mesh-simplification

Implement a simple mesh simplification using:

priority queue
vertex removal

Building on Linux

I have used Ubuntu 14.04 for the project. For other versions the instructions should be similar (check OpenGL Tutorial for other distributions or operating systems).

Dependencies

Install the latest drivers
Install all needed compilers, tools & libs: $ sudo apt-get install cmake make g++ libx11-dev libxi-dev libgl1-mesa-dev libglu1-mesa-dev libxrandr-dev libxext-dev libxi-dev

Building

After clone or download (and unzip) the repository go to the root and type:

$ cd Assignment-01/external/glfw-3.0.3
$ cmake .
$ make all
$ cd ../..
$ mkdir build
$ cd build
$ cmake ..
$ make all

I've used CLion IDE for running and debugging.

Mesh Simplification

1. Priority Queue

The heuristic defined for vertex removal is described on pseudo-code as follows:

Go through all the vertex and calculate their connection with others (edges)
Store the edges on a 2D vector together with the 'index' of its vertex
Sort the vector by the size of the edges (smallest first)
Get the first position of the vector which contains the two vertex to be compared
Verify which of the two vertex has more connections (v1) and choose to be removed

2. Half-Edge Collapse

The technique chosen for vertex removal was the Half-Edge Collapse which works removing a vertex and reconnecting all its connections to another vertex:

![Half-Edge Collapse] (https://github.com/inessadl/computer-graphics/blob/master/Assignment01/images/half-edge-collapse.png)

Pseudo-code:

Go to the vertex to be removed (v1 - defined on priority queue)
Check all the vertex that are connected to that vertex
Remove v1 and reconnect all its connections to v2

References

David Luebke, Benjamin Watson, Jonathan D. Cohen, Martin Reddy, and Amitabh Varshney. 2002. Level of Detail for 3D Graphics. Elsevier Science Inc., New York, NY, USA.

OpenGL Tutorials. Tutorial 1: Opening a Window, Available at: http://www.opengl-tutorial.org/beginners-tutorials/tutorial-1-opening-a-window/ (Accessed: 3rd April 2016).

Mesh Simplification. Standford course (CS 468-10-fall) Lecture Notes. Available on: http://graphics.stanford.edu/courses/cs468-10-fall/LectureSlides/08_Simplification.pdf

Shene, Ching-Kuang. Mesh Simplification. Classes notes. Michigan Technological University. Available on: http://www.cs.mtu.edu/~shene/COURSES/cs3621/SLIDES/Simplification.pdf

inessadl / mesh-simplification