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160B Sprites


Muddyfunster

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1 hour ago, Muddyfunster said:

That workflow is much easier with 160A sprites as you only have 4 indices and 3 actual colours (+ transparent).

 

With 160B you have more of both so the work flow is more complex. To recap what @SmittyB wrote, you either have to adjust the palette declarations (P1C1=$xx and so on) or tweak the index for each graphic.

 

For example, if you have 2 sprites, you might load them something like this :

 

incgraphic moose.png 160A 0 1 2 3

incgraphic dog.png 160A 0 2 1 3

 

 

 

 

160A's I have dine adjustments for.   However, 160B just feels so much more complicated.
Here is a question:  do I have to mention each alphacolor in the list indices?  For example, if every palette has $00 as the alpha, do I need to do this:

incgraphic steve.png 160B 0 1 2 3 0 4 5 6 0 7 8 9 0 10 11 12 where the "0" are entries for each alpha in each palette?

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2 hours ago, fultonbot said:

160A's I have dine adjustments for.   However, 160B just feels so much more complicated.
Here is a question:  do I have to mention each alphacolor in the list indices?  For example, if every palette has $00 as the alpha, do I need to do this:

incgraphic steve.png 160B 0 1 2 3 0 4 5 6 0 7 8 9 0 10 11 12 where the "0" are entries for each alpha in each palette?

 

With 160B first you only need to supply an index for each color used (including transparent).  I use 0 for the transparent color and then from that point you use 1,2,3 (palette 0 or 4), 5,6,7 (1 or 5), 9,10,11 (2 or 6), 13,14,15 (3 or 7). 

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  • 1 year later...

 

On 2/20/2020 at 5:18 PM, Karl G said:

That looks great! Have you considered a Prince of Persia style game?

I'm working on a new project that's not PoP (just to be clear!). But thinking about PoP on the 7800 and thinking about my experiences with E.X.O., suddenly that doesn't seem quite so crazy in terms of feasibility.

Edited by Muddyfunster
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  • 2 months later...
On 7/21/2020 at 6:32 PM, Muddyfunster said:

160B is really nice but it comes at a price, the graphics take a lot more space to store. 

 

If it's just 1 sprite, I adjust the palette to the sprite, if it's more than 1 frame or sprite  then I tend to move the indexes to match each. I find setting every colour to something not in the sprite (like bright pink) means you can check that all of the transparency index are right. I then change 1 colour to say white, see where it changes on the sprite and substitute the correct colour. It sounds long winded but once you get used to it, it's not so bad. With 160A it's much quicker due to only being 3 colours instead of 12. The biggest pain is usually transparency indexes going awry.

.....Unless you can use extra RAM, point your graphics to that, and compress them in the ROM, and decompress them to RAM.

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Hi all,

 

I made a recent discovery in relation to how the indexes are allocated - it was an interesting lightbulb moment after all this time!!

 

It appears indexes are being allocated based on the order the color is found starting left ->, top -> bottom - this includes the transparent color.  So after allocating your colors to the PXCX and then scan through matching the color based on the index.

 

Lets take Arthur from GnG

Arthur.png.7bbb3ca744546a39c3ca7659a6a9e815.png

 

P0C1 = $0f : P0C2 = $37 : P0C3 = $79

incgraphic gfx/arthur0.png 160A 0 3 1 2

 

160B images are the same just spread over the 4 palettes - 0 (transparent), P0-1,2,3, P1-5,6,7 P2-9,10,11 P3-13,14,15

 

Hope that helps! Also if anyone is using Atari Dev Studio, install the Luna Paint extension as it allows you to open/view (and edit images) with VS Code.

 

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On 2/18/2020 at 5:59 PM, Muddyfunster said:

Dude, you never need to apologize about questions.... :)

I'm still not the best at coding. I've made things but not much.

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On 2/18/2020 at 5:59 PM, Muddyfunster said:

Dude, you never need to apologize about questions.... :)

I've coded stuff and I'm good at it (6502 ASM on 7800 specifically) but I'm still learning.

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  • 1 month later...
On 4/3/2022 at 9:14 AM, Muddyfunster said:

 

I'm working on a new project that's not PoP (just to be clear!). But thinking about PoP on the 7800 and thinking about my experiences with E.X.O., suddenly that doesn't seem quite so crazy in terms of feasibility.

If PoP can be done on the 8-bit, it can be done on the 7800. :)

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8 hours ago, Synthpopalooza said:

If you decide to do it, let me know.  I can do music, and it will have it's own unique identity apart from the 8-bit music which also had terrific music.

Thanks Bobby. I'm very tempted but I want to get A.R.T.I. done and I have some original projects to tinker with as well as some Jag stuff. I'll let you know.

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13 hours ago, Ecernosoft said:

Using the Hipass filter on POKEY, you can set the fequency on the hipass to be one step higher using sq-wave and you get weird results. Useful.

 

(Ex. AUDC0 = $Ax, AUDF0 = 120, AUDF2 = 121)

Yes ... and with that, be warned, you are about to go down an enormous rabbit hole with advanced POKEY techniques ... a rabbit hole even I haven't emerged from yet lol

 

The Hi Pass filter (second and third bits on AUDCTL) does a lot of neat things.  In the function you describe, it makes a swirling SID effect.  This is because the filter channel applies a bitwise XOR filter on top of the first channel.  There are other uses too ... you play the same frequency in both but delay one a few ticks, and you can emulate a variable width pulse wave like on the NES.  Vary the period up or down a 4th, fifth, or octave interval, makes interesting sounds. Then there's adding in other distortions, different clock settings, 16-bit mode, etc ... I could go on all day.

 

If you really want to do the deep dive though, find my threads about POKEY experiments, in the 7800 and the 8-bit/5200 forums.  There is a lot unexplored on the POKEY, for sure.

 

Also:  Be aware, some 7800 emulators do not play well with some of these custom settings and tricks.  Thanks to the hard work of @RevEng and @Trebor, though, the latest version of A7800 seems to handle even the most obscure tricks I have thrown at it.  Recommended!

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6 hours ago, Ecernosoft said:

Rabbit hole? More like deep well of cool things lol...

There are a couple of settings in particular, involving distortion 4 @1.79mhz clock using two tone mode (both with the 64 and 15khz clock) that have taken me more than a year to catalog, due to their complexity, and I am not even near done on them yet ... I managed to get enough on one of them to bash out a tune for E.X.O. believe it or not.

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This is one of the threads ...

 

... from when we were trying to fine tune the current emulation in A7800, which is now absolutely spot on.  There may be things in there you will find of interest.  I really need to do a series of tutorials for beginners on the basics of POKEY, followed by all of the special modes, aka 16-bit, hi pass, two-tone, etc.

 

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12 hours ago, Synthpopalooza said:

There are a couple of settings in particular, involving distortion 4 @1.79mhz clock using two tone mode (both with the 64 and 15khz clock) that have taken me more than a year to catalog, due to their complexity, and I am not even near done on them yet ... I managed to get enough on one of them to bash out a tune for E.X.O. believe it or not.

What kind of wave-form does it sound like?

 

12 hours ago, Synthpopalooza said:

This is one of the threads ...

 

... from when we were trying to fine tune the current emulation in A7800, which is now absolutely spot on.  There may be things in there you will find of interest.  I really need to do a series of tutorials for beginners on the basics of POKEY, followed by all of the special modes, aka 16-bit, hi pass, two-tone, etc.

 

Wow! I feel as if you're the god of Pokey documentation. :) 

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  • 1 month later...
On 4/3/2022 at 3:14 PM, Muddyfunster said:

 

I'm working on a new project that's not PoP (just to be clear!). But thinking about PoP on the 7800 and thinking about my experiences with E.X.O., suddenly that doesn't seem quite so crazy in terms of feasibility.

On 4/4/2022 at 2:16 AM, mksmith said:

There is a great version being made on the Pico8 currently! That is an amazing little platform. 

 

On 8/4/2022 at 3:40 AM, Synthpopalooza said:

If PoP can be done on the 8-bit, it can be done on the 7800. :)

On 8/5/2022 at 1:03 PM, Muddyfunster said:

Thanks Bobby. I'm very tempted but I want to get A.R.T.I. done and I have some original projects to tinker with as well as some Jag stuff. I'll let you know.

 

I loved Prince of Persia on Atari ST / Amiga, I was so blown away by the wonderful player sprite animations... Obviously, having a 7800 version would be great but I really would like the beauty of the high resolution animations to be preserved, on the other hand we already have very good low resolution versions, including C64 and Atari 8-bit. About ten years ago (damn), I made some 320B mode mock-ups derived from the Amiga version, but today I could use a few more colors by doing it in 320C mode.

 

 

1964038705_PrinceofPersia7800_320B_grey.thumb.PNG.eb081fdac3cbcae9ed2ad376ba339d40.PNG

 

 

 

1880600892_PrinceofPersia7800_320B_blue.thumb.PNG.a9670281eed912bc0d8007d487cab6c4.PNG

 

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