Bilinear down/upsampling, aligning pixel grids, and that infamous GPU half pixel offset
https://bartwronski.com/2021/02/15/bilinear-down-upsampling-pixel-grids-and-that-half-pixel-offset/ [bartwronski.com]
2021-02-25 01:41
tags:
graphics
programming
It’s been more than two decades of me using bilinear texture filtering, a few months since I’ve written about bilinear resampling, but only two days since I discovered a bug of mine related to it. 😅 Similarly, just last week a colleague asked for a very fast implementation of bilinear on a CPU and it caused a series of questions “which kind of bilinear?”.
So I figured it’s an opportunity for another short blog post – on bilinear filtering, but in context of down/upsampling. We will touch here on GPU half pixel offsets, aligning pixel grids, a bug / confusion in Tensorflow, deeper signal processing analysis of what’s going on during bilinear operations, and analysis of the magic of the famous “magic kernel”.
source: HN
Why are video games graphics (still) a challenge? Productionizing rendering algorithms
https://bartwronski.com/2020/12/27/why-are-video-games-graphics-still-a-challenge-productionizing-rendering-algorithms/ [bartwronski.com]
2020-12-29 01:07
tags:
gaming
gl
graphics
programming
This post will cover challenges and aspects of production to consider when creating new rendering / graphics techniques and algorithms – especially in the context of applied research for real time rendering. I will base this on my personal experiences, working on Witcher 2, Assassin’s Creed 4: Black Flag, Far Cry 4, and God of War.
Many of those challenges are easily ignored – they are real problems in production, but not necessarily there only if you only read about those techniques, or if you work on pure research, writing papers, or create tech demos.
I have seen statements like “why is this brilliant research technique X not used in production?” both from gamers, but also from my colleagues with academic background. And there are always some good reasons!
This is quite extensive.
Bilinear texture filtering – artifacts, alternatives, and frequency domain analysis
https://bartwronski.com/2020/04/14/bilinear-texture-filtering-artifacts-alternatives-and-frequency-domain-analysis/ [bartwronski.com]
2020-04-15 13:10
tags:
graphics
visualization
In this post we will look at one of the staples of real-time computer graphics – bilinear texture filtering. To catch your interest, I will start with focusing on something that is often referred to as “bilinear artifacts”, trapezoid/star-shaped artifact of bilinear interpolation – what causes them? I will discuss briefly some common bilinear filtering alternatives and how they fix those, link a few of my favorite papers on (fast) image interpolation, and analyze the frequency response of common cheap filters.