Good explanation why half-brite is too slow for game engines? - Page 2

alexh · 09 July 2021, 14:11

Quote:

Originally Posted by viddi

Wasn't the Lionheart spider cave level EHB?

If you believe dlfrsilver then yes that was 64-colour EHB.

https://eab.abime.net/showpost.php?p=810485&postcount=9

viddi · 09 July 2021, 14:27

Quote:

Originally Posted by alexh

If you believe DLFSLVR then yes that was 64-colour EHB.

https://eab.abime.net/showpost.php?p=810485&postcount=9

I read some dev story decades ago and they said they could use EHB by using just one type of baddies...

dlfrsilver · 09 July 2021, 14:46

Quote:

Originally Posted by alexh

If you believe DLFSLVR then yes that was 64-colour EHB.

https://eab.abime.net/showpost.php?p=810485&postcount=9

yes it is. The cave levels are in 64 colors EHB. It can be checked with maptapper, but also if you ripp the levels. with 5 bitplans, it doesn't work, but with 6 bitplanes, you have all the colors perfect

jotd · 14 July 2021, 18:55

I suppose that one-on-one fighters use that mode too if mirror matches are allowed (else it takes too much memory to store 2 characters with different colors).

You can enable 6 bitplanes, but never blit anything except the shade (desert strike) or the mask (mirror match), so the DMA isn't that sollicited. At least you don't use the blitter a lot. DMA just fetches 1 more bitplane to compute display. Just leave the bitplane to all zeroes for no effect on colors.

Or you have to design the palette so one particular plane is blitted somewhere else so it changes the colors (Supercars 2 and probably Lotus do that to draw the same bitmap with different colors)

dlfrsilver · 14 July 2021, 19:06

There is a game i discovered lately that is 64 colors halfbright : Darkseed.

Good feat, it has also spoken dialogues on the disk version !

Tigerskunk · 15 July 2021, 06:33

Quote:

Originally Posted by jotd

You can enable 6 bitplanes, but never blit anything except the shade (desert strike) or the mask (mirror match), so the DMA isn't that sollicited. At least you don't use the blitter a lot. DMA just fetches 1 more bitplane to compute display. Just leave the bitplane to all zeroes for no effect on colors.

Still a lot of DMA that gets lost this way... : /

StingRay · 15 July 2021, 09:33

Quote:

Originally Posted by dlfrsilver

There is a game i discovered lately that is 64 colors halfbright : Darkseed.

Darkseed uses a 3/4 bitplane hires interlace screen (BPLCON0 is set to either $3004 or $4004 in the copperlists).

roondar · 15 July 2021, 09:35

Quote:

Originally Posted by Steril707

Still a lot of DMA that gets lost this way... : /

Yeah, losing 5K cycles (assuming a 320x256 screen) out of 70K available isn't nothing

Cammy · 24 July 2021, 00:12

How does Fightin' Spirit move such massive characters all over the screen in EHB at 50fps?

viddi · 24 July 2021, 00:31

Quote:

Originally Posted by Cammy

How does Fightin' Spirit move such massive characters all over the screen in EHB at 50fps?

ECS is in 25fps.
AGA maybe doesn't use EHB.

alain.treesong · 24 July 2021, 13:30

If my memory is good, pinball dreams (and probably the other OCS pinballs from DI) is in EHB.

Galahad/FLT · 24 July 2021, 14:26

Quote:

Originally Posted by alain.treesong

If my memory is good, pinball dreams (and probably the other OCS pinballs from DI) is in EHB.

Pinball Dreams is EHB, but for that game, its not particularly stressed out.

Uses hardware sprites for the ball, the table is complete in memory, and the scrolling up and down is done by changing bitplane pointers.

Lots of the animations are simply colour changes, so this is an area where EHB really shines.

No wonder then it wasn't converted to Megadrive, whilst that machine can display 64 colours, its only has a palette of 512 versus the 4096 of the Amiga, so it wouldn't have been as well shaded on Megadrive.

Retro1234 · 24 July 2021, 18:54

Just curious what would be quicker 64 colour on AGA
or
EHB on 68020?

jotd · 24 July 2021, 20:49

EHB or 6 plane KillEHB (real 64 colors) that's the same speed. Once color registers are loaded, looking them up isn't really a problem.

Retro1234 · 24 July 2021, 23:11

so on a A1200 there would be no difference speed wise to using real AGA 64colours and ecs EHB 64 colours?

jotd · 25 July 2021, 09:44

In terms of DMA bandwidth it's the same thing. It can be slower if you set the 64 colors in the copperlist instead of setting them with CPU beforehand.

Retro1234 · 25 July 2021, 11:04

Probably silly question to you but why include this 64 EHB mode in the chipset instead of real 64 colour if they have the same speed impact?

jotd · 25 July 2021, 11:33

I already asked myself the same question. That can appear pretty much as a stupid idea... I suppose that creating more color registers was more expensive, plus most computers of the era had only 16 colors, so 32 colors was already a good improvement.

EHB was a good way to create shadows in 2D games too. Everything in Amiga is thought for 2D anyway.

pandy71 · 25 July 2021, 15:08

Quote:

Originally Posted by Retro1234

Probably silly question to you but why include this 64 EHB mode in the chipset instead of real 64 colour if they have the same speed impact?

ICS doesn't have EHB mode - 6 bitplanes was obviously for HAM and in OCS providing EHB (engineer way of thinking: we have only 32 color registers but 6 bitplanes and we don't want use HAM - what to do? Aaaa lets use 6-th bitplane as shadow as it is easy modification - set MSB to 0 in CLUT RGB value). was OK workaround for 6 bitplanes capability, no-HAM flag and only 5 bit CLUT entry.

jotd · 25 July 2021, 15:28

makes sense. A kind of HoldAndModify but in another dimension

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14 July 2021, 18:55	#24
jotd This cat is no more Join Date: Dec 2004 Location: FRANCE Age: 52 Posts: 8,162	I suppose that one-on-one fighters use that mode too if mirror matches are allowed (else it takes too much memory to store 2 characters with different colors). You can enable 6 bitplanes, but never blit anything except the shade (desert strike) or the mask (mirror match), so the DMA isn't that sollicited. At least you don't use the blitter a lot. DMA just fetches 1 more bitplane to compute display. Just leave the bitplane to all zeroes for no effect on colors. Or you have to design the palette so one particular plane is blitted somewhere else so it changes the colors (Supercars 2 and probably Lotus do that to draw the same bitmap with different colors)

14 July 2021, 19:06	#25
dlfrsilver CaptainM68K-SPS France Join Date: Dec 2004 Location: Melun nearby Paris/France Age: 46 Posts: 10,412	There is a game i discovered lately that is 64 colors halfbright : Darkseed. Good feat, it has also spoken dialogues on the disk version !

24 July 2021, 00:12	#29
Cammy Registered User Join Date: Aug 2007 Location: Tasmania, Australia Age: 39 Posts: 1,189	How does Fightin' Spirit move such massive characters all over the screen in EHB at 50fps?

24 July 2021, 13:30	#31
alain.treesong Aghnar Join Date: Jan 2019 Location: France Posts: 153	If my memory is good, pinball dreams (and probably the other OCS pinballs from DI) is in EHB.

24 July 2021, 18:54	#33
Retro1234 Phone Homer Join Date: Jun 2006 Location: 5150 Posts: 5,773	Just curious what would be quicker 64 colour on AGA or EHB on 68020?

24 July 2021, 20:49	#34
jotd This cat is no more Join Date: Dec 2004 Location: FRANCE Age: 52 Posts: 8,162	EHB or 6 plane KillEHB (real 64 colors) that's the same speed. Once color registers are loaded, looking them up isn't really a problem.

24 July 2021, 23:11	#35
Retro1234 Phone Homer Join Date: Jun 2006 Location: 5150 Posts: 5,773	so on a A1200 there would be no difference speed wise to using real AGA 64colours and ecs EHB 64 colours?

25 July 2021, 09:44	#36
jotd This cat is no more Join Date: Dec 2004 Location: FRANCE Age: 52 Posts: 8,162	In terms of DMA bandwidth it's the same thing. It can be slower if you set the 64 colors in the copperlist instead of setting them with CPU beforehand.

25 July 2021, 11:04	#37
Retro1234 Phone Homer Join Date: Jun 2006 Location: 5150 Posts: 5,773	Probably silly question to you but why include this 64 EHB mode in the chipset instead of real 64 colour if they have the same speed impact?

25 July 2021, 11:33	#38
jotd This cat is no more Join Date: Dec 2004 Location: FRANCE Age: 52 Posts: 8,162	I already asked myself the same question. That can appear pretty much as a stupid idea... I suppose that creating more color registers was more expensive, plus most computers of the era had only 16 colors, so 32 colors was already a good improvement. EHB was a good way to create shadows in 2D games too. Everything in Amiga is thought for 2D anyway.

25 July 2021, 15:28	#40
jotd This cat is no more Join Date: Dec 2004 Location: FRANCE Age: 52 Posts: 8,162	makes sense. A kind of HoldAndModify but in another dimension

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