transparency problem

[snow_master]

Hi,
i am drawing two objects the first one is opaque , and the second one is semi transparent on a black
background.
the alpha factor of the opaque object is 1.0 and of the transparent one is 0.5
i have the following problem :
if i use the blending functions :
glBlendFunc (GL_SRC_ALPHA, GL_ONE);
or
glBlendFunc (GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
I see only the opaque object and not the transparent one.
if i use :
glBlendFunc(GL_ONE ,GL_ONE);
both objects appear but when they are one in front of the other
the blended pixels turns white, and the transparent object turns white also in some angles when is just
against the black background.(as if it reflects to much light even that the specular component is disabled)
if i use:
glBlendFunc (GL_SRC_ALPHA, GL_SRC_COLOR);
I get good results when the transparent object is in front of the opaque object, but when the transparent
object is on the black background it disappears !!! (if i change the color of the background to white
it works great, but I need it black....)
the display function is :

GLfloat SurfaceColor[4];

// Erase last list
if (m_ListOpenGL)
if (glIsList(m_ListOpenGL))
::glDeleteLists(m_ListOpenGL,1);

// Search for a new list
m_ListOpenGL = ::glGenLists(1);
if(m_ListOpenGL == 0)
return 0;

// Start list
unsigned int NbVertex = (unsigned int)m_ArrayVertex.GetSize();
if(!NbVertex)
return 0;

unsigned int NbFace = (unsigned int)m_ArrayFace.GetSize();
if(!NbFace)
return 0;

CFace3d* pFace;
CVector3d* pVector;
CColor* pColorPrevious;

::glNewList(m_ListOpenGL,GL_COMPILE_AND_EXECUTE);

//the alph value of the mesh
if(m_fTransperentLevel< 1.0)
{
//both objects appear but when are one in fron of the
//other
//the blendind turns white, and the transparent object is
//white in some angles.
//glBlendFunc(GL_ONE ,GL_ONE);
//only the solid object appear, the transperent isn't
//glBlendFunc (GL_SRC_ALPHA, GL_ONE);
//glBlendFunc (GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
//works good but dissapear in black backround
glBlendFunc (GL_SRC_ALPHA, GL_SRC_COLOR);
glEnable(GL_BLEND);
//turn off the depth buffer
glDepthMask (GL_FALSE);
}

// Init color
pFace = m_ArrayFace[0];
pColorPrevious = pFace->GetColor();

::glBegin(GL_TRIANGLE_STRIP);
// form the first two vertices of the N-2 triangle strip.
SurfaceColor[0] = (float)1 / (float)255 * (float)pFace->v(0)->GetColor()->r();
SurfaceColor[1] = (float)1 / (float)255 * (float)pFace->v(0)->GetColor()->g();
SurfaceColor[2] = (float)1 / (float)255 * (float)pFace->v(0)->GetColor()->b();
SurfaceColor[3] = m_fTransperentLevel;
glMaterialfv(GL_FRONT, GL_AMBIENT_AND_DIFFUSE, SurfaceColor);


pVector = pFace->v(0)->GetNormal();
::glNormal3f(pVector->x(),pVector->y(),pVector->z());
::glVertex3f(pFace->v(0)->x(),pFace->v(0)->y(),pFace->v(0)->z());
pVector = pFace->v(1)->GetNormal();
::glNormal3f(pVector->x(),pVector->y(),pVector->z());
::glVertex3f(pFace->v(1)->x(),pFace->v(1)->y(),pFace->v(1)->z());

for(unsigned int i=0; i< NbFace-1; i++)
{
pFace = m_ArrayFace[i];
// Normal (per face)
if(m_NormalBinding == NORMAL_PER_FACE)
{
pVector = pFace->GetNormal();
::glNormal3f(pVector->x(),pVector->y
(),pVector->z());
}
// Color (per face)
if(m_ColorBinding == COLOR_PER_FACE &&
pColorPrevious != pFace->GetColor())
pColorPrevious = pFace->GetColor();
// Normal
if(m_NormalBinding == NORMAL_PER_VERTEX)
{
pVector = pFace->v(2)->GetNormal
();
::glNormal3f(pVector->x(),pVector-
>y(),pVector->z());
}
// Color (per vertex)
if(m_ColorBinding == COLOR_PER_VERTEX &&
pColorPrevious != pFace->v(2)->GetColor())
{
SurfaceColor[0] = (float)1 /
(float)255 * (float)pFace->v(2)->GetColor()->r();
SurfaceColor[1] = (float)1 /
(float)255 * (float)pFace->v(2)->GetColor()->g();
SurfaceColor[2] = (float)1 /
(float)255 * (float)pFace->v(2)->GetColor()->b();
SurfaceColor[3] =
if(m_fTransperentLevel< 1.0)
{
//change the transperent
//object color from the
//original color
SurfaceColor[0] -= 0.4;
if(SurfaceColor[0] < 0)
SurfaceColor[0] = 0;
SurfaceColor[1] -= 0.3;
if(SurfaceColor[1] < 0)
SurfaceColor[1] = 0;
SurfaceColor[2] -= 0.1;
if(SurfaceColor[2] < 0)
SurfaceColor[2] = 0;


}
glMaterialfv(GL_FRONT,
GL_AMBIENT_AND_DIFFUSE,
SurfaceColor);

pColorPrevious = pFace->v(2)->GetColor();
}


// Vertex
::glVertex3f(pFace->v(2)->x(),pFace->v(2)-
>y(),pFace->v(2)->z());

}
//complete the last ring triangle strip
pFace = m_ArrayFace[i-39];
pVector = pFace->v(1)->GetNormal();
::glNormal3f(pVector->x(),pVector->y(),pVector->z
());
::glVertex3f(pFace->v(1)->x(),pFace->v(1)->y
(),pFace->v(1)->z());
pVector = pFace->v(2)->GetNormal();
::glNormal3f(pVector->x(),pVector->y(),pVector->z
());
::glVertex3f(pFace->v(2)->x(),pFace->v(2)->y
(),pFace->v(2)->z());
pFace = m_ArrayFace[i-37];
pVector = pFace->v(1)->GetNormal();
::glNormal3f(pVector->x(),pVector->y(),pVector->z
());
::glVertex3f(pFace->v(1)->x(),pFace->v(1)->y
(),pFace->v(1)->z());


::glEnd();


if(m_fTransperentLevel< 1.0)
{
glDepthMask (GL_TRUE);
glDisable(GL_BLEND);
}
::glEndList();

// List is done now
m_ListDone = TRUE;
m_Modified = FALSE;

return 1;

any ideas ????
thanks in advance

[davepermen]

wow.. lovely knacky..
are you in love? or got payed holidays at work? or what?

yeah, listen to knacky he tells you all you need to know. good luck on reordering your stuff.

[snow_master]

>>I don't mean to offend you
you didn't
>>you have to draw transparent objects >>AFTER opaque ones, and they must be drawn >>in strict order from the far plane to the >>near plane, with glDepthMask(GL_FALSE);
DA, this is the paint function of an object of type 3dMesh, and if you would bother to read the code you would have seen that of the transparency level is < 1.0 (that is the alpha level of the mesh) I transform the depth buffer to a read only mode using glDepthMask(GL_FALSE)
since there are two mesh objects I draw the
opaque one first and then the transparent one and therefore the if condition is being entered during the rendering of the second mesh.

>>Wasn't I nice, everyone?
actually Not really.

[Elixer]

Originally posted by snow_master:
[B][snip]
and if you would bother to read the code you would have seen that ...[snip]
[B]

LOL geeze Knackered... can't you read?

I want that code debugged and ready to go in an hour! Get to it, before we send you to n00bie land!

p.s. Sleep? Whats that? Dunno, but if you don't get any, it sure makes you say strange things!

[snow_master]

>>I didn't bother to read your code because it's almost unreadable

you probably meant you couldn't understand it because things I have long forgotten regarding programming you will probably never learn....

>>and I shouldn't have even replied to you

so don't.
you bother me and spend my valuable (and very expensive) time, and except bitching you aren't being helpful, so just spare me your "wane be" smart answers.

>>You are also very ungrateful

you got to be kidding.....I should be grateful for what ?

[snow_master]

thank god for the internet....otherwise people like you would have never had the chance to interact with people like me...I find it amusing....but you live in this sad comedy.....I pity you.
p.s
if you are such a good programmer (I hope you are because judging your inter relationship with human beans, you probably haven't got any friends....) instead of answering intelligently insulting replays...try to debug the problem and earn some respect...

[gumby]

As a vegetarian, I object to the whole
concept of these "human beans".

[Coconut]

Originally posted by gumby:
As a vegetarian, I object to the whole
concept of these "human beans".

It was a typo. He meant "humans and beans".

[snow_master]

again if you would have bother to read the question and the code....you would have noticed that i tryed many blending functions (including some that are not writen) it didn't made any sence to me either why when the src factor of the blending function is src_alpha (which make sence)that the whight of the closer transparent pixel alpha value will be multiplied, but the dest factor is GL_SRC_COLOR which dosen't make sence at all, but this is the only way i got good results...(when the background isn't black), the reasnobele choise was to put ONE_MINUS_SRC_ALPHA, but as i wrote earlier this method made only the opaque object to appear.
>>God, your spelling is almost as bad as
i appologize for my bad spelling, but english isn't my first language, and actualy i speak read and write in 7 languages.(i bet you do to....)

now, dosen't any one else read this fourum ? can someone please try to be more helpfull...?...?

[snow_master]

please do go away already !!!
now doesn't any one else can please be kind and try to suggest a solution ?