SmoothFacingUtil.java

Go to the documentation of this file.

package com.fs.starfarer.api.util;
 
public class SmoothFacingUtil {
 
    private float turnAcceleration, maxTurnRate;
    private float turnRate;
    
    private float facing;
    
    public SmoothFacingUtil(float turnAcceleration, float maxTurnRate) {
        this.turnAcceleration = turnAcceleration;
        this.maxTurnRate = maxTurnRate;
    }
 
    
    public void advance(float desiredFacing, float amount) {
        float absTurnRate = Math.abs(turnRate);
        
        // v t - 0.5 a t t = dist
        // dv = a t;  t = v / a
        float decelTime = absTurnRate / turnAcceleration; 
        float decelDistance = absTurnRate * decelTime - 0.5f * turnAcceleration * decelTime * decelTime;
        
        float diffWithCurrFacing = Misc.getAngleDiff(facing, desiredFacing);
 
        float turnDir = Misc.getClosestTurnDirection(facing, desiredFacing);
        if (Math.signum(turnRate) == Math.signum(turnDir)) {
            if (decelDistance >= diffWithCurrFacing) {
                turnDir = -turnDir;
            }
        }
        
        turnRate += turnDir * turnAcceleration * amount;
        //turnRate = maxTurnRate * turnDir;
        if (Math.abs(turnRate) > maxTurnRate) {
            turnRate = maxTurnRate * Math.signum(turnRate);
            //System.out.println("capped at " + maxTurnRate);
        }
        
        
        facing += turnRate * amount;
        facing = Misc.normalizeAngle(facing);
        
        if (diffWithCurrFacing < turnRate * amount * 1.5f) {
            facing = desiredFacing;
        }
        
    }
    
 
    public float getFacing() {
        return facing;
    }
 
    public void setFacing(float facing) {
        this.facing = facing;
    }
 
 
    public float getTurnAcceleration() {
        return turnAcceleration;
    }
 
    public void setTurnAcceleration(float turnAcceleration) {
        this.turnAcceleration = turnAcceleration;
    }
 
    public float getMaxTurnRate() {
        return maxTurnRate;
    }
 
    public void setMaxTurnRate(float maxTurnRate) {
        this.maxTurnRate = maxTurnRate;
    }
 
    public float getTurnRate() {
        return turnRate;
    }
 
    public void setTurnRate(float turnRate) {
        this.turnRate = turnRate;
    }
 
    
}