Enabling the z buffer

Graphics and GPU Programming Programming

Started by rileyriley February 02, 2002 04:18 PM

7 comments, last by rileyriley 22 years, 2 months ago

235

Author

February 02, 2002 04:18 PM

I''m using DX 8.1, and having a lot of difficulty getting the z buffer to mask polygons correctly. As of right now, all I''m doing to enable z buffering is:

  	d3dDevice->SetRenderState(D3DRS_ZENABLE, D3DZB_TRUE);
	d3dDevice->Clear(0, NULL, D3DCLEAR_TARGET | D3DCLEAR_ZBUFFER, 0x00000000, 1.0f ,0);
	d3dDevice->BeginScene();

Then I go on to draw two tetrahedrons, using two vertex buffers. Even though (I think) z buffering is enabled, the polygons that I draw last get drawn on top of the first polygons, even when they are farther away from the ''camera''. Am I missing some step, like enabling z buffering for each polygon I draw, or something? In open GL you just enable zbuffering and it''s done - I assumed it was the same in DX, but I could be wrong. Thanks for any help - Riley ps - I know this has probably been answered before, but I''ve exhausted the SDK docs and the search function for gamedev seems to be down. Does anyone else get "query contains only ignored words?"

--Riley

invective

118

February 02, 2002 05:26 PM

Did you SetRenderState(D3DRS_ZENABLE, D3DZB_TRUE) ?

rileyriley

235

Author

February 02, 2002 05:53 PM

Yes - it''s that first line I posted above.

Thanks, and thanks for any future replies -
Riley

--Riley

invective

118

February 03, 2002 01:21 AM

wow, i''m blind...

what card are you using? have you tried checking the return value of the SetRenderState?

a person

118

February 03, 2002 01:30 AM

mistake mde by most ppl (including me), check to see which direction the z buffer is going. (ie is greater z mean closer to viewer or not? i forget the default, its in the docs). also check your projection matrix, possible the vaules are to close or far away form each other (though i doubt this since your polys are being drawn).

also did you enable auto depth buffering when you created the device? if not you will need to create a depth buffer for your device or you wont get z buffer no matter how many times you trun it on.

rileyriley

235

Author

February 03, 2002 11:01 AM

Hmm, I haven''t enabled auto buffering, I think. I''ll try that when I get home.

--Riley

Cirdan

122

February 03, 2002 02:04 PM

Hi, try this line:
pDevice->SetRenderState( D3DRS_ZWRITEENABLE , TRUE );

Cirdan

--== www.DoWhatYouFeel.de

KrazeIke

256

February 03, 2002 02:23 PM

Yeah, you need to set the EnableAutoDepthStencil member of your presentation parameters structure to TRUE and the AutoDepthStencilFormat member to D3DFMT_D16, D3DFMT_D32, etc.

rileyriley

235

Author

February 03, 2002 04:51 PM

Ok, I just hadn''t set my presentation parameters correctly. Thanks for the help! Works fine now.

--Riley

Enabling the z buffer

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