evanw/theta

Theta

Website: http://thetamath.com

This is a simple web app that graphs an equation and allows you to pan and zoom around the coordinate grid. It was my winter 2015-2016 break project, developed here and there over two weeks. Interesting bits:

• Custom equation editor with exponents, fractions, and other stuff
• Live errors inline as you type, sort of like an IDE
• GPU-powered anti-aliased equation rendering, handles equations that are impossible to solve
• Custom text rendering using subpixel anti-aliasing and GPU quadratic curve evaluation (see the article Easy Scalable Text Rendering on the GPU for a detailed description)
• Uses the Skew programming language and the GLSLX compiler, ends up as a few dozen kilobytes of optimized JavaScript
• Abuses GitHub's custom 404 handler to make bookmarkable URLs without needing a hosting provider :)

Examples:

• http://thetamath.com/app/y=sin(3x+sin4(y+sin2(x+siny)))
• http://thetamath.com/app/sin(x-cosπy)≤sin(y+cosπx)
• http://thetamath.com/app/ysqrt(y^2+x^2)=x
• http://thetamath.com/app/sin(2lnr+θ)≤0