I have a billboard quad with a texture mapped onto it.

This is basically some text with transparency.

The billboard floats forwards and backwards from the camera's perspective.

As the billboard moves away (and appears smaller) there is an flickering effect around the edges of the text where there is a stroke border on the actual texture.

I think this is because interpolation is needed as the image which is normally X pixels wide is now shown as only a % of X and some pixels need to be merged together. I guess it's doing nearest neighbour or something? Can anyone point me in the right direction for opengl settings to control this, I'm guessing there is some way of preventing this effect from happening by adjusting the method for how the texture is handled ?