如何在处理中使用鼠标单击？

Question

I was working on an animation on processing. Then, I have a question about the lights. Normally, my code is more long. However, I made a simple code which can usefull also for the beginners.

boolean isOn = false;             // Variable keeping the state of the light
float sphereSize = 100;           // The size of Shpere
float xS = 200; yS = 200; zS = 0; // The coordinates of Sphere

void setup()
{
  size(400, 400, P3D);
  noStroke();
}

void draw()
{
  background(0);
  if (isOn)                       // Checks the state in which the light should be
    lights();
  translate(xS, yS, zS);          // Translate the sphere to the middle of window
  sphere(sphereSize);             // Making a sphere for see ligts
}

void mouseReleased() {            // This function is automatically called in draw method
  if (isOn)                       // After a click the state of the light is inverted
      isOn = false;
    else isOn = true;
}

So, I want to work light only if the mouse click on the sphere. If the mouse click outside the sphere, it will not work. How to solve this problem? Thanks.

Answer 1

Use dist() to compute the Euclidean distance between the mouse position ( mouseX , mouseY ) and the center of the sphere ( xS , yS ).
If the distance is less or equal than the radius ( sphereSize ), then switch the light:

void mouseReleased() {

    float distance = dist(xS, yS, mouseX, mouseY);
    if (distance <= sphereSize)
        isOn = !isOn;
}