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Captain Toenail

Boom Editing

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I am making a map in Boom format, which is unfamiliar to me as I have only worked with regular Doom and ZDoom in Hexen formats, I can do regular translucent lines, but is there a way to make them additive? Also, is there a Boom editing wiki or similiar that I can refer to in the future? The nearest I can find is the Legacy wiki which is confusing

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From the Doom Wiki, on translucency:

The Boom source port implemented translucency using a precalculated lookup table. Each color is multiplied by the user's translucency percentage and then blended with all other colors in the palette in turn. The result of each computation is matched to the closest color in the palette and is stored in a way that allows a simple array index to be computed from the foreground and background colors while drawing graphics. While very fast as far as translucency routines are concerned, the results are not memory friendly: each "TRANMAP" held in memory consumes more than 65 Kilobytes of RAM.


By creating custom tranmaps, you can replicate additive blending (as well as any other blending mode, or different opacities, or even much more unusual special effects) in Boom.

A 100% additive tranmap, created in Photoshop, looks like this and can be used by importing it and saving it as a Doom Flat in XWE (SLumpEd might let you do this, too; I forget whether its incomplete support of large flats is capable of it). To use it in a map, give your translucent lines a tag (and no Translucent special), then create a dummy off-map line with that tag, the translucent special, and the name of the tranmap as their middle texture.

However, ZDoom doesn't support special-effect tranmaps like these, as it only supports tranmaps by guessing their translucency level and using its own translucency code. Graf added support for recognizing 100%-additive tranmaps a while back, and it's in 2.3.0, but the results sometimes differ between the tranmap and ZDoom's emulation of it, and if you want to use any other kinds of tranmap effects you're out of luck.

I'm not aware of a specific Boom editing wiki, but there are plenty of folks around here who can probably help you out with any other questions you have. And be sure to look into voodoo doll/conveyor belt "scripting" :)

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To clarify, for translucency you're using tranmaps, not colormaps.

But Boom's colormap support isn't especially good for what you're probably trying to accomplish: for some reason, they decided to make it only work by coloring the entire visible area when you're standing in the colormapped sector, and not recoloring the affected area at all when you're not standing in it. It was made with deep-water effects in mind and apparently not much else.

While many (or all?) Boom-based ports nowadays replace this behavior with the functional per-sector colored lighting you'd expect, if you're going for actual Boom compatibility in your map it won't act like you want it to.

In addition, IIRC the only way to use it is through transfer-heights (as it was only intended for deep water), so it's rather inconvenient.

If you really need colored lighting in your map, you might get better results just by manually recoloring textures and flats in the affected areas. I've done this in some areas of KDiKDiZD using Photoshop's "Channel Mixer" adjustment (taking the red/green/blue values from the original KDiZD scripts) to extremely convincing effect, though it is a bit of effort to batch-process all the needed textures and flats. :\

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esselfortium said:

While many (or all?) Boom-based ports nowadays replace this behavior with the functional per-sector colored lighting you'd expect, if you're going for actual Boom compatibility in your map it won't act like you want it to.


Actually, the only port doing this is Eternity. All others still have Boom's original behavior.

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A Boom wiki really isn't necessary; there aren't any major paradigm shifts between Doom and Boom editing that are at all hard to get used to for experienced Doom mappers. What you need is boomref.txt - it comes packaged with the Boom engine on this download page.

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