GDC2013Casting a NewLight on a Familiar Face Light Based Rendering in TombRaider

# Where we started
- Tomb Raider: Underworld的引擎（2008）
- forward lighting
- heavy use of lightmap


# lightmap problem with TombRaider2013
- modular workflow in Horizon
    - rapid iteration
    - emphasis on reuse(一块木板可以用来build出小型建筑。。。疯了)
- destructibility in world
- material very complex, can not afford lightmap on disk or in memory


# first pass deferred lighting
- brought in from Deus Ex 3(用的一样的引擎)
- 但是workflow不一样，难用
- art team也觉得除了lightmap别的不能用


# selling the Team on Deferred
- setup pepsi challenge(让consumer决定哪个内部产品)
- 2个team，2个月做same level
    - forward.主要在搞scene cleanup，展UV，bake一次1天
    - deferred. 3-4 days to light the level(剩下的时间都在实现workflow)


# crystal lighting system
- hybrid
    - forward for translucent and complex materials
- various light type and light complexities
- combined with art driven lighting stages(editable in realtime)
- light complexities
    - universal（主要光）
        - used for key lights
        - effect everything in scene
    - fill
        - 不算specular
        - deferred only
        - 就是用来补光、造成bounce的假象的
        - much cheaper on cpu，immediate flushed out from pipeline once scheduled（没太懂这句）
    - AO dark
        - add ambient occlusion to scene(好像就是传说中的负光。。。)
        - 主要是用来做出AO效果，为何不用AO贴图或SSAO？
        - 说是render到half resolution的buffer上
    - player
        - light player seperately from everything else
        - 是吧所有player light的color和direction average出一个来用（主要是cinematic）
    - FX based：用来做出全场景的wet或burn的效果
- light stages