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What exactly are these graphics CVARs?

Posted: Mon Oct 09, 2006 6:35 am
by Smoke
I understand that higher values give prettier graphics--I can see that while testing--but could someone please tell me more specifically what these CVARs do? How do they utilize the GPU and the game engine?

r_colorbits: General color depth, I guess. 16 = 65K colors, 32 = 16.7M colors.

r_depthbits: Some sort of ... buffer ... thingy?

r_texturebits: Textues quality of ... what exactly? Everything?

r_detailtextures: Makes everything brighter, sure, but what else?

r_texturemode: How is this different from, say, r_texturebits?

I thought perhaps someone here with some technical knowledge of the Q3 engine might know.

Re: What exactly are these graphics CVARs?

Posted: Mon Oct 09, 2006 8:41 am
by ouroboro
Smoke wrote:I understand that higher values give prettier graphics--I can see that while testing--but could someone please tell me more specifically what these CVARs do? How do they utilize the GPU and the game engine?

r_colorbits: General color depth, I guess. 16 = 65K colors, 32 = 16.7M colors.

r_depthbits: Some sort of ... buffer ... thingy?

r_texturebits: Textues quality of ... what exactly? Everything?

r_detailtextures: Makes everything brighter, sure, but what else?

r_texturemode: How is this different from, say, r_texturebits?

I thought perhaps someone here with some technical knowledge of the Q3 engine might know.
Well I don't have "technical knowledge," but I know basically what they do:

r_colorbits: General color depth, I guess. 16 = 65K colors, 32 = 16.7M colors.

-- Correct.

r_depthbits: Some sort of ... buffer ... thingy?

-- Correct. The depth (Z) buffer.

r_texturebits: Textues quality of ... what exactly? Everything?

-- Correct.

r_detailtextures: Makes everything brighter, sure, but what else?

-- Adds a second layer of detail. It's effect can be seen most easily on snow. It's not just the brightness, it actually appears more detailed and granulated:

r_detailTextures 0
Image

r_detailTextures 1
Image

r_texturemode: How is this different from, say, r_texturebits?

-- This is where you specify "bilinear" (GL_LINEAR_MIPMAP_NEAREST) or "trilinear" (GL_LINEAR_MIPMAP_LINEAR). There are other (uglier) options as well.