I have a dataset which i put into a 3d texture using GL_LUMINANCE_ALPHA, where the luminance is the value of the data and the alpha value is just 0 for 0 and 255 for everything else. I map this to 3 quads as seen in this screenshot http://b.imagehost.org/view/0649/screen1.png
However the blending is only correct for the last drawn quad. I use
glEnable(GL_BLEND);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);