TurbulenceCalc.java

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package com.fs.starfarer.api.impl.campaign.velfield;
 
import org.lwjgl.util.vector.Vector2f;
 
import com.fs.starfarer.api.util.Misc;
 
public class TurbulenceCalc {
    
    public static Vector2f [] DIRECTIONS = new Vector2f[8];
    static {
        for (int i = 0; i < 8; i++) {
            float angle = i * 45f + 180f;
            DIRECTIONS[i] = Misc.getUnitVectorAtDegreeAngle(angle);
        }
    }
 
//  protected VelocityField field;
//  protected float propagationSpeed;
//
//  public TurbulenceCalc(VelocityField field, float propagationSpeed) {
//      this.field = field;
//      this.propagationSpeed = propagationSpeed;
//  }
    
    
    public static void advance(VelocityField field, float propagationSpeed, float amount) {
        
        Vector2f[][] f = field.getField();
        
        Vector2f[][] delta = new Vector2f[f.length][f[0].length];
        for (int i = 0; i < f.length; i++) {
            for (int j = 0; j < f[0].length; j++) {
                delta[i][j] = new Vector2f();
            }
        }
        Vector2f[][] delta2 = new Vector2f[f.length][f[0].length];
        for (int i = 0; i < f.length; i++) {
            for (int j = 0; j < f[0].length; j++) {
                delta2[i][j] = new Vector2f();
            }
        }
        
        //Vector2f[][] d = field.getDelta();
        
        float mult = propagationSpeed * amount;
        for (int i = 0; i < f.length; i++) {
            for (int j = 0; j < f[0].length; j++) {
                
                addCell(f, delta, i + 1, j + 0, i, j, DIRECTIONS[0], mult);
                addCell(f, delta, i + 1, j + 1, i, j, DIRECTIONS[1], mult);
                addCell(f, delta, i + 0, j + 1, i, j, DIRECTIONS[2], mult);
                addCell(f, delta, i - 1, j + 1, i, j, DIRECTIONS[3], mult);
                addCell(f, delta, i - 1, j + 0, i, j, DIRECTIONS[4], mult);
                addCell(f, delta, i - 1, j - 1, i, j, DIRECTIONS[5], mult);
                addCell(f, delta, i - 0, j - 1, i, j, DIRECTIONS[6], mult);
                addCell(f, delta, i + 1, j - 1, i, j, DIRECTIONS[7], mult);
                //Misc.wiggle(d[i][j], d[i][j].length() * 0.1f);
            }
        }
        
        mult = -1f;
        for (int i = 0; i < f.length; i++) {
            for (int j = 0; j < f[0].length; j++) {
                addCell(delta, delta2, i + 1, j + 0, i, j, DIRECTIONS[0], mult);
                addCell(delta, delta2, i + 1, j + 1, i, j, DIRECTIONS[1], mult);
                addCell(delta, delta2, i + 0, j + 1, i, j, DIRECTIONS[2], mult);
                addCell(delta, delta2, i - 1, j + 1, i, j, DIRECTIONS[3], mult);
                addCell(delta, delta2, i - 1, j + 0, i, j, DIRECTIONS[4], mult);
                addCell(delta, delta2, i - 1, j - 1, i, j, DIRECTIONS[5], mult);
                addCell(delta, delta2, i - 0, j - 1, i, j, DIRECTIONS[6], mult);
                addCell(delta, delta2, i + 1, j - 1, i, j, DIRECTIONS[7], mult);
                //Misc.wiggle(d[i][j], d[i][j].length() * 0.1f);
            }
        }
 
//      for (int i = 0; i < f.length; i++) {
//          for (int j = 0; j < f[0].length; j++) {
//              Misc.wiggle(delta[i][j], delta[i][j].length() * 0.1f);
//              Misc.wiggle(delta2[i][j], delta2[i][j].length() * 0.1f);
//          }
//      }
        
        for (int i = 0; i < f.length; i++) {
            for (int j = 0; j < f[0].length; j++) {
                Vector2f.add(f[i][j], delta[i][j], f[i][j]);
//              Vector2f.add(f[i][j], delta2[i][j], f[i][j]);
//              float len = f[i][j].length();
//              if (len > 70f) {
//                  f[i][j].scale(70f/len);
//              }
            }
        }
        
    }
    
    public static Vector2f getCell(Vector2f [][] data, int i, int j) {
        if (i < 0 || j < 0) return new Vector2f();
        if (i >= data.length || j >= data[0].length) return new Vector2f();
        return data[i][j];
    }
    
    public static void addCell(Vector2f[][] field, Vector2f[][] delta, int fromX, int fromY, int x, int y, Vector2f dir, float propagationMult) {
        Vector2f cell = getCell(field, fromX, fromY);
        Vector2f d = getCell(delta, x, y);
        Vector2f dFrom = getCell(delta, fromX, fromY);
        float dot = Vector2f.dot(cell, dir);
        
        d.x += dir.x * dot * propagationMult;
        d.y += dir.y * dot * propagationMult;
        
        dFrom.x -= dir.x * dot * propagationMult;
        dFrom.y -= dir.y * dot * propagationMult;
    }
    
    public static void addCell(Vector2f cell, Vector2f dir, Vector2f delta) {
        float dot = Vector2f.dot(cell, dir);
        delta.x += dir.x * dot;
        delta.y += dir.y * dot;
    }
}