Amiga: Dedicaded to EHB

[emkay]

Well in this thread I would like to gather informations about AMIGA graphics above the known :-)

 

Seems, some people didn't know that a stock AMIGA with OCS/ECS had a colour mode with non-flickering 64 base colours...

Others may help to make a roundup because I'm searching for a game I had in the past, using EHB (Extra Halfbright) , but I don't even remember the name.

 

Here some examples:

 

Here an official game using EHB:

 

http://hol.abime.net/126

 

 

Following games use the title screen with EHB at least:

http://hol.abime.net/2181

 

The title screen uses 62 colours. Picking a random scanline you gain easily 35 and more colours.

 

 

Similar in this game:

 

http://hol.abime.net/1500

 

Using 61 colours, a random line shows 42 colours.

 

One Screenshot:

 

 

The interesting thing is, that with some additional copper FX a VGA(MCGA) looking graphics is possible. Some people would think this is a VGA screenshot already

[Cybergoth]

Hm... ok, never knew about this HB thing. I think the first Bullfrog game "Fusion" was advertised in the Power Play mag. to use more colors than usual, though i thought the graphics were called HAM or so...

[Rybags]

Strange that it wasn't used so much.

 

Halfbright uses the 6th bit-plane to represent the 32 paletted colours, but at half the luminance.

 

http://en.wikipedia.org/wiki/Original_Amiga_chipset

 

According to that, the mode is available in all Amigas except for early 1000's sold in the US.

[emkay]

Hm... ok, never knew about this HB thing. I think the first Bullfrog game "Fusion" was advertised in the Power Play mag. to use more colors than usual, though i thought the graphics were called HAM or so...

 

Actually, fusion is a 32 colour picture. It looks that colourful due to clever colour transition usage.

 

HAM has some restrictions which makes it good for fullscreen images but not for details.

EHB was great for graphical artists, because they gained colours to give the pictures more depth.

[emkay]

Strange that it wasn't used so much.

 

Halfbright uses the 6th bit-plane to represent the 32 paletted colours, but at half the luminance.

 

 

The very interesting with EHB ist the fact that it offers colours, that are used in Modes like VGA, to dither the "main colours" or to simply use the "new available" colours for giving the image more depth.

[LocalH]

HAM is an interesting mode that basically compresses 12-bit data (4096 colours) down to 6 planes. You have a base pallet of 16 colors that can be used anywhere on the screen, or you also have the capability, for any pixel, to "hold" two of the RGB values from the pixel to the left, and "modify" the remaining one. Most HAM images will contain black and white in the base pallet, because otherwise it would take four pixels to transition from one to the other (the base color, then one pixel to modify each of the RGB values).

 

AGA also offers HAM in an upgraded fashion - instead of using 6 planes, it uses 8, allowing up to 262144 colors with a base pallet of 64 colors. AGA also includes EHB for compatibility purposes, but there is also a bit that will disable EHB (as there are more than enough pallet entries available to replicate EHB functionality, it's only needed for OCS/ECS compatibility).

 

HAM is only useful for still images or precalculated animation due to the aforementioned "fringing" - it would take too much CPU time to try to do the necessary calculations to minimize fringing each frame. At most, I could see using HAM as the background for a flick-screen game, as you wouldn't have to worry about the scrolling causing fringing.

Edited March 26, 2006 by LocalH

[desiv]

HAM is only useful for still images or precalculated animation due to the aforementioned "fringing" - it would take too much CPU time to try to do the necessary calculations to minimize fringing each frame. At most, I could see using HAM as the background for a flick-screen game, as you wouldn't have to worry about the scrolling causing fringing.

 

Pioneer Plague was a fast action arcade style game in HAM mode. It could be done.

 

There were a few other HAM games, but I'm not sure about action games.

 

desiv

[emkay]

How could I forget the ingame loaderscreens of AGONY

Since... I made a conversion of one of them for the A8's

 

 

 

 

 

 

 

 

http://hol.abime.net/3209

[MacbthPSW]

I'm pretty sure the Amiga version of Pirates! used EHB mode, at least for the stills. Really nice version, that.

[emkay]

I'm pretty sure the Amiga version of Pirates! used EHB mode, at least for the stills. Really nice version, that.

 

Sadly, no.

 

But this game seems also to use EHB:

 

http://hol.abime.net/2832/screenshot

[Cybergoth]

Hm... ok, never knew about this HB thing. I think the first Bullfrog game "Fusion" was advertised in the Power Play mag. to use more colors than usual, though i thought the graphics were called HAM or so...

 

I recently found the two articles I was refering to (read: confusing) here

 

About "Fusion" Power Play basically said that "it'll be the first game to make full use of the Amigas capabillities" and that "there'll never be less than 32 colors" on the screen

 

BUT: The game that was supossed to run in HAM mode was called "DDT", a game that Power Play previewed a couple of issues later!