Hydra to 3D Mental Model

hydra-three keeps Hydra's live coding flow, but expands it from image-space composition into a scene-space + image-space workflow.

Core idea

Think in two layers that can feed each other:

1. Signal chain layer

• Hydra transforms (osc, noise, blend, modulate, etc.) generate and transform textures/signals.

1. Scene layer

• Three.js scene graph (scene, group, mesh, lights, world) composes objects and cameras.

In hydra-three, these layers connect directly:

• A Hydra chain can become a Three material (osc().phong()).
• A scene can render to an output or texture and get reused by another chain.

Mental mapping from classic Hydra

| Classic Hydra concept | hydra-three equivalent | | --------------------------- | ----------------------------------------------------- | | osc().color().out() | still valid for texture output | | source chain as final image | source chain as image or material input | | one composition space (UV) | two spaces: UV + scene graph/object space | | feedback via src(o0) | feedback plus scene-to-texture workflows via .tex() |

Rule of thumb

• Use generator chains when your problem is procedural texture/signal design.
• Use scene APIs when your problem is object placement, camera, lighting, or world composition.
• Use both together for most 3D sketches.

Minimal combined example

perspective([2, 2, 3], [0, 0, 0], { controls: true });

const mat = osc(8, 0.1, 0.8).rotate(noise(1).mult(45)).phong();

scene().lights({ all: true }).mesh(gm.box(), mat).out();

Global vs non-global mode mental model

• makeGlobal: true

- functions like osc, scene, gm are installed on window. - best for fast live coding and sketching.

• makeGlobal: false

- call through const H = hydra.synth; H.osc(...); H.scene(...); - best for embedding in serious apps, multi-instance hosts, and isolation.

Semantics to keep in mind

• rotate() in transform chains uses degrees.
• .tex() returns a rendered texture from the chain.
• .texMat() returns a Three material with the chain baked as map.
• autoClear controls accumulation/trails and can be applied at multiple levels.