Develop Reference

2nd uv in Aframe for ambient occlusion

I would like to use baked AO on an obj-model in Aframe. Don Mccurdy explains
that AO needs a 2nd UV channel and how to solve this in Java here:
https://github.com/aframevr/aframe/issues/2721
I tried it but I don`t get it to work!
var geometry = mesh.geometry;
geometry.addAttribute( 'uv2', new THREE.BufferAttribute( geometry.attributes.uv.array, 2 ) );
How do I point this js-lines to my obj-model in Aframe?
Thanks a lot for help, appreciate! Best, can

Ideally, I'd suggest opening the OBJ file in Blender, adding the Ambient Occlusion texture as described in the Blender docs, then exporting to glTF. The rest will be handled automatically with A-Frame's gltf-model component, and will load more quickly.
If converting to another format isn't an option, you'll need to write a custom component that listens for the model to load, then traverses every mesh in the model (there might be more than one!) and creates an extra UV set:
AFRAME.registerComponent('copy-uvs', {
init: function () {
this.el.addEventListener('model-loaded', function (e) {
e.detail.model.traverse(function(object) {
if (object.isMesh && object.geometry.attributes.uv) {
var geometry = object.geometry;
geometry.setAttribute('uv2', geometry.attributes.uv);
console.log('copied UVs!');
}
});
});
}
});
This copy-uvs component would need to be attached to the same element as your OBJ model.

How to remove a symbol from a map

I am currently creating a map which updates based on users selection and displays 5 location closest to them. This works however when the user changes their selection the map updates and displays the 5 NEW locations as well as the 5 OLD locations.
I am not sure how to remove the old symbols.
public void displayResults(ArrayList allLocation) {
SymbolManager sm = new SymbolManager(mapView,map,styleMap);
sm.deleteAll();
SymList.clear();
sm.setIconAllowOverlap(true);
sm.setIconIgnorePlacement(true);
int count = 1;
for (LocationDetails a : allLocation
) {
// gets the distance from user to Location
double LocationLat = Double.parseDouble(a.getLatitude());
double LocationLng = Double.parseDouble(a.getLongitude());
float[] disResult = new float[1];
Location.distanceBetween(lat, lng, LocationLat, LocationLng, disResult);
results.append(count + ": " + a.getName() + " " + "\n");
distanceResults.append(Math.round(disResult[0]) + "m" + "\n");
SymbolOptions symbolOptions = new SymbolOptions()
.withLatLng(new LatLng(LocationLat, LocationLng))
.withIconImage("marker-11")
.withTextField(""+count)
.withIconColor("black")
.withIconSize(2.5f);
SymList.add(symbolOptions);
count++;
}
LatLngBounds latLngBounds = new LatLngBounds.Builder()
.include(SymList.get(0).getLatLng())
.include(SymList.get(1).getLatLng())
.include(SymList.get(2).getLatLng())
.include(SymList.get(3).getLatLng())
.include(SymList.get(4).getLatLng())
.build();
map.animateCamera(CameraUpdateFactory.newLatLngBounds(latLngBounds, 50), 2000);
for(SymbolOptions a : SymList){
sm.create(a);
}
SymList.clear();
}

I have been using mapbox for 3 months. After hours of research I discovered that on Android the only way to remove a Symbol or any element on the map was to reload all the elements from scratch. Unfortunately, there is currently no method to remove a single element.
So I suggest you create a container class in which to save your items.

If your use case only requires showing about five markers on the map at a time, it might be easier to use native sources and SymbolLayers rather than relying on the abstraction provided by the SymbolManager.
For example, this icon updates based on API response Android demo shows how to add a GeoJSON source and corresponding layer to the map, then update said source to get a different visual result. Basically all of the logic you will need is encapsulated here, but your GeoJSON will be a FeatureCollection of multiple (namely, 5) features rather than just one point.
So, you can set up your symbols similarly to how it's done in the linked example:
private void initSpaceStationSymbolLayer(#NonNull Style style) {
style.addImage("space-station-icon-id",
BitmapFactory.decodeResource(
this.getResources(), R.drawable.iss));
style.addSource(new GeoJsonSource("source-id"));
style.addLayer(new SymbolLayer("layer-id", "source-id").withProperties(
iconImage("space-station-icon-id"),
iconIgnorePlacement(true),
iconAllowOverlap(true),
iconSize(.7f)
));
}
, and then update the source's GeoJSON to the new locations closest to the user's position, similar to the updateMarkerPostion method:
private void updateMarkerPosition(LatLng position) {
// This method is where we update the marker position once we have new coordinates. First we
// check if this is the first time we are executing this handler, the best way to do this is
// check if marker is null;
if (map.getStyle() != null) {
GeoJsonSource spaceStationSource = map.getStyle().getSourceAs("source-id");
if (spaceStationSource != null) {
spaceStationSource.setGeoJson(FeatureCollection.fromFeature(
Feature.fromGeometry(Point.fromLngLat(position.getLongitude(), position.getLatitude()))));
}
}
// Lastly, animate the camera to the new position so the user
// wont have to search for the marker and then return.
map.animateCamera(CameraUpdateFactory.newLatLng(position));
}
A few modifications will need to be made, of course, but this option might be more direct for your implementation specifically.

Why do dynamically added symbols show up grey in Mapbox

When I tap the screen, a marker gets added to the middle of a Mapbox map. The first marker shows up as it is supposed to. However as soon as I add a second marker, the markers show up grey.
Here is the code I use to create the symbol source and the symbol layer, as well as the onMapClickListener where the features of the symbol source get updated with the new marker. All this code is in the onStyleLoaded method.
//Create the symbol source
Drawable drawable = ResourcesCompat.getDrawable(getResources(), R.drawable.ic_map_marker_blue, null);
Bitmap marker = BitmapUtils.getBitmapFromDrawable(drawable);
style.addImage(BLUE_MARKER_IMAGE, marker);
GeoJsonSource geoJsonSourceSymbol = new GeoJsonSource(SYMBOL_SOURCE_ID);
style.addSource(geoJsonSourceSymbol);
//Create the symbol layer
symbolLayer = new SymbolLayer(SYMBOL_LAYER_ID, SYMBOL_SOURCE_ID);
symbolLayer.setProperties(iconImage(BLUE_MARKER_IMAGE), iconOffset(new Float[] {0f, -10f}));
style.addLayer(symbolLayer);
mapboxMap.addOnMapClickListener(new MapboxMap.OnMapClickListener() {
#Override
public boolean onMapClick(#NonNull LatLng point) {
final LatLng mapTargetLatLng = mapboxMap.getCameraPosition().target;
Point mapTarget = Point.fromLngLat(mapTargetLatLng.getLongitude(),mapTargetLatLng.getLatitude());
pointList.add(mapTarget);
featureList.add(Feature.fromGeometry(mapTarget));
if (style.getLayer(SYMBOL_LAYER_ID) != null) {
GeoJsonSource geoJsonSourceSymbol = style.getSourceAs(SYMBOL_SOURCE_ID);
if (geoJsonSourceSymbol != null) {
geoJsonSourceSymbol.setGeoJson(FeatureCollection.fromFeatures(featureList));
}
}
return true;
}
});
Is there something I'm doing wrong or is it not possible to dynamically add symbols using data-driven styling?

Are you using an emulator? The Mapbox team already knows of SymbolLayer rendering issues on emulated devices:
https://github.com/mapbox/mapbox-gl-native/issues/10829
https://github.com/mapbox/mapbox-plugins-android/issues/1082

Add space between graph and tick labels in GraphView?

I am trying out the GraphView Library for creating charts on Android. It looks quite decent, but I am wondering if there is a way to add some space between the tick labels and the graph itself. As you can see, there is basically none:
I use the following code to set up the graph (very similar to the example):
GraphView graph = (GraphView)view.findViewById(R.id.graph);
LineGraphSeries<DataPoint> series = new LineGraphSeries<DataPoint>(new DataPoint[] {
new DataPoint(0, 1),
new DataPoint(1, 5),
new DataPoint(2, 3)
});
graph.addSeries(series);
I tried using graph.getGridLabelRenderer().setPadding(), but that just added padding around the whole graph.
So, is there a way to put some padding around those labels?

yes it is possible in the current version in github (will be released in 4.0.1).
There is the method:
graph.getGridLabelRenderer().setLabelsSpace(x)

Follow this example to give your graph a custom label formatter. By doing so, you can at least add space padding to your y-axis labels (if not newline spacing to your x-axis labels).
// GraphView 4.x
graph.getGridLabelRenderer().setLabelFormatter(
new DefaultLabelFormatter() {
#Override
public String formatLabel(double value, boolean isValueX) {
if (isValueX) {
// show normal x values
return super.formatLabel(value, isValueX);
} else {
// show currency for y values
return super.formatLabel(value, isValueX) + " €";
}
}
}
);
I pulled this example from the GraphView documentation.
Otherwise, I found it interesting that someone chose this answer as the best response for a similar question.

Face detection not working for Front Camera

So basically, i have this code,
if(mCamera.getParameters().getMaxNumDetectedFaces()==0)
{
System.out.println("Face detection not avaliable");
}
else
{
System.out.println("Max faces: " + Integer.toString(mCamera.getParameters().getMaxNumDetectedFaces()));
}
mCamera.setFaceDetectionListener(new FaceDetectionListener() {
#Override
public void onFaceDetection(Face[] faces, Camera camera) {
// TODO Auto-generated method stub
System.out.println("Face detection callback called." + Integer.toString(faces.length));
}
});
After calling mCamera.startFaceDetection();, the callback is called, everything works as normal. However, if I change cameras, the same code results in the callback never being called. The getMaxNumDetectedFaces, returns 35 for both cameras, so I assume its supported on the front camera. I can change the camera back and forth, calling this code each time, and it will work for the back camera but not the front one.
Is there anything else I might be doing wrong?

Is it possible that the quality of the camera that's not working (the front one, right?) Isn't accurate enough for the face detection to work? The camera's image may be too noisy for the face detector to work. There are lot of other variables that could be hindering this.
Also doing a search for front camera, it looks like the front camera's points may be mirrored. This is described in: http://developer.android.com/reference/android/hardware/Camera.Face.html
I hope this helps.

Is there a way to check if the camera is being read? Java has always had some issues in registering web cams etc.... Perhaps try to make sure you can see images with the webcam.
Btw, if you want any further help, we will need to know more about the code. library etc....

This code will return the id of your Front facing camera, for others you can change camera.CameraInfo:
private int findFrontFacingCamera() {
int cameraId = -1;
// Search for the front facing camera
int numberOfCameras = Camera.getNumberOfCameras();
for (int i = 0; i < numberOfCameras; i++) {
Camera.CameraInfo info = new Camera.CameraInfo();
Camera.getCameraInfo(i, info);
if (info.facing == Camera.CameraInfo.CAMERA_FACING_FRONT) {
Log.d("FaceDetector", "Camera found");
cameraId = i;
break;
}
}
return cameraId;
}
I had the code which worked on my Gallaxy tablet but it wouldnt call the take foto and as a result wouldnt call face detection in other devices, so after searching for a while I found this solution which worked. I added the following code in the class where takePicture is called :
camera.startPreview();

You can use Webcame for capturing image from webcam. it automatically detects webcam so no need to extra configuration for webcam. it also support more than one webcam at a time.