问题
Does anybody use colorGrading property of the SCNCamera to adjust rendered colors? The colorGrading's contents value must be a 3D color lookup table(LUT) or a 2D texture image the represents such a table arranged in a horzontal strip. So I try to download some 3D color lookup table file whic is .cube format and write some Metal code. But when I run it, I got the whole black scene. But when I move the camera, the black disappear but the colorGranding didn't work that way. So I want to use 2D texture image, but I couldn't find the resources from the internet. The doc says the you can create a basic color table image to create custom effects. But what does it mean? How can I create a basic color table image?
来源：https://stackoverflow.com/questions/42544724/work-inside-colorgrading-property