   GL_UNPACK_ALIGNMENT
  If the internal format to glTexImage2D is GL_RGB8 and I leave the default GL_UNPACK_ALIGNMENT of 4 (I assume it's faster when rows are aligned to 4-bytes), then does the padding happen automatically if the image row size is not divisible by 4?  If not, what's the best way to do it (without having to pad the image data buffer)?Also, I assume unlike setting parameters like GL_TEXTURE_MIN_FILTER and GL_TEXTURE_WRAP_S, it has to be specified before the actual call to glTexImage2D?   
  This is what the driver doeshttp://www.opengl.org/wiki/Common_Mistakes#Unsupported_formats_.232