java操纵杆死区计算

Question

我的问题是：给定x和y，我需要计算所需操纵杆偏转的x和y

这在没有操纵杆死区的情况下很简单——我只使用x和y，不需要操纵

当存在死区时，我希望x=0为零，x=non-zero为该方向上死区外的第一个值

方形死区很简单。在下面的代码中，x和y的值介于-1和1之间。死区范围为0到1（含0到1）

float xDeflection = 0;
if (x > 0)
 xDeflection = (1 - deadzone) * x + deadzone;
else if (x < 0)
 xDeflection = (1 - deadzone) * x - deadzone;

float yDeflection = 0;
if (y > 0)
 yDeflection = (1 - deadzone) * y + deadzone;
else if (y < 0)
 yDeflection = (1 - deadzone) * y - deadzone;

圆形死区更为棘手。经过一番胡闹，我想到了这个：

float xDeflection = 0, yDeflection = 0;
if (x != 0 || y != 0) {
 float distRange = 1 - deadzone;
 float dist = distRange * (float)Math.sqrt(x * x + y * y) + deadzone;
 double angle = Math.atan2(x, y);
 xDeflection = dist * (float)Math.sin(angle);
 yDeflection = dist * (float)Math.cos(angle);
}

以下是极端情况下（死区=0.25）操纵手柄偏转的输出：

Non-square joystick deflection. http://n4te.com/temp/nonsquare.gif

如您所见，偏转不会延伸到拐角处。也就是说，如果x=1，y=1，那么xDeflection和yDeflection都等于0.918。死区越大，问题就越严重，使上图中的绿线看起来越来越像一个圆圈。在死区=1时，绿线是一个与死区匹配的圆

我发现，通过一个小的更改，我可以将绿线表示的形状和剪裁值放大到-1到1之外：

if (x != 0 || y != 0) {
 float distRange = 1 - 0.71f * deadzone;
 float dist = distRange * (float)Math.sqrt(x * x + y * y) + deadzone;
 double angle = Math.atan2(x, y);
 xDeflection = dist * (float)Math.sin(angle);
 xDeflection = Math.min(1, Math.max(-1, xDeflection));
 yDeflection = dist * (float)Math.cos(angle);
 yDeflection = Math.min(1, Math.max(-1, yDeflection));
}

我通过反复试验得出了常数0.71。此数字使形状足够大，使角点位于实际角点的小数点后几位以内。出于学术原因，有人能解释为什么0.71恰好是这个数字吗

总的来说，我不确定我是否采取了正确的方法。有没有更好的方法来实现我需要的循环死区

我已经编写了一个简单的基于Swing的程序来可视化正在发生的事情：

import java.awt.BorderLayout;
import java.awt.CardLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Hashtable;

import javax.swing.DefaultComboBoxModel;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JSlider;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;

public class DeadzoneTest extends JFrame {
 float xState, yState;
 float deadzone = 0.3f;
 int size = (int)(255 * deadzone);

 public DeadzoneTest () {
  super("DeadzoneTest");
  setDefaultCloseOperation(DISPOSE_ON_CLOSE);

  final CardLayout cardLayout = new CardLayout();
  final JPanel centerPanel = new JPanel(cardLayout);
  getContentPane().add(centerPanel, BorderLayout.CENTER);
  centerPanel.setPreferredSize(new Dimension(512, 512));

  Hashtable labels = new Hashtable();
  labels.put(-255, new JLabel("-1"));
  labels.put(-128, new JLabel("-0.5"));
  labels.put(0, new JLabel("0"));
  labels.put(128, new JLabel("0.5"));
  labels.put(255, new JLabel("1"));

  final JSlider ySlider = new JSlider(JSlider.VERTICAL, -256, 256, 0);
  getContentPane().add(ySlider, BorderLayout.EAST);
  ySlider.setInverted(true);
  ySlider.setLabelTable(labels);
  ySlider.setPaintLabels(true);
  ySlider.setMajorTickSpacing(32);
  ySlider.setSnapToTicks(true);
  ySlider.addChangeListener(new ChangeListener() {
   public void stateChanged (ChangeEvent event) {
    yState = ySlider.getValue() / 255f;
    centerPanel.repaint();
   }
  });

  final JSlider xSlider = new JSlider(JSlider.HORIZONTAL, -256, 256, 0);
  getContentPane().add(xSlider, BorderLayout.SOUTH);
  xSlider.setLabelTable(labels);
  xSlider.setPaintLabels(true);
  xSlider.setMajorTickSpacing(32);
  xSlider.setSnapToTicks(true);
  xSlider.addChangeListener(new ChangeListener() {
   public void stateChanged (ChangeEvent event) {
    xState = xSlider.getValue() / 255f;
    centerPanel.repaint();
   }
  });

  final JSlider deadzoneSlider = new JSlider(JSlider.VERTICAL, 0, 100, 33);
  getContentPane().add(deadzoneSlider, BorderLayout.WEST);
  deadzoneSlider.setInverted(true);
  deadzoneSlider.createStandardLabels(25);
  deadzoneSlider.setPaintLabels(true);
  deadzoneSlider.setMajorTickSpacing(25);
  deadzoneSlider.setSnapToTicks(true);
  deadzoneSlider.addChangeListener(new ChangeListener() {
   public void stateChanged (ChangeEvent event) {
    deadzone = deadzoneSlider.getValue() / 100f;
    size = (int)(255 * deadzone);
    centerPanel.repaint();
   }
  });

  final JComboBox combo = new JComboBox();
  combo.setModel(new DefaultComboBoxModel(new Object[] {"round", "square"}));
  getContentPane().add(combo, BorderLayout.NORTH);
  combo.addActionListener(new ActionListener() {
   public void actionPerformed (ActionEvent event) {
    cardLayout.show(centerPanel, (String)combo.getSelectedItem());
   }
  });

  centerPanel.add(new Panel() {
   public void toDeflection (Graphics g, float x, float y) {
    g.drawRect(256 - size, 256 - size, size * 2, size * 2);
    float xDeflection = 0;
    if (x > 0)
     xDeflection = (1 - deadzone) * x + deadzone;
    else if (x < 0) {
     xDeflection = (1 - deadzone) * x - deadzone;
    }
    float yDeflection = 0;
    if (y > 0)
     yDeflection = (1 - deadzone) * y + deadzone;
    else if (y < 0) {
     yDeflection = (1 - deadzone) * y - deadzone;
    }
    draw(g, xDeflection, yDeflection);
   }
  }, "square");

  centerPanel.add(new Panel() {
   public void toDeflection (Graphics g, float x, float y) {
    g.drawOval(256 - size, 256 - size, size * 2, size * 2);
    float xDeflection = 0, yDeflection = 0;
    if (x != 0 || y != 0) {
     float distRange = 1 - 0.71f * deadzone;
     float dist = distRange * (float)Math.sqrt(x * x + y * y) + deadzone;
     double angle = Math.atan2(x, y);
     xDeflection = dist * (float)Math.sin(angle);
     xDeflection = Math.min(1, Math.max(-1, xDeflection));
     yDeflection = dist * (float)Math.cos(angle);
     yDeflection = Math.min(1, Math.max(-1, yDeflection));
    }
    draw(g, xDeflection, yDeflection);
   }
  }, "round");

  cardLayout.show(centerPanel, (String)combo.getSelectedItem());
  pack();
  setLocationRelativeTo(null);
  setVisible(true);
 }

 private abstract class Panel extends JPanel {
  public void paintComponent (Graphics g) {
   g.setColor(Color.gray);
   g.fillRect(0, 0, getWidth(), getHeight());
   g.setColor(Color.white);
   g.fillRect(0, 0, 512, 512);

   g.setColor(Color.green);
   if (true) {
    // Draws all edge points.
    for (int i = -255; i < 256; i++)
     toDeflection(g, i / 255f, 1);
    for (int i = -255; i < 256; i++)
     toDeflection(g, i / 255f, -1);
    for (int i = -255; i < 256; i++)
     toDeflection(g, 1, i / 255f);
    for (int i = -255; i < 256; i++)
     toDeflection(g, -1, i / 255f);
   } else if (false) {
    // Draws all possible points (slow).
    for (int x = -255; x < 256; x++)
     for (int y = -255; y < 256; y++)
      toDeflection(g, x / 255f, y / 255f);
   }

   g.setColor(Color.red);
   toDeflection(g, xState, yState);
  }

  abstract public void toDeflection (Graphics g, float x, float y);

  public void draw (Graphics g, float xDeflection, float yDeflection) {
   int r = 5, d = r * 2;
   g.fillRect((int)(xDeflection * 256) + 256 - r, (int)(yDeflection * 256) + 256 - r, d, d);
  }
 }

 public static void main (String[] args) {
  new DeadzoneTest();
 }
}

Answer 1

这是我拼凑的。它的行为有点古怪，但在边界上是好的：

private Point2D.Float calculateDeflection(float x, float y) {
    Point2D.Float center = new Point2D.Float(0, 0);
    Point2D.Float joyPoint = new Point2D.Float(x, y);
    Double angleRad = Math.atan2(y, x);

    float maxDist = getMaxDist(joyPoint);

    float factor = (maxDist - deadzone) / maxDist;

    Point2D.Float factoredPoint = new Point2D.Float(x * factor, y * factor);

    float factoredDist = (float) center.distance(factoredPoint);

    float finalDist = factoredDist + deadzone;

    float finalX = finalDist * (float) Math.cos(angleRad);
    float finalY = finalDist * (float) Math.sin(angleRad);

    Point2D.Float finalPoint = new Point2D.Float(finalX, finalY);

    return finalPoint;
}

编辑：错过了这个

private float getMaxDist(Point2D.Float point) {
    float xMax;
    float yMax;
    if (Math.abs(point.x) > Math.abs(point.y)) {
        xMax = Math.signum(point.x);
        yMax = point.y * point.x / xMax;
    } else {
        yMax = Math.signum(point.y);
        xMax = point.x * point.y / yMax;
    }
    Point2D.Float maxPoint = new Point2D.Float(xMax, yMax);
    Point2D.Float center = new Point2D.Float(0, 0);
    return (float) center.distance(maxPoint);
}

它保留了角度，但缩放了从0和边界之间的某个位置到死区和边界之间的距离。最大距离各不相同，因为侧面的距离为1，角落的距离为sqrt（2），因此必须相应地改变缩放比例

Answer 2

我会尝试以不同的方式解决这个问题。正如我理解你的要求，算法应该

1. 如果操纵手柄位置在死区之外，则返回x/y值
2. 如果操纵杆（部分）在死区内，则返回0/y、x/0或0/0

假设操纵杆向上推，但x位于定义的水平死区内，则需要坐标（0，y）

因此，在第一步中，我将测试操纵杆坐标是否在定义的死区内。对于一个圆来说，这很容易，你只需要将x/y坐标转换成一个距离（Pythagoras），然后检查这个距离是否小于圆的半径

如果在外面，返回（x/y）。如果在内部，则检查x，以及值是否在其水平或垂直死区内

下面是一份草稿，概述我的想法：

private Point convertRawJoystickCoordinates(int x, int y, double deadzoneRadius) {

    Point result = new Point(x,y); // a class with just two members, int x and int y
    boolean isInDeadzone = testIfRawCoordinatesAreInDeadzone(x,y,radius);
    if (isInDeadzone) {
      result.setX(0);
      result.setY(0);
    } else {
      if (Math.abs((double) x) < deadzoneRadius) {
        result.setX(0);
      }
      if (Math.abs((double) y) < deadzoneRadius) {
        result.setY(0);
      }
    }
    return result;         
}

private testIfRawCoordinatesAreInDeadzone(int x, int y, double radius) {
  double distance = Math.sqrt((double)(x*x)+(double)(y*y));
  return distance < radius;
}

编辑

上述想法使用原始坐标，因此假设原始x值范围为[-255255]，半径为2，将操纵杆设置为x值（-3，-2，-1,0,1,2,3），它将生成序列（-3,0,0,0,0,0,3）。所以死区是空白的，但是从0跳到了3。如果这是不需要的，我们可以将非死区从（[-256，-radius]，[radius，256]）扩展到（标准化的）范围（[-1,0]，[0,1]）

所以我只需要标准化转换后的原始点：

private Point normalize(Point p, double radius) {
   double validRangeX = MAX_X - radius;
   double validRangeY = MAX_Y - radius;
   double x = (double) p.getX();
   double y = (double) p.getY();

   return new Point((x-r)/validXRange, (y-r)/validYRange);
}

简而言之：它将x轴和y轴的有效范围（范围减去死区半径）标准化为[-1,1]，以便将原始_x=半径转换为标准化_x=0

（该方法应该适用于正值和负值。至少我希望可以，我手头没有IDE或JDK可供测试；）

Answer 3

如果你有一个圆形死区，.71实际上是0.70710678或2平方根的一半 毕达哥拉斯定理的计算