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Night textures with alpha channel (Read 228 times)
Jan 12th, 2006 at 1:10pm

9thSimplex   Offline
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Hello,

as oyu may know i am skinning Cantu's 737-200 currently.

I arrived at making the night textures now which brought me to a new question.

I read somewhere that a night texture can also contain 2 channels. Does this statement apply to ALL FS9 planes cominh with bmp night textures? Regarding to my read the primary night texture is the "landinglights+panel lights" status while the alpha channel resembles the "panel lights only" channel.

for cantu'S 737 it is important for me to have acess to both channels as the landing light seems to glow through the whole fuselage. so i have to shut down the landing lights. Currently in this state the cabin windows are dark too... less desirable imho. So i added an alpha channel and saved the bmp as dxt1 compressed with alpha but now i do not even have ANY lights left Sad

Any ideas?

thanks and best regards,
Simplex
 

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Reply #1 - Jan 13th, 2006 at 11:07am

wji   Offline
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What do the night textures look like now in DXTbmp? I do not repaint this model but as noted, these characteristics work across FS9 aircraft (and FS2k2 I presume)

"I read somewhere that a night texture can also contain 2 channels."

That sounds logical enough but what is contained in the Alpha Channel? Here's a night-file someone gave me (with a plain Alpha Channel) which was a vast improvement over the default,  plain-black night textures for another FS9 model:

...
 

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Reply #2 - Jan 14th, 2006 at 5:04am

9thSimplex   Offline
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Hi,

my night texture is close to that beside the fact that i have an alpha channel which is the same than the normal "large" image but without the tail lights and landing light beams --> only the cabin windows are visible in my alpha channel

When I save it as DXT1 the whole bmp (includgin alpha channel) turns black.. Sad
 

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Reply #3 - Jan 18th, 2006 at 9:52pm

Katahu   Offline
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Ok, this is how I understand as far as textures go.

The night effects of the textures that appear in the aircraft model are really called "Light Maps". "Night Textures" seem to refer to the scenery at night. Don't get those two terms confused.

To make a simple texture [with alpha channel] have a light effect at night the following steps are needed:

1. Name the main texture to "whatevernameyouwant_t.bmp" * then apply it to Gmax as a diffuse texture.
2. Create another texture with the light effects highlighted in it to "samenameasmaintexture_l.bmp" **. and they link it to the main texture in Gmax as an illuminated texture.

3. Create an alpha channel with black and white properties and name it "samenameasmaintexture_Alpha_t.bmp" *** and import it into the main texture via DXTBmp utility.

4. Save the main texture [the one with the imported alpha] in the same name and let it overwrite itself *.

5. Reload main texture in Gmax so that it can know that the texture is converted *.

6. Export Gmax model ****.

* the "t" in *_t.bmp tells FS that the texture will be reflective when alpha is applied. If there is no "t" in the end, then the alpha will make the texture transparent when applied.

** the "l" in *_l.bmp tells FS that this texture will be overlapped on top of the main texture in FS. Thus resulting in a merged texture in FS.

*** the "Alpha" in *_Alpha_t.bmp is usually just reference so that you get don't confused which texture is the alpha channel texture.

**** I cannot garantee that you will get it right the first time. But if you do, the aircraft should appear reflective in the day and will light up its textures in the night when you hit the light key. Note: The light effect only works when it's night time.

This is as far as I understand because this is the same technique I have used when I made the textures and applied them to the Chevy addon. I don't know where you read about a texture having two channels. But if you look at the steps above, you can see that the Alpha channel can do two things but not both at once.

The Alpha can only create either a transparent effect or a reflective effect in FS, but not both at the same time. The light effects are achieved by the light map that is linked to the main texture. Here is a little hierarchy list I made just to simply things:

I. Object model
---A. Main_Texture_t.bmp [with alpha channel imported]
------1. Main_Texture_l.bmp

Get the idea?

However, I don't know how to maintain the reflective effect when lights are switch on at night. The reflections are lost when lights are on at night.
 
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Reply #4 - Jan 20th, 2006 at 10:12pm

SHV0151   Offline
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Correct me if I am wrong, but I dont think DXT1 can have an alpha channel.
 

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Reply #5 - Jan 20th, 2006 at 10:48pm

Katahu   Offline
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Quote:
Correct me if I am wrong, but I dont think DXT1 can have an alpha channel.


Given my experience with DXT1, I don't think so either. But DXT3 can.
 
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