帶網格的二維數組

Question

我創建了一個使用龜圖形繪製不同形狀的程序。在400x400像素的JFrame的頂部有一個5x5的分離網格。它包裹着頂部/底部和左/右，以防形狀過度。

我現在需要做的是添加一個2d數組，創建一個400x400的0數組。如果一隻烏龜穿過任何像素（對應於二維數組中的一個點），則需要將0改爲1.最好的方法是什麼？我們最終致力於康威生命遊戲的功能。

Answer 1

在我看來，最好的方法是跟蹤龜的位置（X & Y），方向double變量，然後使用基本的三角函數來計算下一個「像素」，即龜甲命中。我假設你將使用計時器或循環來運行此代碼，因此它可能看起來像這樣：

//This code is somehwere in your program 
class Turtle 
{ 
    private double x; 
    private double y; 
    private double direction; //direction in radians 
    public double getX() { 
     return x; 
    } 
    public void setX(double x) { 
     this.x = x; 
    } 
    public double getY() { 
     return y; 
    } 
    public void setY(double y) { 
     this.y = y; 
    } 
    public double getDirection() { 
     return direction; 
    } 
    public void setDirection(double direction) { 
     while(direction > Math.PI * 2) 
     { 
      direction -= Math.PI * 2; 
     } 
     while(direction < 0) 
     { 
      direction += Math.PI * 2; 
     } 
     this.direction = direction; 
    } 
} 

private static final int GRID_WIDTH = 400; 
private static final int GRID_HEIGHT = 400; 


private Turtle myTurtle = new Turtle(); 
private boolean[][] grid = new boolean[GRID_WIDTH][GRID_HEIGHT]; 
JFrame myJFrame = new JFrame(); 
private Graphics gridImage = myJFrame.getGraphics(); 

private void initialise() 
{ 
    for(int y = 0; y < GRID_HEIGHT; y++) 
    { 
     for(int x = 0; x < GRID_WIDTH; x++) 
     { 
      grid[x][y] = false; 
     } 
    } 

    gridImage.setColor(Color.BLACK); 
    gridImage.fillRect(0, 0, GRID_WIDTH, GRID_HEIGHT); 
    gridImage.setColor(Color.white); 
} 

//This code would be inside the loop or timer callback function 
private void myMainFunction() 
{ 
    double newX, newY; 
    double deltaX, deltaY; 

    deltaX = Math.cos(myTurtle.getDirection()); 
    deltaY = Math.sin(myTurtle.getDirection()); 

    newX = myTurtle.getX() + deltaX; 
    newY = myTurtle.getY() + deltaY; 

    if(newX < 0) 
    { 
     newX += GRID_WIDTH; 
    } 
    else if(newX > GRID_WIDTH) 
    { 
     newX -= GRID_WIDTH;  
    } 

    if(newY < 0) 
    { 
     newY += GRID_HEIGHT; 
    } 
    else if(newY > GRID_HEIGHT) 
    { 
     newY -= GRID_HEIGHT; 
    } 

    grid[(int)Math.floor(newX)][(int)Math.floor(newY)] = true; 

    gridImage.fillRect((int)Math.floor(newX), (int)Math.floor(newY), 1, 1); 
    myJFrame.update(gridImage); 

    myTurtle.setX(newX); 
    myTurtle.setY(newY); 
}