Maybe this'll sound crazy, but your app running ok (with shadow mapping) - it's not black (it's "blended" into colors of sorrounding enviroment). I haven't got property linear filter, cause I've got ATi card (and it's not giving bilinear PCF by hardware).

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Well, that should be possible in several ways, i'm gonna to look at that today later (afternoon) ;) - I need some sleep and it's around 1 AM - oh almost morning again :D - here in Czech Republic (GMT+1)

Well, I found a way how to solve shadow mapping and ambient lighting WITHOUT extension :). It's multi pass algorythm (who'd expected that?) - 2 pass.

1. Pass - render scene into texture WITHOUT shadow mapping and without lighting (so everything would be in full colored texture or full color).

2. Pass - render scene normally (this means with lighting and with shadow mapping), then draw one fullscreen quad blended additively into rendered scene. And voilá - shadows and ambient lighting running without extensions :)

There's alternative for ATi cards, it's hand-coded linear filter in X and Y direction of texture (so it's bilinear filter), but i don't know if it's possible without shaders (I'm doing it using shaders). I'm using PCML shadow mapping filter, which uses bilinearly filtered shadow maps - but there's way to use bilinear filtered shadows using variance shadow maps (they've got several disadvantages, but much more advantages - and the major advantage is speed...). Anyway to your app - it crashed several times, Stencil shadows weren't working (Stencil shadow volumes), but that all can be fixed ;). Don't know why it doesn't running properly on your PC, but I can test that on several other PCs if you want.