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Colour blindness HLSL shader for XNA

I’ve recently been thinking about accessibility and ways of adding various aids to my games to make them more enjoyable / playable to gamers with physical disabilities. So, first up, I’ve written a shader to simulate various forms of colour blindness and a little sample application that allows you to switch between 3 different forms of colour deficient vision: Protanopia (absence of red retinal photoreceptors), Deutanopia (absence of green) and Tritanopia (absence of blue). Normal color vision is trichromatic. It is initiated by the absorption of photons in three classes of cones, the peak sensitivities of which lie in the long-wavelength (L), middle-wavelength (M), and short-wavelength (S) regions of the spectrum. Therefore any color stimulus can be specified by three numbers, the cone responses; and all colors visible to the color-normal observer are included in a three-dimensional color space. Reduced forms of color vision arise from the effective absence of one of the retinal photopigments of the L type in protanopes, the M type in deuteranopes, and the S type in tritanopes.  For dichromatic observers any color stimulus initiates only two cone responses, and all colors that they can discriminate are included in a two-dimensional color space. Compared with trichromatic vision, dichromatic vision entails a loss of discrimination and results in a reduced color gamut. If anybody is interested, the code can be found here: http://www.pumpkin-games.net/downloads/src/XNAColourBlindnessSimulator.zip Caveats: The ‘magic’ numbers used in the shader were initially designed to work with older CRT monitors.  I’m not sure how this will affect the filters when viewed on newer LCDs. I’m continuing research around this area and will post findings as and when. Typically you would use as a post process filter to simulate how your game would look to dichromats. Sources: http://vision.psychol.cam.ac.uk/jdmollon/papers/Dichromatsimulation.pdf http://gimp.sourcearchive.com/lines/2.6.6-2/display-filter-color-blind_8c-source.html http://www.iamcal.com/toys/colors/ Sometimes it is not possible, desirable or practical to alter artwork offline to cater for all gamers.  So the next task is to create a post process component that can (in real time) dynamically alter the colour range of the final output so that it is more friendly to colour deficient players. This component could be turned on or off depending on a players needs (e.g off for a ‘normal vision’ gamer and on for a dichromat). The approach I’m attempting to take is outlined in the following paper: http://www.inf.ufrgs.br/~oliveira/pubs_files/CVD_PCA/Machado_Oliveira_EuroVis2010.pdf

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Pumpkin Games at GameCityNights

Posted by Paul | Posted in Uncategorized | Posted on 29-04-2011

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I attended GameCityNights yesterday.

“AN AFTER-DARK EXPLORATION OF VIDEOGAME CULTURE”

Stuart Gilray from Just Add Water was there doing the one on one, describing how he got into the industry and showing some of the new Stranger’s Wrath HD artwork, which looked pretty.  There was a live video interview with Lorne Lanning of Oddworld fame which was thoroughly entertaining; touching on socially designed games and why he believes classic games can stand the test of time just as well as classic movies. And a section on Second Life that was highly amusing by (I think) a fella called Paul Butler.

They also showcase indie games there which is the main reason I attended. I must thank Bob Fearon for putting my name forward and Chris White for making it happen.  There are usually 3 or 4 screens available to indie devs so I took my Xbox and demoed Doppelganger and the latest WIP build of Droid Assault. It was fascinating seeing other people experience the games for the first time and try and learn the mechanics (by trial and error – not a SINGLE person read the ‘how to play’ screens, not one).

It quickly became apparent that Droid will require some kind of tutorial – without reading the instructions (or having me direct their actions) players simply attempted to kill all the bots without using the transfer mechanism to build a team. Some players struggled with the twin stick control too so my intention to add a few different methods was vindicated.

So, all in all, it was a really enjoyable evening – a few beers, a decent chicken curry, some interesting chat and I got to show off a couple of games.

Cya next month!

(if you fancy showing your stuff send me a message and I’ll put you in touch with Chris to set it up).

 

 

Comments (3)

fog said on 01-05-2011

Nice one Paul.

You aren’t really surprised that nobody read your “how to play” screens though surely? :)

I think you’re right and a tutorial is probably needed for Droid Assault otherwise most people will play it as a traditional shmup.

“You’re playing it wrong!”….sound familiar? ;)

Paul Cunningham said on 01-05-2011

Yeah, I am :-) “How to play” and “Comtrols” are always the first screens I look at when playing a new game. I must be the exception then.

You should come down when you’re feeling up to it. Your stuff would go down great there.
Dirk said on 26-05-2011

Hey Paul,

Yeah, make them do basic training as a part of the game. They don’t pass that, they don’t move onto the game ……

How’s life anyhow :)

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