Subject: A new colour display technology From: "Andrew Davie" <atari2600@xxxxxxxxxxxxx> Date: Sun, 22 Aug 2004 22:45:36 +1000 |
I thought I'd post this idea to the list, in case someone wants to have a go at implementing it. I don't have the time right now, but I do know it will work. This is a new technique for displaying colour graphics. You may recall, some time ago we went through an interesting development process which culminated in the Interleaved Chronocolor(TM) technique. In a nutshell, this technique had the red components only of a line of pixels on one line, green components only, of the next line and blue components only of the third line. It then displayed successive frames (3 in total) where the component colour for each line was successively the red pixels, the green pixels, and then the blue pixels. In summary, in three frames on any given scanline you'd see all the red pixels only, then all the green pixels only, then all the blue pixels only. And the successive lines would be 'out of phase' by displaying the next-colour (red green or blue) from the line above. And *finally* this technique actually managed to look OK by preprocessing of the image -- separating an image into separate colour planes and then (and this is the REALLY important bit) colour-reducing these planes to a single bit per pixel WITH DITHERING. The dithering was the ultimate important step to getting the best quality from the technique. OK, now here's the new technique; We start with the same base frame as before -- a single colour per line, with each successive line alternating between red, green, blue. Now we can consider each group of three scanlines (for any pixel position) forming a RGB triad (ie: a visible colour to the eye). If this is ALL that we do, then we have an OK-looking image which actually looks like it's in colour from a distance. The memory requirements are 1/3 of the original interleaved chronocolor(TM) technique, but this technique is a lot less flickery. Actually, it doesn't flicker at all. So it's an acceptable method. But consider if we also combine the above two techniques with an interlaced display. The really nice thing about an interlaced display is that each scanline of field 2 of a frame will be inbetween scanlines of the previous field. So, if our first field displayed an image as described above (ie: with successive lines having RGBRGBRGB format), and we used an image for the second field with successive lines offset by a colour position (ie: BRGBRGBRG format), then as a part of the interlacing process of the TV, what the eye would ACTUALLY see would be a combnied frame (interlaced) with a very interesting potential combination of scanline/colour/pixels. Consider a vertical representation of the lines we're displaying.... FIELD 1 FIELD 2 R1 b1 G2 r1 B3 g1 R4 b2 G5 r2 B6 g3 What we effectively see if we combine triplets of lines (two from one field and the one inbetween from the other field) are R1b1G2/G2r1B3/B3g1R4 etc, and also b1G2r1/r1B3g1/g1R4b2 etc. we also get vertical triplets R1G2B3 (1st three lines of field 1) and G2B3R4 (2nd three lines) etc. same for vertical triplets in field 2 (eg: b1r1g1) These triplets all operate simultaneously (that is, they combine in the eye to give an overall impression of colour for an area; they do not specifically refer to an individual pixel). In fact, colours are shared between multiple pixels. But the overall effect of this two frame technique with interlacing is; * no flicker (other than interlacing, which we're all used to) * 2/3 of the graphics memory requirement of interleaved chronocolor(tm) * improved perceived resolution (we're doubling vertical resolution with the interlacing anyway) * a much nicer image overall. OK, proof is in the pudding. I will do this when I get time, but thought I'd write it down in case I get run over by a truck. I dub this technique "Interlaced spasticolor(TM)" Cheers A
Current Thread |
---|
|
<- Previous | Index | Next -> |
---|---|---|
Re: [stella] New game - Fall Down, Kroko | Thread | Re: [stella] New game - Fall Down, Erik Eid |
Re: [stella] New game - Fall Down, Kroko | Date | RE: [stella] New game - Fall Down, Aaron |
Month |