I'm starting to implement HDR in my scene. I have a few questions after reading online and going through the HDR_Pipeline demo in the SDK.
I setup my render target texture as D3DFMT_A16B16G16R16F. How do I actually get those extra bits of color? If I render my scene as-is and then render that texture out to the screen, it's exactly the same.
The HDR_Pipeline actually has a pixel shader that multiplies each RGB by a scalar factor. Is this how HDR is done? So, every object (or really every shader) in my scene now has to multiply it's pixel RGB by some magical scalar factor so I can later use that for my luminance calculation? Is this how everyone does it, take the result RGB from a model and multiply it by some scalar to get over 1.0 results?
Is there anyway faster to get the average or log luminance value other than downsampling? If not, do people generally start at 256x256 for a total of 9 downsamples? The HDR_Pipeline used 3x3 downsamples instead of 2x2, is that better?