ODD Bumpmap issue

Nemo Krad

I have bought a book on shaders and have been going through the tutorials with some success.

However I now have a rather odd issue with my bumpmap shaders... I have three shaders, a bumpmap shader, a parallax bumpmap shader and a self shadowing bumpmap shader. My issue is that when I run my engine with the bumpmap shaders I get a rather odd effect happening, but (after many days of trying to sort this out) I found that if I run FX Composer prior to running my engine, this oddity seems to go away.

This leads me to think that FX Composer is setting some render states that I am not aware of and need to set for my bumpmap shaders. Is anyone able to let me know what render states I need to set or even if this is what is causing this odd behavior

My shaders before running FX Composer http://www.randomchaos.co.uk/XNA/Examples/before.jpg

My shaders as FX Composer is running http://www.randomchaos.co.uk/XNA/Examples/during.jpg

My shaders after FX Composer has ran http://www.randomchaos.co.uk/XNA/Examples/after.jpg

Here are the shaders:

Shawn Hargreaves - MSFT

That is extremely peculiar! It ought not be possible for one app to affect the rendering of another, because renderstates are not shared between apps (unless there's a really nasty bug in your drivers).

You could try using PIX to capture a frame both when the rendering is correct and when it is broken, and then see what renderstates are different between the two.

Nemo Krad

Shawn,

It is indeed odd, it has been giving me a headache for about a week now!

Forgive my ignorance but what is PIX and where can I get it to try this out

Thanks.

Shawn Hargreaves - MSFT

PIX is part of the DirectX SDK. It lets you capture frames of your game, see exactly what render calls you issued, what renderstates are set, etc.

Nemo Krad

Shawn,

I have ran PIX and captured the render state before and after FX Composer has been ran, I now have a shead load of data and don't know how to compare it other than going through it line by line. Is there a method to compare the two PIX Events without me trawling through them one line at a time

Thanks.

Nemo Krad

Now this gets stranger....

I just took a look at the images in my PIX file and they both look fine Yet when I took the first snap shot the bump map rendering was all munched up like before, the second shot was after I ran FXC and the render was sorted out... yet the images in the PIX file are identical rendering....

I guess there is no need to trawl through the data in there now as it obviously sees the two dumps the same.

What could possibly be going on

I also logged off and back on to see if this would set the render back to it's initial state, but it did not I needed to either totally shut down and restart my PC or play around with FXC until it killed the render again. I could then get back to a good render state by just running FXC with without editing any thing other than the opening project it launches with.

Could this be down to me having a damaged copy of either FXC or GSE I have replaced r updated almost everything else other than the framework the and the IDE.

Anyone got any ideas

Thanks.

Shawn Hargreaves - MSFT

This sounds very much like a graphics driver problem to me.

Nemo Krad

Yes I agree.

The trouble with that is that I have renewed my drivers and now have the latest ones for my card and the issue persists...

I take it there is nothing else you can suggest

Nemo Krad

OK, some progress, but could still do with a little help or even an explanation of what might be going on here.

my bumpmap shaders are using vs_2_0 and ps_2_0, if I render another mesh after this using vs_1_1 and ps_2_0, the image sorts it's self out. I think that is why FXC fixes the issue up until I render a bumpmap in it and it sends the render back to the munched up state.

So my work around is to ensure I have a draw call after all my bump mapping that uses a vs_1_1 VertexShader.

Can anyone shed any light on this, or is this the only way I can fix this

Thanks.

Shawn Hargreaves - MSFT

That absolutely sounds like a driver problem. I don't know that there's anything you can do about that, assuming you have the latest drivers for your card, unfortunately.

Nemo Krad

I thought as much...

Thanks for taking the time to take a look anyway. If I come across a definitive solution for this then I will post it here.

Thanks again.

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