[sldev] Improving the avatar in SL: hair...

[Lawson English]

Matthew Dowd wrote:
>> In theory you could just allow people to write shaders in GLSL. I'm not
>> up on the spec but seems to me that should be safe, the worst people
>> could do is maybe lock up the video card, and I would hope that would
>> only be because of bugs in the GL driver's compiler.
>>     
>
> You are basically writing machine code to run on the GPU - there's limited checking even a perfect/bug free driver could do.
>
> I think it would be inevitable that someone would produce a prim which would cause a GPU to spin at 100% locking up the machine and possibly causing hardware damage if you are overclocking and your cooling isn't up to scratch! And it would be inevitable that some griefer would use this to crash anyoone in range...
>
> Apart from real power users/graphics programmer gurus, there are probably only a limited number of effects that people would want/need (bump mapping, specular diffusion etc.) and I would have thought that these could be parametricised via additional alpha channels. If implemented properly this could be done so that it becomes very easy to download and plug in additional shaders (basically this should be a shader file, and a config file saying which alpha channel should be used for the parameters, which are dropped into a directory the viewer polls at startup).
>   
If you're not familiar with it, check out Quartz Composer on the Mac, 
which allows people to string together arbitrary numbers of plug-ins to 
create customized filters. If you need a custom filter, QC supports a 
small subset of the OpenGL assembly language, so you can code your own.