Android Open Source - WATisRain Util

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Back to project page WATisRain.

License

The source code is released under:

MIT License

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Java Source Code

package com.lucky.watisrain.backend;
/*from  w w w.j  a va  2s  .c  o m*/
/**
 * Some useful methods
 */
public class Util {
  
  /**
   * Generates unique ID given building name and floor number like MC:3 
   */
  public static String makeBuildingAndFloor(String location, int floor){
    return location + ":" + floor;
  }
  
  public static String getBuilding(String combinedID){
    int ix = combinedID.indexOf(':');
    if(ix == -1) return combinedID;
    return combinedID.substring(0, ix);
  }
  
  public static int getFloor(String combinedID){
    int ix = combinedID.indexOf(':');
    if(ix == -1) return 1;
    return Integer.parseInt(combinedID.substring(ix+1));
  }
  
  
  /**
   * HACK: This is a global variable to make the pathing weight adjustable from
   * outside the backend module.
   * 
   * This number represents the "unwillingness" ratio of going outside. For example,
   * 3.0 means that travelling 1m outside is equal to travelling 3m outside.
   */
  public static double GLOBAL_PATHING_WEIGHT = 3.0;
  
  
  /**
   * Given two vectors a and b, return the unit vector that goes in the opposite direction
   * of them. For example, if a = (1,0) and b = (0,1), the return (-sqrt 2, -sqrt 2)
   */
  public static double[] findOppositeVector(double a1, double a2, double b1, double b2){
    
    // Fudge stuff, makes it less likely for the case that they are exactly the
    // opposite direction (which results in a division by zero)
    a1 += 0.0001;
    a2 += 0.0001;
    
    // Normalize a and b
    double length_a = Math.sqrt(a1*a1 + a2*a2);
    double length_b = Math.sqrt(b1*b1 + b2*b2);
    a1 /= length_a;
    a2 /= length_a;
    b1 /= length_b;
    b2 /= length_b;
    
    // Take negative of sum
    double c1 = -a1-b1;
    double c2 = -a2-b2;
    
    // Normalize c
    double length_c = Math.sqrt(c1*c1 + c2*c2);
    c1 /= length_c;
    c2 /= length_c;
    
    return new double[]{c1,c2};
  }

}

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