Surface Visualizer

Language

• Español
• English

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Table of contents

1. Summary
2. Install
   1. Previous requirements
   2. Install process
3. Usage
   1. Controls
      1. Mouse
      2. Keyboard shortcuts
   2. Language
   3. Parameterization
   4. Visualization
   5. Lighting

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Summary

Surface Visualizer is a program for visualizing 2-manifolds, defined with charts, allowing homotopies representation. Its objective is represent correctly the surface, using triangle tessellation.

Also, it will show some characteristics of the Morse function height, which domain is this surface (in the future the user will be able to define their own Morse function).

Instalation

Previous requirements

These are the previous requirements to install de program:

• Ubuntu 18.04 LTS OS or later (or similar).
• GPU: compatible with OpenGL 4.4 version or later (for tessellation shader, etc). You can see it (after the installation) running the command:

glxinfo | grep "core profile version string"

• Dependencies: make, to run makefile and apt to install packages.

For the compilation of the program, it will need the following dependencies, although they will be automatically upgrade during the installation process:

• gcc, g++, version 11 or later.
• flex.
• bison, version 3.5 or later (source files are included in the folder).
• libglapi-mesa, mesa-utils y mesa-common-dev, free software implementation of OpenGL.
• libglfw3 y libglfw3-dev, required for OS window management.

Install process

Clone or download this repository. Then initialize the command line in the folder program and run the following command:

make install

which will update all dependencies and install Bison (used on processor program). If the installation goes wrong, you need to review the previous requirements.

If the installation goes well, you must finalize installation by compiling the project, using this command:

make

As a consequence, the program will start.

Usage

After installing the program, we can start it by using make on the folder program or running the next command:

./bin/program

At start, it will use the last compiled parameterization, always saved on the file lastParam.in.

If you don't know how some interface element works, just let the mouse over it for a few seconds and an information window will appear explaining its functionality.

Controls

In this section I will explain the basic mouse and keyboard controls.

Mouse

In addition to interacting with the interface, you will be able to:

• Right button: rotate the camera around the surface (orbital camera).
• Left button: move the camera horizontally and vertically.
• Scroll: zoom control.
• Middle button: reset camera position.

Keyboard shortcuts

I added some shortcuts for a more comfortable use:

• LCtrl + R: activate/deactivate auto-rotation.
• LCtrl + P: switch between polygon and filled modes.
• LCtrl + N: activate/deactivate normal visualization.
• LCtrl + L: run the processor and compile shaders.

Language

You can select the language you want, if it is available on the folder languages, on Menu window.

Parameterization

You will be able to select a predefined parameterization (exists some examples on the folder manifolds) or create one.

If you decide to create one, edit window will appear with the following example code, showing a typical parameterization scheme:

//-- Structure example with sphere parameterization --//

// Define constants
PI2 : real = 2*PI;

// Define aditional functions
compx(u, v : real) : real = cos(v*PI)*cos(u*PI2);
compy(u, v : real) : real = cos(v*PI)*sin(u*PI2);
compz(u, v : real) : real = sin(v*PI);

// Define de main function.
f(u, v : real) : vec3 = vec3(compx(u,v), compy(u,v), compz(u,v));

// You can use another function to redefine the domain instead of [0,1]x[0,1].
g(u, v : real, t0, t1 : real) : vec3 = f(t0 * (u-0.5), t1 * (v-0.5));

// To plot 'g', it must return a 'vec3' type and the first two arguments must be reals.
plot g;

You can open this editor whenever you want, to do some change on the actual surface's definition. If there are any errors (lexical, syntactical or semantical) it will be shown in this window.

All the changes will be automatically saved on the file lastParam.in. If you want to save it in the original file, press the button Save.

In addition to the base params, you can use time parameters, which objective is to allow representations of homotopies (in a smooth animation). You can change those parameters in the Parameters window (fixed domain [0,1]).

Visualization

You can visualize the following characteristics:

• Filled surface, with a plain base color (by default).
• Polygon mode, always in dark.
• The following vectors, for all initial mesh vertexs or all generated vertexs (it depends on the respective button):
  • Tangent
  • Bitangent
  • Normal
• Differential area, by using color (simulating the real axis), in other words, the area of the transformed triangles via the parameterization (directly depends on the parameterization).
• Gauss curvature, by using color, it not depends on the parameterization.
• Morse function height, by using color, showing levels. You can indicate the number of leves you want.
• Critical points of the Morse function height, also by using color.

Lighting

You can change every Phong coefficient (from the Phong lighting model). Also you will be able to change the light position with the item light vector (unstable functionality).