Idea for math experts...

페이지 9/9
2 | 3 | 4 | 5 | 6 | 7 | 8 |

By ro

Scribe (4479)

ro의 아바타

01-06-2007, 15:07

thaz a cool trick I haven't seen/used before, interesting.
Running Naked in a Field of Flowers

By Maggoo

Paragon (1214)

Maggoo의 아바타

01-06-2007, 17:17

Damagex/TurboR: To display 424 lines it's simply using the interlaced mode by getting 2 images (212 lines) to be displayed alternatively. It gives the illusion of doubling the resolution but has the negative effect of giving a flickering a lot. You can also use this to give the illusion of more colors (flickering between 2 colors to give the illusion of a 3rd one). By using overscan you can add more "real" lines to be displayed in the top and bottom border of the image, however this is nowhere near 424 lines.

ro: you can download an example of overscan with source code here http://vscreen.hypercu.be/unreleased.htm (check for overscan). BTW, instead of changing the VDP register bit for the number of lines displayed, you can also mess with the frequency bit (50/60hz) in the same way. This produces odd results but most monitors don't seem to enjoy that trick very much (got a Commodore 1084 to hiss at me doing that :P)

By poke-1,170

Paragon (1763)

poke-1,170의 아바타

01-06-2007, 17:34

I think such a trick of fast flickering was used on the 64 for a game called mayhem in monsterland, one of the last 64 games of it's time.
It gave the illusion of having more then the 16 colours. But I guess using dithering works nicer, no flickering and with 2 colours you can create convincable gradients. Or with checkered rasters (which you don't see on a TV anyway)

By jltursan

Prophet (2542)

jltursan의 아바타

01-06-2007, 18:15

Although I guess that the "extra colors" routine is a bit cpu time consuming I wonder if SymbOS could implement the SC7 "extra colors" as a new feature?, wallpapers could be nicer with that!. How much CPU time is free each line after changing the palette?

By Maggoo

Paragon (1214)

Maggoo의 아바타

01-06-2007, 20:05

Although I guess that the "extra colors" routine is a bit cpu time consuming I wonder if SymbOS could implement the SC7 "extra colors" as a new feature?, wallpapers could be nicer with that!. How much CPU time is free each line after changing the palette?

Noooot a good idea. Changing the colors is not the issue, but to do so at different lines you have to manage VDP interupts (wait for the VDP to refresh that line) for each line the palette has to change. This may be good for demos or a slide show where all that matters is the visual effect but not for an OS where the CPU has to be free to perform other tasks.

By NYYRIKKI

Enlighted (5875)

NYYRIKKI의 아바타

01-06-2007, 20:42

@ Sonic_Aka_T
Very nice Tongue I just would not call the files .HAM... Maybe .PCH ?

@ manuel
Is it enough information that BMW has 128 colors? Tongue (Lazy bastard am I)

@DamageX
The trick goes as turbor and Maggoo already explained.

@Maggoo
There is a difference between 2 pictures after each other and interlacing... If you want more colors by showing two pictures alternatively you need to set EO (bit 2 in register 9), but if you want to double the resolution you need to set also IL (bit 3 in register 9)

The 480 lines was done by using both interlacing and overscan as manuel already guessed.

@jltursan
No palette changes to SymbOS! Current implementation is best!

By turbor

Champion (486)

turbor의 아바타

01-06-2007, 23:05

Damagex/TurboR: To display 424 lines it's simply using the interlaced mode by getting 2 images (212 lines) to be displayed alternatively.
....
By using overscan you can add more "real" lines to be displayed in the top and bottom border of the image, however this is nowhere near 424 lines.

I didn't mention interlace since DamageX seemed to know that one already, hence him asking for 'more than 424' (=2*212 interlaced)
Seems like I need to take more time to write more elaborate answers instead of assuming that my way of thinking is clear to everyone Smile

By Maggoo

Paragon (1214)

Maggoo의 아바타

02-06-2007, 03:36

My bad. I just re-read your post and it's clear now. I thought the question was about displaying 424 lines instead of more than 424 lines. Dug me Tongue

By AuroraMSX

Paragon (1901)

AuroraMSX의 아바타

02-06-2007, 09:16

thaz a cool trick I haven't seen/used before, interesting.
Running Naked in a Field of Flowers
Muh? You've never seen Unknown Reality or played Ark-a-Noah? Shame!

By NYYRIKKI

Enlighted (5875)

NYYRIKKI의 아바타

02-06-2007, 17:57

According to my latest tests (look here http://www.msx.org/forumtopicl7400.html ) it would be possible to display 512*512 picture with 512 colors! There should be still enough time to change whole palette during the "VBLANC". It is just that I need quite a custom loader for these pictures. ._,

페이지 9/9
2 | 3 | 4 | 5 | 6 | 7 | 8 |