AssetManager is not working from NDK

Question

I am working with OpenGL ES 3.0 and using Eclipse NDK for rendering volume data with Google Nexus. I am using AssetManager for loading the volume data which is a raw file of 16 MB to the real device but it's not working. I stored the resource in the Asset folder included headers too but still i am receiving the same error in logcat __load_uniform_float:802>:GL_INVALID_OPERATION I tried to Google some related examples but couldn't find any.

Here is my code:

int LoadVolume()
{
    GLubyte *pdata;
    const unsigned int BUFFER_SIZE = XDIM*YDIM*ZDIM;
    GLubyte buffer[BUFFER_SIZE];
    AAssetManager*mgr;
    AAsset* asset=AAssetManager_open(mgr,"Engine256.raw",AASSET_MODE_BUFFER);
    if(!asset)
    {
    __android_log_print(ANDROID_LOG_ERROR, "TAG", "_ASSET_NOT_FOUND_");
     return 0;
    }
    pdata=(GLubyte*)AAsset_read(asset,buffer,BUFFER_SIZE);

    AAsset_close(asset);

   glGenTextures ( 1,&textureId );
   glBindTexture ( GL_TEXTURE_3D,textureId );
   glTexImage3D ( GL_TEXTURE_3D, 0, GL_RED,XDIM, YDIM, ZDIM, 0,
                  GL_RED, GL_UNSIGNED_BYTE,pdata);

   glTexParameteri ( GL_TEXTURE_3D, GL_TEXTURE_MIN_FILTER, GL_LINEAR );
   glTexParameteri ( GL_TEXTURE_3D, GL_TEXTURE_MAG_FILTER,GL_LINEAR);
   glTexParameteri ( GL_TEXTURE_3D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE );
   glTexParameteri ( GL_TEXTURE_3D, GL_TEXTURE_WRAP_T,GL_CLAMP_TO_EDGE );
   glTexParameteri ( GL_TEXTURE_3D, GL_TEXTURE_WRAP_R, GL_CLAMP_TO_EDGE);

   glBindTexture ( GL_TEXTURE_3D, 0 );
   return 1;
}

copy your code and paste it and select the complete code and format it by using Control+k — Shailendra Madda, Jul 07 '14 at 07:03
Please specify what is not working. Don't let us guess please. Which line causes the error? How much is buffer size actually? — greenapps, Jul 07 '14 at 07:16
You are loading the file in memory (not to the device) and do nothing with the content in buffer. Now where is the code error line? — greenapps, Jul 07 '14 at 07:23
i just started ndk a few days back so i have no idea.there is no error shown in line but failed to load data and i dont know the reason. — user3492894, Jul 07 '14 at 07:28

score 8 · Accepted Answer · edited May 23 '17 at 10:32

If you look at these two lines:

AAssetManager*mgr;
AAsset* asset=AAssetManager_open(mgr,"Engine256.raw",AASSET_MODE_BUFFER);

You're declaring mgr as a pointer variable, but you don't assign a value to it. Then you use it on the next line, while it's uninitialized.

You need to pass an AssetManager object from your Java code into the native code through your JNI interface, and then obtain the AAssetManager by using this call, where assetManager is the Java object passed in, which comes into the native code as a jobject type parameter.

AAssetManager *mgr = AAssetManager_fromJava(env, assetManager);

This question/answer show in some more detail how to pass the Java object to the native code: Can't access AAssetManager in native code passed from Java in WallpaperService.

AssetManager is not working from NDK

1 Answers1