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Silverlight Rendering Speed vs WPF

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    I have to say, i'm seriously impressed with the speed of the software rendering in Silverlight. I dont know whether it's the time based animations or coding, but it really flies on my P4 2ghz.

    I'd be interested to know whether the renderer was the backend sliced out of the WPF software-only renderer, or whether it was developed specifically for the silverlight project.

    However, one thing does concern me. It actually seems faster than hardware accellerated WPF. To put it simply, software rendering in Silverlight seems a lot smoother and more responsive than hardware rendering on my DX9-compatible Geforce 6200. I know the 6200 is hardly top end, but surely those few hundred million transistors should provide some benefit? Or is it just bogged down by the layers of .NET that have to be traversed to reach the 3D hardware itself?.

    Don't get me wrong here, I truely believe WPF is an excellent platform, and is going to open up some seriously cool apps in a year or so, but slower than silverlight, in software?

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    How many visuals are there on your Silverlight and WPF app?

       WPF uses retained mode graphical rendering model, this model is optimized for rendering a small portion of visual update, if you have say 4000 visuals on your scene, and you wanna update them all, WPF probably cannot render them smoothly, on the contrary, I guess Silverlight uses a immediate mode graphical rendering model, and it is suitable for large visual update.

       So even if WPF is hardware accelerated, but at some unusual circumstance (such as the one I've mentioned above), WPF's rendering will probably be slower than its Silverlight counterpart.

       As to the implementation of Silverlight's graphical rendering mechanism, I've heard that Microsoft comes up with a home made software rasterizer for Silverlight, the reason why don't use GDI here is that GDI cannot render video, and what's more, GDI doesn't support alpha channel blending. but after rasterizing the scene, Silverlight will end up using GDI to display the scene, this is in essence a normal bitblt operation indeed.


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