[SOLVED] How To Get File In Assets From Android NDK

How To Get File In Assets From Android NDK

I'm trying to access an image file in the assets folder from the native side. Now I can successfully search through the assets folder and its subdirectories locating the particular file that I am looking for:

AAssetDir* assetDir = AAssetManager_openDir(asset_manager, "images");
const char* filename;
while ((filename = AAssetDir_getNextFileName(assetDir)) != NULL)
{
   __android_log_print(ANDROID_LOG_DEBUG, "Debug", filename);
}

AAssetDir_close(assetDir);

I am also using OSG. I set the image as a texture to my shader with the following code:

texture->setImage(osgDB::readImageFile(fileNameWithPath));

But that file name must include the absolute path as well since it is not located in the same directory. However I found out that I cannot get the absolute path for the assets directory, being that it is compressed along with the APK.

Being that I can't access the absolute path, what other way could I use to get the image? Also to note, I do want to keep the files in the asset folder as appose to the sd card.

Solution

You can read the image from an asset with AAssetManager_open & AAsset_read, but since asset lies in apk you can't get a file path name for it - it is also compressed there. You can save the data to a file and read from that file later or you can directly process the chunk you got from your asset file if OSG allows.

From here:

AAssetDir* assetDir = AAssetManager_openDir(mgr, "");
const char* filename = (const char*)NULL;
while ((filename = AAssetDir_getNextFileName(assetDir)) != NULL) {
    AAsset* asset = AAssetManager_open(mgr, filename, AASSET_MODE_STREAMING);
    char buf[BUFSIZ];
    int nb_read = 0;
    FILE* out = fopen(filename, "w");
    while ((nb_read = AAsset_read(asset, buf, BUFSIZ)) > 0)
        fwrite(buf, nb_read, 1, out);
    fclose(out);
    AAsset_close(asset);
}
AAssetDir_close(assetDir);