Wipe
A 1970s vision mixer's wipe generator for Resolume
What it does
An FFGL mixer for Resolume Arena and Avenue, and the second mixer in the Stoatworks fleet. A 1970s vision mixer didn't store its wipes as pictures. It made them live from a few analogue waveform generators running at line and field rate (a horizontal ramp, a vertical ramp, and horizontal and vertical parabolas), combined them in a small matrix by adding them or taking the larger, and compared the result against the fader's level. Where the waveform was below the level you saw B, and above it, A.
So every pattern here is a formula in two ramps. Horizontal and Vertical are a ramp each, Box takes the larger of the two, Diamond adds them, Circle adds the two parabolas, Clock is the angle and Matrix is a per-cell threshold order. What the hardware was famous for then comes out by itself. Softness is the comparator's gain, so an edge's width follows the waveform's slope, and a circle's edge is softer near its middle than at its rim. The border is a second comparator a little above the level. Modulation is a sine added to the waveform, which wobbles the edge. And a circle is an ellipse unless the generator compensates for the picture's aspect, as the real ones had to.
The fader is called Opacity on purpose: Resolume binds a mixer parameter of that name to the layer's own opacity fader, so the layer fader drives the wipe. Edge law is what the hardware did, a level linear in the fader. Area law solves the level so the B area is exactly the fader, for every pattern. A positioner moves the closed patterns and the clock, Multiple runs the waveforms at up to eight times the line rate, and Flip-Flop reverses alternate transitions.
You choose it as a layer's Blend Mode: the layer below is A, and the clip on this layer is B.
It's also an OpenFX transition for DaVinci Resolve, Vegas Pro and Natron, and a two-input node for Nuke and Fusion, with every pattern, border and modulator. Flip-Flop is Resolume-only.
- Chosen as a layer's Blend Mode in Resolume, installed in Extra Effects like any FFGL plugin
- Horizontal, Vertical, Box, Diamond, Circle, Clock and Matrix wipes, each a waveform and a comparator
- The layer's opacity fader drives the wipe, in Edge or Area law
- Softness as comparator gain: a circle's edge is softer near its middle
- A border as a second comparator, in any colour, with its own softness
- Positioner, rotation, aspect, modulation and Multiple up to 8 × 8
- Reverse and Flip-Flop, as on the hardware
- Universal macOS bundle and a Windows x64 DLL
Where it stands
v0.2.0, which adds the OpenFX build, and early days. It hasn't been loaded into Resolume on macOS yet. On Windows, Resolume Arena 7.27.1 (software rendering) loads it from Extra Effects, offers it as a layer Blend Mode, initialises it cleanly and binds its Opacity to the layer's opacity fader, all probed over REST and read from the plugin's own log, but nobody has looked at a frame of its output in Resolume yet. Arena hides a mixer's first parameter, so Wipe's first is Aspect Comp on purpose, which keeps every other control reachable. The OpenFX build has been checked in DaVinci Resolve Studio 21.1 on macOS; Vegas, Nuke and Natron are untried. The pattern generator is measured by an offline harness driving the real plugin class with two inputs at two different sizes, checking each claim against a closed form at two rasters: padding never reaches the picture, Opacity 0 and 1 give A and B bit for bit on all seven patterns, hard and soft edges land where they should, every pattern's B area matches the fader in Area law to within 0.33 px of area, a circle's soft edge widths match the parabola's closed form, and a one-character sabotage of its own shader fails five checks. All 21 sweepable controls change the picture. Render cost on macOS is 0.12 ms a frame at 4K, and Area law adds a CPU solve of up to about 8 ms on frames where something changed at Multiple 8 × 8. Premultiplied alpha is assumed. There's a user guide and a browser demo, which is a port rather than the plugin, but no presets. The macOS builds are signed and notarised. Try it in your own rig before you trust it in a show.
Watch it running
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