Hi,

I need to use glBlendEquation but I can't.
Compilation always send me the error : undefined reference to 'glBlendEquation'

I include files :
#include < gl/glut.h >
#include < interfaces/glut.h >

and glut.h includes all files for gl including file glext.h that contain definition for the glBlendEquation function.
so, why compilation report error ?

Thank you.

Kindest Regards,
AmiDARK

Last edited by AmiDARK on 08-Apr-2011 at 11:01 PM.

@AmiDARK

glBlendEquation is not supported in MiniGL, so you will have to find an other solution.

@shadow
err ... So ... impossible do to some ghosting/transparency effects like DBPro in AmiDARK Engine then ...

@AmiDARK

Use glBlendFunc() and alpha channels for transparancy etc.

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@broadblues
Yes but it's too limitative ...
For example; to do bright ghosting.

@AmiDARK

What's "bright ghosting" ?

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@broadblues
Look this image :

It's a particle system I've done on PC with DarkBASIC Professional.
The transparency is done without Alpha channel.
It is only done with blending set to "add"

Look for example this next one :
XQuadEditor Sample SnapShot
The "warp" effect, is only "bright ghosting" too.

On PC for example, I have created a "2D Plasma" effect like on old Amiga simply by adding 3 plains objects with 3 different textures ( 1 red, 1 green, 1 blue ):

The plasma result :


On AmigaOS when using Alpha, On only get this :

I use what is advised for transparency on OpenGL websites :
Quote:

glEnable( GL_BLEND ); glEnable( GL_DEPTH_TEST ); glEnable( GL_ALPHA_TEST ); glAlphaFunc( GL_NOTEQUAL, 0 ); glBlendFunc( GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA );

I was thinking that setting glBlendEquation to ADD may help me getting the result I want...

Any one have a Clue ?

Kindest Regards,
AmiDARK

@AmiDARK

for additive blending just use gl_one, gl_one as blendfunc

@kiero
ok
will try

thanks

@AmiDARK
or try GL_SRC_ALPHA, GL_ONE for additive with alpha.

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EDIT :
@Kiero & Daytona675x :
Using your param, I get totally white screen ...

Last edited by AmiDARK on 09-Apr-2011 at 02:49 PM.

@AmiDARK

For the plasma effect, if you make the textures solid colour and move the "brightness" into the alpha channel, how does it look with additive+alpha blending?

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@AmiDARK
Quote:

Using your param, I get totally white screen ...

That may have many reasons. Without further knowledge and/or a complete code listing we can only speculate. It may be one of those, for example:

- are you not clearing the screen? If not it will all sum up to white pretty fast.

- what are you adding together? A fully red, green and blue texture? That turns out to be white then.

- your textures are invalid, therefore GL uses the default texture.

- you did not enable texturing and glColor is white or grey.

etc. etc. etc.

Last edited by Daytona675x on 09-Apr-2011 at 03:54 PM.

_________________
AmigaOS 4.1 FE (sam460ex Radeon 9200 / RadeonHD), MorphOS 3.8 (PowerMac G4 733MHz Radeon 9000), AROS (x86), A1200 (060 80MHz Indivision MK2), A500, A600, CDTV
Wings Remastered Development Diary