Richard Costello's Coding memories

[kamelito]

Hi Ric,

Thanks for the image, as everybody see, Ramrod is smiling, maybe because he knows that one day he'll be available for all its fans

kamelito

[Galahad/FLT]

Originally Posted by Ricardo

Why didn't I use movem.w ?

1st to post correct answer gets a nice Ramrod pici (excluding moderators who could modify posts of course )

I didn't see this!

[tomcat666]

Is this the greatest thread ever or what ?

[dlfrsilver]

Yes it is doh!

[Toffee]

Really interesting reading all of this thread!

Did you ever try to include parallax scrolling in your games ? It was only really custom Amiga games which did this well E.G Shadow of the Beast, Lion Heart, Agony, Elfmania etc.

[ Show youtube player ]

Notice the parallax effect on the lava

[ Show youtube player ]

I think the foreground playfield is in 4/5 planes because the background is done with repeating sprites using the copper!

[Ricardo]

Originally Posted by Toffee

Really interesting reading all of this thread!

Did you ever try to include parallax scrolling in your games ? It was only really custom Amiga games which did this well E.G Shadow of the Beast, Lion Heart, Agony, Elfmania etc.

[ Show youtube player ]

Notice the parallax effect on the lava

[ Show youtube player ]

I think the foreground playfield is in 4/5 planes because the background is done with repeating sprites using the copper!

Thats a very nice use of the Amiga's hardware and like demo's you can tell it was designed for the Amiga because it stretches the playfields, hardware sprites and colours to the limit - there's a fairly complex copperlist driving all that activity.

I never really played with the Amiga's hardware that much because to use it in the ways this game does means designing things very specifically. Things like quantity and size of sprites and restricting horizontal scan lines of the background / foreground to 7/8 colours.

For example Gauntlet II easily had x12 16 colour sprites on a horizontal line which meant they had to be software based.

In Mortal Kombat the character sprites were again too big for hardware sprites, in MKI I initially created my blitter routine to use x3 16 colour hardware sprites for player 1, welded to a blitted strip for the rest. I couldnt use the 4th hardware sprite (remember there are only x4 16 colour, or x8 4 colour) because the screen width was stealing the 4th sprites DMA. I would have had to reduce the screen width by 16 pix to use the 4th and I think it was already 304 pixels wide visible (320 including the scroll buffer).

Then I ran into the A500's timing issue where a pair of the 3rd sprites planes would loose their DMA slot occasionally causing screen glitches - so I ended up turning the 3rd one off. It ended up being a right pain using the hardware sprites (all the extra code for managing the different data format for the hardware sprites) for little benefit. Remember the sprite source was in FastRAM so the 68K still had to decompress the data into the hardware sprite space in ChipRAM - hence I dumped it for MKII and nobody ever really noticed. Atleast I think I ditched it for MKII, I may have dropped it near the end of MKI development to reduce code size etc.

I was always frustrated by the knock on effect of game demands where you couldnt do one thing because of that which meant you couldnt then do something else etc. Whilst I loved the Amiga and it really is a cool piece of kit I its only design flaw was providing both the CPU and custom hardware direct access to all the memory all the time. It would have been better if the ChipRAM had been paged, so the 68K could see, say, 128K at a time whilst the custom hardware could see the other 384K. That would have given all the 68K's cycles for more hardware sprites, whilst the 68K could have truelly parallel processed controlling the custom hardware via the custom registers. That would have made the Amiga more like the arcade machines I was trying to emulate.

The other problem I had was creating games that were being written for all formats, sharing source graphics etc. at the time writing solely for the Amiga was a luxury my mortgage lender would not have been happy about . But I do think the best games were the originals, that were developed specifically for the machine, so that the game had playability, smooth 50Hz framerate and gorgeous graphics, albeit with lots of background action and only a small amount of foreground action.

If you take the background away from the game you linked to above the foreground becomes a pretty boring place, take the background away from MKII and you still have a lot of action all the time. So I guess its swings and roundabouts.

[dlfrsilver]

Valdyn, the main lionheart character use 119 frames alone. each enemy use between 12-20 frames each, not counting the background parts....

but well, bubba and stix use more than 200 frames for the main character, Brian the lion from psygnosis use ~220 frames alone, etc.....

[Ricardo]

In fact, having thought about it, my frustrations all started with the small number of narrow hardware sprites the Amiga had.

As soon as you can use the hardware sprites the background becomes independent of the foreground which means no blitting to replace bits of background overwritten, only 1 screen freeing up 32Kish and no cycle hit on drawing sprites to the screen and palette independence.

The Amiga has an unusually small number of hardware sprites (per scan) given the other features its custom chips had, in hindsight, I think it would have been infinitely better if the sprites could have stole cycles off the 68K and had their own palettes. Then the rest of the hardware would have made sense.

Imagine an Amiga with the capability of x20 16 colour, 16 pixel wide sprites per scan

Also is it my memory thats bad (dont have the hardware ref to hand) but as soon as you went dual playfield were you not restricted to two 8 colour playfields (one only actually 7 + transparent) ?

[StingRay]

Originally Posted by Ricardo

Also is it my memory thats bad (dont have the hardware ref to hand) but as soon as you went dual playfield were you not restricted to two 8 colour playfields (one only actually 7 + transparent) ?

That's correct, 2x3 bitplanes max. in dual playfield mode.

[Ricardo]

Originally Posted by StingRay

That's correct, 2x3 bitplanes max. in dual playfield mode.

I was wondering if you could do 4 plane / 2 plane, or if it was fixed at 3 / 3 as I think it was. That would explain the subtle shaded low colour count, repeated pattern background used in the paralax effects.

The large fire ball is technically interesting though (in the above game).

[tomcat666]

Originally Posted by Ricardo

I was wondering if you could do 4 plane / 2 plane, or if it was fixed at 3 / 3 as I think it was. That would explain the subtle shaded low colour count, repeated pattern background used in the paralax effects.

The large fire ball is technically interesting though (in the above game).

From the Amiga Hardware Reference manual:

Number of Bitplanes
    "turned on"          Playfield 1*       Playfield 2*

         0                   None               None

                          __________
         1               |1         |
                         |__________|
                          __________         __________
         2               |1         |       |2         |
                         |__________|       |__________|
                          __________         __________
         3               |1 ________|_      |2         |
                         |_|3         |     |__________|
                           |__________|
                          __________         __________
         4               |1 ________|_      |2 ________|_
                         |_|3         |     |_|4         |
                           |__________|       |__________|
                          __________         __________
         5               |1 ________|_      |2 ________|_
                         |_|3 ________|_    |_|4         |
                           |_|5         |     |__________|
                             |__________|
                          __________         __________
         6               |1 ________|_      |2 ________|_
                         |_|3 ________|_    |_|4 ________|_
                           |_|5         |     |_|6         |
                             |__________|       |__________|

     *NOTE:  Either playfield may be placed "in front of" or
             "behind" the other using the "swap-bit"


       FIGURE 3-13: How Bitplanes are assigned to duel playfields.

Oh, if any1 wants a read through it ... here it is: http://pc.sux.org/tomcat/AMIHARRE.zip

[Toffee]

Originally Posted by Ricardo

I was wondering if you could do 4 plane / 2 plane, or if it was fixed at 3 / 3 as I think it was. That would explain the subtle shaded low colour count, repeated pattern background used in the paralax effects.

The large fire ball is technically interesting though (in the above game).

I think Lionheart only has 1 16 colour playfield. The background is also 16 colours (excluding Copper colour changes) and is made from repeating sprites. I found this in another thread:-

"I don't know which was the game was first to use repeated sprites to form another playfield - Risky Woods and Leander come to mind - these allow you to have 16 colours in the foreground and 16 (attached sprites) in the background. But of course you have to repeat the graphics as there is no DMA time left to load new graphics and reposition the sprites across the screen. But from a technical point of view, that was a neat trick."

http://eab.abime.net/showthread.php?t=31773&page=2

[Toffee]

My favorite Copper trick can be seen here:-

[ Show youtube player ]

Yeah the game is just using AGA 2*4 bitplane screens. The textured cylinder background is done by resizing each scan line separately with the Copper. This magic is done by adjusting the scroll register across the scaline with the Copper to shrink it. Of course the shading is just done by using the Copper to switch all colours each scanline.

How did they ever discover this ?!

[pmc]

Cool effect Toffee - I'd never seen that before...

[zenox98]

Have I seen a similar effect in Super Stardust, or am I tripping ?!?

[Ironclaw]

Originally Posted by Toffee

My favorite Copper trick can be seen here:-

[ Show youtube player ]

Yeah the game is just using AGA 2*4 bitplane screens. The textured cylinder background is done by resizing each scan line separately with the Copper. This magic is done by adjusting the scroll register across the scaline with the Copper to shrink it. Of course the shading is just done by using the Copper to switch all colours each scanline.

How did they ever discover this ?!

I prefer the sky level.... it's a bit simpler, but clouds are nice :P

[ Show youtube player ] at 4:32

[Ricardo]

Originally Posted by Toffee

I think Lionheart only has 1 16 colour playfield. The background is also 16 colours (excluding Copper colour changes) and is made from repeating sprites. I found this in another thread:-

"I don't know which was the game was first to use repeated sprites to form another playfield - Risky Woods and Leander come to mind - these allow you to have 16 colours in the foreground and 16 (attached sprites) in the background. But of course you have to repeat the graphics as there is no DMA time left to load new graphics and reposition the sprites across the screen. But from a technical point of view, that was a neat trick."

http://eab.abime.net/showthread.php?t=31773&page=2

Hmmm now I need to start reading ...

I thought the hardware sprite data was fetched during horizontal fly back, if thats so then how do you repeat the 4 16 pixel sprites 5 times across the screen ahhhh I see ... same data but keep changing the sprite co-ordinates, that way you get 48 pixels of clock count for the copper to change the x coordinate of a hardware sprite, that would be easy yes, simple when you think about it

That then explains the foreground "big ball", but it does mean there should be loads more sprite action as the foreground isnt hardware sprite limited.

I need to read the manual and watch that vid again now .

[Toffee]

Originally Posted by Ricardo

Hmmm now I need to start reading ...

I thought the hardware sprite data was fetched during horizontal fly back, if thats so then how do you repeat the 4 16 pixel sprites 5 times across the screen ahhhh I see ... same data but keep changing the sprite co-ordinates, that way you get 48 pixels of clock count for the copper to change the x coordinate of a hardware sprite, that would be easy yes, simple when you think about it

That then explains the foreground "big ball", but it does mean there should be loads more sprite action as the foreground isnt hardware sprite limited.

I need to read the manual and watch that vid again now .

Bingo!

But it's the background that's done with hardware sprites (the repeating mountains). I imagine the foreground is just blitter objects using what little Blitter time you have left

Of course there is nothing to stop you having 2 playfields of 8 colours and a third using repeated hardware sprites. Then just use the Blitter for all your sprites

I think Agony does this on an A500 wow!

[ Show youtube player ]

[Ironclaw]

Originally Posted by Toffee

[ Show youtube player ]

Nice link.. recorded by me :P.. pwnage

I love the ingame music in Agony.. except the rest, like title, loading and outro tunes.

[Toffee]

Originally Posted by Ironclaw

Nice link.. recorded by me :P.. pwnage

I love the ingame music in Agony.. except the rest, like title, loading and outro tunes.

Haha I just noticed that. What a beautiful game ! Damn it was hard to. Respect for beating it !