plib-users

[Plib-users] Transparency?

[Tinoshi K. <ti...@li...>]

Hello!

I've got a problem with the clouds in the sky... I can't figure out why =
my clouds are ugly and those of sky.cxx are so beautiful... I've copied =
that code, except for the windowing: now I use PW... It seems that my =
clouds are not transparent, well, I see them and they are moving well, =
but they are 'flat', not puffy. Seems that their alpha is set to 1.0, I =
cannot explain that better. They seem pieces of paper flying through the =
sky, not vapour. Should I set some OpenGL state? I tried to use glut =
instead of PW but this is not the answer! It seems to me that in sky.cxx =
nothing of strange is set up, it's very 'simple', so i don't know what =
to do... 

Re: [Plib-users] Transparency?

[<jni...@ya...>]

are you sure you have a full 32bit alpha channel
image, like that of a image.rgba file? if not you can
get transparency without "masking".


john

--- Tinoshi Kitazawa <ti...@li...> wrote:

> Hello!
> 
> I've got a problem with the clouds in the sky... I
> can't figure out why my clouds are ugly and those of
> sky.cxx are so beautiful... I've copied that code,
> except for the windowing: now I use PW... It seems
> that my clouds are not transparent, well, I see them
> and they are moving well, but they are 'flat', not
> puffy. Seems that their alpha is set to 1.0, I
> cannot explain that better. They seem pieces of
> paper flying through the sky, not vapour. Should I
> set some OpenGL state? I tried to use glut instead
> of PW but this is not the answer! It seems to me
> that in sky.cxx nothing of strange is set up, it's
> very 'simple', so i don't know what to do... 

Re: [Plib-users] Transparency?

[Steve B. <sjb...@ai...>]

Tinoshi Kitazawa wrote:
> Hello!
>  
> I've got a problem with the clouds in the sky... I can't figure out why 
> my clouds are ugly and those of sky.cxx are so beautiful... I've copied 
> that code, except for the windowing: now I use PW... It seems that my 
> clouds are not transparent, well, I see them and they are moving well, 
> but they are 'flat', not puffy. Seems that their alpha is set to 1.0, I 
> cannot explain that better. They seem pieces of paper flying through the 
> sky, not vapour. Should I set some OpenGL state? I tried to use glut 
> instead of PW but this is not the answer! It seems to me that in sky.cxx 
> nothing of strange is set up, it's very 'simple', so i don't know what 
> to do... 

Sounds like glAlphaFunc/glAlphaRef are set up differently...or perhaps
glEnable(GL_BLEND) isn't set...or glBlendFunc is wrong.

Hard to know for sure.

---------------------------- Steve Baker -------------------------
HomeEmail: <sjb...@ai...>    WorkEmail: <sj...@li...>
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Re: [Plib-users] Transparency?

[Tinoshi K. <ti...@li...>]

Ok!

Problem solved! I did set up blending and alpha and stuff, but just before 
the main loop... now I've copy&pasted the same code just before the 
sky->postDraw and everything works perfectly! The strange thing is that in 
sky.cxx those gl functions are never called! Probably I've got something in 
my code before the sky postDraw that disables blending... but I don't know 
where.
Thank you so much!!!