Light Painter [EXPERIMENTAL!][1.21.4]

Overview

MAY CONTAIN BUGS!!!

NOT 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 (most of the time)

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 multiple passes in three main stages: finding light centers, constructing search tree, and computing final lighting per pixel. Performance is achieved through use of shading passes to store point light information in a designated light texture. 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 50 lights. Real world performance scaling, however, is not linear. Use Universal version. 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], push time entities to (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.

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

post_effect/transparency.json

• uniform Range light approximate range in blocks. Default 128.0.
• uniform FOV approximate FOV. Affects light position precision. Default 70.0.
• uniform Intensity light strength on solid objects. Default 1.0.
• uniform IntensityT light strength on translucent objects. Default 0.5.

shaders/include/utils.glsl

• NEAR near clipping plane in blocks. Do not change. Default 0.05.
• FAR approximate far clipping plane in blocks. Affects light position precision. Default 1024.0.
• 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.
• 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 item render precision. Default 0.025.

Credits

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