better touch anchor creation

Author: codeanticode

debug/apps/arscene/src/main/java/arscene/Sketch.java

@@ -33,24 +33,25 @@ public void draw() {
 
     lights();
 
-/*
     if (mousePressed) {
       // Create new anchor at the current touch point
       if (selAnchor != null) selAnchor.dispose();
-      selAnchor = new Anchor(tracker, mouseX, mouseY);
+      Trackable hit = tracker.get(mouseX, mouseY);
+      if (hit != null) selAnchor = new Anchor(hit);
+      else selAnchor = null;
     }
-*/
 
     // Draw objects attached to each anchor
     for (Anchor anchor : regAnchors) {
       if (anchor.isTracking()) drawBox(anchor, 255, 255, 255);
+
+      // It is very important to dispose anchors once they are no longer tracked.
       if (anchor.isStopped()) anchor.dispose();
     }
-    tracker.clearAnchors(regAnchors);
+    if (selAnchor != null) drawBox(selAnchor, 255, 0, 0);
 
-    if (selAnchor != null) {
-      drawBox(selAnchor, 255, 0, 0);
-    }
+    // Conveniency function in the tracker object to remove disposed anchors from a list
+    tracker.clearAnchors(regAnchors);
 
     // Draw trackable planes
     for (int i = 0; i < tracker.count(); i++) {

mode/libraries/ar/src/processing/ar/Anchor.java

@@ -16,9 +16,10 @@ public Anchor(Trackable trackable, float x, float y, float z) {
     id = g.createAnchor(idx, x, y, z);
   }
 
-  public Anchor(Tracker tracker, int mx, int my) {
-    this.g = tracker.g;
-    id = g.createAnchor(mx, my);
+  public Anchor(Trackable trackable) {
+    this.g = trackable.g;
+    id = g.createAnchor(trackable.hit);
+    trackable.hit = null;
   }
 
   public void dispose() {

mode/libraries/ar/src/processing/ar/PGraphicsAR.java

@@ -257,6 +257,24 @@ public boolean trackableSelected(int i, int mx, int my) {
   }
 
 
+  protected HitResult getHitResult(int mx, int my) {
+    for (HitResult hit : surfar.frame.hitTest(mx, my)) {
+      Trackable trackable = hit.getTrackable();
+      if (trackable instanceof Plane) {
+        Plane plane = (Plane)trackable;
+        if (trackPlanes.contains(plane) && plane.isPoseInPolygon(hit.getHitPose())) {
+          return hit;
+        }
+      }
+    }
+    return null;
+  }
+
+  protected int getTrackable(HitResult hit) {
+    Plane plane = (Plane) hit.getTrackable();
+    return trackPlanes.indexOf(plane);
+  }
+
   public float[] getTrackablePolygon(int i) {
     return getTrackablePolygon(i, null);
   }
@@ -315,16 +333,21 @@ public int createAnchor(int mx, int my) {
       if (trackable instanceof Plane) {
         Plane plane = (Plane)trackable;
         if (trackPlanes.contains(plane) && plane.isPoseInPolygon(hit.getHitPose())) {
-          Anchor anchor = hit.createAnchor();
-          anchors.put(++lastAnchorId, anchor);
-          return lastAnchorId;
+          return createAnchor(hit);
         }
       }
     }
     return 0;
   }
 
 
+  protected int createAnchor(HitResult hit) {
+    Anchor anchor = hit.createAnchor();
+    anchors.put(++lastAnchorId, anchor);
+    return lastAnchorId;
+  }
+
+
   public void deleteAnchor(int id) {
     delAnchors.add(id);
   }

mode/libraries/ar/src/processing/ar/Trackable.java

@@ -2,8 +2,11 @@
 
 import processing.core.PMatrix3D;
 
+import com.google.ar.core.HitResult;
+
 public class Trackable implements PAR {
   protected PGraphicsAR g;
+  protected HitResult hit;
 
   private int id;
   private PMatrix3D m;

mode/libraries/ar/src/processing/ar/Tracker.java

@@ -1,5 +1,7 @@
 package processing.ar;
 
+import com.google.ar.core.HitResult;
+
 import java.lang.reflect.Method;
 import java.util.ArrayList;
 import java.util.Collection;
@@ -49,6 +51,18 @@ public Trackable get(String id) {
     return trackables.get(id);
   }
 
+  public Trackable get(int mx, int my) {
+    HitResult hit = g.getHitResult(mx, my);
+    if (hit != null) {
+      int idx = g.getTrackable(hit);
+      Trackable t = get(idx);
+      t.hit = hit;
+      return t;
+    } else {
+      return null;
+    }
+  }
+
   protected void create(int idx) {
     if (trackableEventMethod != null) {
       try {