Question

短暂停顿 - 我使用wad JavaScript library创建随机音调生成器。我正试图让发电机“滑动”。间距之间，如下伪码：

确定当前音高（randomNum）
确定下一个音高（randomNext）
确定下一个音高是高还是低
播放当前音高并保持一秒
快速播放当前音高和下一音高之间的所有音高，以提供“滑动”。效果 - 这是不起作用的部分！
播放下一个音高并保持一秒钟（然后将其重新指定为当前音高）。

如果我从if语句中删除for循环并从变量手动设置其起始音高，它将按预期运行。

我做错了什么？我的if语句有问题吗？用我的for循环？

有问题的代码是：

// play the first pitch    
function playFirst() {
            if(!stopped){
                window.randomNum = Math.round(Math.random()*200 + 100);
                console.log("randomnum is now "+ randomNum);
            }
            playRandom();
        }

// play and loop subsequent pitches
        function playRandom(){
            if(!stopped){

                var randomNext = Math.round(Math.random()*200 + 100);
                console.log("randomNext is now " + randomNext);

                var howManyCents = randomNum - randomNext;
                console.log(howManyCents + " cents");

// ascending note slide condition
                if (randomNum < randomNext) {
                    console.log("randomnum is less!");

                    var inbetweenNum = randomNum + 1;

// for loop - the part with the problem! 
                    for (var i = 0; i < howManyCents; i++) {
                        inbetweenNum = randomNum + i;
                        console.log("inbetween number is " + inbetweenNum); 
                        inbetween.play({ pitch : inbetweenNum });
                        console.log("played inbetween up"); 
                    }
// descending note slide condition
                } else {
                    console.log("randomnum is more!");

                    var inbetweenNum = randomNum - 1;

// another problematic for loop
                    for (var i = 0; i > howManyCents; i--) {
                        inbetweenNum = randomNum - i;
                        console.log("inbetween number is " + inbetweenNum); 
                        inbetween.play({ pitch : inbetweenNum });
                        console.log("played inbetween down");
                    }
                } 
// actually play the note
                bell.play({ pitch : randomNext, wait: 0 });
                console.log("played randomnext" + randomNext);

// reassign the new note as the current note
                randomNum = randomNext;
                console.log("randomnum is now" + randomNum);

                setTimeout(playRandom,1500); // and loop it
            }
        }

我已经制作了完整程序here的JSFiddle。

非常感谢任何帮助！

Answer 1

该块的条件是randomNum < randomNext，但howManyCents是randomNum - randomNext，在这种情况下将为负值。循环条件，然后 - i < howManyCents，i从0开始，将永远不会成立。

您可以使用i < -howManyCents，或将Math.abs(randomNum - randomNext)分配给howManyCents，i > howManyCents和i--。

for循环if if语句不会运行，我不确定为什么

1 个答案: