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Update On New Performance Image Formats

John Hankinson

Posts 6
24 Apr 2019 15:34

Hi all,

We've been doing some experimentation with some new image-buffer formats to see how close to full 32bit ARGB quality we can get while keeping the bandwidth requirements as low as possible.

16bit hi-color has been a common option in this space.

RGB565(16bit) preserves a lot of the full 32bit colour detail but does not offer any form of alpha-channel.

ARGB4444(16bit) provides an acceptable quality with 16 levels of transparency for transient effects (especially in high-speed game play for example).

The new format we've been working on is a Hybrid 16bit mode that allows for greater dynamic range of opaque pixels while still providing enough levels of alpha to achieve good-looking transparent effects and smoother anti-aliased/blended edges.

AMMX currently supports direct conversion to/from RGB565, with these new formats we are investigating the possibility to expand AMMX to directly support the new formats offering developers a wide selection of high performance options for different types of sprite/blit or single pixel manipulation.

Full 32bit ARGB sample image, combining smooth backgrounds, alpha blending, transparency and soft edges:
Result using current 16bit formats:
Result using the new hybrid format:
(As you can see the quality is almost identical to the full 32bit image for half the bandwidth and storage).

Another example showing an image with variable transparency:
Using the new 4444 16bit format:
There will still be times when 32bit ARGB is the only option that provides the desired quality, so this would still be an available option:

Steve Ferrell

Posts 402
24 Apr 2019 18:41

The hybrid format looks amazing.  Great work!

Gunnar von Boehn
(Apollo Team Member)
Posts 5404
24 Apr 2019 19:37

Many thanks awesome post!

Thanks for the effort to create those example pictures I think this makes it very clear.

The new hybrid format for AMMX looks to be nearly as good as 32bit.
As its twice as fast I think its great for games.

Paul H

Posts 13
24 Apr 2019 19:44

Sounds good! How does the new format work and is it easy to convert GFX to this format?

Vojin Vidanovic
(Needs Verification)
Posts 1896/ 1
24 Apr 2019 19:52

    Its nice to have near 32-bit quality at 16-bit performance/VRAM hit. That is kind of Amiga way since Vamps performance isnt unlimited and such approach was kind of part of Amiga tradition (HAM6/8 was nice, but almost still images only or game background-intro,EHB64 was last nice trick that worked even in games. This kind of solution that works almost everywhere is great!).
    Even when performance becomes greater, its nice to have more of memory, CPU and bandwidth remaining :) Such small tricks made Amiga games and applications great in the past!
    Hope AMMX accelerated datatypes for new format could be created, so a lot of old software could make use of import/export.

John Hankinson

Posts 6
24 Apr 2019 21:19

Exactly, the idea is that the developer is not restricted in any way.. you can still use the full ARGB32 where it's required, for example some demo-scene effects may already run over 60fps using argb32.. so why not.. but this just provides another h/w accelerated option to push the Vamp to even greater heights!

The format will be very simple to convert to/from so we'd definitely provide the details on how to do this and a tool of some type probably as well.

Kef Emzy

Posts 46
28 Apr 2019 18:47

Gunnar von Boehn wrote:

  Many thanks awesome post!
  Thanks for the effort to create those example pictures I think this makes it very clear.
  The new hybrid format for AMMX looks to be nearly as good as 32bit.
  As its twice as fast I think its great for games.

  Would there be any interest in a compressed 8-bit mode with 24 bit color reproduction? It's palette free and fairy easy to convert to from 24 bit. Could be useful for intro screens and simple 24 bit animations... Quality is excellent, usually better than HAM10 would have been.

Philippe Flype
(Apollo Team Member)
Posts 299
28 Apr 2019 20:17

Impressive demonstration John!

John William

Posts 467
29 Apr 2019 05:32

Philippe Flype wrote:

Impressive demonstration John!

Hehe...thanks man! I tried hard! - evil grin -

Grzegorz Wójcik (pisklak
(Apollo Team Member)
Posts 83
29 Apr 2019 10:29

One pic is worth 1000 words :)
Thx for this comparasion pictures! This new hybrid format looks very nice !

posts 10