Significant differences between DX8 and DX9 Rendering?

[TheGolem]

I have noticed that there seems to be a significant difference between the rendering frontends. I wrote a really simple 3D Pong game with Irrlicht. I sent it to a buddy of mine who was unable to run it (as it turned out, his DX is borked, so no worries). So I recompiled the Program which used DX9 before on DX8. That didn't solve the problem, but thats not the point. When I ran it myself, I noticed interesting differences between DX8 and DX9 Rendering.
Let me explain: The Pong game I wrote uses Test SceneNodes only. I wanted to keep things simple, and I really REALLY suck at modelling I made some bmp files, all unicolor in red, green, blue and gray, and assigned those as textures to the respective nodes. In DX9, it worked like a charm. However, in DX8, there are these strange black parts in the texture (which arent there in the bmp file). When I made these screenshots, I also noticed that the color of the Score numbers is different: In DX8, they are much more pale.

This is how it is supposed to be looking, how it looks in DX9:


And this is how it looks in DX8:

[Homer]

I have noticed this, too, but I think this appeared first with Irrlicht 0.6 or 0.5.2. In previous versions everything worked fine. Here is a sample screenshot:



I've got another problem with the dx9 renderer in fullscreen-mode, just see this screenshot:



In window-mode I could fix this problem with enabling the stencil buffer (simply changed one parameter: createDevice(..., ..., ..., true, ...), but in fullscreen-mode I still get those drawing errors. When I move through my city, some triangles seem to "move", some appear and disappear. Very crazy effect...
In OpenGL-mode everything works fine, but the framerate is a bit slower there.

[niko]

I think this is caused by the d3d8 mipmap level generation. It has some problems currently, because I was not able to use the d3dX version, I commented this in the corresponding .cpp file. I'll try correct this with the next release.

[Jedive]

Yep, I also noticed this on my game. The mip-mapping in DX8 was looking really bad (was getting darker with the distance), while in DX9, everything looks much better.