如何在处理中只在鼠标悬停时播放一次声音？

Question

当鼠标移到处理中的按钮上时，我正在尝试播放声音。目前，它正在一遍又一遍地播放，因为我的按钮类在 draw() 函数中。我理解为什么会发生这种情况，但我想不出一种只播放一次声音同时仍与我的overRect() 函数绑定的方法。

主要：

import processing.sound.*;

PlayButton playButton;
SoundFile mouseOverSound;
SoundFile clickSound;
color white = color(255); 
color gray = color(241, 241, 241);
PFont verdanabold; 

void setup() 
{
  size(720, 1280);
  textAlign(CENTER);
  rectMode(CENTER);

  verdanabold = createFont("Verdana Bold", 60, true);  
  playButton = new PlayButton();
  mouseOverSound = new SoundFile(this, "mouseover.wav");
  clickSound = new SoundFile(this, "click.mp3");
}

void draw()
{
  background(gray);
  playButton.display(); // draw play button
}

playButton 类：

class PlayButton // play button
{
  float rectX = width/2; // button x position
  float rectY = height-height/4; // button y position
  int rectWidth = 275; // button width
  int rectHeight = 75; // button height
  boolean rectOver = false; // boolean determining if mouse is over button

  void display() // draws play button and controls its function
  {
    update(mouseX, mouseY);

    if(rectOver) // controls button color when mouse over
    {
      fill(white);
      mouseOverSound.play(); // play mouse over sound
    }
    else
    {
      fill(gray); 
    }

    strokeWeight(5); // button
    stroke(black);
    rect(rectX, rectY, rectWidth, rectHeight);

    textFont(verdanabold, 48); // button text
    fill(black);
    text("PLAY", rectX, rectY+15);

    if(mousePressed && rectOver) // if mouse over and clicked, change to state 1
    {
      state = 1;
      clickSound.play(); // play click sound
    }
  }

  void update(float x, float y) // determines if mouse is over button using overRect(), changes boolean rectOver accordingly
  {
    if(overRect(rectX, rectY, rectWidth, rectHeight))
    {
      rectOver = true;
    }
    else
    {
      rectOver = false; 
    }
  }

  boolean overRect(float rectX, float rectY, int rectWidth, int rectHeight) // compares mouse pos to button pos and returns true if =
  {
     if(mouseX >= rectX-rectWidth/2 && mouseX <= rectX+rectWidth/2 && mouseY >= rectY-rectHeight/2 && mouseY <= rectY+rectHeight/2)
     {
       return true;
     }
     else
     {
       return false;
     }
  }
}

Answer 1

想通了。 初始化 int i = 0。当鼠标悬停在按钮上时，在 i

编辑 playButton 类：

class HowToButton // how to button
{
  float rectX = width/2; // button x position
  float rectY = height-height/8; // button y position
  int rectWidth = 275; // button width
  int rectHeight = 75; // button height
  boolean rectOver = false; // boolean determining if mouse is over button
  int i = 0;

  void display() // draws how to button and controls its function
  {
    update(mouseX, mouseY);

    if (rectOver) // controls button color when mouse over
    {
      fill(white);
      while(i < 1) // play sound while i < 1
      {
       mouseOverSound.play(); // play mouse over sound
       i++; // increment i so sound only plays once
      }
    }
    else
    {
      fill(gray); 
      i = 0; // set i back to 0 when mouse leaves bounds of button
    }

    strokeWeight(5); // button
    stroke(black);
    rect(rectX, rectY, rectWidth, rectHeight);

    textFont(verdanabold, 48); // button text
    fill(black);
    text("HOW TO", rectX, rectY+15);

    if(mousePressed && rectOver) // if mouse over and clicked, change to state 2
    {
      state = 2;
      clickSound.play(); // play click sound
    }
  }

  void update(float x, float y) // determines if mouse is over button using overRect(), changes boolean rectOver accordingly
  {
    if(overRect(rectX, rectY, rectWidth, rectHeight))
    {
      rectOver = true;
    }
    else
    {
      rectOver = false; 
    }
  }

  boolean overRect(float rectX, float rectY, int rectWidth, int rectHeight) // compares mouse pos to button pos and returns true if =
  {
     if(mouseX >= rectX-rectWidth/2 && mouseX <= rectX+rectWidth/2 && mouseY >= rectY-rectHeight/2 && mouseY <= rectY+rectHeight/2)
     {
       return true;
     }
     else
     {
       return false;
     }
  }
}

Answer 2

您可以使用boolean 变量来指示声音是否已经在播放。像这样的：

if(mousePressed && rectOver && !alreadyPlaying)
{
  alreadyPlaying = true;
  state = 1;
  clickSound.play(); // play click sound
}

实际上，您也许可以使用state 变量：

if(mousePressed && rectOver && state != 1)
{
  state = 1;
  clickSound.play(); // play click sound
}

您还可以查看您正在使用的声音库，它可能有一个功能可以告诉您声音是否已经在播放，您可以以相同的方式使用它。