Category Archives: Engine Tech

Adventures in Fisheye Lenses

By Jonathan Blow | Published: January 22, 2011

During the past couple of weeks, we have been doing some experiments for The Witness that involve pre-rendering a scene with a fisheye lens and then using that render during gameplay. If I were to say exactly what this is for, it would be a massive spoiler, so I’ll just say it’s for a kind [...]

Also posted in Development | 16 Comments

Experiments in Texturing

By Jonathan Blow | Published: November 5, 2010

Something like a year and a half ago, when I was starting to get serious about making The Witness, I was talking to Casey Muratori about 3D modeling and texturing. Braid was a 2D game; The Witness being 3D meant that it would be much more expensive and difficult to make, so I was doing [...]

Also posted in Development | 19 Comments

Hemicube Rendering and Integration

By Ignacio Castaño | Published: September 29, 2010

One of our aims with our global illumination implementation was to keep it as simple as possible, while still obtaining good performance, and we hoped to achieve that by using the GPU. While the are several approaches to compute global illumination in the GPU, the most simple one that we could come up with was [...]

Posted in Engine Tech | 15 Comments

Computing Alpha Mipmaps

By Ignacio Castaño | Published: September 9, 2010

A little problem that we had when we started to create trees and vegetation is that the standard mipmap generation algorithms produced surprisingly bad results on alpha tested textures. As the trees moved farther away from the camera, the leafs faded out becoming almost transparent. Here’s an example. The following tree looked OK close to [...]

Posted in Engine Tech | 29 Comments

Kriging is cool.

By Jonathan Blow | Published: May 24, 2010

In The Witness we decided that it’s a good idea to have a heightfield terrain making up the bulk of the island surface.  The advantages of this are in rendering performance and in ease of texturing (it is relatively easy, with one continuously-parameterized terrain block, to get rid of seams; if your terrain is a [...]

Posted in Engine Tech | 30 Comments

Graphics Tech: Shadow Maps (part 2): Save 25% texture memory, and possibly much more.

By Jonathan Blow | Published: April 21, 2010

In the previous part, I talked about my reasons for wanting to use Cascading Shadow Maps (one of the biggest: image stability), then said that we had implemented Michal Valient’s version of the algorithm, and mostly liked it, but wanted to reduce the memory usage. This time I’ll show how to reduce the memory usage by [...]

Posted in Engine Tech | 27 Comments

Lightmap Parameterization

By Ignacio Castaño | Published: March 30, 2010

As explained by Jon in his previous post, we are using precomputed global illumination in The Witness, and one of my first tasks was to work on that system. I have developed some interesting technology to compute automatic paramaterizations, to formulate the lighting computations in a way that can be easily mapped to the GPU, [...]

Posted in Engine Tech | 9 Comments

Graphics Tech: Lighting Comparison

By Jonathan Blow | Published: March 29, 2010

It seems like time to post some images from the in-progress precoputed lighting tech that Ignacio is working on.  See here for a description of the basics behind what we are doing for lighting.  The lightmaps are now 16-bit and these shots use a simple exponential tone mapper. First, I’ve taken shots from 3 positions [...]

Posted in Engine Tech | 10 Comments

Graphics Tech: Shadow Maps (part 1)

By Jonathan Blow | Published: March 3, 2010

The Witness contains a mixture of indoor and outdoor scenes, but much of the game takes place outdoors with a very long view distance (you can see the entire island at once if you have a good vantage point).  So I wanted to implement a shadow system that would work robustly, provide high visual quality, [...]

Posted in Engine Tech | 22 Comments

Graphics Tech: Precomputed Lighting

By Jonathan Blow | Published: March 1, 2010

For the past 15 years or so, graphics technology in games has been driven by shooters.  Most shooters generate visual interest in their scenes by having lots of dynamic lights, with extreme use of bump mapping, and moving shadows, and particle effects. For The Witness, I wanted to develop a graphical style that values simplicity. [...]

Also posted in Development | 30 Comments

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