   Night-time simulation?
  I'm looking to do lighting simulations like in Age of Mythology or WarCraft3, mainly a night time effect. I'm not sure of what filters to use, I'd guess something in the way of gray scaling and lowered brightness and a hue shift. Can somebody point me in the right direction?[Edited by - overeasy on May 6, 2009 9:28:58 PM]
From an older reply in another thread:Three papers come to mind:Night Rendering [pdf] (Jensen et al.)A Physically-Based Nightsky Model [pdf] (Jensen et al.)A Spatial  Post-Processing Algorithm for Images of Night Scenes (Thompson, Shirley, Ferwerda)Even if you are not going to implement those techniques, they provide highly valuable information on what makes up a rendering of a night scene; realistic synthesization of night scenes is not only shutting down the light and adding a blue shift ;);  Realistic night may not be desirable, because you wouldn't see anything.   ;Quote:Original post by loufoqueRealistic night may not be desirable, because you wouldn't see anything.You are such an, astute. If one just wouldn't see anything, why would one bother creating night-sky models?Maybe the OP said something like "I'd guess something in the way of gray scaling and lowered brightness and a hue shift", and the papers show why and how, and how to get a realistic night-sky. Having a night-sky model handy means that you can easily tweak it so that it fits your needs.The following example is a tweaked Preetham sky; actually, the only thing I tweaked was to filter colors a bit so it looks more "romantic":(source)Further, if you are so deep into science, why didn't you know that physically based models generally yield data of high resolution, data that can easily be tone-mapped or just be brightened up?   ;  The OP asked for a night-time look for a game, and was given links to realistic simulations. I'm just saying realistic night-time simulation might not be desirable for a game because it might impair playability.How thick are you?   ;Quote:Original post by loufoqueHow thick are you? *I am so clever. Formidable. Let's just not check what others say, and call them straight thick*Specifically A Physically-Based Nightsky Model (the third link in my quite huge list) says right in the abstract:Quote:The standard technique for making images viewed at daytimelighting levels look like images of night scenes is to use a low overall contrast,low overall brightnesses, desaturation, and to give the image a "blue shift".This paper introduces two other important effects associated with viewingreal night scenes: visible noise, and the loss of acuity with little correspondingperceived blur.Or in simple english: It is about how to give an image, that has been shot at daytime, the look of an image at night-time. Alone in that quote, it already mentions e.g. the following effects: blue shift, low contrast, noise, and more.Quote:I'm just saying realistic night-time simulation might not be desirable for a game because it might impair playability. because you wouldn't see anything.Now here I am really thick. What is bad about having a semi-automatic simulation where you have not to tweak all parameters and all the look all the time, but instead just choose a KISS conformant tone mapper that does not much more than brightening the sky a bit? And who said you have to apply the sky lighting towards your scene in an unbiased manner? I stop here, before I further discuss with you, be so kind, just look at the papers.   ;  I just change the glColor3f from (1.0f,1.0f,1.0f) to dark blue.  KISS principle.  Hell yeah.   ;  You're thick, phresnel, because you are missing my point.I am saying that a realistic night simulation (as in a simulation of night that is exactly the same as the real world) in a game might impair playability because the player may not see sufficiently well to enjoy playing the game.Nothing more, nothing less. I have not read the papers and their content is totally irrelevant to my point.Also, please refrain from deviating from my remarks to launch personal attacks in the future. This is getting old. Thank you.Quote:Let's just not check what others say,You cannot expect people on a forum to analyze in depth every single previous answer to a thread before replying.   ;  loufoque; In this instance you launched the attack first by phresnel 'thick' in the first place with no reason.In short; cut it out.   ;Quote:Original post by icecubeflowerI just change the glColor3f from (1.0f,1.0f,1.0f) to dark blue.  KISS principle.  Hell yeah.In case that this is intended a reply to my posts: No, I really was talking about implementing the day-scene/night-look-tonemapper, or a physically based approach, onto which you can in effect apply a KISS conformant tone mapper or some filter to make it brighter ;)edit: Otoh, your post was obviously a joke. Need coffee. More. [smile]   