Computer Graphics with Photoshop - Working with transparent images

Author

Working with transparent images

Nicholas Sherlock

2004-10-04, 4:14 am

Hey all,

I'm trying to make semi-transparent images for use inside a game that I'm
making. I can't seem to get photoshop to export a 32bit bitmap with
transparency information in one of the channels (Ie. 256 shades of opacity).
It doesn't seem to be capable of exporting TGA images with transparency
information either. What am I doing wrong? Is there a plugin available to
add this very basic functionality to PhotoShop? Gif or PNG is not an option
here.

Cheers,
Nicholas Sherlock

Sean

2004-10-04, 4:14 am

On Mon, 4 Oct 2004 19:56:00 +1300, "Nicholas Sherlock"
<n_sherlock@hotmail.com> reverently intoned upon the aether:

> Hey all,
>
> I'm trying to make semi-transparent images for use inside a game that I'm
> making. I can't seem to get photoshop to export a 32bit bitmap with
> transparency information in one of the channels (Ie. 256 shades of opacity).
> It doesn't seem to be capable of exporting TGA images with transparency
> information either. What am I doing wrong? Is there a plugin available to
> add this very basic functionality to PhotoShop? Gif or PNG is not an option
> here.
>
> Cheers,
> Nicholas Sherlock
>

You should be able to write TIFFs with alpha channels so you might
explore that option.

just a thought,

Sean

"In the End, we will remember not the words of our enemies,
but the silence of our friends."

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Photo Archive @ http://www.tearnet.com/Sean
Last Updated 29 Sept. 2004

Nicholas Sherlock

2004-10-04, 4:14 am

Sean wrote:
> On Mon, 4 Oct 2004 19:56:00 +1300, "Nicholas Sherlock"
> <n_sherlock@hotmail.com> reverently intoned upon the aether:
>
>
> You should be able to write TIFFs with alpha channels so you might
> explore that option.

Thanks, but I can only really import BMPs and TGAs into my application. PNGs
are too messy for me as they require an extra conversion before the engine
can use them and I have no facility for TIFF import.

Cheers,
Nicholas Sherlock

bogus

2004-10-04, 12:14 pm

Check the specifications for BMP and TGA. I don't think they support 256
shades of transparency. If so, you are on mission impossible.

I have been able to make PCX files with only color set as transparent for a
game programmer. Makes it difficult to use transparency. On trick is to put
the image on the same color background. That way the fringe pixels match
the color of the background you place them into.

Nicholas Sherlock wrote:

> Sean wrote:
>
>
>
> Thanks, but I can only really import BMPs and TGAs into my application. PNGs
> are too messy for me as they require an extra conversion before the engine
> can use them and I have no facility for TIFF import.
>
> Cheers,
> Nicholas Sherlock
>
>

Peter Wollenberg

2004-10-04, 12:14 pm

"Nicholas Sherlock" <n_sherlock@hotmail.com> wrote:

>Hey all,
>
>I'm trying to make semi-transparent images for use inside a game that I'm
>making. I can't seem to get photoshop to export a 32bit bitmap with
>transparency information in one of the channels (Ie. 256 shades of opacity).
>It doesn't seem to be capable of exporting TGA images with transparency
>information either. What am I doing wrong? Is there a plugin available to
>add this very basic functionality to PhotoShop? Gif or PNG is not an option
>here.
>

Photoshop CS will export TGA-Files with an alpha channel, BTDT. When
the people at

http://wiki.beyondunreal.com/wiki/A...el_To_TGA_Files

are right, there was a bug in the PS 7.0 TGA export filter which was
fixed in 7.01

Peter

Tacit

2004-10-04, 12:14 pm

>I'm trying to make semi-transparent images for use inside a game that I'm
>making. I can't seem to get photoshop to export a 32bit bitmap with
>transparency information in one of the channels (Ie. 256 shades of opacity).

Here is what you do:

Create your image as RGB.

Load the transparency as a selection.

Save the transparency as an alpha channel.

Save in TGA format.

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Nicholas Sherlock

2004-10-04, 7:14 pm

Tacit wrote:
>
> Here is what you do:
>
> Create your image as RGB.
>
> Load the transparency as a selection.
>
> Save the transparency as an alpha channel.
>
> Save in TGA format.

Thanks, that works perfectly. I'm also applying to Adobe for free access to
the SDK, so if anyone is interested in bitmap with transparency support,
I'll (hopefully) soon have it available.

Cheers,
Nicholas Sherlock