VFXWeaver API

A client-side VFX library/API for Minecraft 26.2, 26.1.x and 1.21.11 (Fabric and NeoForge). Drop-in cinematic effects — screen post-processing, camera shake, block/entity overlays, in-game screen images and real desktop picture windows — either from chat commands, from datapacks, or programmatically from your own mod through a tiny Java API.

Author: Artition · License: MIT

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What it does

• 30+ post-processing effects rendered through a ping-pong FBO (fullscreen, per-pixel shaders): chromatic aberration, color grading, distortion, dent, gradient map, posterize, blur, pixelate, hue isolation, vignette, screen flash, motion blur, bloom, film grain, scanlines, depth of field, letterbox, invert, vortex, speed lines, slice shift, noise warp, solarize, double vision, eyelids, iris wipe, digital glitch, VHS, shockwave, afterimage, stop motion, and the world/sky texture patterns.
• Screen images — screen_image draws a picture (a resource-pack PNG with an optional .mcmeta animation, or an image a mod registers) over the game frame at a chosen screen layer: under the GUI, above the hand, or over everything including chat and hotbar.
• Desktop picture windows — window_create / window_control open a real frameless, transparent, click-through window on the desktop and show a picture in it; move, resize, fade and retitle it by name. Neither is a post-processing pass nor world geometry.
• Camera effects — simplex-noise shake with a smooth envelope, dutch-angle roll, FOV modifier.
• World overlays — block_tint / block_outline (world-space geometry), light_beam, pulse_ring, guide_line, particles and block_chain.
• Entity effects — entity_tint / entity_outline / entity_displace applied to entities by UUID (second-pass model render, texture-aware).
• Datapack-defined effects — plain JSON, no code. Keyframe animation, easing curves, world/camera/player bindings, math expressions, collections, sounds.
• Server → client triggers — effects fired from a server command, or from your own mod over the network.
• Public Java API for other mods (VFXAPI), including registerImage to show an image your own mod renders.

Requirements

Minecraft	26.2, 26.1.x, 1.21.11
Loader	Fabric (>= 0.18.4 on 26.x / >= 0.17.3 on 1.21.11) or NeoForge
Fabric API	required on Fabric
Java	25+

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Effect types

Screen post-processing

Effect	What it does
chromatic_aberration	RGB channel separation toward the screen edges
color_grade	Saturation / contrast / brightness + tint
distortion	Barrel / pincushion distortion of the screen
dent	Local radial (or line) warp around a point / segment
gradient_map	Maps luminance into a two-color gradient (linear or hard threshold)
posterize	Reduces the number of colors (clean quantization)
blur	Two-pass Gaussian blur
pixelate	Pixelation
hue_isolation	Keeps one hue, the rest goes grayscale
vignette	Darkens / colors the screen edges
screen_flash	Fullscreen color overlay
motion_blur	Directional blur from camera rotation speed
bloom	Glow around bright areas
film_grain	Animated film grain
scanlines	CRT bands drifting across the screen
depth_of_field	Tilt-shift: sharp band, blur away from it
letterbox	Cinematic bars top/bottom
invert	Inverts the screen
vortex	Swirls pixels into a funnel around a point
speed_lines	Speed lines from the screen borders toward a point, random length per line
slice_shift	A straight line slices the frame; the halves slide along it
noise_warp	Animated value-noise field warps the picture in fluid patches
solarize	Bright pixels invert, dark stay untouched
double_vision	Two ghost copies of the frame with a slow drift
eyelids	Two soft curved dark lids slide in from top and bottom
iris_wipe	Old-film iris transition: everything outside a circle goes black
digital_glitch	Band tearing + RGB split in gated bursts
vhs	Worn tape: tracking band, wobble, colour bleed, washed contrast
shockwave	A refraction ring ripples outward from a point
afterimage	Decaying history echo — trails linger in a feedback buffer
stop_motion	The picture updates only a few times per second
surface_pattern	A shape/texture projected onto the surface behind the pixel (screen layer 0)
sky_pattern	A shape/texture drawn on the sky dome

Screen images & desktop windows

Effect	What it does
screen_image	Draws a picture over the game frame at a chosen screen_layer
window_create	Opens a click-through picture window on the desktop
window_control	Moves, resizes, fades and retitles an existing window by name

Camera

Effect	What it does
camera_shake	Simplex-noise shake with smooth envelope
camera_roll	Dutch-angle tilt with optional sinusoidal wobble
fov_modifier	Field-of-view change

World overlays — block_tint, block_outline, light_beam (soft vertical column), pulse_ring (expanding ring), guide_line (dashed parabola arc), particles (vanilla particles in animated shapes), block_chain (real block-model links) Entity effects — entity_tint, entity_outline (by UUID), entity_displace (per-vertex displaced echo)

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Quick start

All mutating commands require operator rights (/vfx list is open to all).

/vfx play vfxweaver:screen_flash
/vfx play vfxweaver:speed_lines {count:80, length:0.8, seed:"t * 2.0"}
/vfx play vfxweaver:screen_image {texture:"vfx_demos:textures/vfx/screen_anim", size_w:0.3, size_h:0.3}
/vfx playat vfxweaver:block_outline 100 64 200
/vfx playentity vfxweaver:entity_outline @e[type=!player,distance=..10]
/vfx stop vfxweaver:speed_lines
/vfx set vfxweaver:motion_blur {intensity:0.8}     # live override a running effect
/vfx list

Datapack effects (no modding)

Drop a JSON into data/<namespace>/vfx/<name>.json, run /reload, and the effect id is <namespace>:<name>:

{
  "type": "speed_lines",
  "duration": 60,
  "easing": "ease_out_cubic",
  "params": {
    "count": 80,
    "length": { "expr": "0.4 + 0.4 * t" },
    "seed": { "expr": "t * 2.0" },
    "intensity": 1.0
  }
}

• Animated params via keyframes (t = 0..1 progress) or math expressions over player state (health, hunger, speed, light level, time of day, position).
• World/camera/player bindings (bind: screen_x, bind: proximity, ...) so effects follow the world instead of the screen.
• Collections — play several child effects with per-child delays.
• Definitions sync automatically to clients on join and after /reload on dedicated servers.

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Java API (for other mods)

Static entry point dev.vfxweaver.api.VFXAPI — a one-liner per call.

// Server → client
VFXAPI.sendEffect(serverPlayer,
    Identifier.fromNamespaceAndPath("vfxweaver", "screen_flash"),
    Map.of("intensity", 0.8F), null);

// With a world anchor (block/entity effects follow the position)
VFXAPI.sendEffect(player, effectId, somePos, Map.of(), null);

// Locally on the client (no packet)
VFXAPI.playEffect(Identifier.fromNamespaceAndPath("vfxweaver", "camera_shake"),
    20, Map.of("amplitude_x", 0.2F), null);

// Show an image your own mod renders (ARGB pixels), anywhere a texture id is accepted
VFXAPI.registerImage(Identifier.fromNamespaceAndPath("mymod", "textures/hud/icon"),
    width, height, argbPixels);

// Stop / live-tune
VFXAPI.sendStop(player, effectId);
VFXAPI.sendSetParam(player, effectId, "intensity", 0.3F);
VFXAPI.sendKeyframe(player, effectId, "intensity", 10, 1.0F, EasingType.EASE_OUT_CUBIC);

The network layer (vfxweaver:vfx_trigger) is protocol-versioned; the client silently ignores packets with an incompatible version. Full API, packet layout and definition-registry access are documented in the repo's docs/API.md.

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Docs

Commands, effect params, datapack format, bindings — the full usage guide is in the project repo. Build it yourself with ./gradlew build (requires JDK 25), or grab a release jar from the Releases tab.

• Repo: https://github.com/Artition/VFX-Weaver
• Docs: https://artition.github.io/VFX-Weaver/