Problem with Effect transparent textures created in DXTBmp

[old_wombat]

Posted this question in the FS2004 forum with no help, so am trying posting it here.

I have finally got the aircraft carrier wake.bmp file right, but there is a display problem. I have masked of parts of the bmp to make it transparent, using the old bright - green - for - transparent bit in Paintbrush and then making it a transparent bitmap in DXTBmp.

This works fine, except for one thing. The border between the transparent and the coloured bits is being rendered as a medium grey line, of constant apparent (displayed) thickness. As a result, from a long way away, that dominates the entire texture, making the whole Effect appear to be grey. I can post some screen caps if this is not clear.

I have also tried using packages other than DXTBmp, but have found nothing that works with FS. The only comment made on the other forum was that this might be a driver issue. I have installed the latest NVidia drivers only a few weeks ago, that hasn't helped. I accept that it might be driver related, as there are still a couple of problems with the NVidia using the screen in portrait mode, which is pretty well essential for landing on a carrier.

Any positive suggestions are welcome.

Steve from Mudgee.

[StringBean]

Sounds like a slight discrepancy between the diffuse and the alpha.

What .bmp format are you using?

Can you post 2 pics, 1 for the diffuse and 1 for the alpha?

peace,
the Bean

[old_wombat]

Beano, don't really understand the word "diffuse" in this context. I found a bitmap picture, and using Paintbrush, edited it to the shape I wanted and then greened out the parts I wanted transparent. I then converted it using DXTBmp. I tried several formats, with "Extended 16-bit 555-1" and "DXT1 Old Code with Alpha" giving the best results.

To save on unwanted images, can you please tell me which of these you want me to post:

- The original BMP that I modified. It has the transparent areas painted in green.
- The image bmp that DXTBmp created from the above.
- The alpha bmp that DXTBmp created from the above.
- Some screen caps at various distances from the carrier showing the various issues in the wake effect.

Steve from Mudgee.

[StringBean]

Beano, don't really understand the word "diffuse" in this context. ..

That would be the RGB image.

To save on unwanted images, can you please tell me which of these you want me to post:

How about..

- The original BMP that I modified. It has the transparent areas painted in green.
- Some screen caps at various distances from the carrier showing the various issues in the wake effect.

One clear shot of the effect in the sim should be sufficient.

peace,
the Bean

[old_wombat]

OK, here goes.

Hmm, looks like it wont allow me to attach BMPs, only the JPGs, and that makes a difference. The dark green border to the light green in the fx_wake_01 is only a JPG effect. It is not there in the BMP file. The green there is pure (0, 255, 0) right up to the "water".


In the other file, you can see the grey border to the edge of the wake. This screen cap is done from close up, but even here, where it is near the carrier (and hence further from "me") the wake effect is more and more grey.


Steve from Mudgee.

[StringBean]

From the FS9 SDK...

Texture Types
Two texture types can be used in special effects: alpha and additive. Alpha textures are full color and include a transparency mask (alpha channel). Additive textures, on the other hand, have no alpha channel. The transparency of an additive texture is based off of color values within the texture. Color values in the texture are added to the background color. If an additive texture is triggered against pure white, nothing happens because the values are already maximized at 255, 255, 255, which represents the RGB value for white. Any part of the texture that you want to be invisible must be pure black (or else you’ll just get expanding squares). Additive textures are best used when the effect is simulating something bright—like fire or a light.

I would try pure black (0,0,0) instead of green and save as 256 color or create a proper alpha and save as DXT1.

To create the alpha change the solid green to solid black and everything else as pure white. Save that as filename_alpha.bmp.

Open the original image in DXTBmp, import alpha and use filename_alpha.bmp then save as DXT1.

You could also try a slight fade between the white and the black in the alpha and save as DXT3, though this would require a gradient tool which I think Paintbrush is lacking.

peace,
the Bean

[old_wombat]

Thanx Beano. You've confused me somewhat because what you suggest in the first three lines is exactly what DXTBmp does "automatically" when you open an image - whatever is in green becomes an Alpha channel mask, exactly as you say.

However, your last line is very promising, if DXTBmp can do that. My original image is simple enough that I can quickly make a three level gradient in Paintbrush "manually". I'll give that a go and report back.


Steve from Mudgee

[old_wombat]

Well that didn't work at all. Making a black/lite_grey/dark_grey/black graded ALpha channel took no time at all. And when I opend it in DXTBMp it looked OK. But DXTBmp's version of DXT3 does not do any transparency at all.

I might go back to my working DXT1. Make the foam at the edge of the wake a little darker, that way the boundary might no be noticeable.
Other than that I am giving up on this problem.


Steve from Mudgee.