るるなのパン

javascript:(function(){if(window.rurunaPan){window.rurunaPan.toggle();}else{class%20RurunaPan{constructor(){this.isRun=false;this.$video=document.querySelector("video");this.ctx=new%20AudioContext();this.src=this.ctx.createMediaElementSource(this.$video);this.pan=this.ctx.createStereoPanner();}start(){this.src.connect(this.pan);this.pan.connect(this.ctx.destination);this.curPos=0;let%20old_videoPos=0;this.intervalId=setInterval(()=>{const%20videoRect=this.$video.getClientRects()[0];const%20videoPos=window.screenX+(videoRect.left+videoRect.width/2);if(videoPos==old_videoPos)return;old_videoPos=videoPos;let%20pos=1-2*videoPos/window.screen.width;this.curPos=Math.max(-1,Math.min(1,-pos));this.pan.pan.setValueAtTime(this.curPos,this.ctx.currentTime);},1000/60);this.isRun=true;}stop(){clearInterval(this.intervalId);this.pan.pan.setValueAtTime(0,this.ctx.currentTime);this.isRun=false;}toggle(){if(this.isRun){this.stop();}else{this.start();}}}window.rurunaPan=new%20RurunaPan();window.rurunaPan.start();}})();