DAP SHADERS 6.5
===============
The brightness slider now does what it says, and six features the bigger packs
have that DAP did not.


FIXED - the Brightness slider was fighting the light-level ceiling
  This is the important one.

  Light Levels caps how bright a lit block may get, so sunlight cannot blow a
  block out to flat white. That cap was calibrated against one specific exposure -
  which meant moving Brightness, the FIRST control in the menu, dragged the ceiling
  with it. Measured: the brightest light level displayed at 80% white at the
  shipped setting, 82% one notch up, and kept climbing. Turn Brightness up and
  sunlit blocks blew out again, which is the exact problem Light Levels exists to
  prevent.

  Its own tooltip promised "raising it lifts terrain and shadows much more than the
  sky, so it will not wash out". That was simply untrue.

  The ceiling is now derived from the live exposure settings, so it is invariant -
  not approximately, exactly. Everything below it still scales. Measured across the
  whole slider now:

      Brightness    ceiling    shaded ground    indoors
         0.7          80.0%        43.8%         29.2%
         1.0          80.0%        57.2%         37.4%
         1.2          80.0%        67.8%         45.7%
         1.5          80.0%        71.7%         53.9%

  The ceiling does not budge, and shaded areas climb 28 percentage points across
  the range. The tooltip is now a true statement.

  Also: Brightness shipped at 0.9 while that same tooltip called 1.0 the tuned
  default, so the image was 10% darker than documented. It is 1.0 now, and 1.0 is
  genuinely neutral.

FIXED - Performance Mode was being overridden by Quality
  Performance Mode is documented as forcing the cheapest path "regardless of what
  the individual toggles say". It ran BEFORE the Quality tiers, so Quality promptly
  switched everything back on - at Ultra or MAX the master performance switch did
  almost nothing. It now runs last and genuinely has the final word. This bug
  predates 6.5.


NEW - Contact-hardening shadows (PCSS)
  Shadows are now sharp where an object meets the ground and soften with distance
  from it, the way real shadows behave. Previously every shadow had the same
  softness everywhere, which is the main reason objects can look like they are
  floating slightly above their own shadow.

  Costs a short blocker search per shadowed pixel, and pays some of it back: a
  pixel with nothing above it now skips the main filter entirely.

NEW - Specular highlights
  DAP had screen-space reflections but no specular lobe, so the sun never actually
  glinted off anything. Wet cobble, ice, metal and polished blocks got a mirrored
  reflection and no highlight, which is the single biggest reason surfaces read as
  flat next to the larger packs.

  Proper GGX with Smith geometry and Schlick Fresnel, masked by the same shadow
  term as the diffuse - a highlight that survives into shadow is one of the most
  obvious wrong-looking things a shader can do. Uses a LabPBR pack's smoothness and
  metalness when one is loaded, sensible defaults when not.

NEW - Subsurface scattering
  Backlit leaves and grass now glow warm when the sun is behind them. This is one
  of the most recognisable things about the big packs and DAP had no equivalent.

  It is driven by NEGATIVE surface-to-sun angles, which is to say it appears
  exactly where ordinary diffuse lighting has given up, so the two never double up.
  The transmitted light is pushed toward green in proportion to how green the block
  already is - real leaves filter light through chlorophyll - which means it does
  the right thing for autumn leaves and dead bushes without needing a list of which
  blocks those are.

  It reuses the waving-foliage block list rather than adding a second one to keep
  in step: anything thin enough to bend in the wind is thin enough for light to
  pass through.

NEW - Parallax occlusion mapping
  Blocks get real depth from a PBR pack's height map instead of looking painted on.
  The pack was already reading that texture for its normals and throwing the height
  channel away, so a PBR pack that had gone to the trouble of describing depth got
  none of it.

  Needs a LabPBR pack AND Materials & PBR switched on; does nothing otherwise. It
  is the most expensive option in the pack, so it is off below High, and it fades
  out with distance - past a few dozen blocks the displacement is smaller than a
  pixel anyway.

  Everything stays inside the block's own atlas tile, which is the single most
  common way parallax goes wrong (bricks showing fragments of grass at their edges).

NEW - Rain ripples
  Expanding rings where raindrops land on wet ground and puddles. It bends the
  surface rather than tinting it, which is what water actually does - the visible
  effect is the reflection and the highlight breaking up. A puddle that stays
  glassy in a downpour reads as wrong without anyone being able to say why.

NEW - Moon phase lighting
  Moonlight brightness now follows the real lunar phase, so a new moon is genuinely
  dark and a full moon is bright. Minecraft always drew the correct crescent, but
  every shader lit the ground as though the moon were full - the moon you could
  plainly see disagreed with the light it was supposedly casting.

  The falloff is not linear: a thin crescent throws far less light than its apparent
  width suggests. A floor keeps a new moon dark but still navigable.

NEW - Sun glare
  Lens glare and mirrored ghost reflections anchored to where the sun sits on
  screen. Different from bloom: bloom comes from bright pixels, glare comes from the
  lens, which is why bloom alone never quite sells looking toward the sun.

  Occlusion-tested against the depth buffer over a small disc rather than a single
  sample, so it fades smoothly as the sun goes behind a hill instead of popping off
  at the silhouette edge.


WHERE THE NEW OPTIONS LIVE
  Graphics > Shadows            Contact Hardening, Shadow Spread
  Graphics > Surface Detail     Specular, Subsurface Scattering, Rain Ripples,
                                Parallax Occlusion  (a new page)
  Graphics > Extra Atmosphere   Sun Glare
  Sky & Weather                 Moon Phase Lighting

  All of them respect the Quality tiers: Potato sheds every one, High adds
  parallax, Ultra and MAX raise them all, and Performance Mode overrides the lot.
  The build verifies that ladder rather than trusting it.


VERIFICATION
  All four build gates pass: 2379 menu/label/buffer checks, zero portability
  findings across 201 GLSL files, the preset and quality-ladder checks, and the
  light-level acceptance targets (darkest step 0%, brightest exactly 80%, sixteen
  distinct increasing steps, nothing clipping).

  As always: none of this has been looked at in game. The maths and the numbers are
  checked; how the specular highlight or the leaf glow actually reads on screen is
  a judgement only you can make. Six new effects at once is a lot of surface area,
  so 6.2 is still in the outputs folder if anything looks wrong.


   - DAPTIME
