RE: [Algorithms] Can a diffuse color component co-exist with dyna mic lighting?

[Ian T. <ia...@re...>]

You could use the TFactor to modulate the colour to provide the fade out.
Then you don't have to fudge with the diffuse colour channel/material.

Stage0 : texture modulate diffuse
Stage1 : current modulate factor

Set factor to RGBA(0xff,0xff,0xff,alpha).  This will probably disable a
texture channel for some cards, since the seconds stage is occupied.  

===
ian thomson - programmer - relic entertainment 
---
	Contrary to popular belief, the most dangerous animal is not the
lion or tiger or even the elephant.  The most dangerous animal is a shark
riding on an elephant, just trampling and eating everything they see. -Jack
Handey, Deep Thoughts

> -----Original Message-----
> From: Ratcliff, John [mailto:jra...@ve...]
> Sent: Sunday, March 04, 2001 9:36 AM
> To: 'gda...@li...'
> Subject: [Algorithms] Can a diffuse color component co-exist with
> dynamic lighting?
> 
> 
> Ok, first of all I know that I can do this with a vertex 
> shader if I want,
> so that's not really the issue.  Using the fixed function 
> pipe I'm curious
> if I can do the following.
> 
> I have a vertex format that includes a diffuse color 
> component, not because
> I need the color, but because I need the alpha.  I use the 
> iterated alpha
> value to fade out at distance.  However, I would like to 
> enable lighting
> calculations.  Since I've provided my own diffuse component, 
> the lighting
> doesn't take effect, right?  Is there a way, with the fixed 
> function pipe,
> to have it retain my alpha value, but include it's color/lighting
> calculation?
> 
> Thanks,
> 
> John
> 
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