Lynx Hi Colour / Hi Res

[GadgetUK]

Hi,

 

Probably a question for Sage since he's already done the hi colour slideshow app, but how exactly is the high colour achieved? This is something Candle may try to support in his LCD replacement, if its at all possible (well, anything is possible, its a question of how many hours, days, weeks etc something takes to decide if its worth the effort).

 

I had assumed that it was done by displaying an image, then the same image but using a slightly different palette?

 

Thanks

[GadgetUK]

Does no one know exactly how it works? I guess what I would like to understand is how the palette is chosen for the 2nd frame, theres obviously a formula. And what does it translate into - ie, do you gain another 16 colours by the process, I am guessing not but really we need to understand how this is achieved with the current Lynx LCD in order for Candle to try and support it in FPGA.

 

I guess if no one can answer I will do some tests and reverse it the harder way. I want to add proper to support into Handy as well.

[108 Stars]

Best PM sage in case he does not see the thread here.

[GadgetUK]

PM sent to Sage! Thanks. I never know whether I am annoying people when I PM them =P

[sage]

I explained it already several times. It works very well because the LCD display is really slow.

It will neither work in emulation nor with scan converter.

 

Anyway it is unclear to me until now how candles approach will hande the different refresh frequencies used. the lynx lcd can be programmed to "unusual" frequencies no (old) RGB monitor can handle. (well actually, you programm mikey refresh logic, not the lcd...)

 

PS: Emulation _can_ simulate that (in some way) if you use special video parameters (inegrate over several frames).

PSS: In principle this can be done in FPGA logic as well, but its additional work.

Edited April 4, 2013 by sage

[candle]

i know it has to be adaptive (basically 4 times the line frequency) to provide best matching possible, but i can't do much about speed of tft matrix

if i had bare panel with separate vneg and vpos supplies, then i could make it by regulating these voltages, but it would add to power supply complexity

 

anyways,

 

 

don't know how it suppose to look, and it looks worse in real than on picture, but this is due to fixed scan rate of current implementation

[GadgetUK]

Looks great from the photo, but I know what you mean about fixed scan rate, ive seen the same thing in emulators as well - its a two fold problem really.

[sage]

even harder to judge for us...

[sage]

if you want to play abit around, you can use BmConvert /slideshow creator to gererate pictures in different modes and load them by comlynx or to flashcart, whatever you prefer.

[sage]

i know it has to be adaptive (basically 4 times the line frequency) to provide best matching possible, but i can't do much about speed of tft matrix

if i had bare panel with separate vneg and vpos supplies, then i could make it by regulating these voltages, but it would add to power supply complexity

 

I didnt get that point.

 

don't know how it suppose to look, and it looks worse in real than on picture, but this is due to fixed scan rate of current implementation

 

Anyway, I you want me to test your board with some crazy video settings and refresh rates, i might consider this.

I have Xilinx programmers here, but I am not sure if the software supports Alterra or Lattice programming... actually why not, its jtag anyway.

[Cammy]

Without any tricks using the LCD, can't the Lynx display thousands of colours onscreen with palette slicing? Having a separate 16 colour palette for each line?

Edited April 4, 2013 by Cammy

[candle]

in dev docs it is said that you need at least 2 lines to change complete palette, thus, just to be safe, vertical sync is 3 lines wide

but sure, if on a8 we can slice 4 colors indexes producing things like these i don't see why not to do that with lynx having over 2 times faster cpu and tiny resolution

the only thing you really need is some sort of software that would process image data

 

otoh, interlacing is very cheap cpu-time wise, and if it might look desirable on slow and very small display, it is not acceptable on bigger format

[Shawn Jefferson]

Even on the Lynx there is some "flicker", at least I find that on Alpine Games which uses a similiar method I believe.

[sage]

in dev docs it is said that you need at least 2 lines to change complete palette, thus, just to be safe,

 

If you do it clever you can change several colors in the HBL, but not all of them. I am talking about HBL NOT scan line!. Actually this mode was(is) implemented in BmConvert/Slideshow, but as it takes too much CPU power, its unusable for games. If you want to chnage the other coloras with the line, you need accurate timing, which means you have to disable all other interrupts. The software code to do that is a mess and it does not really improve the quality of teh pictures over what i am using in the slideshows.

 

vertical sync is 3 lines wide

but sure, if on a8 we can slice 4 colors indexes producing things like these i don't see why not to do that with lynx having over 2 times faster cpu and tiny resolution

the only thing you really need is some sort of software that would process image data

 

otoh, interlacing is very cheap cpu-time wise, and if it might look desirable on slow and very small display, it is not acceptable on bigger format

[sage]

Even on the Lynx there is some "flicker", at least I find that on Alpine Games which uses a similiar method I believe.

 

exactly same, as I processed the picture

[roland p]

don't know how it suppose to look, and it looks worse in real than on picture, but this is due to fixed scan rate of current implementation

Will you support 1:1 framerate in the future?

[sage]

If you do it clever you can change several colors in the HBL, but not all of them. I am talking about HBL NOT scan line!. Actually this mode was(is) implemented in BmConvert/Slideshow, but as it takes too much CPU power, its unusable for games. If you want to chnage the other coloras with the line, you need accurate timing, which means you have to disable all other interrupts. The software code to do that is a mess and it does not really improve the quality of teh pictures over what i am using in the slideshows.

 

Actually, I had some examples on my website long time ago. but i think i removed athem some years ago, when stuff started to show up on "rom sites".

[johannesmutlu]

This is an incredible great example of what the atari lynx could do, what this demo does is refreshing the same frame with a different colorpallet 16 times ps,to avoid flickering,it taking advantage of the low responsive color lcd screen and it's color blending feature, thus getting the effect of having 256 colors atonce.

Just imagine a digital camera and/or movie player for the lynx wich uses this hi-color mode,would be great.