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transperency problem

Started by hello_there Nov 23, 2003 at 6:46 PM 6 replies 650+ views

Original Post

Nov 23, 2003 at 6:46 PM

i''m using a 32 bit targa file for my graphics and I have a texture for the mouse pointer. I do this to get the transperency glEnable(GL_ALPHA_TEST); glAlphaFunc(GL_GREATER, 0); //draw quad glDisable(GL_ALPHA_TEST); it works but around the none transperent bit it goes white. how do i stop it from doing that?.

hello_there

Nov 23, 2003 at 7:03 PM

I tried this as well but it put the back ground colour around the edges instead of the texture that''s behind it.

glEnable(GL_BLEND);
glEnable(GL_ALPHA_TEST);
glAlphaFunc(GL_GREATER, 0);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);

//draw quad

glDisable(GL_BLEND);
glDisable(GL_ALPHA_TEST);

how do you make it work properly

Digitalfragment

Nov 23, 2003 at 7:24 PM

Make sure that the texture was saved to video memory with the Alpha channel included (ie, GL_RGBA not GL_RGB) and dont bother with an Alpha Test, just:

glBlendFunc( GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA );
glEnable ( GL_BLEND );

drawMy1337Quads();

glDisable ( GL_BLEND );