   FBO + multisample + RA textures
  I have problem with using RA (LUMINANCE_ALPHA) textures with FBO & multisampling.If I create RA16F multisample rendertarget and render scene and then downsample it to "normal" RA16F rendertarget, I lose alpha channel.However, if I use RGBA16F as rendertarget, everything works fine (but I need just two channels for VSM).No errors are generated (I check glError after each GL call).   
  To render to a 2-component texture, use the GL_ARB_texture_rg extension.Here's the spec http://www.opengl.org/registry/specs/ARB/texture_rg.txt   ;  GL_RG16F does the trick. Thanks!   