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Using the Alpha Channel
<p>Another way to specify non-filtered transmit transparency in an image
map is by using the alpha channel. PNG file format allows you to store
a different transparency for each color index in the PNG file, if desired.
If your paint programs support this feature of PNG you can do the transparency
editing within your paint program rather than specifying transmit values
for each color in the POV file. Since PNG and TGA image formats can also
store full alpha channel (transparency) information you can generate image
maps that have transparency which isn't dependent on the color of a pixel
but rather its location in the image.
<p>Although POV uses transmit 0.0 to specify no transparency and 1.0 to
specify full transparency, the alpha data ranges from 0 to 255 in the opposite
direction. Alpha data 0 means the same as transmit 1.0 and alpha data 255
produces transmit 0.0.
<p>This is all the infomation I could find about using the alpha channel.
I may be dense; but I cannot for the life of me; determine exactly how
to use this feature from the above information. Any additional help would
be greatly appreciated
<p>James Wood wrote:
<blockquote TYPE=CITE>I also read the docs. If I want to do something;
I go to the docs first. Follow instructions. Experiment! Maybe a lot! Maybe
not! It depends on how successful I was and how clear the docs are. A lot
of it is quite clear! Some of it is not!
<br>An example is this current problem. How to make a transparent background.
<p>According to the docs; I should be able to use the following:
<br>"background {color transmit 1.0}"
<br>Turn on alpha channel with "+UA"
<br>This has left me with a gray background and I cannot seem to get it
totally transparent. The ambiguity is that in the docs it states that the
alpha data ranges from 0 to 255 with 0 being transparent and 255 being
opaque; but it does not say as to where these values can be set.
<br>My question is; Am I doing it properly or not. Am I missing something.
Where is the information located so that I may be successful in this endeavor?
<p>James Wood wrote:
<blockquote TYPE=CITE>How do I make the background transparent? Or prepare
to do so in another program? Also How is the alpha channel used?</blockquote>
</blockquote>
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