【解决方法】
在iClient3D for Webgl中可以使用divide(left, right, result) 方法对两种颜色求商
使用方法参考下方代码
var a = new SuperMap3D.Color(1,1,1,1);
var b = new SuperMap3D.Color(1,0,1,0.5);
var result = new SuperMap3D.Color();
SuperMap3D.Color.divide(a, b, result)
console.log("a",a,"b",b,"result",result);