[YM!] Veil Iris Lights Compat (VILC)

Version 1.6.0

Added

• Veil spot lights (SpotLightData) are now rendered with Iris shaderpacks and in the fallback pass, including voxel occlusion. They share the area-light budget
• Optional spot-light shaping for addons: AreaLightShapeRegistry.set(SpotLightData, focus, lensRadius) adds beam focus and a lens radius; the soft edge comes from Veil's own spot angle
• Light beams: Veil's in-scattering strength (point, area and spot lights) is now rendered as visible light in the air, with voxel shadows and dithered raymarching. New "Light beams" on/off toggle and "Light beam quality" option (Low/Medium/High = 8/16/32 steps, default on and Medium); costs nothing when no light has in-scattering
• Light extras API for addons: AreaLightShapeRegistry.setExtras(LightData, skipFirstPerson, chromaticFringe) lets a light skip the first-person hand/held item (e.g. flashlights) and adds a chromatic fringe at the cone edge

Changed

• The voxel shadow option is now a master switch: when enabled, every Veil light casts voxel shadows regardless of its own occlusion flag (light mods often leave it off, so the option appeared to do nothing)
• Spot-light lenses are round: the lens radius used to clamp to a square whose corners followed the light's roll, so beams looked square and rotated with the view direction
• Removed the "Detailed normals" option: since the depth-edge fixes it made no visible difference. Normals now always use the precise neighbour sampling within 64 blocks; its slot in the settings screen holds the new light beam toggle
• Light beams are raymarched in a separate half-resolution pass (same shader, beam output only) and upsampled bilinearly in the composite: about a quarter of the beam cost, which matters for wide, long-range lights (e.g. a 64 block hanging lamp). The full-resolution lighting pass no longer computes beams
• First-person hand detection now compares against Iris' pre-hand depth buffer (pixel exact) instead of a fixed screen region; lights other than skipFirstPerson lights now light the hand

Fixed

• Overlapping colored lights mix properly (red + blue = magenta etc.): each light is now compressed on its own before accumulation instead of compressing only the sum, which let the closer light dominate the hue completely and split overlaps along a hard edge. Single lights look unchanged
• Fixed black pixels around foliage, leaves and grass with shaderpacks: neighbouring sky pixels reconstructed to infinite positions and turned the surface normal into NaN
• Fixed dashed dark outlines along depth edges (grass blades, flowers, leaves in front of the ground): the screen-space derivatives paired edge pixels with a neighbour on another surface, tilting the normal away from the light. Depth edges are now detected relative to the pixel footprint and use the closer neighbour (or a camera-facing normal for one-pixel-wide blades)
• Large FPS drops with active Veil lights:
  • Light beams only raymarch where the view ray passes through a light's range instead of along the whole ray for every light
  • Voxel shadows inside light beams only run on "High" beam quality (they cost steps x lights x shadow ray per pixel)
  • Surface lighting skips the shadow ray for light contributions below ~0.2 % (invisible fringes of a light's range)
• Remaining dark outlines around small depth steps (flower petals on grass, blade bottoms), which were too short for the edge threshold: within 64 blocks normals now always use the closer of both neighbours
• Light beams swimming around while walking, also for static spotlights: the beam rays started at the camera position without view bobbing, while the scene is rendered with it. Rays now start at the real eye position taken from the projection
• Crash (access violation in the graphics driver) when enabling voxel shadows while a shaderpack is active: Veil creates the voxel grid texture on first use with a client-memory upload and does not reset the pixel unpack state, which Iris' pipeline can leave with a bound unpack buffer or skip values. VILC now resets the unpack state around the voxel grid setup and restores it afterwards