# Transition Catalog
Hard rules, scene template, and routing to implementation code. Read the reference file for the transition type you need — don't load all of them.
## Contents
- Hard rules for CSS transitions
- Shader transitions
- Scene template
- CSS transition examples
- Shader transition routing
## Hard Rules (CSS)
These cause real bugs if violated.
**Scene visibility:** Scene 1 visible by default (no `opacity: 0`). Scenes 2+ have `opacity: 0` on the CONTAINER div. GSAP reveals them. No visibility shim (`timedEls`).
**Fonts:** Just write the `font-family` you want — the compiler embeds supported fonts automatically via `@font-face` with inline data URIs. No need for `` tags or `@import`. Works in all contexts including sandboxed iframes.
**Element structure:** No `class="clip"` on scene divs in standalone compositions. Only the root div gets `data-composition-id`/`data-start`/`data-duration`.
**Overlay elements:** Staggered blocks = full-screen 1920x1080, NOT thin strips. Glitch RGB overlays = normal blending at 35% opacity, NOT `mix-blend-mode: multiply` (invisible on dark backgrounds). Light leak overlays = larger than the frame (2400px+), never a visible shape. Overexposure = use `filter: brightness()` on the scene, not just a white overlay.
**VHS tape:** Clone actual scene content with `cloneNode(true)`, NOT colored bars. Each strip: wider than frame (2020px at left:-50px). Red+blue chromatic copies at z-index above main strip. Seeded PRNG for deterministic random offsets.
**Z-index:** Gravity drop, zoom out, diagonal split need outgoing scene ON TOP (`zIndex: 10`) so it exits while revealing the new scene behind (`zIndex: 1`).
**Page burn:** Content burns with the page — no falling debris. Hide scene1 via `tl.set` at burn end, NEVER `onComplete` (not reversible). `onUpdate` must restore `clipPath: "none"` when `wp <= 0` for rewind support. Incoming scene fades from black at 90% through burn.
**Clock wipe:** 9-point polygon with intermediate edge positions. Step through 4 quadrants with separate tweens.
**Grid dissolve:** Cycle 5 palette colors per cell, not monochrome.
**Blinds count by energy:** Calm: 4h/6v. Medium: 6-8h/8v. High: 12-16h/16v.
**Don't use:** Star iris (polygon interpolation broken), tilt-shift (no selective CSS blur), lens flare (visible shape, not optical), hinge/door (distorts too fast).
## Shader Transitions
Shader setup, WebGL init, capture, and fragment shaders are handled by `@hyperframes/shader-transitions` (`packages/shader-transitions/`). Read the package source for API details. Compositions using shaders must follow the shader-compatible CSS rules in `overview.md` (this directory).
## Scene Template
```html
```
Every transition follows: position new scene → animate outgoing → swap → animate incoming → clean up overlays.
## CSS Transitions
All code examples use `old` for the outgoing scene-inner selector and `new` for the incoming, with `T` as the transition start time. Read the reference file for the type you need.
| Type | Transitions | Reference |
| -------------- | ---------------------------------------------------- | -------------------------------- |
| Push | Push slide, vertical push, elastic push, squeeze | `transitions/css-push.md` |
| Radial / Shape | Circle iris, diamond iris, diagonal split | `transitions/css-radial.md` |
| 3D | 3D card flip | `transitions/css-3d.md` |
| Scale / Zoom | Zoom through, zoom out | `transitions/css-scale.md` |
| Dissolve | Crossfade, blur crossfade, focus pull, color dip | `transitions/css-dissolve.md` |
| Cover | Staggered blocks, horizontal blinds, vertical blinds | `transitions/css-cover.md` |
| Light | Light leak, overexposure burn, film burn | `transitions/css-light.md` |
| Distortion | Glitch, chromatic aberration, ripple, VHS tape | `transitions/css-distortion.md` |
| Mechanical | Shutter, clock wipe | `transitions/css-mechanical.md` |
| Grid | Grid dissolve | `transitions/css-grid.md` |
| Other | Gravity drop, morph circle | `transitions/css-other.md` |
| Blur | Blur through, directional blur | `transitions/css-blur.md` |
| Destruction | Page burn | `transitions/css-destruction.md` |
## Shader Transitions
WebGL shader transitions are provided by `@hyperframes/shader-transitions` (`packages/shader-transitions/`). The package handles setup, capture, WebGL init, render loop, and GSAP integration. Read the package source for available shaders and API — do not copy raw GLSL manually.
The built-ins are not a ceiling. For an effect no built-in covers, you can write custom GLSL from scratch, adapt shader code found online (ShaderToy, GLSL Sandbox, GitHub), or build a custom CSS transition that fits no existing category — combine clip-path, transforms, and filters in new ways. If the storyboard calls for an effect that doesn't exist yet, build it; the framework renders anything a browser can run.