Mandelbrot Explorer

OVERVIEW

Mandelbrot Explorer is an interactive Linux application for exploring the Mandelbrot set. It displays a dynamic image of the set which you can traverse in real time using the mouse. The following parameters can be configured:

• Colour palette
• Zoom depth limit
• Level of detail
• Initial position
• Resolution
• Textual display of coordinates and scale

Mandelbrot Explorer can also save and load positions, making it easy to return to them. It is written in C++ with OpenGL.

Note: Windows users can run Mandelbrot Explorer on the latest version of WSL, which supports GUI applications.

DEPENDENCIES

The following tools must be installed on your system:

• C++ 17
• OpenGL 4.5
• CMake 3.2
• GLFW 3.2.1
• GLEW
• FreeType
• fmt
• Catch2

The font FreeSans.ttf must be installed at:

/usr/share/fonts/gnu-free/FreeSans.ttf

QUICKSTART

In the root directory of the repo:

mkdir build
cd build
cmake ..
cmake --build .

Then launch with:

./mandelbrot_explorer

CONTROLS

MOUSE

Click-and-drag to traverse. Use the mouse scroll wheel to zoom.

KEYBOARD

Press the Q key to quit.

To save the current explorer state:

1. Press the S key.
2. Click on the terminal window.
3. Type a name for the save file.
4. Press enter.
5. Click on the Mandelbrot Explorer window to continue exploring.

The save file is created in the directory where mandelbrot_explorer is being executed.
Saved states can be loaded on startup via the command-line interface (see "OPTIONS").

OPTIONS

Configure Mandelbrot Explorer via the command line at startup:

  ./mandelbrot_explorer <option1> <value1> <option2> <value2> . . . 

The following options are provided:

Option	Description
-d	Set window dimension i.e. resolution (width = height, in number of pixels). Accepts int in range [250, 1000]. Window is always square, and is not resizable. Default is 750.
-x	Set initial x-position of image center. Accepts double in range [-2.0, 2.0]. Default is -0.5.
-y	Set initial y-position of image center. Accepts double in range [-2.0, 2.0]. Default is 0.0.
-s	Set initial image scale. If precision is set to float (default), accepts float in range [0.00001, 100.0]. If precision is set to double, accepts double in range [0.00000000000002, 100.0]. Default is 1.5.
-i	Set maximum number of iterations used in fractal-generation algorithm. Accepts int in range [16, 50000]. Greater values produce more detailed images. Default is 250. Note that greater values will degrade performance more or less quickly depending on your hardware. When increasing this value, try increments of a few hundred or so. If you find a region that is all black at a deep level of zoom, increasing this value will usually reveal hidden details.
-c	Set colour palette. Accepts the following strings: greyscale, woodstock, abyss, spectrum. Default is greyscale.
-p	Set numerical precision (controls zoom depth limit). Accepts the following strings: float, double. Default is float. float configures the explorer to use single-precision floating point computations. This gives better performance, with a shallower maximum zoom. double configures the explorer to use double-precision floating point computations. This gives worse performance, with a deeper maximum zoom.
-t	Toggle the textual display of current position and scale. Accepts the following strings: true, false Default is true. In text display, "X" is the x-coordinate of the current image center, "Y" is the y-coordinate of the current image center, and "S" is the scaleof the current image.
-l	Load state from a save file. Accepts path to save file (relative path from directory where mandelbrot_explorer is being executed). Cannot be used in conjunction with any other options.

OPTIONS EXAMPLES

To run the explorer with a window dimension of 500 pixels, at a starting position of (-0.3731, -0.6466), and a starting scale of 0.05:

./mandelbrot_explorer -d 500 -x -0.3731 -y -0.6466 -s 0.05

To run the explorer with a maximum number of iterations of 500, using the "woodstock" colour palette:

./mandelbrot_explorer -i 500 -c woodstock

The run the explorer using the "abyss" colour palette, at double precision, and without the text display:

./mandelbrot_explorer -c abyss -p double -t false

To load a saved state from a file called "mysavefile":

./mandelbrot_explorer -l mysavefile

TESTING

After building, run the test program:

./test_state_manager

This tests the functionality for parsing command-line input, loading state, and saving state. To test rendering and user input, run the program and verify its behaviour manually.