Problem with fod

Graphics and GPU Programming Programming

Started by Arkanoid April 03, 2012 07:21 PM

9 comments, last by Arkanoid 12 years ago

Arkanoid

109

Author

April 03, 2012 07:21 PM

I found this sample from msdn how to create fog:







float Start = 0.5f, // Linear fog distances

End = 1000;



// Enable fog blending.

g_pd3dDevice->SetRenderState(D3DRS_FOGENABLE, TRUE);



// Set the fog color.

g_pd3dDevice->SetRenderState(D3DRS_FOGCOLOR, 0x00ffffff);



// Set fog parameters.





g_pd3dDevice->SetRenderState(D3DRS_FOGVERTEXMODE, D3DFOG_EXP);

g_pd3dDevice->SetRenderState(D3DRS_FOGSTART, *(DWORD *)(&Start));

g_pd3dDevice->SetRenderState(D3DRS_FOGEND, *(DWORD *)(&End));

but i see only a white screen, without any objects...where is wrong here?

Waterlimon

4,401

April 03, 2012 07:38 PM

should 1000 be 1000.0f?

o3o

InvalidPointer

1,842

April 04, 2012 02:39 PM

You copied the 'linear fog' code instead of the 'exponential fog' code

[source]if(D3DFOG_LINEAR == Mode)
{
// This is what you copied, notice the condition above
g_pDevice->SetRenderState(D3DRS_FOGVERTEXMODE, Mode);
g_pDevice->SetRenderState(D3DRS_FOGSTART, *(DWORD *)(&Start));
g_pDevice->SetRenderState(D3DRS_FOGEND, *(DWORD *)(&End));
}
else
{
// This is what you want to be using, i.e. D3DFOG_LINEAR is *not* your fog mode
g_pDevice->SetRenderState(D3DRS_FOGVERTEXMODE, Mode);
g_pDevice->SetRenderState(D3DRS_FOGDENSITY, *(DWORD *)(&Density));
}[/source]

clb: At the end of 2012, the positions of jupiter, saturn, mercury, and deimos are aligned so as to cause a denormalized flush-to-zero bug when computing earth's gravitational force, slinging it to the sun.

Arkanoid

109

Author

April 04, 2012 05:12 PM





g_pd3dDevice->SetRenderState(D3DRS_FOGENABLE, TRUE);



// Set the fog color.

g_pd3dDevice->SetRenderState(D3DRS_FOGCOLOR, 0x00ffffff);



// Set fog parameters.



g_pd3dDevice->SetRenderState(D3DRS_FOGVERTEXMODE, D3DFOG_EXP2);

g_pd3dDevice->SetRenderState(D3DRS_FOGDENSITY, 100);

in this variant - i have white screen too

InvalidPointer

1,842

April 04, 2012 09:55 PM

Have you experimented at all with adjusting the fog density value? It's entirely possible that things are working as intended though it looks different from what you want.

21st Century Moose

13,459

April 04, 2012 10:46 PM

Density also needs the float/DWORD trick, and should be quite low - it's a long time since I've used fixed pipeline fog, but if memory serves you should start at about 0.1 and work downwards from there.

Direct3D has need of instancing, but we do not. We have plenty of glVertexAttrib calls.

Arkanoid

109

Author

April 05, 2012 01:13 PM

g_pd3dDevice->SetRenderState(D3DRS_FOGDENSITY, 0.001f);

and white screen too...

froop

642

April 05, 2012 01:19 PM

I think he means like this:

float fogStart = 0.1f;
float fogEnd = 1000.0f;

device->SetRenderState(D3DRS_FOGENABLE, TRUE);
device->SetRenderState(D3DRS_FOGSTART, *(DWORD *)&fogStart);
device->SetRenderState(D3DRS_FOGEND, *(DWORD *)&fogEnd);
device->SetRenderState(D3DRS_FOGTABLEMODE, D3DFOG_LINEAR);

21st Century Moose

13,459

April 05, 2012 01:41 PM

Fog start and end are not valid for exp2 mode. You need to set density the same way that you were originally setting start and end in your first post, like so:



float Density = 0.001f;

g_pd3dDevice->SetRenderState(D3DRS_FOGDENSITY, *(DWORD *)(&Density));

Direct3D has need of instancing, but we do not. We have plenty of glVertexAttrib calls.

froop

642

April 05, 2012 02:03 PM

oops sorry for adding even more confusion. wanted to point out the float/DWORD thing

Problem with fod

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