   Loss of precission with glGetTexImage
  Hi there.I'm having some issues with glGetTexImage and the image data it returns.The case is that I have an application that uses and modifies a source texture attached to an FBO. This application works with floating point values and it requires some precission so I tested that the output data at least mantained input data precission, but this don't happen.A simple test I did is simply upload and download the source data, and the result is that when I download the texture from GPU memory, all luminance values are rounded to the nearest integer or integer + 0.5 value.The test code is this: glTexImage2D(GL_TEXTURE_2D, 0, GL_LUMINANCE_ALPHA16F_ARB, m_config->textureSize[0],m_config->textureSize[1], 0, GL_LUMINANCE_ALPHA, GL_FLOAT, m_config->textureData);float before =  m_config->textureData[0];glGetTexImage(GL_TEXTURE_2D, 0, GL_LUMINANCE_ALPHA, GL_FLOAT, m_config->textureData);if (before != m_config->textureData[0]) {printf ("Source and downloaded data are not the same\n");return;}Any ideas please?Regards.   
  You have a texture which uses 16-bit floats (usually called "halfs"), but providing float data, this WILL cause some precision loss, since halfs have less precision than floats.   ;  Thanks HuntsMan!, you are right, if I use GL_LUMINANCE_ALPHA32F_ARB instead of GL_LUMINANCE_ALPHA16F_ARB when loading my texture, there's no loss of precission.Anyway, I think this is pretty strange, because half floating point precission would be enougth for what I need because I'm not using huge values far from zero.Regards.   