VFXWeaver API

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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

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

Effect types

Screen post-processing

Screen images & desktop windows

Camera

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)

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//vfx/.json, run /reload, and the effect id is :`:

{
  "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.

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.

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/