assimp.assimp/code/glTFExporter.cpp

/*
Open Asset Import Library (assimp)
----------------------------------------------------------------------

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All rights reserved.

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following disclaimer.

* Redistributions in binary form must reproduce the above
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* Neither the name of the assimp team, nor the names of its
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"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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*/



#ifndef ASSIMP_BUILD_NO_EXPORT
#ifndef ASSIMP_BUILD_NO_GLTF_EXPORTER

#include "glTFExporter.h"
#include "Exceptional.h"
#include "StringComparison.h"
#include "ByteSwapper.h"

#include <assimp/version.h>
#include <assimp/IOSystem.hpp>
#include <assimp/Exporter.hpp>
#include <assimp/material.h>
#include <assimp/scene.h>

#include <boost/foreach.hpp>
#include <boost/scoped_ptr.hpp>
#include <boost/shared_ptr.hpp>

#include "glTFAssetWriter.h"

using namespace rapidjson;

using namespace Assimp;
using namespace glTF;

namespace Assimp {

    // ------------------------------------------------------------------------------------------------
    // Worker function for exporting a scene to GLTF. Prototyped and registered in Exporter.cpp
    void ExportSceneGLTF(const char* pFile, IOSystem* pIOSystem, const aiScene* pScene, const ExportProperties* pProperties)
    {
        // invoke the exporter
        glTFExporter exporter(pFile, pIOSystem, pScene, pProperties, false);
    }

    // ------------------------------------------------------------------------------------------------
    // Worker function for exporting a scene to GLB. Prototyped and registered in Exporter.cpp
    void ExportSceneGLB(const char* pFile, IOSystem* pIOSystem, const aiScene* pScene, const ExportProperties* pProperties)
    {
        // invoke the exporter
        glTFExporter exporter(pFile, pIOSystem, pScene, pProperties, true);
    }

} // end of namespace Assimp



glTFExporter::glTFExporter(const char* filename, IOSystem* pIOSystem, const aiScene* pScene,
                           const ExportProperties* pProperties, bool isBinary)
    : mFilename(filename)
    , mIOSystem(pIOSystem)
    , mScene(pScene)
    , mProperties(pProperties)
{
    boost::scoped_ptr<Asset> asset(new glTF::Asset(pIOSystem));
    mAsset = asset.get();

    if (isBinary) {
        asset->SetAsBinary();
    }

    ExportMetadata();

    //for (unsigned int i = 0; i < pScene->mNumAnimations; ++i) {}

    //for (unsigned int i = 0; i < pScene->mNumCameras; ++i) {}

    //for (unsigned int i = 0; i < pScene->mNumLights; ++i) {}


    ExportMaterials();

    ExportMeshes();

    //for (unsigned int i = 0; i < pScene->mNumTextures; ++i) {}


    if (mScene->mRootNode) {
        ExportNode(mScene->mRootNode);
    }

    ExportScene();


    glTF::AssetWriter writer(*mAsset);
    writer.WriteFile(filename);
}


static void CopyValue(const aiMatrix4x4& v, glTF::mat4& o)
{ 
    o[ 0] = v.a1; o[ 1] = v.b1; o[ 2] = v.c1; o[ 3] = v.d1;
    o[ 4] = v.a2; o[ 5] = v.b2; o[ 6] = v.c2; o[ 7] = v.d2;
    o[ 8] = v.a3; o[ 9] = v.b3; o[10] = v.c3; o[11] = v.d3;
    o[12] = v.a4; o[13] = v.b4; o[14] = v.c4; o[15] = v.d4;
}

inline Ref<Accessor> ExportData(Asset& a, std::string& meshName, Ref<Buffer>& buffer,
    unsigned int count, void* data, AttribType::Value typeIn, AttribType::Value typeOut, ComponentType compType, bool isIndices = false)
{
    if (!count || !data) return Ref<Accessor>();

    unsigned int numCompsIn = AttribType::GetNumComponents(typeIn);
    unsigned int numCompsOut = AttribType::GetNumComponents(typeOut);
    unsigned int bytesPerComp = ComponentTypeSize(compType);

    size_t offset = buffer->byteLength;
    size_t length = count * numCompsOut * bytesPerComp;
    buffer->Grow(length);

    // bufferView
    Ref<BufferView> bv = a.bufferViews.Create(a.FindUniqueID(meshName, "view"));
    bv->buffer = buffer;
    bv->byteOffset = 0;
    bv->byteLength = length; //! The target that the WebGL buffer should be bound to.
    bv->target = isIndices ? BufferViewTarget_ELEMENT_ARRAY_BUFFER : BufferViewTarget_ARRAY_BUFFER;

    // accessor
    Ref<Accessor> acc = a.accessors.Create(a.FindUniqueID(meshName, "accessor"));
    acc->bufferView = bv;
    acc->byteOffset = offset;
    acc->byteStride = 0;
    acc->componentType = compType;
    acc->count = count;
    acc->type = typeOut;

    // copy the data
    acc->WriteData(count, data, numCompsIn*bytesPerComp);

    return acc;
}

namespace {
    void GetMatScalar(const aiMaterial* mat, float& val, const char* propName, int type, int idx) {
        if (mat->Get(propName, type, idx, val) == AI_SUCCESS) {}
    }
}

void glTFExporter::GetMatColorOrTex(const aiMaterial* mat, glTF::TexProperty& prop, const char* propName, int type, int idx, aiTextureType tt)
{
    aiString tex;
    aiColor4D col;
    if (mat->GetTextureCount(tt) > 0) {
        if (mat->Get(AI_MATKEY_TEXTURE(tt, 0), tex) == AI_SUCCESS) {
            std::string path = tex.C_Str();

            if (path.size() > 0) {
                if (path[0] != '*') {
                    std::map<std::string, size_t>::iterator it = mTexturesByPath.find(path);
                    if (it != mTexturesByPath.end()) {
                        prop.texture = mAsset->textures.Get(it->second);
                    }
                }

                if (!prop.texture) {
                    std::string texId = mAsset->FindUniqueID("", "texture");
                    prop.texture = mAsset->textures.Create(texId);
                    mTexturesByPath[path] = prop.texture.GetIndex();

                    std::string imgId = mAsset->FindUniqueID("", "image");
                    prop.texture->source = mAsset->images.Create(imgId);

                    if (path[0] == '*') { // embedded
                        aiTexture* tex = mScene->mTextures[atoi(&path[1])];

                        uint8_t* data = reinterpret_cast<uint8_t*>(tex->pcData);
                        prop.texture->source->SetData(data, tex->mWidth, *mAsset);

                        if (tex->achFormatHint[0]) {
                            std::string mimeType = "image/";
                            mimeType += (memcmp(tex->achFormatHint, "jpg", 3) == 0) ? "jpeg" : tex->achFormatHint;
                            prop.texture->source->mimeType = mimeType;
                        }
                    }
                    else {
                        prop.texture->source->uri = path;
                    }
                }
            }
        }
    }

    if (mat->Get(propName, type, idx, col) == AI_SUCCESS) {
        prop.color[0] = col.r; prop.color[1] = col.g; prop.color[2] = col.b; prop.color[3] = col.a;
    }
}

void glTFExporter::ExportMaterials()
{
    aiString aiName;
    for (unsigned int i = 0; i < mScene->mNumMaterials; ++i) {
        const aiMaterial* mat = mScene->mMaterials[i];

        
        std::string name;
        if (mat->Get(AI_MATKEY_NAME, aiName) == AI_SUCCESS) {
            name = aiName.C_Str();
        }
        name = mAsset->FindUniqueID(name, "material");

        Ref<Material> m = mAsset->materials.Create(name);

        GetMatColorOrTex(mat, m->ambient, AI_MATKEY_COLOR_AMBIENT, aiTextureType_AMBIENT);
        GetMatColorOrTex(mat, m->diffuse, AI_MATKEY_COLOR_DIFFUSE, aiTextureType_DIFFUSE);
        GetMatColorOrTex(mat, m->specular, AI_MATKEY_COLOR_SPECULAR, aiTextureType_SPECULAR);
        GetMatColorOrTex(mat, m->emission, AI_MATKEY_COLOR_EMISSIVE, aiTextureType_EMISSIVE);

        GetMatScalar(mat, m->shininess, AI_MATKEY_SHININESS);
    }
}

void glTFExporter::ExportMeshes()
{
    for (unsigned int i = 0; i < mScene->mNumMeshes; ++i) {
        const aiMesh* aim = mScene->mMeshes[i];

        std::string meshId = mAsset->FindUniqueID(aim->mName.C_Str(), "mesh");
        Ref<Mesh> m = mAsset->meshes.Create(meshId);
        m->primitives.resize(1);
        Mesh::Primitive& p = m->primitives.back();

        p.material = mAsset->materials.Get(aim->mMaterialIndex);

        std::string bufferId = mAsset->FindUniqueID(meshId, "buffer");

        Ref<Buffer> b = mAsset->GetBodyBuffer();
        if (!b) {
            b = mAsset->buffers.Create(bufferId);
        }

        Ref<Accessor> v = ExportData(*mAsset, meshId, b, aim->mNumVertices, aim->mVertices, AttribType::VEC3, AttribType::VEC3, ComponentType_FLOAT);
        if (v) p.attributes.position.push_back(v);

        Ref<Accessor> n = ExportData(*mAsset, meshId, b, aim->mNumVertices, aim->mNormals, AttribType::VEC3, AttribType::VEC3, ComponentType_FLOAT);
        if (n) p.attributes.normal.push_back(n);

        for (int i = 0; i < AI_MAX_NUMBER_OF_TEXTURECOORDS; ++i) {
            if (aim->mNumUVComponents[i] > 0) {
                AttribType::Value type = (aim->mNumUVComponents[i] == 2) ? AttribType::VEC2 : AttribType::VEC3;
                Ref<Accessor> tc = ExportData(*mAsset, meshId, b, aim->mNumVertices, aim->mTextureCoords[i], AttribType::VEC3, type, ComponentType_FLOAT, true);
                if (tc) p.attributes.texcoord.push_back(tc);
            }
        }

        if (aim->mNumFaces > 0) {
            unsigned int nIndicesPerFace = aim->mFaces[0].mNumIndices;
            std::vector<uint16_t> indices;
            indices.resize(aim->mNumFaces * nIndicesPerFace);
            for (size_t i = 0; i < aim->mNumFaces; ++i) {
                for (size_t j = 0; j < nIndicesPerFace; ++j) {
                    indices[i*nIndicesPerFace + j] = uint16_t(aim->mFaces[i].mIndices[j]);
                }
            }
            p.indices = ExportData(*mAsset, meshId, b, indices.size(), &indices[0], AttribType::SCALAR, AttribType::SCALAR, ComponentType_UNSIGNED_SHORT);
        }

        switch (aim->mPrimitiveTypes) {
            case aiPrimitiveType_POLYGON:
                p.mode = PrimitiveMode_TRIANGLES; break; // TODO implement this
            case aiPrimitiveType_LINE:
                p.mode = PrimitiveMode_LINES; break;
            case aiPrimitiveType_POINT:
                p.mode = PrimitiveMode_POINTS; break;
            default: // aiPrimitiveType_TRIANGLE
                p.mode = PrimitiveMode_TRIANGLES;
        }
    }
}

size_t glTFExporter::ExportNode(const aiNode* n)
{
    Ref<Node> node = mAsset->nodes.Create(mAsset->FindUniqueID(n->mName.C_Str(), "node"));

    if (!n->mTransformation.IsIdentity()) {
        node->matrix.isPresent = true;
        CopyValue(n->mTransformation, node->matrix.value);
    }

    for (unsigned int i = 0; i < n->mNumMeshes; ++i) {
        node->meshes.push_back(mAsset->meshes.Get(n->mMeshes[i]));
    }

    for (unsigned int i = 0; i < n->mNumChildren; ++i) {
        size_t idx = ExportNode(n->mChildren[i]);
        node->children.push_back(mAsset->nodes.Get(idx));
    }

    return node.GetIndex();
}


void glTFExporter::ExportScene()
{
    const char* sceneName = "defaultScene";
    Ref<Scene> scene = mAsset->scenes.Create(sceneName);

    // root node will be the first one exported (idx 0)
    if (mAsset->nodes.Size() > 0) {
        scene->nodes.push_back(mAsset->nodes.Get(size_t(0)));
    }

    // set as the default scene
    mAsset->scene = scene;
}

void glTFExporter::ExportMetadata()
{
    glTF::AssetMetadata& asset = mAsset->asset;
    asset.version = 1;

    char buffer[256];
    ai_snprintf(buffer, 256, "Open Asset Import Library (assimp v%d.%d.%d)",
        aiGetVersionMajor(), aiGetVersionMinor(), aiGetVersionRevision());

    asset.generator = buffer;
}







#endif // ASSIMP_BUILD_NO_GLTF_EXPORTER
#endif // ASSIMP_BUILD_NO_EXPORT