Thread: About rendering in a far point

Hello, I have a question about the glance's reach in a terrain rendering. I'm using DevC++-MingW and dx4devcpp libraries (from www.gamecoding.co.uk, it's DirectX 8).
I have seen that on rendering a big terrain the objects rendered farest from the view point are not displayed (or maybe the objects rendered farest that x pixels from the view point are not diplayed); also I can see that when I move away the view point from the object it is 'undisplayed' gradually, so finally it disappears (it happens moving away over any of the axes).
Let me attach some images to ilustrate that: on the first it's all right, on the second the 'terrace' starts to disappear on the left side, on the third is disappearing from both sides, and in the last one is only a 'triangle'.

The display mode is set to 800x600, format D3DFMT_X8R8G8B8, RefreshRate 75; the backbuffer SwapEffect=D3DSWAPEFFECT_DISCARD, EnableAutoDepthStencil true, AutoDepthStencilFormat=D3DFMT_D16. The terrain is a 50x50 quadrants, each of 40x40, and it is rendered using an index buffer.

My question is: what is that effect? or ¿where can I find info about it and solve that problem? I have downloaded de DirectX9 documentation, done an 'overlook', but I can't find anything about it (I'm not an usually english speaker/reader/writer, so maybe I missed something while reading the documentation).

Thank's in advance
Niara

look up D3DXMatrixPerspectiveFovLH(...), the last param is the far distance, e.g. everything after that point will be clipped (disappear), just set it higher

Hello X PaYnE X, thank's for your time and your help, that was exactly the thing. Now it seems for me a banal question (5 minutes ago it was a big problem); can see that I must read better the dx manual before do so basic questions in those usual functions (I think that is a usual function because I have used D3DXMatrixPerspectiveFovLH since the first triangle on the 'very beguiner's tutorial chapter 0' , and I never stopped to think about it).
ending: thank's for your time and your help
Niara

To eliminate those artifacts at the far clip plane, use pixel fog, range fog, or vertex fog.

Hello Bubba, thank's for your time and help; I have already taked a look at the fog technique, but let me fight with it some days, I'll try to set it up in the terrain far borders.
Does the fog spend more capacity than a far view? (althought using fog I can make more elegant terrains, I think).
jbosch(vosk)

Here is another example:

And here is the same shot with fog start and fog end indicated.

Hello Bubba, nice shots. I had already setted up the fog effect and it works fine, but I have find a derived effect: on writing text with the DX DrawText() function it sets the text color to the fog color (only if D3DRS_FOGENABLE is TRUE). I haven't find any reference to that secondary effect on the DirectX Programer's Reference, so for the moment to avoid it I disable the fog effect (also works if I set the fog color to the text color), draw the text, and re-set the fog to it's original. A second way could be drawing 2D sprites from a charset map, but I think that maybe it would be slower (althought for the moment the game speed isn't the problem). Let me append two images: in the first I set up the linear fog (start 1.0f, end 2000.0f, red) and draw green text without disabling the fog; the result is that the text is auto setted to the fog color. On the second I set up the fog, disable before draw the text, and re-set the fog effect. The code I used to do it:

Code:

//setting up the fog
float inici=1.0f;
float final=2000.0f;
g_pd3ddevice->SetRenderState(D3DRS_FOGENABLE,TRUE);
g_pd3ddevice->SetRenderState(D3DRS_FOGCOLOR,D3DCOLOR_XRGB(255,0,0));
g_pd3ddevice->SetRenderState(D3DRS_FOGVERTEXMODE,D3DFOG_LINEAR);
g_pd3ddevice->SetRenderState(D3DRS_FOGSTART,*(DWORD*)(&inici));
g_pd3ddevice->SetRenderState(D3DRS_FOGEND,*(DWORD*)(&final));

Code:

//creating the font
LOGFONT LogFont={16,0,0,0,FW_NORMAL,false,false,false,DEFAULT_CHARSET,OUT_TT_PRECIS, CLIP_DEFAULT_PRECIS,PROOF_QUALITY,DEFAULT_PITCH,"Verdana"};
D3DXCreateFontIndirect(g_pd3ddevice,&LogFont,&g_Font);
//g_Font is a LPD3DXFONT

Code:

/*
The draw text function from a call such like
m_pTipog1->mostraTexte("the text",10,10,D3DCOLOR_XRGB(0,255,0));
where m_pTipog1 is an object created with an HFONT created with the CreateFont() Win32 API standard function, and D3DXCreateFont(device,HFONT_last_created,LPD3DXFONT);
That LPD3DXFONT is wich I'll use to draw the text
*/
void CTipografia::mostraTexte(LPSTR tx,int x,int y,D3DCOLOR color)
{
RECT area;
area.left=x;
area.top=y;
area.right=0;
area.bottom=0;

m_pTipog->Begin();
g_pd3ddevice->SetRenderState(D3DRS_FOGENABLE,FALSE);
m_pTipog->DrawTextA(tx,-1,&area,DT_CALCRECT,0);
m_pTipog->DrawTextA(tx,-1,&area,DT_LEFT,color);
g_pd3ddevice->SetRenderState(D3DRS_FOGENABLE,TRUE);
m_pTipog->End();
/*
where m_pTipog is the LPD3DXFONT previously created
*/
}

I think I haven't forgot anything.
Is that secondary fog effect normal and the disabling the fog before draw text a right solution?
Thank's

Niara