p5.js noErase()用法及代码示例

function setup() { 
    createCanvas(600, 400); 
    textSize(20); 
    firstBlockSlider = createSlider(50, 250, 75, 1); 
    firstBlockSlider.position(30, 50); 
   
    secondBlockSlider = createSlider(50, 250, 175, 1); 
    secondBlockSlider.position(30, 120); 
} 
   
function draw() { 
    clear(); 
    fill('black'); 
    text("Move the slider below to change the"
        + " first block's position", 20, 30); 
    text("Move the slider below to change the"
        + " second block's position", 20, 100); 
    text("The black circle demonstrates the"
        + " erase area", 20, 170); 
   
    fill('red'); 
    rect(firstBlockSlider.value(), 200, 50, 100); 
   
    // Start erasing with erase() 
    erase(); 
    circle(150, 250, 100); 
   
    // Stop erasing with noErase() 
    noErase(); 
   
    fill('red'); 
    rect(secondBlockSlider.value(), 200, 50, 100); 
   
    // Circle to illustrate the erase position 
    noFill(); 
    circle(150, 250, 100); 
}