Well, you need to set the domain to render as the smoke volume. How you do that is to change the domain material type to ‘volume’ and set the density to 0. Next, go into the texture panel and create a new texture, and set it to ‘voxel data’ in the drop down bar at the top. Then select your domain object in the settings, and turn the density slider up to 1 in the influence settings.
[Edit: Oh, you’re talking about GLSL…]
The default BI material is a surface material, not a volume. If you create it in Cycles and switch to BI, then add a new material, that will be the default material until you change it. The surface of the domain is of course a cube. You do want to render the domain, so don’t turn off its visibility. What you want to render is its volume. That means you need a volume material, not the default.
in GLSL viewport if I select the domain I can see the smoke, as you can see in the bottom image:
the question is how I can hide the orange line of the selection in viewport (without turn off my smoke too). I try “Only Render” too without result.
Any idea?