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HDR Experiments

mittens Moderator Member since: 11/26/2000 From: Austin, TX, United States

Image Posted - 4/26/2006 12:44:21 AM

HDR Shot 2

Torque Demo HDRized

Custom GUI

Lately I've been working a lot more with the Torque Shader Engine and, specifically, I've been working on a bloom effect (yay pixel shaders). At first I took the basic "fake bloom" route that every single game within the last two years has both used and abused in a very, very common way. Some games even go so far (or, rather, not nearly far enough) as to just apply a general brightening filter to the entire screen buffer and the end result is primarily an effect that really does nothing more than wash or smudge the clarity of the scene. As of right now the only game I'm aware of that does real HDR (high-dynamic range) is Far Cry, which implemented the HDR effects in a post-release patch (1.3, if my memory serves me). The actual shaders that are primarily responsible for the effect in Far Cry appear to be straight from the DirectX 9.0 SDK "HDRLighting" sample, though the HardOCP article linked would have me believe that it is based entirely on methods presented by OpenEXR (which the SDK gives no reference to). So, either way, the effect exists in Far Cry. And it's pretty.

As a note of interest, I was using Torque as a testing grounds for all these. It really is quite a nice engine... Especially for prototyping, if not for using it for an actual game.

Before I start showing all the pretty screenshots, let me show a kind of "before" picture set (in the GUI one, focus on the building, not the GUI) that shows what the game looked during a prepubescent period -- Shot 1 and Shot 2.

With that said, I was lead down a similar path in my work lately. First I decided upon a "fake bloom" method that used similar techniques as mentioned above, but with fairly "hacked" calculations. This produced some of the following screenshots -- Shot 1 and Shot 2.

I was very unhappy with the overall "look" of the final scene after I had worked with the fake bloom effect. The very, very overly done bloom in the above screenshots is partially to blame on the actual blurring shader that I was using, but the hacked bloom calculations were also just missing something that I couldn't put my finger on. So, after another few hours of work, I was able to figure out how to get the HDR rendering working without too much trouble, and produced these screenshots (with a slightly different blurring algorithm for the shader employed) -- Shot 1 and Shot 2.

The overall look in the above screenshots was what I was going for, as the final produced images just felt a lot more vibrant than anything I had produced before, but this time I would say that the final effect was actually too subtle. I wanted the final effect to be subtle in screenshots (which can never really show this kind of effect very well), but not so subtle as to be really easy to overlook. I then took another solid five-six hours just trying to perfect the blur shaders, and eventually I ended up with an effect that I thought was pretty damn good. The following screenshots are pretty close to the current version I'm working with, though I ended up reducing the area of the blur (which is a separable gaussian blur) by a few pixels since I felt these screenshots were just a bit too overdone -- Shot 1 and Shot 2.

That about covers it; I also have a shot of the Torque Shader demo customized (up above in the selectable area) and then there's the GUI system of the engine which I worked with to make look fairly perty; full gallery of the GUI can be found here.

Trent Polack
Game Designer, LightBox Interactive
Twitter :: Polycat

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