
+
+        for (unsigned i = 0; i < mesh->mNumVertices; i++) {
+            mesh->mVertices[i] = src.vtx[i];
+            mesh->mNormals[i] = src.nrm[i];
+            mesh->mTextureCoords[0][i] = src.uv[i];
+        }
+        for (unsigned i = 0; i < mesh->mNumFaces; i++) {
+            mesh->mFaces[i] = src.faces[i];
+        }
+
+        sib->meshes.push_back(mesh);
+    }
+
+    obj.meshCount = sib->meshes.size() - obj.meshIdx;
+    sib->objs.push_back(obj);
+}
+
+// ------------------------------------------------------------------------------------------------
+static void ReadMaterial(SIB *sib, StreamReaderLE *stream) {
+    aiColor3D diff = ReadColor(stream);
+    aiColor3D ambi = ReadColor(stream);
+    aiColor3D spec = ReadColor(stream);
+    aiColor3D emis = ReadColor(stream);
+    float shiny = (float)stream->GetU4();
+
+    uint32_t nameLen = stream->GetU4();
+    aiString name = ReadString(stream, nameLen / 2);
+    uint32_t texLen = stream->GetU4();
+    aiString tex = ReadString(stream, texLen / 2);
+
+    aiMaterial *mtl = new aiMaterial();
+    mtl->AddProperty(&diff, 1, AI_MATKEY_COLOR_DIFFUSE);
+    mtl->AddProperty(&ambi, 1, AI_MATKEY_COLOR_AMBIENT);
+    mtl->AddProperty(&spec, 1, AI_MATKEY_COLOR_SPECULAR);
+    mtl->AddProperty(&emis, 1, AI_MATKEY_COLOR_EMISSIVE);
+    mtl->AddProperty(&shiny, 1, AI_MATKEY_SHININESS);
+    mtl->AddProperty(&name, AI_MATKEY_NAME);
+    if (tex.length > 0) {
+        mtl->AddProperty(&tex, AI_MATKEY_TEXTURE_DIFFUSE(0));
+        mtl->AddProperty(&tex, AI_MATKEY_TEXTURE_AMBIENT(0));
+    }
+
+    sib->mtls.push_back(mtl);
+}
+
+// ------------------------------------------------------------------------------------------------
+static void ReadLightInfo(aiLight *light, StreamReaderLE *stream) {
+    uint32_t type = stream->GetU4();
+    switch (type) {
+    case 0: light->mType = aiLightSource_POINT; break;
+    case 1: light->mType = aiLightSource_SPOT; break;
+    case 2: light->mType = aiLightSource_DIRECTIONAL; break;
+    default: light->mType = aiLightSource_UNDEFINED; break;
+    }
+
+    light->mPosition.x = stream->GetF4();
+    light->mPosition.y = stream->GetF4();
+    light->mPosition.z = stream->GetF4();
+    light->mDirection.x = stream->GetF4();
+    light->mDirection.y = stream->GetF4();
+    light->mDirection.z = stream->GetF4();
+    light->mColorDiffuse = ReadColor(stream);
+    light->mColorAmbient = ReadColor(stream);
+    light->mColorSpecular = ReadColor(stream);
+    ai_real spotExponent = stream->GetF4();
+    ai_real spotCutoff = stream->GetF4();
+    light->mAttenuationConstant = stream->GetF4();
+    light->mAttenuationLinear = stream->GetF4();
+    light->mAttenuationQuadratic = stream->GetF4();
+
+    // Silo uses the OpenGL default lighting model for it's
+    // spot cutoff/exponent. AssImp unfortunately, does not.
+    // Let's try and approximate it by solving for the
+    // 99% and 1% percentiles.
+    //    OpenGL: I = cos(angle)^E
+    //   Solving: angle = acos(I^(1/E))
+    ai_real E = ai_real(1.0) / std::max(spotExponent, (ai_real)0.00001);
+    ai_real inner = std::acos(std::pow((ai_real)0.99, E));
+    ai_real outer = std::acos(std::pow((ai_real)0.01, E));
+
+    // Apply the cutoff.
+    outer = std::min(outer, AI_DEG_TO_RAD(spotCutoff));
+
+    light->mAngleInnerCone = std::min(inner, outer);
+    light->mAngleOuterCone = outer;
+}
+
+static void ReadLight(SIB *sib, StreamReaderLE *stream) {
+    aiLight *light = new aiLight();
+
+    while (stream->GetRemainingSizeToLimit() >= sizeof(SIBChunk)) {
+        SIBChunk chunk = ReadChunk(stream);
+        unsigned oldLimit = stream->SetReadLimit(stream->GetCurrentPos() + chunk.Size);
+
+        switch (chunk.Tag) {
+        case TAG('L', 'N', 'F', 'O'): ReadLightInfo(light, stream); break;
+        case TAG('S', 'N', 'A', 'M'): light->mName = ReadString(stream, chunk.Size / 2); break;
+        default: UnknownChunk(stream, chunk); break;
+        }
+
+        stream->SetCurrentPos(stream->GetReadLimit());
+        stream->SetReadLimit(oldLimit);
+    }
+
+    sib->lights.push_back(light);
+}
+
+// ------------------------------------------------------------------------------------------------
+static void ReadScale(aiMatrix4x4 &axis, StreamReaderLE *stream) {
+    aiMatrix4x4 scale;
+    scale.a1 = stream->GetF4();
+    scale.b1 = stream->GetF4();
+    scale.c1 = stream->GetF4();
+    scale.d1 = stream->GetF4();
+    scale.a2 = stream->GetF4();
+    scale.b2 = stream->GetF4();
+    scale.c2 = stream->GetF4();
+    scale.d2 = stream->GetF4();
+    scale.a3 = stream->GetF4();
+    scale.b3 = stream->GetF4();
+    scale.c3 = stream->GetF4();
+    scale.d3 = stream->GetF4();
+    scale.a4 = stream->GetF4();
+    scale.b4 = stream->GetF4();
+    scale.c4 = stream->GetF4();
+    scale.d4 = stream->GetF4();
+
+    axis = axis * scale;
+}
+
+static void ReadInstance(SIB *sib, StreamReaderLE *stream) {
+    SIBObject inst;
+    uint32_t shapeIndex = 0;
+
+    while (stream->GetRemainingSizeToLimit() >= sizeof(SIBChunk)) {
+        SIBChunk chunk = ReadChunk(stream);
+        unsigned oldLimit = stream->SetReadLimit(stream->GetCurrentPos() + chunk.Size);
+
+        switch (chunk.Tag) {
+        case TAG('D', 'I', 'N', 'F'): break; // display info, not needed
+        case TAG('P', 'I', 'N', 'F'): break; // ?
+        case TAG('A', 'X', 'I', 'S'): ReadAxis(inst.axis, stream); break;
+        case TAG('I', 'N', 'S', 'I'): shapeIndex = stream->GetU4(); break;
+        case TAG('S', 'M', 'T', 'X'): ReadScale(inst.axis, stream); break;
+        case TAG('S', 'N', 'A', 'M'): inst.name = ReadString(stream, chunk.Size / 2); break;
+        default: UnknownChunk(stream, chunk); break;
+        }
+
+        stream->SetCurrentPos(stream->GetReadLimit());
+        stream->SetReadLimit(oldLimit);
+    }
+
+    if (shapeIndex >= sib->objs.size()) {
+        throw DeadlyImportError("SIB: Invalid shape index.");
+    }
+
+    const SIBObject &src = sib->objs[shapeIndex];
+    inst.meshIdx = src.meshIdx;
+    inst.meshCount = src.meshCount;
+    sib->insts.push_back(inst);
+}
+
+// ------------------------------------------------------------------------------------------------
+static void CheckVersion(StreamReaderLE *stream) {
+    uint32_t version = stream->GetU4();
+    if (version < 1 || version > 2) {
+        throw DeadlyImportError("SIB: Unsupported file version.");
+    }
+}
+
+static void ReadScene(SIB *sib, StreamReaderLE *stream) {
+    // Parse each chunk in turn.
+    while (stream->GetRemainingSizeToLimit() >= sizeof(SIBChunk)) {
+        SIBChunk chunk = ReadChunk(stream);
+        unsigned oldLimit = stream->SetReadLimit(stream->GetCurrentPos() + chunk.Size);
+
+        switch (chunk.Tag) {
+        case TAG('H', 'E', 'A', 'D'): CheckVersion(stream); break;
+        case TAG('S', 'H', 'A', 'P'): ReadShape(sib, stream); break;
+        case TAG('G', 'R', 'P', 'S'): break; // group assignment, we don't import this
+        case TAG('T', 'E', 'X', 'P'): break; // ?
+        case TAG('I', 'N', 'S', 'T'): ReadInstance(sib, stream); break;
+        case TAG('M', 'A', 'T', 'R'): ReadMaterial(sib, stream); break;
+        case TAG('L', 'G', 'H', 'T'): ReadLight(sib, stream); break;
+        default: UnknownChunk(stream, chunk); break;
+        }
+
+        stream->SetCurrentPos(stream->GetReadLimit());
+        stream->SetReadLimit(oldLimit);
+    }
+}
+
+// ------------------------------------------------------------------------------------------------
+// Imports the given file into the given scene structure.
+void SIBImporter::InternReadFile(const std::string &pFile,
+        aiScene *pScene, IOSystem *pIOHandler) {
+
+    auto file = pIOHandler->Open(pFile, "rb");
+    if (!file)
+        throw DeadlyImportError("SIB: Could not open ", pFile);
+
+    StreamReaderLE stream(file);
+
+    // We should have at least one chunk
+    if (stream.GetRemainingSize() < 16)
+        throw DeadlyImportError("SIB file is either empty or corrupt: ", pFile);
+
+    SIB sib;
+
+    // Default material.
+    aiMaterial *defmtl = new aiMaterial;
+    aiString defname = aiString(AI_DEFAULT_MATERIAL_NAME);
+    defmtl->AddProperty(&defname, AI_MATKEY_NAME);
+    sib.mtls.push_back(defmtl);
+
+    // Read it all.
+    ReadScene(&sib, &stream);
+
+    // Join the instances and objects together.
+    size_t firstInst = sib.objs.size();
+    sib.objs.insert(sib.objs.end(), sib.insts.begin(), sib.insts.end());
+    sib.insts.clear();
+
+    // Transfer to the aiScene.
+    pScene->mNumMaterials = static_cast<unsigned int>(sib.mtls.size());
+    pScene->mNumMeshes = static_cast<unsigned int>(sib.meshes.size());
+    pScene->mNumLights = static_cast<unsigned int>(sib.lights.size());
+    pScene->mMaterials = pScene->mNumMaterials ? new aiMaterial *[pScene->mNumMaterials] : nullptr;
+    pScene->mMeshes = pScene->mNumMeshes ? new aiMesh *[pScene->mNumMeshes] : nullptr;
+    pScene->mLights = pScene->mNumLights ? new aiLight *[pScene->mNumLights] : nullptr;
+    if (pScene->mNumMaterials)
+        memcpy(pScene->mMaterials, &sib.mtls[0], sizeof(aiMaterial *) * pScene->mNumMaterials);
+    if (pScene->mNumMeshes)
+        memcpy(pScene->mMeshes, &sib.meshes[0], sizeof(aiMesh *) * pScene->mNumMeshes);
+    if (pScene->mNumLights)
+        memcpy(pScene->mLights, &sib.lights[0], sizeof(aiLight *) * pScene->mNumLights);
+
+    // Construct the root node.
+    size_t childIdx = 0;
+    aiNode *root = new aiNode();
+    root->mName.Set("<SIBRoot>");
+    root->mNumChildren = static_cast<unsigned int>(sib.objs.size() + sib.lights.size());
+    root->mChildren = root->mNumChildren ? new aiNode *[root->mNumChildren] : nullptr;
+    pScene->mRootNode = root;
+
+    // Add nodes for each object.
+    for (size_t n = 0; n < sib.objs.size(); n++) {
+        ai_assert(root->mChildren);
+        SIBObject &obj = sib.objs[n];
+        aiNode *node = new aiNode;
+        root->mChildren[childIdx++] = node;
+        node->mName = obj.name;
+        node->mParent = root;
+        node->mTransformation = obj.axis;
+
+        node->mNumMeshes = static_cast<unsigned int>(obj.meshCount);
+        node->mMeshes = node->mNumMeshes ? new unsigned[node->mNumMeshes] : nullptr;
+        for (unsigned i = 0; i < node->mNumMeshes; i++)
+            node->mMeshes[i] = static_cast<unsigned int>(obj.meshIdx + i);
+
+        // Mark instanced objects as being so.
+        if (n >= firstInst) {
+            node->mMetaData = aiMetadata::Alloc(1);
+            node->mMetaData->Set(0, "IsInstance", true);
+        }
+    }
+
+    // Add nodes for each light.
+    // (no transformation as the light is already in world space)
+    for (size_t n = 0; n < sib.lights.size(); n++) {
+        ai_assert(root->mChildren);
+        aiLight *light = sib.lights[n];
+        if (nullptr != light) {
+            aiNode *node = new aiNode;
+            root->mChildren[childIdx++] = node;
+            node->mName = light->mName;
+            node->mParent = root;
+        }
+    }
+}
+
+#endif // !! ASSIMP_BUILD_NO_SIB_IMPORTER