• Interactive Poisson Blending on GPU
• Simplest and Fastest GLSL Edge Detection using Fwidth

# Category: Misc

## Gradient, Circulation, Laplacian, Divergence, Jacobian, Hessian, and Trace

Here is a summary of all these concepts. Most the concepts are from Wikipedia. A larger figure is shown below: In mathematics, the gradient is a multi-variable generalization of the derivative. While a derivative can be defined on functions of a single variable, for functions of several variables, the gradient takes its place. The gradient…

## Estimated Cost of Per Atom Function in Real-time Shaders on the GPU

I have created a grouped list of estimated cost of instructions according to this Chinese reference. This may not be accurate, but is mostly correct from my experience. Some intuitions are: Abs, saturate are free (Why is clamp in GLSL not free? I doubt it) Log, exp, sqrt are almost free! (That’s why Kernel Foveated Rendering…

## The Web Version of My AI Chatbot – LJAI

LJAI is a personal chatbot hosted in my private server, available on the WeChat platform by searching 爱打滚的玲酱, and now available via the Web platform! What makes LJAI different is the virtual and real mapping of our own cat. Recently, we have acquired over 120 users, and thousands of chat messages. http://veritayuan.com/lingjiang  Compared with the…

## Exploration of the IEEE-754 Floating Point Standard

IEEE-754 Question: Execute the following while loops (modifying the code to add a counter). Explain the reasons these loops for the observed count value.

Solution The counter is 53, 1024, 1075 for the above three for loops. The code is attatched in 4.2. According to IEEE-754 (double precision), the machine epsilon is \$2^{-52}\$….

## Some random summaries on deferred rendering

Here are some random thoughts and summaries on deferred rendering pipeline. Deferred shading is generally faster than forward shading According to Unity3D, As a general rule, Deferred Rendering is likely to be a better choice if our game runs on higher-end hardware and uses a lot of realtime lights, shadows and reflections. Forward Rendering is…

## Some issues in VR – A personal note

Vergence-accommodation conflict Vergence movements are closely connected to accommodation of the eye. Under normal conditions, changing the focus of the eyes to look at an object at a different distance will automatically cause vergence and accommodation, sometimes known as the accommodation-convergence reflex. Visual odometry Match moving VR in practice GPU-based rendering (almost) as usual (OpengGL,…

## My Chatbot in WeChat Platform

It is nothing related with AR and VR. But in the era of AI, who wouldn’t want to develop a cute chatbot? Feel free to scan the QR code below to follow our cute pet 🙂  Most of the code is based upon Python. I have developed the following functionalities. AIML matching Dictionary Idiom Wikipedia…

## Hopf Fibration

According to Wikipedia:  In the mathematical field of differential topology, the Hopf fibration (also known as the Hopf bundleor Hopf map) describes a 3-sphere (a hypersphere in four-dimensional space) in terms of circles and an ordinary sphere. Discovered by Heinz Hopf in 1931, it is an influential early example of a fiber bundle. Technically, Hopf found a many-to-one continuous function (or “map”) from the 3-sphere onto the 2-sphere such that each distinct point of the 2-sphere comes from…

## Dotted Drawing / Sketch Effect

After lunch, I want to replicate the sketch shader I wrote for the Pencil-vs-Camera project. Additionally, I wrote a one-pass shader for dotted drawing / sketch post processing effect, which I think is more aesthetically pleasing. Dotted Drawing Demo Click on the play button in the left bottom corner of the embedded ShaderToy window below, to…