我的问题：给定x和y，我需要计算所需操纵杆偏转的x和y。
当没有操纵杆死区时这很简单 - 我只使用x和y而不进行操作。
当存在死区时，我希望x = 0为零，x =非零，作为该死区以外的第一个值。
方形死区很简单。在下面的代码中，x和y从-1到1（包括-1和1）。死区从0到1，包括在内。
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;
圆形死区比较棘手。经过一番愚弄，我想出了这个：
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);
}
这是极端情况下操纵杆偏转的输出（死区= 0.25）：
Non-square joystick deflection. http://n4te.com/temp/nonsquare.gif
如您所见，偏转不会延伸到角落。 IE，如果x = 1，y = 1则xDeflection和yDeflection都等于0.918。随着较大的死区，问题变得更加严重，使得上图中的绿线看起来越来越像圆圈。在deadzone = 1时，绿线是一个与死区匹配的圆圈。
我发现通过一个小的改变，我可以扩大绿线所代表的形状和-1到1之外的剪辑值：
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));
}
我从试验和错误中得出了常数0.71。这个数字使形状足够大，角落在实际角落的几个小数位内。出于学术原因，任何人都可以解释为什么0.71恰好是这样做的数字？
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完成我需要的循环死区？
我已经编写了一个简单的基于Swing的程序来直观显示正在发生的事情：
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();
}
}
答案 0 :(得分：4)
如果你有一个圆形的死区，.71实际上是0.70710678或2的平方根的一半 根据毕达哥拉斯定理计算
答案 1 :(得分：3)
我试着稍微改变一下这个问题。正如我已经了解了您的要求，算法应该
假设操纵杆被向上推，但x在定义的水平死区内，你想要坐标（0，y）。
因此，在第一步中，我将测试操纵杆坐标是否位于定义的死区内。对于圆形，它非常简单，您只需将x / y坐标转换为距离（Pythagoras）并检查该距离是否小于圆半径。
如果它在外面，则返回（x / y）。如果它在里面，检查x以及值是否在它们的水平或垂直死区内。
这是一个概述我的想法的草稿：
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;
}
修改
以上思路使用原始坐标，因此假设原始x值范围为[-255,255]，半径为2，并将操纵杆设置为x值（-3，-2，-1,0,1， 2,3），它将产生序列（-3,0,0,0,0,0,3）。所以死区被消隐了，但是从0跳到3。如果这是不需要的，我们可以将非死区从（[-256，-radius]，[radius，256]）“拉伸”到（标准化）范围（[-1,0]，[0,1]）。
所以我只需要对转换后的原始点进行标准化：
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raw_x = radius转换为normalized_x = 0.
（该方法应该适用于正值和负值。至少我希望它可以，我目前没有IDE或JDK可以测试;）
答案 2 :(得分：3)
这就是我一起扔的东西。它表现得有点奇怪，但在界限上它很好：
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);
}
它保留角度，但是缩放从0到边界之间到死区和边界之间的距离。最大距离变化，因为它的边是1，角的是sqrt（2），所以必须相应地改变比例。