java - 如何从斜坡获得角度？

Question

所以我目前正在制作一个游戏，我需要从斜坡上获取我在游戏中工作的 AI 的角度。但是，它并没有按我的预期工作，并且只有在我使用这个功能时才会发生，我在做了几个小时的研究后制作了这个功能。

请记住，我在学校只学了代数和几何 1，我一直在尝试在空闲时间自学代数和几何 2 以及微积分。

public static double angleFromSlope(double rise, double run)
{
    double r;
    if (run == 0.0)
    {
        r = (Math.atan(0) * 180 / Math.PI);
    } else if (rise == 0.0)
    {
        r = (Math.atan(0) * 180 / Math.PI);
    } else
    {
        r = (Math.atan(rise / run) * 180 / Math.PI);
    }

    if (rise >= 0 && run >= 0)
    {
        return r;
    }

    else if (rise >= 0 && run <= 0)
    {
        return Math.abs(r + 90) + 90;
    }

    else if (rise < 0 && run < 0)
    {
        return Math.abs(Math.abs(r) + 180);
    }

    else
    {
        return Math.abs(r + 90) + 270;
    }

}

编辑：

public static void main(String[] args)
{
    double angle = 90;

    double[] dir = DirFromAngle(angle);

    System.out.println(dir[0] + " " + dir[1]);

    double[] line = new double[]
    { 10, 10, 10 + (dir[0] * 10), 10 + (dir[1] * 10) };

    double[] rn = riseOverRun(line);

    double a = angleFromSlope(rn[0], rn[1]);

    System.out.println(a);

}

public static double[] DirFromAngle(double angle)
{
    double b = Math.toRadians(angle);

    double[] output = new double[]
    { Math.sin(b), Math.cos(b) };
    return output;
}

public static double[] riseOverRun(double[] line)
{
    // 0 - X1, 1 - Y1, 2 - X2, 3 - Y2
    double[] output = new double[]
    { (line[3] - line[1]), (line[2] - line[0]) };
    return output;
}

public static double angleFromSlope(double rise, double run)
{
    double r;
    if (run == 0.0)
    {
        r = (Math.atan(0) * 180 / Math.PI);
    } else if (rise == 0.0)
    {
        r = (Math.atan(0) * 180 / Math.PI);
    } else
    {
        r = (Math.atan(rise / run) * 180 / Math.PI);
    }

    if (rise >= 0 && run >= 0)
    {
        return r;
    }

    else if (rise >= 0 && run <= 0)
    {
        return Math.abs(r + 90) + 90;
    }

    else if (rise < 0 && run < 0)
    {
        return Math.abs(Math.abs(r) + 180);
    }

    else
    {
        return Math.abs(r + 90) + 270;
    }

}

标签： java

Answer 1

您最好使用点和线来解释您要计算的内容。一个点包含 x、y，一条线有 2 个点。画出形状也可以更好地理解。

import java.awt.Canvas;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.Toolkit;
import java.util.ArrayList;
import java.util.List;

public class AngleFromSlope extends Canvas {
    protected static class Point {
        private final double x, y;
        
        protected Point(double x, double y) {
            this.x = x;
            this.y = y;
        }

        @Override
        public String toString() {
            StringBuilder builder = new StringBuilder();
            builder.append("(");
            builder.append(x);
            builder.append(", ");
            builder.append(y);
            builder.append(")");
            return builder.toString();
        }               
        
    }
    
    protected static class Line {
        private final Point p1, p2;
        
        protected Line(Point p1, Point p2) {
            this.p1 = p1;
            this.p2 = p2;
        }

        @Override
        public String toString() {
            StringBuilder builder = new StringBuilder();
            builder.append("[");
            builder.append(p1);
            builder.append(", ");
            builder.append(p2);
            builder.append("]");
            return builder.toString();
        }               
        
    }
    
    protected List<Line> lines = new ArrayList<>();
    
    public void paint(Graphics graphics) {
        Graphics2D g2d = (Graphics2D) graphics.create();                
            g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
            g2d.setRenderingHint(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BICUBIC);
            g2d.setRenderingHint(RenderingHints.KEY_ALPHA_INTERPOLATION, RenderingHints.VALUE_ALPHA_INTERPOLATION_QUALITY);
            g2d.setRenderingHint(RenderingHints.KEY_COLOR_RENDERING, RenderingHints.VALUE_COLOR_RENDER_QUALITY);
            g2d.setRenderingHint(RenderingHints.KEY_DITHERING, RenderingHints.VALUE_DITHER_DISABLE);
            g2d.setRenderingHint(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY);
            int m = getHeight()/2;
            g2d.translate(0, m);
            // flip about y-axis
            g2d.scale(1,-1);
            // first shift "up" (negative) m pixels
            g2d.translate(0,-m);
            
            for(Line line : lines) {
                g2d.drawLine((int) line.p1.x, (int) line.p1.y, (int) line.p2.x, (int) line.p2.y);
                System.out.println(line);
            }
            g2d.dispose();
    } 

    public static void main(String [] args) throws java.io.IOException {        
        AngleFromSlope canvas = new AngleFromSlope();
        java.awt.Frame frame = new java.awt.Frame("AngleFromSlope");
        frame.setSize(500, 500);

        Dimension dim = Toolkit.getDefaultToolkit().getScreenSize();
        frame.setLocation(dim.width/2-frame.getSize().width/2, dim.height/2-frame.getSize().height/2);
        
        final int SCALE = 50;
        final int BASE = 4, HEIGHT = 4;

        Point a = new Point(SCALE, SCALE);
        Point b = new Point(SCALE + BASE * SCALE, SCALE);
        Point c = new Point(SCALE + BASE * SCALE, SCALE + HEIGHT * SCALE);
        Line line1 = new Line(a, b);
        canvas.lines.add(line1);

        Line line2 = new Line(a, c);        
        canvas.lines.add(line2);
        Line line3 = new Line(b, c);
        canvas.lines.add(line3);
        
        double slope = (c.y - a.y) / (c.x - a.x);
        System.out.println("Slope: " + slope);

        double theta = Math.atan(slope);  
        System.out.println("θ: " + Math.toDegrees(theta));

        frame.add(canvas);
        frame.setVisible(true);
        frame.addWindowListener(new java.awt.event.WindowAdapter() {
            public void windowClosing(java.awt.event.WindowEvent e) { 
                System.out.println("Closing program");      
                System.exit(0); }
        } );        

    }
}