Black or White Border/Shadow around PNGs in SDL/OPENGL

Question

having the same issue as this: Why do my sprites have a dark shadow/line/frame surrounding the texture? however, when I do the fix suggested there (changing GL_SRC_ALPHA to GL_ONE) it just replaces the black border with a white border on the images. was able to find a lot of results on google from people finding black borders and fixing it with the GL_ONE change, but no results for white borders. any ideas?

heres some of my relevant code.

init:

glMatrixMode(GL_PROJECTION);
glLoadIdentity(); 
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glEnable(GL_DEPTH_TEST);
glEnable(GL_MULTISAMPLE);
glEnable(GL_TEXTURE_2D);
glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
glAlphaFunc(GL_GREATER, 0.01);
glEnable(GL_ALPHA_TEST);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
glEnable(GL_BLEND);

when each texture is loaded:

glGenTextures(1, &textureID);
glBindTexture(GL_TEXTURE_2D, textureID);
gluBuild2DMipmaps(GL_TEXTURE_2D, GL_RGBA, surface->w, surface->h, GL_BGRA, GL_UNSIGNED_BYTE, surface->pixels);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

thanks!

Answer 1

It seems you are using non-power of 2 texture dimensions and mipmapping which calls for trouble because the minifying interpolation has incomplete information along the edges. Prefer to manually expand all textures to power of 2 before loading. Use the desired color for those padding pixels.

If you have many small textures of arbitrary dimension it might also be a good idea to create a single power of 2 texture atlas.