hi guys !
i am programming some kind of software where i need to blend textured polys with the background ... the texturemap has an alpha channel and i set the texture environment mode to GL_REPLACE (glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE)) so that the rgba value of my texturemap is used instead of the fragment color of the poly or stuff ... ok now i enable blending and i choose a blending func ... so that i can blend it with the background ... but on the edges of the opaque areas there is a very mysterious effect ... there is a little bit of the color of the texmap where alpha is 255 blended with the color of that areas of texmap where alpha is 0 ... if i use GL_NEAREST as texfilter it works but if i use GL_LINEAR it would'nt work ... so that i see this blending effect where no blended should be ...
ok some of you may say that the teximage has allready this effect but it is produced mysteriously by opengl or my graphics board ... i don't know ... on the image there are just 0's and 255's alphavalues so that there is a hard boarder between the totally opaque and totally transparent areas ...
maybe you can help me or know what the reason is ? may it be my graphics board ?
maybe you need some kind of picture ?
the good one:
and the bad one:
would be nice if someone has any kind of hint !
Edited by - Sebbi on November 25, 2001 2:59:32 PM