• light: fix black noise in some cases when using -bounce. (reported by Pritchard)
• light: try to limit artifacts caused by "too many lightstyles on a face",
  by saving the 4 brightest lightmaps. The previous behaviour was random,
  so you would likely get bad artifacts when that warning occurred.
• light: restore and expand the "unmatched target" warnings.
  Now checks "target", "killtarget", "target2", "angrytarget", "deathtarget".
  Also checks for any "targetname" that is never targetted.
• light: restore support for skip-textured bmodels with "_shadow" "1".
  This is only supported on bmodels where all faces are textured with "skip".
• light: add "_lightignore" model key, makes a model receive minlight only.
• qbsp: accept absolute path to map (reported by lurq)

Bugfixes:

• light: fix shadow-casting bmodels that touch the world from messing up
  sample points on world faces, and prevent the world from messing up
  bmodel sample points (regression in 0.15.5)
• light: clamp lightmap samples to 255 before smoothing, downscaling.
  reduces jaggies in cases with very bright lights casting hard shadows.
• light: fix order of "_project_mangle" value to be consistent with "mangle"
• light: various crash fixes
• light: minlight no longer bounces

Performance:

• light: new, faster raytracing backend (Embree)
• light: estimate visible bounding box each light by shooting rays in a sphere.
  this gives a speedup similar to vised maps in 0.15.5, without requiring
  the map to be vised. As a downside, there is a small chance of
  introducing artifacts where lights cut off too soon.
  Disable with "-novisapprox".
• light: bounce lighting code redesigned to use less memory

Other:

• all: windows builds now require MSVC 2013 runtime:
  https://www.microsoft.com/en-ca/download/details.aspx?id=40784
• all: restore Windows XP support

• rebuild OS X binary as it was built in debug mode by accident

New features:

• light: added a better options summary with the -help flag
• light: added -bounce option, "_phong", "_project_texture" key
• light: use vis data to accelerate lighting
• light: "_minlight_exclude" key to exclude a texture from receiving minlight
• light: add "_sun2" "_sun2_color" "_sun2_mangle" which creates a second sun
  (unrelated to "_sunlight2" which is the sky dome light)
• vis: support .prt files written by bjptools-xt
• qbsp: add -objexport flag

Bugfixes:

• vis: fix ambient sounds when using func_detail, broken in tyrutils-ericw-v0.15.3

New features:

• light: new -parse_escape_sequences command-line flag.
  The \b escape sequence toggles red text on/off, you can use this
  in any strings in the map file.
  e.g. "message" "Here is \bsome red text\b..."
• light: new -surflight_dump command-line flag. Saves the lights generated
  by surfacelights to a mapname-surflights.map file.
• light: new _sunlight3 and _sunlight3_color keys. Same as _sunlight2,
  except creates suns on the bottom hemispere (_sunlight2 creates
  suns on the top hemisphere.)
• build: support compiling with Visual Studio

Bugfixes:

• light: fix antilights (broken in last release)
• light: fix _mincolor to accept 0-1 float colors
• light: fix surface lights on rotating bmodels from incorrectly spawning
  lights near the origin
• qbsp: log coordinates for CheckFace errors
• qbsp: round texture coordinates that are close to integers, for Darkplaces
  compatibility
• qbsp: remove 128 char limit on entity key/value values

• hexen2 support, patch from Spike
• light: add "_surface_spotlight" key for making surface lights into
  spotlights based on the surface normal
• vis: Reuse each cluster's visdata for all leafs in the cluster
• light: add "-sunsamples" flag to control number of samples for
  _sunlight_penumbra and _sunlight2
• qbsp: add "-epsilon" option to control ON_EPSILON, from txqbsp-xt
• light: silence "no model has face" warning generated by "skip" faces.
• light: fix "-gate" (was calculating too-large bounding spheres for delay 2
  lights.)
• qbsp: updates to the "-maxNodeSize" feature added in 0.15.2 to be closer to
  the txqbsp-xt version.
• light: Adjust the trace algorithm to match that in q3map.
• qbsp: print coordinates for "New portal was clipped away" warning

• qbsp: add "-maxNodeSize" option, from txqbsp-xt. Defaults to 1024. Makes large
  maps process much faster and should generate better bsp trees.
  If it causes a problem disable with "-maxNodeSize 0"
• qbsp: make "mixed face contents" and "degenerate edge" non-fatal, from txqbsp-xt
• qbsp: make "-oldaxis" the default. new "-nooldaxis" flag to get the previous behaviour.
• light: add "-surflight_subdivide" flag to control amount of surface lights created
• light, vis: use below normal process priority on Windows
• light: allow negative surface light offset
• light: average the lit file color components to generate the bsp lightmap value.
  TODO: use a perceptually weighted average.
• light: fix lighting of hipnotic rotating entities.
• light: fix crash in "Bad texture axes on face:"
• light: fix surface lights being mistakenly duplicated
• light: add "-onlyents"
• light: add "-dirtangle" setting to control dirtmapping cone angle, default 88 degrees.

• light: .lux file support from Spike, for deluxemapping
• light: add gamma control with -gamma flag and "_gamma" key
• light: various optimizations
• light: rename -dirty flag to -dirt for consistency
• light: make fence texture tracing opt-in with the "-fence" flag.
  fix an issue with fence texture coords.
• light: support switchable lights with any light* classname, not just "light"
• light: fix debugging spam output from last build