Thread (18 messages) 18 messages, 3 authors, 2004-08-01

Re: [Question] Colour management

From: Ville Syrjälä <syrjala@sci.fi>
Date: 2004-07-31 13:31:35

On Sat, Jul 31, 2004 at 06:26:27PM +0800, Antonino A. Daplas wrote:
	In directcolor mode where the channel size != CLUT register size, setting
the CLUT is a bit tricky. 

Take for example, RGB555. Assuming an 8-bit CLUT size, each channel can only
accept a total of 32 entries (2 power of 5).  Since an 8-bit CLUT has 256 entries,
then the driver needs to step by 8 (256/32).  The code is like this then:

red_reg[index * 8] = red
green_reg[index * 8] = green
blue_reg[index * 8] = blue

Some hardware require that all 8 entries needs to be filled up.
I noticed you do this in i810fb. What happens if you don't do this?

AFAIK mach64 doesn't need this.

-- 
Ville Syrjälä
syrjala@sci.fi
http://www.sci.fi/~syrjala/


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