Immersion
Description:	Demo from french ctrl+alt+del group
Download:	immersion.lha       (TIPS: Use the right click menu if your browser takes you back here all the time)
Size:	5Mb
Version:	1.0
Date:	25 Sep 2026
Author:	ctrl+alt+del, port by kas1e
Submitter:	kas1e
Email:	kas1e/yandex ru
Homepage:	https://www.youtube.com/@OMEGA12001
Requirements:	Working setup with mesa.library
Category:	demo/scene
License:	Other
Distribute:	yes
Min OS Version:	4.1
FileID:	14093
Videos:
Comments:	0
Snapshots:	0
Videos:	1
Downloads:	28  (Current version)
	28  (Accumulated)
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  H - Immersion
  AmigaOS4 port (c) kas1e
  =======================

  ABOUT
  -----

  H - Immersion in its original  form is  a 64kB intro created by the  French
  demogroup  Ctrl-Alt-Test.  The code was written by Julien "Zavie" Guertault
  and Laurent "LLB" Le Brun. The music was composed by Daniel Lindholm.

  A first version was presented at Revision 2017 and ranked 5th out of 10.The
  final version, with a different ending, was released in December 2017; that
  is the version we ported to AmigaOS4.

  If you are interested in digging into the details of how the demo was done,
  you can always visit CTrl-Alt-Test's place for more info:

  https://www.ctrl-alt-test.fr/2018/a-dive-into-the-making-of-immersion/


  AMIGAOS4 PORT
  -------------

  For the AmigaOS4 port,I had to do some heavy lifting: initial generation of
  textures was taking some time on the CPU, so I first used them as  external
  files, but it was about 30 MB of data: no way! So, at first I converted all
  textures to WebP while keeping 1:1 quality,but it was still 22 MB. Then the
  small ones were  embedded in the  binary as WebP, while the large ones were
  moved to be generated directly on the GPU, where I calculate many pixels in
  parallel and keep the results ready for rendering,without the need for slow
  CPU generation and extra memory copies.

  Music also comes as an external Opus file, as the original SSE-based  synth
  is quite  heavy  when ported to 20 years old PPC CPUs. Opus was chosen over
  MP3 just to save a bit more space as well.

  The  binary itself  also had some  work done: getting rid of C++ baggage in
  file I/O by replacing it with C equivalents,and shrinking SDL2, which I use
  together with Mesa.

  So all this brings the package down to a reasonable size,while keeping load
  /generation time reasonable (~35sec on X1000), and, thanks to Mesa, all the
  visuals, shaders and co. remain 1:1 the same.

  Everything is statically  linked, so you  have nothing to worry about: just
  unpack and watch.

  On an AmigaONE X1000/2 GHz with a Radeon RX 570, you  may expect from 90 to
  200 FPS across the whole demo (FPS can be  seen in the title of  the window
  when in window mode).


  COMMAND-LINE OPTIONS
  --------------------

  Usage:

      Immersion [options]

  Options:

      --windowed
      --window
      --win
          Start in a window. Fullscreen desktop mode is used by default.

      --width N
          Set the startup width.
          Default: 1280

      --height N
          Set the startup height.
          Default: 720

      --debug
          Show diagnostic output

      --help
      -h
          Display the command-line help and exit.


  RUNTIME CONTROLS
  ----------------

      Alt+Enter / Left mouse-button dbl-click
          Toggle fullscreen and windowed modes.

      Escape
          Exit the intro.

  (c) kas1e 24.09.2026