# Fraktaler 3

# 6.2.1 Bugs In Version 1

These bugs are all fixed in later versions:

• zooming out too far crashes program:

  terminate called after throwing an instance of 'std::length_error'
    what():  vector::_M_default_append
  Aborted
  

  fixed in v1.1

• high powers may render incorrectly (iteration bands due to overflow); workaround: reduce bailout escape radius; partially fixed in v1.1 with workaround: disable low range type float in wisdom;

  Example power 5 location: fraktaler-3-power-5.f3.toml

  Bad image with version 1:

  

  Good image with version 1-4 or later (prerelease):

  

• high powers may render incorrectly (perturbation glitches); no workaround; fixed in v1.1

  Example power 100 location: fraktaler-3-power-100.f3.toml

  Bad image with version 1:

  

  Good image with version 1-4 or later (prerelease):

  

• non-central reference (e.g. translation after Newton zooming) can cause badly framed batch mode renders (looks fine in interactive mode); do a small batch render to check before large render; workaround: save, delete reference real imag period from toml, reload; fixed in v1.1

  Example location: fraktaler-3-batch-noncentral-v1-bad.f3.toml / fraktaler-3-batch-noncentral-v1-workaround.f3.toml

  Badly framed image with version 1:

  

  Well-framed image with version 1.1 (or v1 using workaround delete reference from toml):

  

• combining multiple settings files in batch mode may not work reliably leading to bad images (formula is reset to default Mandelbrot if file doesn’t have any formula); workaround: combine by hand into one toml file; fixed in v1.1

• bad wisdom file causes abnormal program exit; for example, if a number type has no associated devices:

  terminate called after throwing an instance of 'std::out_of_range'
    what():  [error] key "device" not found
   --> unknown file
      |
   23 | [type.float]
      | ~~~~~~~~~~~~ in this table
  Aborted
  

  workaround: delete type entirely if there are no devices for it; fixed in v1.1

• smooth iteration count is incorrect for powers other than 2; only visible if colouring raw data externally; no workaround; fixed in v1.1

  Example power 4 location: fraktaler-3-power-4.f3.toml

  Example palette for KF2+: fraktaler-3-power-4.kfp

  Bad image with version 1 (colourized with KF2+):

  

  Good image with version 1-4 or later (prerelease) (colourized with KF2+):

  

• EXR images saved by interactive mode are too bright (frames are summed instead of averaged) and flipped vertically workaround: adjust exposure (stops = -log2(subframes)) and flip in post; fixed in v1.1

  Example with 16 subframes (same location as above): fraktaler-3-batch-noncentral-v1-workaround.f3.toml

  Bad image with version 1:

  

  Good image fixed with post processing in GNU IMP (-4 stops exposure adjustment, vertical flip):

  

  Good image also results from version 1-5 or later (prerelease);

• loading parameters in interactive mode may cause image size confusion; fixed in v1.1 (image size in interactive mode is locked to window size)

• adjusting reflection/rotation in transformation dialog is not intuitive; fixed in v1.1

• auto stretch fails when reflection is active; workaround: disable reflection and flip image in post; fixed in v1.1

• Newton zooming fails when reflection is active; workaround: disable reflection; fixed in v1.1

• Newton zooming may enable reflection; doesn’t cause further issues in v1.1;

• batch mode reported tile count progress uses tiles started rather than finished; fixed in v1.1

• interactive mode progress reporting is misleading sometimes; fixed in v1.1

• cancelling tiles rendering on CPU without OpenCL takes too long; fixed in v1.1

• wisdom benchmarking does not take account of hardware map (have to delete device for all types to prevent device being benchmarked) fixed in v1.1

Bugs found in later versions may also be found in this version.

# 6.3.1 Bugs In Version 1.1

These bugs are fixed in later versions:

• large reference (for example beyond the left tip of the needle) leads to bad images; workaround:
  1. shift the view so that the reference is not too large and the fractal is visible;
  2. enable reuse reference in the algorithm dialog;
  3. frame the view to your liking;
  4. when it happens again after zooming deeper, disable reuse reference and repeat from step 1;
  fixed in v1.2 and v2.1

# 6.4.1 Bugs In Version 1.2

These bugs are fixed in later versions:

• live web version does not work (missing ccall symbol).

  fixed in v1.2.1 and v2.1

Bugs found in later versions may also be found in this version.

# 6.5.1 Bugs In Version 1.2.1

Bugs found will be listed here.

# 6.6.1 Bugs In Version 2

These bugs are fixed in later versions:

• large reference (for example beyond the left tip of the needle) leads to bad images; workaround:

  1. shift the view so that the reference is not too large and the fractal is visible;
  2. enable reuse reference in the algorithm dialog;
  3. frame the view to your liking;
  4. when it happens again after zooming deeper, disable reuse reference and repeat from step 1;

  fixed in v1.2 and v2.1

• BLA steps text entry doesn’t work properly; workaround: set desired BLA steps in the perturb iterations field, edit BLA steps text entry, reset pertub iterations field to previous value;

  fixed in v2.1

# 6.7.1 Bugs In Version 2.1

Bugs found will be listed here.

# 7.3.1 Version 3 Beta

Please test the beta releases here and provide feedback:

• https://fraktaler.mathr.co.uk/download/preview/ Windows (EXE), Android (APK), Linux (7Z source for all platforms)

• https://fraktaler.mathr.co.uk/live/preview/ Web

Known issues:

• documentation is incomplete or otherwise out of date.

• Android version can sometimes end up in fantasy locations, where trying to recreate the image from its supposed parameters fails. Possibly related to extensive use of multi-touch navigation?

• no on-screen keyboard in Web version on Android, making it impossible to edit various options; tested with Fennec f-Droid browser; workaround: use Android version.

• Web and Android versions should not have “quit when done” option in render window.

• no ARM builds for Windows: I have no way to test them.

• any more issues you find and report will be listed here and hopefully fixed before the full release.

Final release expected early July 2024.

# 7.4.1 Soon

• Linux

  • check everything works on Debian

• Windows

  • check everything works in Wine

  • check everything works in Windows 11 VM

  • check everything works in Windows on hardware

• Android

  • check everything works on Android 7 tablet

• Web

  • check everything works in Firefox ESR on Debian

  • check everything works in Chromium on Debian

  • check everything works in Firefox ESR on Windows

  • check everything works in Chromium on Windows

  • check everything works in Fennec f-Droid on Android

# 7.4.2 Later

• Linux

  • desktop entry with icon

  • Debian package

  • build instructions for other distributions

• Windows

  • GUI on ARM is missing

  • aarch64 crashes in Wine on rpi3

  • armv7 untested (no multi-arch on rpi3)

  • stdio vs cmd shell vs msys terminal

• Android

  • fantasy locations with multitouch zooming?

  • log crashes somehow and start with option not to restore persistence

• Web

  • export/import parameters to/from URL hash (base64)

  • think of a way to make default canvas size vary (fill browser window)

• FreeBSD

  • see if support is possible / easy

• macOS

  • find someone to do any work required

• bundle examples in app and allow unpacking somewhere?

• batch enhancements

  • batch mode Newton zooming

  • “are you sure” program close confirmation dialog

• check sRGB (un)packing when EXT_color_buffer_float is not used

• more exciting default colouring

• very high resolution support (images larger than maximum OpenGL texture size)

• do proper filtering when downscaling large image to small window

• optional delay before recolouring tiles after parameters change, instead of immediately on every adjustment; optionally infinite delay with button (+ keyboard shortcut) to force recolour

• optional delay before recalculating fractal after settings change, instead of automatically on gesture end; optionally infinite delay with button (+ keyboard shortcut) to force recalc

• optimizations (mainly: reduce GPU round-trips - currently tiles are computed with OpenCL, downloaded to host, uploaded to OpenGL for colouring, then downloaded for assembly into larger image, which is then uploaded to OpenGL again for display…)

• improve keyboard navigation in user interface

• option to select sub-region for auto stretch de analysis

• transform dialog issues

  • auto stretch de should update preview transform before rendering starts

  • rotation slider should update preview

  • rotation slider interacts strangely with stetch

• location dialog issues

  • changing values (particularly zoom depth) should update preview transform before rendering state

• in interactive mode, sort tiles by distance from center of image, and compute nearest ones first

• first launch wizard / tour of UI

  • or maybe a video tutorial series

• research atom domain size estimates for non-Mandelbrot fractals

• research Misiurewicz domain size estimate for non-Mandelbrot fractals

• a way to specify default values, ranges, preferred widgets, etc

  • consider FragM-style annotations in comments

  • or mega-widget combining (log) sliders, colour selector, etc

• load images for colouring

  • 1d gradients

  • 2d images

  • texture arrays (videos imported using ffmpeg?)

• low/high bailout, stripe colouring, etc:

  • expose low precision version of formula to colouring shader

  • expose low precision version of C coordinates to colouring shader

• colouring post processing pass custom GLSL

  • exposure

  • tone mapping

  • colour adjustment

  • vignette

  • text overlay

  • etc

• zoom depth and other text overlay without GLSL hacks

  • custom font loading

  • format strings (double mantissa + int exponent)

  • option for zoom depth as double exponent (log of zoom)

• headless colouring

  • OSmesa software OpenGL

  • OpenCL colouring snippet

• custom transformation GLSL

  • given pixel coordinates, calculate coordinates in unit disk where magnitude 1 corresponds to corners of image

  • low discrepancy sequences (based on plastic number)

  • derivatives for DE colouring

  • INPUTS

    • i:[0,w), j:[0,h)

    • w, h

    • sample, nsamples

    • frame, nframes

    • log(zoom)

    • random seed

    • skew matrix

  • OUTPUTS

    • x, y

    • dxi, dxj, dyi, dyj

    • also needs inverse transformation to find i,j given x,y for interaction from GUI

  • LIBRARY

    • low discrepancy sequence

    • dual numbers

    • prng hash

    • default transformations

      • rectangle

      • exponential map

      • Riemann sphere / equirectangular

  • OUTPUT

    • need to analyze for BLA radius

    • analyse derivatives to see if sufficient precision?

  • PARAMS

    • introspected uniforms

• embed Lua scripting

  • adjustment of OpenGL colouring parameters

  • zoom and pan by image coordinates

  • Newton zoom by image coordinates

  • autoskew DE function

  • provide access to raw subframe(s) data

  • provide access to raw histograms

  • provide access to output image RGB histograms (HDR)

  • port Rodney’s colouring palette auto-white balance

  • control batch rendering for non-standard videos

  • needs a way to wait for actions to finish

  • needs a way to interrupt/resume scripts if necessary

  • needs a way to ask for user to peform actions in case full automation is not possible (e.g. a Julia morphing helper tool)

• port feature-finder from Imagina

  • autofocus mode for scroll wheel

• fix OpenCL GPU timeouts

  • maximum time target per kernel invocation (e.g. 100ms)

  • limit total number of steps per kernel

  • 1D kernel manually initialized in Z order

  • either initialize or load in progress iterations from buffer

  • either output raw data or store in progress iterations to buffer

  • atomic counter to get index for in progress output

  • stop when in progress buffer is empty

  • ping-pong two in-progress buffers

  • automatically compacted (reduce memory bandwidth)

• automatic tile size adjustment w.r.t device count and image size

• eventually merge with zoomasm for all-in-one program

• fix IO

  • CLI should have an option to save TOML from argument (which could be an image)

  • report estimated file size before saving

  • check available disk space and warn before saving if too low) (especially with zoom out sequence)

• optimize MPFR memory allocation

  • period detection

  • root finding

  • size calculation

• optimize conformal formulas

  • use complex numbers instead of matrices

  • Mandelbrot set / multibrot only?

  • disable stretch transformation

• computation adjustments

  • compute analytic dDE/dij (see Cheritat’s wiki)

  • replace NF,T with final Z > R, degree for better interpolation?

  • exponential smoothing, consider interactions with BLA

  • interior colouring via (convergent, periodic) exponential smoothing

  • iteration count per step vs per +c

  • reference compression

• number type wisdom

  • compute sizeof and take memory availability into account

  • report/limit memory used for reference and BLA

• extend colouring algorithms

  • port nice algorithm from Rodney, parameterized

  • allow custom OpenCL source for colouring snippet (no parameters)

  • use OSMesa to do colouring without a DISPLAY

• compat with other software

  • KFR location import, including metadata from image files

  • KFR location export, including metadata to image files

  • KFP palette import (with default GLSL implementation copied from KF)

  • KF custom GLSL import mode (see zoomasm)

  • custom GLSL export for zoomasm

• image export

  • EXR with (downscaled) preview image

  • set JPEG export quality

• save log/linear histogram options in GUI settings; log by default

• exponential map

  • DE direction is relative to strip (not really a bug in fraktaler-3, should be possible to fix zoomasm)

  • option to change stretch factor (default 2)

  • option to make conformal (adjust stretch factor based on image size)

  • report stretch factor

  • make GUI interactions sensible

  • implement within custom GLSL?

  • change skew matrix over radial direction for zoom+skew animation (needs to have rate limited to avoid “sonic boom”)

• history browser

  • sqlite3 database

  • handle multiple concurrent sessions (PID + start time)

  • auto-store thumbnails

  • maximum total size limit for thumbnails (prune at random?)

  • undo / redo by copying previous states

• autosave/resume

  • metadata file with append-only log (updated last in case of power failure)

  • mmap reference orbit file

  • mmap 1 raw subframe file

  • (atomically) sync every few minutes and when done

  • mmap accumulated subframes file

  • (atomically) sync after subframe accumulated (rate limited)

  • resume from saved data

  • SIGHUP to batch process triggers autosave and continue

  • SIGINT/TERM trigger autosave and exit

  • Windows equivalents to signals?

  • GUI controls for batch rendering?

• mandelbrot-perturbator annotations overlay

• cross-hair cursor when over fractal

• target cursor when Newton zooming is activated

• touchscreen improvements

  • double tap to activate Newton zooming

• time-based ETA reporting

  • single image

  • Newton zooming

  • zoom out sequence

• check website for new version (button in GUI)

• tutorial on using with Zoomasm

• wishlist: Nova, Magnet (suggested by Alex)

• wishlist: smooth scrolling zoom animation

• high DPI display support

  • automatically adjust UI scale on first launch

• check non-ASCII paths

• make saved files appear in OS recent files list