# StereoViewer — primitive for transitions (glsl)

> **For AI agents:** find the right skill in one call — `curl -s "https://skills.varg.ai/api/search?q=<what the person wants>"` returns the matching use case and the best skills with install commands, as markdown (Russian works too). Full index: https://skills.varg.ai/llms.txt. Every page has a markdown twin: add `.md` to its path. Before generating anything, show the person the options on the use-case page.

Both shots shrink into rounded cards that slide past each other, like a stereo-viewer reel

- **Install:** `npm install gl-transitions`
- **Registry:** gl-transitions · **Framework:** glsl · **License:** MIT
- **Docs and preview:** https://gl-transitions.com/editor/StereoViewer
- **Source:** https://github.com/gl-transitions/gl-transitions/blob/master/transitions/StereoViewer.glsl
- **Example:** https://skills.varg.ai/previews/lib-gl-transitions-stereo-viewer.mp4?v=59993 (Rendered by varg from the library’s own code (GL Transitions · rendered by varg))
- **Time:** Seek-safe. Time is an input, so frame N always renders the same. Drop it into a render as it is.
- **Runs:** local render, free
- **Aspect:** any

## Prompt that renders it frame-exact

Add the "StereoViewer" transition from GL Transitions (by Ted Schundler, BSD 2-Clause, not MIT: fine in a commercial video, but keep the Ted Schundler copyright header if you ship the shader code; https://gl-transitions.com/editor/StereoViewer, GLSL source https://github.com/gl-transitions/gl-transitions/blob/master/transitions/StereoViewer.glsl) between photos of a retro slideshow or a memories montage: 1.2 s, ease-in-out. The frame goes fully dark for a beat at the midpoint, between the two cards. Remotion: `npm install gl-transitions @gl-transitions/remotion @remotion/transitions`, then a `<TransitionSeries.Transition>` with `presentation={glTransition({ name: "StereoViewer", params: { zoom: 0.88, corner_radius: 0.22 } })}` and `timing={linearTiming({ durationInFrames: 36, easing: Easing.inOut(Easing.cubic) })}` (36 frames at 30 fps). HyperFrames: draw the GLSL on a full-frame WebGL canvas over the cut, with the outgoing and incoming frames as the from/to textures, and compute progress from the composition time, clamp((t − cutStart) / 1.2, 0, 1) through the easing; never from requestAnimationFrame or a timer, so every frame renders the same. ffmpeg's xfade can't run GLSL. `zoom` (0.88, range 0.5–1) is how far the cards shrink and `corner_radius` (0.22) their rounding. Where the shader draws no image it returns transparent pixels, which encode as black: put a backdrop color or a blurred copy of the frame under the canvas.

## Used in

- [Beat-synced slideshow](https://skills.varg.ai/video/beat-slideshow.md)
- [Music video](https://skills.varg.ai/video/music-video.md)
- [Kinetic manifesto](https://skills.varg.ai/video/manifesto.md)
- [News broadcast package](https://skills.varg.ai/video/news-package.md)
- [Photo memories](https://skills.varg.ai/video/memories.md)
- [Game trailer](https://skills.varg.ai/video/game-trailer.md)

## More transitions

- [Chromatic Aberration Wipe](https://skills.varg.ai/component/hf.chromatic-aberration-wipe.md) — `npx hyperframes add chromatic-aberration-wipe`
- [Colorama Wipe](https://skills.varg.ai/component/hf.colorama-wipe.md) — `npx hyperframes add colorama-wipe`
- [Cross Warp Morph](https://skills.varg.ai/component/hf.cross-warp-morph.md) — `npx hyperframes add cross-warp-morph`
- [Cut the Curve](https://skills.varg.ai/component/hf.cut-the-curve.md) — `npx hyperframes add cut-the-curve`
- [Directional Wipe](https://skills.varg.ai/component/hf.directional-wipe.md) — `npx hyperframes add directional-wipe`
- [Domain Warp Dissolve](https://skills.varg.ai/component/hf.domain-warp-dissolve.md) — `npx hyperframes add domain-warp-dissolve`