Make it so that drive assist occurs only when bounding box is seen

Author: alexander-mcdowell

Robot2019/src/main/java/frc/robot/lib/Limelight.java

@@ -23,15 +23,18 @@ public Limelight() {
 
   // Adjusts the distance between a vision target and the robot. Uses basic PID with the ty value from the network table.
   public double distanceAssist() {
+    tv = table.getEntry("tv").getDouble(0.0);
     ty = table.getEntry("ty").getDouble(0.0);
     SmartDashboard.putNumber("Crosshair Vertical Offset", ty);
     ta = table.getEntry("ta").getDouble(0.0);
     double adjustment = 0.0;
     double area_threshold = 0.5;  // TODO: Set the desired area.
     double Kp = 0.2;   // TODO: Set PID K value.
 
-    if (ta < area_threshold) {
-      adjustment += Kp * ty;
+    if (tv == 1.0) {
+      if (ta < area_threshold) {
+        adjustment += Kp * ty;
+      }
     }
     return adjustment;
   }