I'm rendering many
ofImages with binary alpha channels (no grey values) into an FBO. Around the binary alpha mask edges I see what looks like a single pixel fringe that appears to be some automatic antialiasing. I have explicitly disabled MSAA when I allocate my FBO:
montage.allocate(maxTextureSize, maxTextureSize, GL_RGBA, 0); // No MSAA
Following is what I end up with (RGB and A). Note the light (near transparent) 1px border in the alpha channel on the right.
I took the same two images and aligned them manually in GIMP to produce what I expect to happen in ofx shown in the following images. Note the lack of border in the alpha channel.
Since this does not seem to be MSAA, and the border is not in the
ofImage alpha channels, it seems to be an artifact from rendering into the FBO. I'm using of_v0.9.8_linux64_release.
How can I disable this behaviour?