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Sunday, October 23, 2011

Cliffs of Dover released - first hiccup

The Epilepsy Filter controversy
Soon after release it emerged that part of the issue behind the poor frame rates was an 'Epilepsy filter'. A piece of code added to the game, to reduce the risk of players experiencing an epilepsy episode. At first the rumour was that this was done at the insistence of distributor, UbiSoft, out of fear of legal issues. The developers, 1C, quickly denied this on their official forums:
"Our game did cause wide-scale epilepsy failures when tested. Propellers, muzzle flashes, smoke puffs, explosions, falling bombs, flying or taxiing between buildings, sun shining through canopy framework, etc, they were all causing potentially seizure-inducing flashes.

We worked hard to address all these issues individually, but since a flight sim is all about fast-moving large objects, there were just too many instances of things causing high-contrast flashes.

So, as we were running out of time, WE decided to implement this epilepsy filter as a stop-gap measure.

The filter sits on top of the game's graphics wrapper. It saves a previous frame, and then compares it pixel-by-pixel to the new frame. When two pixels are found with a high degree of contrast between them, the new pixel is toned down to make the change less drastic.

This causes a visual effect somewhere between bloom and motion-blur that removes virtually all instances of high-contrast flashes.

However this pixel-by-pixel frame analysis and modification takes up additional resources, it in fact delays the showing of each new frame until each pixel of it checked, and therefore the filter is causing deteriorated performance that is especially notable on lower-end machines.

We are continuing to work to optimize the game and to increase its framerate. Ubisoft has been very patient and understanding with us throughout the entire process, and we are continuing to work with them very closely to find the best solution to epilepsy issues.

In summary, I want to stress that it is OUR code and OUR game engine that is causing performance issues. And it US who has to make it better, and that's exactly what we pledge to do.
They advised that there was a config.ini text file alteration that could be made to turn the Epilepsy Filter off. Our trusty reporter 'Sim' tried this in his Russian version of CoD.
"I think this is a placebo," he said, "I could see no difference."
It is still too early in the life of this sim to conclude whether it will survive this difficult birth. Certainly there are some nice looking videos emerging as players sort through the game settings and find compromises.

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