1. Incoming Radiance Simulation: In this stage you need to approximate the lighting that shines into your virtual camera / eye. This value should be completely unclamped and can reach values of 0.0001f and 1000000.0f (High Dynamic Range).
Typical Passes in this stage are: G-Buffer Generation, Light Accumulation, Shadow Mapping, SSAO, Sky Rendering, Volumetric Light Scattering, ...
2. Lens Simulation: In this stage you simulate how the incoming lighting gets modified by travelling through the lenses. Lenses typically cause interreflections of the incoming radiance which appear as lens flares on the final image, also lenses might need to focus onto a specific distance (depth of field). Bloom might also occur because the glass is not perfectly pure. Also the lenses might refrect the light, which causes chromatic aberration on cheap lenses.
Typical Passes in this stage are: Lens Flares, Bloom, Depth of Field, Chromatic Aberration
3. Aperture Simulation: The camera / eye needs to adapt to the current average luminance of the incoming lighting, unless you want to set the exposure manually. You should simulate this in this stage.
Typical Passes in this stage are: Average Luminance Calculation, Exposure Adjustment
4. Retina Simulation: In this stage you simulate how the incoming adjusted lighting affects the retina. You need to translate the incoming high dynamic range lighting to the range [0; 1]. The resulting image can be shown on the screen, but you might want to add HUD elements before.
Typical Passes in this stage are: Tone Mapping
You could swap the second and third stage, because the iris of an eye and the aperture of a camera are actually in front of the lenses. But the result should be the same and this is typically the way it's implemented, because exposure ajustment might be done inside the tone mapper.
Also, in your case, you don't want to apply bloom to an untextured render of your scene. Bloom is done inside your eye / camera in the real world and I don't think your eyes see the world untextured
1. Should I use bloom & tonemapping on the specular component ? (to me it seems to distort the form and "energy" of my specular quite a bit)
You should apply it on everything the virtual eye sees.
Edited by CryZe, 13 September 2012 - 01:29 AM.
I'm quite confused in what you're doing, so I'm going to tell you, how your engine should be structured if you want it to be as realistic as possible. I'm going to divide it into different ordered stages: