修改Live2d使用C++层加载Asset资源

原生官方使用的是java层加载Asset资源，然后通过jni获得java加载好的 char* 数据

char *JniBridgeC::LoadFileAsBytesFromJava(const char *filePath, unsigned int *outSize) {
    JNIEnv *env = GetEnv();

    // ファイルロード //文件加载
    jbyteArray obj = (jbyteArray) env->CallStaticObjectMethod(g_JniBridgeJavaClass,
                                                              g_LoadFileMethodId,
                                                              env->NewStringUTF(filePath));
    *outSize = static_cast(env->GetArrayLength(obj));

    char *buffer = new char[*outSize];
    env->GetByteArrayRegion(obj, 0, *outSize, reinterpret_cast(buffer));
   
    return buffer;
}

我们需要更改在c++中直接加载Asset资源，抛弃java层，提高io效率

char* JniBridgeC::LoadFileAsBytesFromCpp(const char *filePath, unsigned int *outSize) {
    JNIEnv *env = GetEnv();

    jobject assetManager = env->CallStaticObjectMethod(g_JniBridgeJavaClass,g_SetAssetManagerId);
    AAssetManager* mgr = AAssetManager_fromJava(env, assetManager);
    if(mgr==NULL)
    {
        LOGE(" %s","AAssetManager==NULL");
    }
    

    AAsset* asset = AAssetManager_open(mgr, filePath,AASSET_MODE_UNKNOWN);
    if(asset==NULL)
    {
        LOGE(" %s","asset==NULL");
    }
    off_t bufferSize = AAsset_getLength(asset);
    unsigned int size = bufferSize;
    *outSize = size;
    char *buffer=(char *)malloc(bufferSize+1);
    buffer[bufferSize]=0;
    int numBytesRead = AAsset_read(asset, buffer,bufferSize);
    AAsset_close(asset);

    return buffer;
}

然后在LAppPal.cpp调用这个函数的地方更换掉

csmByte* LAppPal::LoadFileAsBytes(const string filePath, csmSizeInt* outSize)
{
    //filePath;//
    const char* path = filePath.c_str();

    // file buffer
    //char* buf = JniBridgeC::LoadFileAsBytesFromJava(path, outSize);
    char* buf = JniBridgeC::LoadFileAsBytesFromCpp(path, outSize);

    return reinterpret_cast(buf);
}