使用箭头键进行aim的Java处理

Question

我正在使用Java Processing 3制作一个两人坦克游戏。下面是我的炮塔代码。目前我有炮塔的瞄准跟随鼠标在tDir中，我希望能够使用向上和向下箭头移动瞄准从0到90度向上和向下。

我该怎么做呢？多谢了。

/*
Uzair
*/

PVector mPos; //mouse position
PVector tPos; //position of turret
PVector tDir; //the firing direction of the turret
 int gravMult = 3;

void setup() {
  size(1200, 600);
  init();
}

void init() {
  //PVector initializations
  mPos = new PVector(); //zero til mouse x and y exist
  tPos = new PVector(width/8, height);
  tDir = new PVector(); //
}
void draw() { 
  //clear last frame
  background(100,100,140);

  //check keys to see if there is new key input for turret
  if (keyPressed){
    if (key == 'w'){
      tDir.y -= 10;
    }
    else if (key == 's'){
      tDir.y += 10;
    }
  }

  mPos.set(mouseX, mouseY);
  tDir = PVector.sub(mPos, tPos);
  tDir.normalize();
  tDir.mult(50);

  //draw
  fill(255);  
  ellipse(tPos.x, tPos.y, 40, 40);
  strokeWeight(5);
  line(tPos.x, tPos.y, tPos.x + tDir.x, tPos.y + tDir.y);
  fill(255, 0, 0);
  ellipse(tPos.x + tDir.x, tPos.y + tDir.y, 10, 10);
}

Answer 1

从0度到90度上下瞄准

这听起来像是增加一个角度/旋转，而不是像当前一样增加y位置。

你需要做极坐标（角度/半径）到笛卡尔坐标(x，y)的转换。

x = cos(angle) * radius
y = sin(angle) * radius

tDir.x = cos(angle) * 50;
tDir.y = sin(angle) * 50;

PVector mPos; //mouse position
PVector tPos; //position of turret
PVector tDir; //the firing direction of the turret
 int gravMult = 3;
//angle in radians
float angle = 0;

void setup() {
  size(1200, 600);
  init();
}

void init() {
  //PVector initializations
  mPos = new PVector(); //zero til mouse x and y exist
  tPos = new PVector(width/8, height * .75);
  tDir = new PVector(); //
}
void draw() { 
  //clear last frame
  background(100,100,140);

  //check keys to see if there is new key input for turret
  if (keyPressed){
    if (key == 'w'){
      angle -= 0.1;
      tDir = PVector.mult(PVector.fromAngle(angle),50);
    }
    else if (key == 's'){
      angle += 0.1;
      tDir = PVector.mult(PVector.fromAngle(angle),50);
    }
  }else if(mousePressed){
    mPos.set(mouseX, mouseY);
    tDir = PVector.sub(mPos, tPos);
    tDir.normalize();
    tDir.mult(50);
  }
  //draw
  fill(255);  
  ellipse(tPos.x, tPos.y, 40, 40);
  strokeWeight(5);
  line(tPos.x, tPos.y, tPos.x + tDir.x, tPos.y + tDir.y);
  fill(255, 0, 0);
  ellipse(tPos.x + tDir.x, tPos.y + tDir.y, 10, 10);
}