GSOC 2014 Application: Implementing Visuals Layer

Name: M S Suraj

E-mail: mssurajkaiga@gmail.com

Telephone: 91-7507164048

Time zone: UTC +05:30 (Indian Standard Time)

IRC: mssurajkaiga

Github: mssurajkaiga

Skype: mssurajkaiga

Twitter: mssuraj2010

Blog: http://www.mssuraj.in

Bio

I am a 3rd (pre-final) year undergraduate majoring in Electrical and Electronics Engineering at BITS Pilani, Goa campus in India. I have very good knowledge of C/C++ and have been programming in Python for past two years. My goal is to pursue research in Computer Graphics, particularly in realistic rendering and real-time rendering.

Project Details

Title

Implementing Visuals layer and related functionality in vispy

Abstract

Vispy currently offers a Pythonic interface to OpenGL, gloo, which requires the knowledge of OpenGL and shaders. The next step towards achieving Vispy's primary goal, ie providing independence from OpenGL for the end-users, is the visuals layer. The visuals layer provides an abstraction layer over gloo and lets you create and modify visual objects on the scene with a Pythonic interface. The objective of this proposal is to implement high-priority visuals using the visuals architecture and related functionality for the same.

Features

This is a rough sketch of the features I plan to implement and how I intend to implement them.

Visual

Each Visual will have the following features:

Integration with vispy.color
Clean pythonic interface

For example, A green circle could be created by any of the following:

cv = CircleVisual(pos=(1,0,0), rad=3.0, color=(0,1,0,1))

cv = CircleVisual(pos=(1,0,0), rad=3.0, color=ColorArray('green'))

cv = CircleVisual(pos=np.array([1,0,0]), rad=3.0, color=ColorArray((0,1,0,1)))

Once created, the visuals can be easily modified as well.

cv.color(ColorArray('blue')) will change it to blue colored circle.

Extensible shader support
Each graphic will be implement as efficiently as possible.
Examples depicting functionality

LineVisual

Implemented but further extension can be done

Tessellation algorithm in vispy.geometry

Before implementing PolygonVisual, Delaunay triangulation will be ported from scipy.spatial.Delaunay into vispy.geometry.

PolygonVisual

Parameters:

pos: set of vertices representing the polygon to be rendered

color: (R, G, B, A) or vispy.color.ColorArray object

border: (size, style, color)

PolygonVisual will require the use of tessellation algorithm to be provided by vispy.geometry.

EllipseVisual

Parameters:

pos : position

rad : (x-radius, y-radius)

color: (R, G, B, A) or vispy.color.ColorArray object

border: (size, style, color)

EllipseVisual will have two implementations -

using PolygonVisual

using PointsVisual

The default behavior is to choose the best suited implementation depending on the number of ellipses and the sizes to be rendered. The user can override the default behavior and explicitly use the implementation he/she desires.

CircleVisual

Parameters:

pos : position

rad : radius

color: (R, G, B, A) or vispy.color.ColorArray object

border: (size, style, color)

It will inherit from EllipseVisual but with only one value for x and y radii.

MeshVisual
TextVisual

Parameters:

pos : position

font : font-name

color: (R, G, B, A) or vispy.color.ColorArray object

size: font-size

TextVisual will be implemented by rendering text to texture and displaying it using existing ImageVisual.

Timeline

Pre-GSoC (till 21st April):	Become more familiar with the code-base
Community Bonding Period (22nd April - 18th May):	Read up on ideas and source-codes relevant to Visuals and discuss them with mentors. Also, code contributions would be low due to final exams, as mentioned in Other Schedule Information.
Week 1 (19th May - 25th May):	[Coding period starts] Working on issues pertaining to LineVisual.
Week 2 and 3 (26th May - 8th June):	Implementing tessellation algorithms in vispy.geometry either from scratch or port it from scipy.spatial or from CGAL.
Week 4 and 5 (9th June - 22nd June):	Implement PolygonVisual based on vispy.geometry package
Mid-term Evaluation (23rd June - 27th June):	Finish up on any left-over work and submit for evaluation.
Week 6 and 7 (28th June - 11th July):	Implementing EllipseVisual and CircleVisual
Week 8 and 9 (12th July - 25th July):	Work on MeshVisual implemented by Luke and create examples.
Week 10 and 11 (26th July - 8th August):	Implement TextVisual with font, color and size support.
Week 12 (9th August - 15th August):	Finish up left-over work and documentation
Final Evaluation (18th August - 25th August):
Post GSoC (beyond 25th August):	Implement full-fledged TextVisual support Complete vispy.geometry package Implement GraphVisual, BezierCurveVisual, NurbsSurfaceVisual, VolumeVisual

Contributions

Merged

Unmerged

https://github.com/vispy/vispy/pull/193

Other Schedule Information

I have my final semester exams from 2nd to 15th May and will be returning home on 16th May (midway Community Bonding Period). So during this period I won't be contributing much code, just lightly reading up relevant references and documentation. Apart from these I have my summer vacation till August 1st when my college reopens. As the first few weeks won't be heavy, I can contribute as per GSOC timeline.