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.float image format for HDR textures in UDK

elementrix
polycounter lvl 15
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elementrix polycounter lvl 15
hey guys, I read in the UDK documentation that you can import .float images for HDR textures, does anyone have any clue on how to make a .float from an .hdr or .exr image?

I tried google but I didn't really find anything on this format.
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  • Ben Apuna
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    Ben Apuna
    It looks like HDR Shop has the capability to do the conversion (save as -> *.float, *.raw). I haven't ever tried to bring a .float into UDK though.

    FWIW Picturenaut is another good free HDR image manipulation app, though it doesn't save .float it can do other interesting things.
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  • Tyrone70
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    Tyrone70
    You can, but it won't support the float data.
    HDR Support

    Only RGBA render-to-texture resources can be created at this time. Support for floating point HDR targets may be added in the future.

    Instead, use the technique they provide to fake HDR lighting.
    http://udn.epicgames.com/Three/MaterialExamples.html#Simulated HDR

    Just out of curiosity, why did you want to import HDR image into UDK?

    *edit* WHOA! My mistake. That quote was in regards to render to texture. This is an interesting question. I'll test something out real quick.
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  • Tyrone70
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    Tyrone70
    ok, so for some reason, HDR Shop won't let me save in float format. But, under the Compression Setting for textures, there's one for TC_HighDynamicRange. try that and see what happens.
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  • elementrix
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    elementrix polycounter lvl 15
    I wanted to do some tests with rendering out HDR skydomes/lightmaps and using those in UDK. I tried to export as .float from HDR shop, but udk keeps saying the import failed and I did put it on TC_HighDynamicRange.

    I also tried to import an HDR psd with those settings, it did import but the result is very weird, like an image made out of red/green/blue pixels like your tv set.

    I guess it's not really a big problem, I was just curious how it worked because the option is in there. I could also fake it by multiplying some LDR textures so they do get over 1.
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  • Tyrone70
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    Tyrone70
    I think people have tested that before and got bad results. I don't think true HDRI lighting can be done in realtime with any application right now. Everyone just use's an ambient cubemap, which I'm trying to figure out at the moment.
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