Shader
A Shader element runs a live GLSL fragment shader — generated, animated visuals rendered on the GPU. Use it for VJ backdrops, motion graphics, plasma and particle effects, and audio‑reactive visuals that move to the music.
Add it: Add Element → Shader…, which opens the Shader Editor.
The Shader Editor
The editor lets you start from a bundled preset or write your own code:
- A preset list of ready‑made shaders (see below). Selecting one loads its code.
- A code area with syntax highlighting where you can edit the GLSL or paste your own fragment shader.
- Compile / Preview to render the shader live so you can see it before adding it.
When you accept, the shader becomes a card that renders continuously on whichever deck it's fired to.
Built‑in presets
Prism ships 16 presets. Non‑reactive presets animate on their own:
- Neon Kaleidoscope, Cyberpunk Horizon Grid, Falling Cyber Particles, Rotating Hypnotic Rings, Abstract Quantum Strings, Geometric Portal Matrix, Neon Particle Swarm, Cosmic Plasma Flares.
The audio‑reactive presets (7) move to the music when you feed them sound — and fall back to a gentle time‑based animation when no audio is connected:
- Audio‑Reactive Wave — a waveform that ripples with the sound.
- Audio‑Pulse VU Bars — classic VU‑style bars.
- Radial Spectrum Ring (new) — mirrored FFT bars radiating from a centre ring that pulses on the beat, with drifting glow particles (cyan).
- LED Matrix Equalizer (new) — a block/LED equalizer, columns rising green → yellow → red with the spectrum.
- Spectrum Mirror Skyline (new) — a dense forest of neon frequency needles with a floor reflection, hue sweeping across the spectrum.
- Spectral Bloom (new) — a central polar bloom whose spikes are carved by the FFT; bass swells it, beats flash the rim (pink → blue).
- Particle Terrain (new) — a 3D field of glowing dots whose surface ripples to the spectrum; beats lift and brighten the whole terrain (white → rose).
- Neon Wave Curtain (new) — a curtain of glowing vertical lines that fold in waves driven by bass and level (violet → hot pink).
Audio‑reactive shaders
Shader cards have an extra audio‑in port. Wire a sound source into it and the shader receives a live audio spectrum it can react to. There are two ways to feed it:
- Directly — connect a clip's audio or a Mic Input (microphone/line‑in) into the shader's audio‑in.
- Through an Audio Script node — this gives you control over the analysis (FFT size, number of bands, smoothing, beat sensitivity) that drives the shader.
Smooth idle when audio pauses. When you pause the clip or audio, reactive shaders no longer freeze or cut abruptly — the level, spectrum, and beat pulse fade smoothly to their idle state over a fraction of a second, then the shader continues its own time‑based motion. Resuming brings the reactivity right back.
See Audio nodes for how to wire audio into a shader.
Writing audio‑reactive shaders
If you write your own GLSL, Prism sets these uniforms every frame — declare only the ones you use:
| Uniform | Type | Meaning |
|---|---|---|
u_resolution | vec2 | Output size in pixels |
u_time | float | Seconds since the shader started |
u_hasAudio | bool | true while audio is flowing |
u_audioLevel | float | Overall loudness (RMS), 0..1 |
u_bands | vec3 | (low, mid, high) energy, 0..1 |
u_bass / u_mid / u_treble | float | Components of u_bands |
u_beat | float | Onset pulse that spikes on a beat, then decays |
u_spectrum | sampler2D | FFT magnitudes — sample x∈[0,1] low→high, read .r |
u_spectrumSize | int | Number of valid spectrum bins |
Any extra value a Script node sends is also exposed
as a uniform — e.g. returning { intensity = 0.8, tint = {1, 0.2, 0.4} }
provides u_intensity (float) and u_tint (vec3). Sample the spectrum with:
float mag = texture(u_spectrum, vec2(f, 0.5)).r; // f = 0..1
What it can do
- Generate endless looping visuals with zero source footage.
- React to live audio for music‑driven backdrops.
- Transform and position on a canvas, or run full‑screen as a background under other layers.