2D antialiased graphics using OpenGL

[Billy Biggs]

Martijn Sipkema (msipkema@sipkema-digital.com):

> > I mean, you make a reasonable argument.  If framebuffers were linear
> > intensity values rather than voltage values, a lot of things would
> > be easier, including being able to turn 'naive' hardware
> > implementations of algorithms such as compositing to be correct.
> > All of this is true.
> >
> > But I don't buy the argument that OpenGL expects a linear
> > framebuffer. [...]
> 
> Actually, I don't think OpenGL really cares about gamma, but the way
> blending and smooth shading is defined is only correct for a gamma
> corrected frame buffer. It is _impossible_ to do rendering in a
> nonlinear color space without a loss in performance, e.g. write only
> algorithms would now need to be read-write. It is IMHO better to just
> use a higher resolution framebuffer.

  Well up until now I have avoided the higher-bit framebuffer issue.  I
kind of assumed that if you had a 10 bit per channel pixel format, that
it would be linear and all of the advantages hold.  Similarly if we had
a floating point framebuffer.  I don't know if either is true.

  But using the LUTs and screwing all of the 2D code that currently
assumes sRGB seems wrong and broken, just like using 8 bit per channel
linear intensity pixels is a horrible loss in quality.

  -Billy