hi. I'm beginner.

any one help me.

i was copy  zok_lods's code in my VideoPlayback.cpp and VideoPlaybackRenderer.java.

and than...

how can i use this in my VideoPlayback.java??

 show me example plz

Excellent!

Thanks ALESSANDRO.  I can now get the imagetarget.

Thanks again for your help

Hi, it looks like this line:

jstring js = env->NewStringUTF( imageTarget->getName() );

is wrong; it should be:

jstring js = env->NewStringUTF( imageTarget.getName() );

so, you should rebuild with ndk-build and check that the build is successfull before running the Java app.

 Thanks but it wont display the name of marker

Heres my code in my VideoPlayback.cpp

JNIEXPORT void JNICALL
Java_com_qualcomm_QCARSamples_VideoPlayback_VideoPlaybackRenderer_renderFrame(JNIEnv* env, jobject obj)
{
    //LOG("Java_com_qualcomm_QCARSamples_VideoPlayback_GLRenderer_renderFrame");

    // Clear color and depth buffer
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    // Get the state from QCAR and mark the beginning of a rendering section
    QCAR::State state = QCAR::Renderer::getInstance().begin();

    // Explicitly render the Video Background
    QCAR::Renderer::getInstance().drawVideoBackground();

    glEnable(GL_DEPTH_TEST);
    
    // We must detect if background reflection is active and adjust the culling direction. 
    // If the reflection is active, this means the post matrix has been reflected as well,
    // therefore standard counter clockwise face culling will result in "inside out" models. 
    glEnable(GL_CULL_FACE);
    glCullFace(GL_BACK);
    if(QCAR::Renderer::getInstance().getVideoBackgroundConfig().mReflection == QCAR::VIDEO_BACKGROUND_REFLECTION_ON)
        glFrontFace(GL_CW);  //Front camera
    else
        glFrontFace(GL_CCW);   //Back camera

   
    for (int i=0; i<NUM_TARGETS; i++)
    {
        isTracking[i] = false;
        targetPositiveDimensions[i].data[0] = 0.0;
        targetPositiveDimensions[i].data[1] = 0.0;
    }

    // Did we find any trackables this frame?
    for(int tIdx = 0; tIdx < state.getNumTrackableResults(); tIdx++)
    {
        // Get the trackable:
        const QCAR::TrackableResult* trackableResult = state.getTrackableResult(tIdx);
        const QCAR::ImageTarget& imageTarget = (const QCAR::ImageTarget&) trackableResult->getTrackable();

        int currentTarget;
        //TEST FROM ALESSANDRO

        	 jstring js = env->NewStringUTF(imageTarget->getName());
        	 jclass javaClass = env->GetObjectClass(obj);
        	 jmethodID method = env->GetMethodID(javaClass, "setTargetName", "(Ljava/lang/String;)V");
        	 env->CallVoidMethod(obj, method, js);
    ..

And in VideoPlaybackRenderer.java i made a method like this for displaying the targetname

   public void setTargetName(String targetname)
    {
    	Log.d("TARGETNAME==>", targetname);
    }

In Java, the method must not be declared "native"; in this case it is just a standard Java method, in which you define your logic:

 public void setTargetName(String name) {
   // TODO do something with the 'name' variable

  }

Thanks AlessandroB,

But i how can i set method called "setTargetName(String name)" in ImageTargetsRenderer.java?

i did it like this ist correct? 

  public native void setTargetName(String name);

Hi, suppose you have a method called "setTargetName(String name)" defined in your class ImageTargetsRenderer.java, then the code to pass the name to that Java method from C++ would be:

const QCAR::TrackableResult* result = state.getTrackableResult( tIdx );
const QCAR::Trackable& trackable = result->getTrackable();

jstring js = env->NewStringUTF( trackable.getName() );
jclass javaClass = env->GetObjectClass( obj );
jmethodID method = env->GetMethodID(javaClass, "setTargetName", "(Ljava/lang/String;)V");
env->CallVoidMethod(obj, method, js);

How can i pass the imageTarget.getName() to java?

because it is in videoplayback.cpp

Hi, if you want to retrieve the name of an image target (so that you can play a video from a URL based on that name), you could simply use the getName() function of the ImageTarget class.

 const QCAR::TrackableResult* result = state.getTrackableResult(tIdx);
 const QCAR::Trackable& trackable = result->getTrackable();
 const char *name = trackable.getName();