Holofoil
Holographic trading-card foil, for Resolume
What it does
An FFGL effect for Resolume Arena and Avenue: SW Holofoil. Holographic foil is aluminium embossed with ridges about a micron apart, and ridges that fine make a diffraction grating: each wavelength of the lamp's light leaves at its own angle, so the colour you see depends on where the lamp is, where your eye is and which way the card's tipped. The plugin works that out for every pixel of the clip, through the grating equation and the colour matching functions your eyes come with, and adds the light to the print.
Foil Area picks the finish. Art Window is the holo, a foil window behind the picture; Around Art is the reverse holo, foil everywhere else; Whole Card does the lot. Bright Ink and Dark Ink put foil only where the print is light or dark, and Clip Alpha follows the clip's own transparency. Pattern decides what's embossed. Rainbow is one grating across the card and Crosshatch is two crossed ones, while Cosmos, Cracked Ice and Sparkle are cells with a grating each, so they flash one at a time rather than sweep. Groove Depth takes a rainbow foil down to a cold, mostly silver one, and Roughness gives you etched.
Tip the card by hand, or let Motion tip, swing or circle it, on its own clock or on Resolume's beat. Lamp Orbit holds the card still and walks the lamp round it instead, so the colours follow the light. The lamp's a strip light out of the box, because a plain grating under a small round lamp gives you one thin streak of rainbow, which is physically correct and, as a light show, a bit of a let-down.
- Six foil areas: Art Window (holo), Around Art (reverse holo), Whole Card, Bright Ink, Dark Ink and Clip Alpha
- Five patterns: Rainbow, Crosshatch, Cosmos, Cracked Ice and Sparkle
- Colour from the grating equation through the CIE 1931 colour matching functions, with Groove Depth deciding how much stays in the mirror
- A lamp you can place, size, stretch into a strip and brighten, and Roughness for etched and brushed finishes
- Tilt by hand, or Motion's Tip, Swing, Circle and Lamp Orbit, free-running or on the beat or bar
- Ink that filters the foil the way printing ink does, and a Mix that fades in light
- Universal macOS bundle and a Windows x64 DLL
Where it stands
Released at v0.1.0. On Windows it's been in Resolume: the release build loads in Resolume Arena 7.27.1 on a test machine with no GPU, all 36 of its parameters arrive as declared, it renders with a clean log, and every control that can act on a still picture changed Arena's picture. Everything else is checked offline, by a harness that drives the plugin's own shader. Each pixel's light is within 0.18 % of a wavelength-by-wavelength sum of the grating equation that shares none of the plugin's shortcuts, the mirror highlight lands within a thousandth of a pixel of where the geometry puts it, a holo and a reverse holo add up to the clip plus a whole foil, and at zero Mix the clip comes through bit for bit. Seventeen deliberately wrong models and 29 one-character mutants are all caught, and all 31 controls change the picture. There's a user guide and a browser demo, which draws what the plugin draws to within a level on the Mac it was checked on. Still open: it's never been loaded into Resolume on macOS, nobody has watched Motion Sync follow Arena's transport, and nobody has held it up beside a real foil card, so the finishes follow textbook optics and typical hologram figures rather than measurements of any card.
Watch it running
Nothing loads from YouTube until you press play.Watch it there instead