Things never understand

[magistral]

Hi,

Someone remembers those cheap PC conversions like indiana jones and the fate of atlantis?... those 256 to 32 colors conversions?... i never understand why they didn't use HAM mode. At last, almost all screens are static in those games... any tips?.

btw: Someone wants to help me to convert the graphics?. I think with a 2 meg amiga 500 we can make a good HAM conversion.

Greets.

[lempkee]

there are many reasons i guess but here is one... as you said its a conversion... had it been the other way around it may have been using halfbrite system or whatever to gain more colors on screen etc....

btw, some games look better with 32 colors but yes.... some 256col games looks amazing.

Crucial ones?

HAM is 4096 colors from a pallette
256col means 256.000 colors

another one?

Amiga 1200 never did sell as good as the A500 did and therefor software publishers and devs always tried to walk on safe ground when it came to dooing AGA (256.000 colors) conversions etc..

(maybe you see it now..... )

[CLS2086]

Yes, but the data space on the floppy would be very big  :roll:

[Lando]

You can't really use HAM with dynamically animated objects - the backgrounds may be static but the characters and so on are all animated.  The colour of each pixel depends on the colour of the previous pixel, so you'd get streaking all over the place as the characters moved around in front of the background.  

It would have been cheaper to dynamically alter the palette with the copper depending on the colours required for each scanline.  Even in low-res 5 bitplane mode the A500 isn't limited to 32 colours - the copper can be used to change the contents of the colour registers as the screen is drawn.  But Lucasarts weren't really making much use of the Amiga chipset, it was like you say just a cheap PC port (shovelware).

[Zener]

The Amiga versión has the same data as the PC versión. Not exactly the same but the graphics are in 256 colors. The conversion to 32cols makes the latest games soooo slow. HAM mode is not possible but a 256 color version for AGA is!

[pixie]

@lempkee:

HAM is 4096 colors from a pallette
256col means 256.000 colors

HAM has a 12bit scope, meaning, it has (2^4)*(2^4)*(2^4) combination of colours [4096 (2^12)], and 16(2^4) levels of gray.

AGA had 256 registered colours out of a 24bit scope, and 256(2^8) levels of gray.

But if you had a palette of 16bit as in some VGA cards, you would only have 256 colours out of a palette of 264.112, and 64(2^6) levels of gray.

The 264112 colours of AGA are due to HAM-8 mode were it only had 2^6 levels of gray from a 16Bit scope

@lando:

You can't really use HAM with dynamically animated objects - the backgrounds may be static but the characters and so on are all animated. The colour of each pixel depends on the colour of the previous pixel, so you'd get streaking all over the place as the characters moved around in front of the background.

Although HAM isn't used because of speed and the fringing effect, there were other ways to bring more colours on A500. Universe was an example with 256 colour at the same time.

But Lucasarts weren't really making much use of the Amiga chipset, it was like you say just a cheap PC port (shovelware).

Lucas Arts made use of the copper, it used multiple screens, one for the gamescreen and another for the functions menu and inventarium which should had give it at least 64 diferent colours at the same time.

[SamuraiCrow]

The problem with the color fringing of HAM mode is because the HAM mode isn't fully paletted.  Only the 16 "base pairs" are paletted.  The modify mode requires the pixel to the left of it remain static so that it can create the correct modification of that color.

Sprites, however, do not modify the screen memory thus making the possibility of at least one HAM mode game: "Pioneer Plague" possible.  Since ECS sprites are 16 pixels wide and limited to 15 colors of 4 sprites horizontally from each other or each of 3 colors of 8 sprites horizontally, the use of sprites for all animated objects is impractical.  The AGA chipset could make wider sprites but were still stuck to the same palette limitations.

[irishmike]

Well I am new enough to the platform that I am unaware of what HAM is.  I suppose it is a non-issue with my A1200?

Anyhow, I got a kick out of the phrase "shovelware" to discribe the ports of PC games to the Miggie :-)

Sorry about this post being off-Topic but just wanted to put in my .02 worth.

[pixie]

@irishmike :

Well I am new enough to the platform that I am unaware of what HAM is. I suppose it is a non-issue with my A1200?

It is less prone to fringing, but still applies

[bloodmoney]

How about a port for this....

 :-D Amiga Hardware

Graffiti

[InTheSand]

irishmike wrote:
Well I am new enough to the platform that I am unaware of what HAM is.

Have a Google around, you'll find plenty of articles on HAM, e.g. this one from Wikipedia.

Essentially, it's a way of using less graphics memory to represent more colours on-screen, at the expense of having to deal with certain side-effects.

 - Ali

[leirbag28]

HAM games are possible without fringing....one just has to think outside the box of "supposed" Amiga limitations.

Here is how its completely possible without any fringing:

Ever used Brilliance?  or Broadcast Titler 2?   well they use 2 or more different screens at different resolutions and different colors at once, and like brilliance.....the tools screen can be completely seperate from the resolution of the Image thats being painted.........this same technique can be applied to a game.........................the backgrounds can be HAM and the Sprites and characters can be on a different screen and different resolution and different colors and then like a draggable screen, placed ontop of the HAM background without any effect to the HAM game backgrounds which can also be animated mind you.
Broadcast Titler runs fantastically smooth on a 7mhz 2mb or 3mb Amiga, I think the game will do the same.especially since it will probably be running in 352 x 240  and Broadcast Titler runs in 720 x 480 Hires Interlaced!  so just imagine!


Its Possible! because Amiga Makes It Possible!

[SamuraiCrow]

I think you may be confusing HAM mode with Copper.  HAM mode requires all of the bitplanes be active at once therefore it is impossible to use a "separate screen" for the BOBs.  The sprite graphics are independant of the bitplanes, however, and can be set to other colors using the copper but are still limited to 15 colors each.  (All assuming ECS/OCS.)

[balrogsoft]

HAM mode isn't the better graphic mode for games, but exist more than one game using HAM mode, i found this searching through google:
http://eab.abime.net/archive/index.php/t-5973.html

[Tricky]

Lando wrote:
You can't really use HAM with dynamically animated objects - the backgrounds may be static but the characters and so on are all animated.

Unless one uses hardware sprites for the animated objects.  But this of course limits us to 15 colours for these objects at 64 pixels wide, or 3 colours at 128 pixels wide.