title: Texture filtering of 32bit integer or float textures on OpenGL ES 3.0
body: <p>I have a large 32bit integer texture (<code>R32I</code>), and I need to perform bilinear filtering on it. I naively thought that I'd simply have to enable the filtering on my texture, but it seems that the whole thing is not as simple. The <a href="http://www.khronos.org/registry/gles/specs/3.0/es_spec_3.0.3.pdf" rel="nofollow">OpenGL ES 3.0 specification</a> has a list of texture formats on pages 129-131, and the <code>R32I</code> format is not marked as texture-filterable. All the integer format seems to be unfilterable, and floating point formats larger than 16 bit as well. I could use both, an integer or a floating point format, but 16 bit are simply not enough precision for my data.</p>
  
  <p>Now I can of course perform the filtering manually in a shader, but I'm wondering if there are GPUs that can actually filter these formats and how I could detect if the GPU is able to do this?</p>
  
  <p>Are there severe performance drawbacks to performing the bilinear filtering manually in a shader? Or is it merely convenience, then there would be no reason for me to try to make the automatic filtering work for my texture.</p>