   FBO+GLSL readback normalization problem
  Hi,I'm trying to read back FBO data to system memory but somehow it only accept in range of 0-1 as input in GLSL and convert into 0-255 range to FBO. for instance, in GLSLgl_FragColor = vec4(0.5, 10, 100, 1.0)is read in FBO readback as(127, 255, 255, 255) I created a RGBA8 texture and attached to FBO:glBindTexture  (TEXTURE_TARGET, GL_iTexID);glTexParameteri(TEXTURE_TARGET, GL_TEXTURE_MIN_FILTER, GL_NEAREST);glTexParameteri(TEXTURE_TARGET, GL_TEXTURE_MAG_FILTER, GL_NEAREST);glTexImage2D   (TEXTURE_TARGET,0,GL_RGBA8, SCREEN_WIDTH, SCREEN_HEIGHT,0, GL_RGBA,GL_UNSIGNED_BYTE,0);How can I read/write a UINT or UBYTE in GLSL/FBO properly ?Thanks in advance.   
  That's because of your texture format, GL_RGBA8 is a RGBA texture with unsigned normalized (Hence the 0-1 range) integers, with 8 bits per channel.There is more formats, such as GL_R8UI (one channel, 8 bits per channel, unnormalized unsigned int), you can view all of them in the GL_EXT_texture_integer and GL_ARB_texture_rg extensions, which are core in GL 3.0/3.1   