SkyruneShader v4 - Iris + Sodium (Minecraft Java, Fabric)

INSTALL
  Drop this .zip (do not unzip) into  .minecraft/shaderpacks/
  Options > Video Settings > Shader Packs > SkyruneShader

FIXED IN v4
  - ENTITY SHADOWS. shadow.vsh used the shadowModelView uniform directly,
    which drops the per-entity model transform, so player and mob shadows
    landed in the wrong place while terrain shadows looked fine. It now uses
    gl_ModelViewMatrix / gl_ProjectionMatrix, which include that transform.
  - Sunlight and water reflections toned down (SUN_STRENGTH, WATER_REFLECT,
    WATER_SPECULAR are all adjustable in Shader Options).

NEW IN v4
  - Glowing ores, driven by block.properties + mc_Entity. The glow is masked
    by saturation and brightness so only the mineral pixels light up, and it
    fades in as ambient light drops so ores pop in caves.
  - Flashlight: focused cone along your view direction.
  - Underwater rework: depth-attenuated water fog, rippling caustics, and
    correct handling of the water surface seen from below (mostly total
    internal reflection rather than sky).

FLASHLIGHT AND THE "C" KEY
  A shader pack cannot read the keyboard - Iris exposes no key state to
  shaders, and this is by design (Iris is a shaders mod only). The flashlight
  is therefore toggled in:
      Shader Options > LIGHTING > Flashlight
  There is no way to bind it to C from inside the pack. The closest thing to
  a key-driven light is the handheld light, which is already automatic:
  hold a torch or lantern and it lights your surroundings.

SHADER OPTIONS
  LIGHTING - sun, ambient, moon, torches, handheld, flashlight, ore glow
  WATER    - waves, reflection, sun glint, underwater density, caustics
  QUALITY  - god rays, soft shadows, distance fog
  GRADE    - exposure, saturation, vignette

IF A ROUND BLACK BLOB STILL FOLLOWS ENTITIES
  That is vanilla's fake entity shadow, drawn by the game itself, not by this
  pack. Look for an "Entity Shadows" toggle in Sodium / Sodium Extra.

PERFORMANCE (in order of impact)
  1. QUALITY > God ray quality -> 4
  2. QUALITY > Soft shadows -> 0
  3. LIGHTING > Flashlight -> 0 when unused
  4. shadowMapResolution 1024 -> 512 in ALL 7 files that declare it:
     shadow.vsh, gbuffers_terrain.fsh, gbuffers_hand.fsh,
     gbuffers_textured_lit.fsh, gbuffers_entities.fsh,
     gbuffers_water.fsh, composite.fsh
  5. shadowDistance 80.0 -> 48.0 in the same files
