From: Jay Link (jlink@ilbbs.com)
Date: Fri 27 Oct 2000 - 16:55:32 IST
> Everytime you want to change the color c, you first do a c++, then you change > it with gl_setpalettecolor. why can't this be done without the 'c++'? > > I tried this, and it didn't work without it. I really had to change the value > of c... what actually happens when i do c++? When you tried it, was the entire screen one color? (I'm pressed for time here, so I can't experiment, but I wrote that code sample, so I'll help the best I can :-) ). When you set your graphics mode, you select 'x' number of colors. For example, one mode might allow for 256 colors, and another for 16 million. I believe that gradient example used a 256-color mode, which means that you get 256 seperate colors to play around with. Now, instead of just accepting the default colors, the program customizes a number of them with gl_setpalettecolor(). This gives the various shades of blue. It's only to save a loop that the palette is customized as the lines are drawn. The complete palette could be set first, and then the lines drawn. Note that if you set a palette color, draw with it, and then change that palette color, then your previously-drawn shapes using that color will change to match the new palette. I suspect this is what happened with your gradient program. > And another thing about the color issue, I've tried playing around with this > for quite a long time now, and I've noticed that the more variables I create, > the less colors I can use.... for example, there was a moment that when I > added just one more integer, my red color (wich was c_red, set with > gl_setpalettecolor(c_red,63,0,0);) would just dissapear! Can you show us the code on this one? At the moment, all I can think is that you've exceeded the number of colors that your chosen screen mode will allow, but I can't say for sure without seeing anything. -JL ------------------------------------------------------------------ Unsubscribe: To: listbot@svgalib.org Body: unsubscribe linux-svgalib
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