Re: [Mesa3d-users] Anti-aliasing lines Intel GMA 4500 question

[Brian P. <br...@vm...>]

Stefan Parvu wrote:
> Hi Brian,
> 
> Probable this would make things clear:
> 
> Nvidia:
>   OpenGL vendor string: NVIDIA Corporation
>   OpenGL renderer string: Quadro FX 1500/PCI/SSE2
>   OpenGL version string: 2.1.2 NVIDIA 190.53
> 
>   GL_LINE_WIDTH_GRANULARITY = 0.1
>   GL_LINE_WIDTH_RANGE = 0.5 10.0
> 
> 
> Intel:
>   OpenGL vendor string: Tungsten Graphics, Inc
>   OpenGL renderer string: Mesa DRI Mobile Intel GM45 Express Chipset
>                           GEM 20090712 2009Q2 RC3
>   OpenGL version string: 2.1 Mesa 7.6
>   GL_LINE_WIDTH_GRANULARITY = 0.5
>   GL_LINE_WIDTH_RANGE = 1.0 5.0
> 
> As you said with NVIDIA I have much higher degree and better quality.
> So this looks specific to each OpenGL implementation. Question is why in 
> Mesa we have GL_LINE_WIDTH_GRANULARITY = 0.5 instead of 0.1 like in NVIDIA 
> case ? Is it direct dependant of the GPU, or the driver ... !?

The Intel i965 line width register only has one fractional bit.

-Brian