Shading different on ATI / NVIDIA cards

[mrdoubleb]

Hi we just added a light to our scene for shaders. Now we noticed it looks good on all ATI cards but somehow on NVIDIA cards its working not that good. I already search for a bit but couldnt find anything.

Nvidia:


Ati:


Notice the different shadow on the front and at the front small weapon and the top hatch.

And yes we have tried on several pc's.

Also when u turn the tank the shading with ATI is nice diffuse but on NVIDIA the shadings are ON/OFF

Someone know if this is a issue? or else how to fix this?

[hybrid]

Looks like your normals are not normalized. Did you set the material flag NORMALIZE_NORMALS when scaling meshes? Some cards cope quite good with non-normalized normals, but others don't.

[mrdoubleb]

Looks like your normals are not normalized. Did you set the material flag NORMALIZE_NORMALS when scaling meshes? Some cards cope quite good with non-normalized normals, but others don't.

Yes those are set after scaling... so thats not the problem i think?

[hybrid]

Ok, so are the bright areas textures with a different texture? Could be a wrong texture size or wrapping mode which is unsupported by the driver.

[mrdoubleb]

Ok, so are the bright areas textures with a different texture? Could be a wrong texture size or wrapping mode which is unsupported by the driver.

there are 3 textures:

the barrel
turret
tankbase

they are all the same texture they are applied in maya. And are loaded via the .mtl file exported by maya. The objects are loaded as .obj files exported by maya.

[hybrid]

Ah, .obj materials support bump mapping (parallax/normal maps), which could also cause some problems. Can you upload at least the material file? Also, make sure that the sizes of the textures are power-of-two. Although, usually ATI has more problems with NPOT textures.

[Erelas]

Hi there, I'm in the OP's team.

The problem we are facing is not the difference in brightness on top of the tank turret, those parts don't have a texture assigned to it yet, but a lambert material type I think (.mtl file says illum instead?), with some different colors.

The actual problem is that diffuse lighting is different on the cards:



Here are the contents of our .mtl file:

Code: Select all

newmtl surfaceShader1SG
illum 4
Kd 0.00 0.00 0.00
Ka 0.00 0.00 0.00
Tf 1.00 1.00 1.00
map_Kd ../textures/camo.jpg
Ni 1.00
newmtl surfaceShader2SG
illum 4
Kd 0.11 0.11 0.11
Ka 0.00 0.00 0.00
Tf 1.00 1.00 1.00
Ni 1.00
newmtl surfaceShader3SG
illum 4
Kd 0.00 0.00 0.00
Ka 0.00 0.00 0.00
Tf 1.00 1.00 1.00
Ni 1.00

Our camo texture actually was NPOT (500*500), that wasn't the cause though.

Thanks for helping so far.

[hybrid]

This could be a problem with the color material setting. Try to alter the setting to ECM_NONE or ECM_AMBIENT to avoid getting to bright diffuse colors. But it looks more like a problem with normal handling, still. Check the barrel, the facetted look on ATI shows an approximated, but working normal. The NVidia version is completely lacking any separation of the faces.

[LizardGamer]

Are the video drivers updated?

[ChaiRuiPeng]

Are the video drivers updated?

checking that usually fixes these related problems for me 9/10 times.

gotta stay on top of those driver updates!

[hybrid]

I think I didn't suggest to check the driver settings so far. Make sure that you don't have some user defined settings for 'maximal speed' or something like that. Otherwise, some settings from Irrlicht could be overridden by the driver.

[Erelas]

We fixed the problem, it actually was the light radius of the light node in our scene that was too high (We tried to simulate the sun).
Bit weird that this is handled differently on ati and nvidia.

Now shading is pretty much identical on both cards, so case closed. Thanks for the help!