Frame Rate Independent Damping using Lerp

A quick aside for those not familiar with Unity: Each script has three different update functions that can be called. Update is called as you would expect, and LateUpdate is a version that’s called well, later on in the frame. Both of these should use the global (yikes) Time.deltaTime to access the variable frame time. FixedUpdate uses Time.fixedTimeDelta and runs on a fixed timestep, so can potentially run multiple times per frame. The Great Lerping Problem It seems to crop up on the Unity forums again and again and again…

Derivative Map Artifacts

I had been suffering from some strange artifacts on the edges of my objects when using derivative maps. After much time spent in GPU Perf Studio, I finally realised that my mipmap generation was not correct. It was introducing one extra column of garbage at every level. My use of FXAA and anisotropic filtering was just making the problem more evident. I would recommend using regular trilinear filtering for derivative maps anyway. So, mea culpa and all that. Let the name of Morten Mikkelsen and derivative maps be cleared!

Derivative Maps vs Normal Maps

This post is a quick follow up to my previous post on derivative maps. This time I’m going to compare the quality and performance of derivative maps with the currently accepted technique, normal maps. I’ll be using the precomputed derivative maps for comparison since the ddx/ddy technique just isn’t acceptable in terms of quality. Quality Here’s the close up shot of the sphere with the moon texture again. This shows the derivative map implementation, and if you mouse over, you’ll see the normal map version. There are some slight differences…

Cubemap Texel Solid Angle

Warning: This post is going to be pretty math heavy. If you suck at math, then go and read this first, then come back. If you still think that you suck, then I suggest going to Khan Academy and start watching videos. You won’t regret it! I was reading through the AMD CubeMapGen source last week and came across the code for calculating the solid angle of a cube map texel. This code piqued my interest, since it seemed very terse for what I thought would be a horrific calculation….

UI Anti-Aliasing

I’ve been working on making a really simple IMGUI implementation for my engine at home. I like to do a little bit of research when I’m approaching something new to me like this, so I went hunting around for publicly available implementations. While doing this, I came across Mikko Mononen’s implementation in Recast. I was impressed when I ran the demo with how smooth his UI looked. It turns out that he’s using a little trick (which I’d never seen before, but I’m sure is old to many) to smooth…

MockItNow: Now with Win64 goodness!

A couple of fine chaps named Julian Adams and Clement Dagneau from my previous company Black Rock Studios (née Climax Racing) took it upon themselves to tackle the daunting task of  porting MockItNow to x64 (MSVC). They’ve kindly shared their efforts back with the main repository in google code. Feel free to profit from their hard work! Thanks a lot Julian & Clement!

Another MockItNow Update

I fixed a problem with the EXPECT_THROW macro (I had uploaded the wrong file). Also, I added the ability to stub out results for function arguments passed by pointer. I would recommend downloading the zip file to take a look since there were a few files that had to change this time. I added one new example to show the new functionality.


A couple of days ago, I stacked the random assortment of books I had lying on my desk at work, and for some reason I decided to take a photo. It’s a bit of a mixed bag of good and not-so-good books. Every now and then I know I’m in trouble because I have to whip out the yellow maths book to remind myself of something that I have forgotten. I enjoy the challenge of reading the quaternions book, but it’s pretty hard to motivate myself to really get into…

Nothing To Report

Well, there’s not much to report really. I’ve been spreading myself very thin recently, investigating a few different things, so I thought might be nice to post a status update. Variance Shadow Maps Yes, I’m jumping on the variance shadow maps boat. They look nice, they’re easy to implement, and have relatively small overhead over traditional shadow maps. I read the article in GPU Gems 3, which is also available here, and it was pretty easy to implement from there. It probably took me about 2 hours to go from…