[Scummvm-devel] Alpha blending (0.13.0)

Joost Peters joostp at 7fc1.org
Fri Feb 13 17:04:45 CET 2009


Max Horn schreef:

> I should add at this point that yesterday, I modified the  
> VectorRendererSpec / VectorRendererAA code on trunnk (*not* the  
> release branch) to use Graphics::PixelFormat instead of ColorMasks.  
> This way, the same code should work on arbitrary graphics surfaces,  
> with arbitrary color formats (well, 16 bit only for now, but it would  
> be easy to allow 32 bit pixels, too). Drawback: It will be slower now,  
> again. But I have no idea what impact that would have, exactly. In  
> particular, very frequently called core routines like blendPixelPtr()  
> now use R/G/B/alpha masks stored in (const) member variables, instead  
> of compile-time constants. This could conceivably cause slow downs; or  
> it might be almost as fast after all. Hard to say from here.
> 
> So, what would be really nice is some serious benchmarking / profiling  
> of VectorRendererSpec / VectorRendererAA on some low-spec platforms,  
> to find out if and where there are bottlenecks. And then we can try to  
> make it faster.

I know this isn't very scientific, but FWIW; after trying for a bit on 
PSP (at the default 222mhz) I don't notice any performance hit / difference.


Regards,
Joost




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