Light Painter [1.21.6 - 1.21.8]

Overview

MAY CONTAIN BUGS!!!

MAY NOT BE COMPATIBLE WITH PREVIOUS VERSION!!! DO NOT LOAD OLD LIGHTS WITH THE NEW LIGHT PAINTER!!!

Screen space point lights using MC's exposed transparency shaders. Requires "Fabulous" graphics setting.

What it does:

• dynamic placable lights of any hue and any brightness
• customizable color using custom_model_data colors component
• fair performance hit (for what it does)
• datapack includes custom spawners for placing and deleting lights
• correctly blends with transparency
• lighting translucent blocks
• fade out at long ranges
• render occluded lights

What it does not do:

• render out of frame lights
• does not factor in diffuse lighting equation (cos theta)
• shadows / occlusion checking

What is achievable:

base world	light markers added	final result

Feature differences:

Version	Range	Tranlucent Shading	Close Ups	Long Range
Universal	128	Yes	Yes	Yes
Lite (deprecated)	40	No	Yes	No
Standard (deprecated)	48	Yes	Yes	No
Extended (deprecated)	128	Yes	Ok...	Yes

Design and Performance

This shader is composed of four main stages: finding light centers, constructing search tree, constructing spatial bins, and computing final lighting per pixel. Performance is achieved by storing point light information in a designated light texture and sorting the lights spatially for fast lookup in the shading stage. This allows for vastly reduced texture accesses during the final rendering pass, resulting in performance that scales linarly with number of lights. This is by no means scientific, but the performance hit is around 50% with 100 lights. Real world performance scaling, however, may not be linear. Use Universal version for best results. Alternate versions are deprecated and not maintained.

Usage

See License.md for license info. This utility is a resourcepack + datapack combo. Installation of the datapack is not strictly required, but it is useful for ease of use. To get lights (datapack):

/function lights:give/....

To access lights to move or modify them (datapack):

/execute as @e[tag=light,sort=nearest,limit=1] ....

Shading Passes and Descriptions

rendertype_item_entity_translucent_cull

• Transform custom model to billboard. Find approximate center pixel of marker and discard rest. Compress the marker depth to [0.0, 0.025], item entities use (0.025, 1.0].

filter

• Filter minecraft:item_entity target for light markers.

blur_custom

• Blur using pseudo random samples for better perf at same blur level.

centers

• Find centers of each light marker by discarding adjacent pixels.

aggregate_1, aggregate_2, aggregate_3, aggregate_4, aggregate_5

• Compute layers in search tree.

aggregate_6

• Traverses search tree to store light screen coordinates into a light storage texture.

zone_calc

• Place light references in spatial bins.

light_apply, light_apply_t, light_apply_i

• Computes lighting color at each screen pixel and apply the lighting to designated target. minecraft:main, minecraft:translucent, minecraft:item_entity.

transparency

• Custom transparency pass that hides light markers and uses blend results of light_apply and light_apply_t for composite.

Configuration

shaders/include/utils.glsl

• LIGHTRANGE light approximate range in blocks. Default 128.0.
• LIGHTINTENSITY light strength on solid objects. Default 1.0.
• LIGHTINTENSITYT light strength on translucent objects. Default 0.5.
• LIGHTR distance in blocks where a pixel is considered out of a light's range. Default 8.0.
• SPREAD how much a light spreads. BOOST may need to increase if this increases. Default 3.0.
• BOOST how much to boost lights. Similar to Intensity but applies before composite and HDR mapping. Default 10.0.
• CUTOFF at what level where light is considered 0.0. Default 0.02.
• NEAR near clipping plane in blocks. Do not change. Default 0.05.
• FAR approximate far clipping plane in blocks (4 * render range). Affects light position precision. Default 1024.0.
• FOV approximate FOV. Affects light position precision. Default 70.0.
• LIGHTALPHA marker texture alpha. Use an uncommon alpha, best if less than 0.1 and greater than ALPHACUTOFF. Default 24.0/255.0.
• LIGHTDEPTH depth buffer reserved for lights. Increase this to improve light position precision at the cost of minimum item depth. Default 0.025.
• LIGHTVOLX number of spatial bins along the x axis in camera space. May affect performance. Default 32.
• LIGHTVOLZ number of spatial bins along the z axis in camera space. May affect performance. Default 16.
• AGGSTEP0 first level search tree downscale. May affect performance. Default 8.
• AGGSTEP1 second level search tree downscale. May affect performance. Default 8.

Credits

• example screenshots are from the map "Cyberpunk Project" by Elysium Fire
• Jatzylap for providing custom light colors using item tint