Turtle Project Java - turtle-graphics

Question

I'm working on a project where we are supposed to have a turtle that can take the commands forward, left, right, penUp, penDown, penColor and quit. When the pen is down it's supposed to draw a line between points. As the turtle moves it should leave a footprint. Left and right are supposed to change the direction in degrees. So far I can't get it to draw more points. This is the code I have so far one class main and one turtle
import java.util.Scanner;
public class Main {
public static void main(String[] args) {
Turtle t = new Turtle();
Scanner keyboard = new Scanner(System.in);
String command;
StdDraw.setPenRadius(0.05);
t.Draw();
do {
System.out.println("Enter A Command: forward, right, left, penup, pendown, pencolor, or quit");
command = keyboard.next();
if (command.equalsIgnoreCase("quit")){
break;
}
else if (command.equalsIgnoreCase("pencolor")) {
System.out.println("Enter A Color: Red, Green, Black, Yellow, Blue");
String color = keyboard.next();
t.setColor(color);
t.Draw();
}
else if (command.equalsIgnoreCase("forward")) {
System.out.println("Enter The Number of Steps You Would Like To Move");
int steps = keyboard.nextInt();
t.moveForward(steps);
t.Draw();
} else if (command.equalsIgnoreCase("right")) {
System.out.println("Enter The Number Of Degrees You Would Like To Move");
String radAngle = keyboard.next();
t.Draw();
} else if (command.equalsIgnoreCase("left")) {
System.out.println("Enter The Number Of Degrees You Would Like To Move");
String radAngle = keyboard.next();
t.Draw();
} else if (command.equalsIgnoreCase("penup")) {
t.putPenUp();
t.Draw();
} else if (command.equalsIgnoreCase("pendown")) {
t.putPenDown();
t.Draw();
}} while (!(command.equalsIgnoreCase("quit")));
}
}
public class Turtle {
private double location;
public double xCoord;
public double yCoord;
double direction;
private boolean penPosition;
public static boolean penDown = false;
public static boolean penUp = true;
private int red;
private int green;
private int blue;
private int steps;
public Turtle() {
xCoord = .5;
yCoord = .5;
penPosition = penUp;
location = 90;
}
public void Draw(){
StdDraw.setPenColor(StdDraw.BLACK);
StdDraw.point(xCoord, yCoord);
}
public void setColor(String color) {
if (color.equalsIgnoreCase("red")) {
red = 255;
green = 0;
blue = 0;
} else if (color.equalsIgnoreCase("green")) {
red = 0;
green = 255;
blue = 0;
} else if(color.equalsIgnoreCase("blue")) {
red = 0;
green = 0;
blue = 255;
} else if(color.equalsIgnoreCase("yellow")) {
red = 255;
green = 255;
blue = 0;
} else if(color.equalsIgnoreCase("black")) {
red = 0;
green = 0;
blue = 0;
} else {
red = 0;
green = 0;
blue = 0;
}
}
public void moveForward(int steps) {
double radAngle = Math.toRadians(location);
double newx = xCoord + (Math.cos(radAngle) * steps);
double newy = yCoord + (Math.sin(radAngle) * steps);
StdDraw.point(newx, newy);
StdDraw.line(xCoord, yCoord, newx, newy);
StdDraw.show();
}
public void putPenDown() {
penPosition = penDown;
if (true) {
// StdDraw.line(x, y, xCoord, yCoord);
}
} public void putPenUp() {
penPosition = penUp;
// StdDraw.line(xCoord, yCoord, newx, newy);
}
}

Answer 1

Your program has several problems: StdDraw thinks of the coordinate plane as going from 0.0 to 1.0 so your integer steps don't make sense unless you scale it into StdDraw coordinates -- in my example below I divide the plane into 100 steps; your moveForward() function didn't set the xCoord and yCoord variables to the new location after the move so the turtle never really went anywhere; it isn't clear why you rely on your Draw() so much as it doesn't really do much; the program exit logic was broken; the turning logic was broken and incomplete.
In my rework below, I've made some simplifications for example purposes: I've moved the main() routine into Turtle to avoid the extra file/class; I've implemented simpler colors since what you had wasn't working -- you can add back your RGB model; I've simplified the pen up/down logic to make it more practical.
import java.awt.Color;
import java.util.Scanner;
public class Turtle {
private double degAngle;
public double xCoord;
public double yCoord;
private boolean penDown;
private Color penColor;
private int steps;
public Turtle() {
xCoord = 0.5;
yCoord = 0.5;
penDown = true;
penColor = StdDraw.BLACK;
degAngle = 90;
StdDraw.setPenRadius(0.01);
}
public void Draw() {
if (penDown) {
StdDraw.setPenColor(penColor);
StdDraw.point(xCoord, yCoord);
}
}
public void setColor(String color) {
if (color.equalsIgnoreCase("red")) {
penColor = StdDraw.RED;
} else if (color.equalsIgnoreCase("green")) {
penColor = StdDraw.GREEN;
} else if (color.equalsIgnoreCase("blue")) {
penColor = StdDraw.BLUE;
} else if (color.equalsIgnoreCase("yellow")) {
penColor = StdDraw.YELLOW;
} else {
penColor = StdDraw.BLACK;
}
this.Draw(); // show new color
}
public void moveForward(int steps) {
double radAngle = Math.toRadians(degAngle);
double newx = xCoord + (Math.cos(radAngle) * steps / 100);
double newy = yCoord + (Math.sin(radAngle) * steps / 100);
if (penDown) {
StdDraw.setPenColor(penColor);
StdDraw.line(xCoord, yCoord, newx, newy);
}
xCoord = newx;
yCoord = newy;
}
public void turnRight(double angle) {
degAngle += -angle;
}
public void turnLeft(double angle) {
degAngle += angle;
}
public void putPenDown() {
penDown = true;
}
public void putPenUp() {
penDown = false;
}
public static void main(String[] args) {
Turtle t = new Turtle();
Scanner keyboard = new Scanner(System.in);
String command;
t.Draw(); // show turtle
do {
System.out.println("Enter a command: forward, right, left, penup, pendown, pencolor, or quit");
command = keyboard.next();
if (command.equalsIgnoreCase("quit")) {
break;
} else if (command.equalsIgnoreCase("pencolor")) {
System.out.println("Enter a color: red, green, black, yellow, blue");
t.setColor(keyboard.next());
} else if (command.equalsIgnoreCase("forward")) {
System.out.println("Enter the number of steps you would like to move");
t.moveForward(keyboard.nextInt());
} else if (command.equalsIgnoreCase("right")) {
System.out.println("Enter the number of degrees you would like to turn");
t.turnRight(keyboard.nextDouble());
} else if (command.equalsIgnoreCase("left")) {
System.out.println("Enter the number of degrees you would like to turn");
t.turnLeft(keyboard.nextDouble());
} else if (command.equalsIgnoreCase("penup")) {
t.putPenUp();
} else if (command.equalsIgnoreCase("pendown")) {
t.putPenDown();
}
} while (true);
System.exit(0);
}
}
USAGE
% java Turtle
Enter a command: forward, right, left, penup, pendown, pencolor, or quit
pencolor
Enter a color: red, green, black, yellow, blue
green
Enter a command: forward, right, left, penup, pendown, pencolor, or quit
forward
Enter the number of steps you would like to move
20
Enter a command: forward, right, left, penup, pendown, pencolor, or quit
left
Enter the number of degrees you would like to turn
120
Enter a command: forward, right, left, penup, pendown, pencolor, or quit
forward
Enter the number of steps you would like to move
20
Enter a command: forward, right, left, penup, pendown, pencolor, or quit
left
Enter the number of degrees you would like to turn
120
Enter a command: forward, right, left, penup, pendown, pencolor, or quit
forward
Enter the number of steps you would like to move
20
Enter a command: forward, right, left, penup, pendown, pencolor, or quit
quit
%
OUTPUT