Created attachment 55 [details]
logic-op updated EXT_framebuffer_sRGB specification

The EXT_framebuffer_sRGB specification missed specifying the proper interaction with glLogicOp consistent with precedent.

The precedent set by ARB_color_buffer_float and prior extensions that introduced floating-point color components to OpenGL is that the bit-wise LogicOp doesn't make sense when the color value is not a fixed-point value.

So these specifications (and now the core) say if the logic op is enabled and you are rendering to such a buffer, the logic op "has no effect".

When a framebuffer is rendered as sRGB, like floating-point, a bit-wise operation does make good sense.

This precedent should be applied whenever the destination color format is not a simple fixed-point format.

Alex Eddy and Chris Niederauer @ Apple first raised this issue.

I'm attaching an updated EXT_framebuffer_sRGB specification.

Also see the related Khronos bug 359.

- Mark