我怎么能用颜色调色着色器将RGBA转换成BGRA

Question

I was to do the swizzling as, if I try to convert it later then it seems to be very slow. Any examples?

I am using this to make video of my application

I currently use

 glReadPixels(x, y, width, height, GL_RGBA, GL_UNSIGNED_BYTE, data);

and it returns me data in RGBA format, I need to convert it to BGRA how can I do it efficiently?

Answer 1

You know there is a BGRA format, which glReadPixels can deliver:

glReadPixels(x, y, width, height, GL_BGRA, GL_UNSIGNED_BYTE, data);

And in fact it's recommended you use BGRA for reading pixels, since this is the ordering most GUI systems use internally, thus saving a conversion step.