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Lighting:_Best_Practices.md

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+Here we'll run down the practices of lighting your map using
+[WorldSpawn](/WorldSpawn "wikilink") and [vmap](/vmap "wikilink").
+
+## Basic Rules {#basic_rules}
+
+-   Point lights are hard to maintain, use surface lights (either
+    [vmap_surfaceLight (Material
+    Command)](/vmap_surfaceLight_(Material_Command) "wikilink") or
+    [light_surface](/light_surface "wikilink"))
+-   [light_environment](/light_environment "wikilink") will do a bulk of
+    the world lighting, it should even be used in afternoon and dark
+    settings
+-   Avoid ambient lighting, unless you know exactly what you want, or
+    you're in a completely interior-only map
+
+## Global settings {#global_settings}
+
+[light_environment](/light_environment "wikilink") will do the bulk
+work. It emits light from any sky surface, such as `common/skyportal`.
+The amount of samples specify how many **passes** are done. This will be
+~evened~ out to match the desired **intensity**, so increasing samples
+does **not** make the map brighter.
+
+Using more than 1 sample is useful if you want less harsh-shadows. Even
+a value of 4 with a `sunspreadangle` of e.g. 5-10 degrees is sensible
+for day-time maps. It makes them look less artifacting too. The theory
+is, the cloudier the world is, the softer the shadows are - so we need
+more **samples** and a `sunspreadangle` that's wider to accommodate
+that.
+
+The `sunspreadangle` will determine how far apart the different samples
+will be spread. E.g. if you set it to '0' it will do nothing. Every
+light_environment sample will take place on the exact same spot, from
+the same angle. However if you set it to 360 (the maximum amount), each
+sample will spread out to get a full 360 coverage of the map. Resulting
+in a lightmap without any real contrasting shadows.
+
+## Which light_environment color to use? {#which_light_environment_color_to_use}
+
+99% of the time it's going to be white. Let `_ambient` inside your
+light_environment tint the shadows the color of the sky, let radiosity
+do its job. Radiosity can't do its job if the sun color is non-white.
+
+**The effects of radiosity will be barely visible using a non-white
+light_environment color.**
+
+## Ambient color? {#ambient_color}
+
+Set `_ambient` in your light_environment to whatever the color of the
+sky is set to. This determines the color of the shadows cast by the
+light_environment. **This does not create a minimum ambient intensity in
+the process**
+
+## Minimum light intensity {#minimum_light_intensity}
+
+A really ugly hack, only use it in the worst case scenario.
+
+In your [worldspawn (Entity)](/worldspawn_(Entity) "wikilink") keys, you
+can add a `_minlight` intensity value, as well as a `_minlight_color`
+value. This is not something you want to use for anything looking good.
+
+It raises the lighting level-wise, but keeps the light values of each
+entity/sky/shader intact. A much worse alternative is the worldspawn
+`_ambient` key.
+
+**You will never achieve truly black areas in your map after this. Be
+warned.**
+
+## What about the worldspawn **_ambient** key? {#what_about_the_worldspawn__ambient_key}
+
+The overall lighting level of the map is raised. This has the tendency
+to flatten the difference between light and shadow. The dynamic range is
+utterly destroyed.
+
+## What about the worldspawn **_floodlight** key? {#what_about_the_worldspawn__floodlight_key}
+
+With floodlight, light becomes darker in closed spaces and brighter in
+wide open spaces.
+
+The worldspawn key for that is `_floodlight`, with you specifying:
+
+` `**<red color>` `<blue color>` `<green color>` `<travel distance>` `<intensity>**
+
+The side effect is that it'll obviously act as a contrasting knob. It
+**does not fix spaces where light wasn't present to begin with**!
+
+There are very few artistic use cases for this. However, if your map is
+looking very dull/flat, it could help a lot.
+
+## Should I use radiosity? How many bounces? {#should_i_use_radiosity_how_many_bounces}
+
+Half-Life 2 compiled with a maximum of 8 bounces, that is sensible. You
+can even set it to 100 and it'll stop once photons lose their energy.
+
+**And of course yes you should use radiosity... Damn it, that fixes most
+lighting problems!**
+
+[Category: Level Design](/Category:_Level_Design "wikilink")