Create: Gravity Batteries

First release.

• Gravity Battery. Goes on a shaft like a Rope Pulley, takes hold of a glued structure hanging below it, and winds it up or lets it down on its own according to whether the rest of the kinetic network has stress capacity to spare. Rotation direction does not steer it: turn it either way and it charges.
• Power is the weight and runtime is the drop, with total energy the two multiplied. Speed changes neither — a battery on a fast network drains faster and supplies more in exact proportion.
• The drop is measured when the weight is picked up, by walking Create's own collision test down the shaft, so the charge readout means something in the room the battery is actually standing in.
• The weight falls until it runs into something and stops there, and a battery whose weight is resting supplies nothing.
• Goggles show the mode, why an idle battery is idle, a charge bar and the weight.
• An animated Ponder scene.
• Reads out three ways, each carrying one thing: a comparator gives the charge 0-15, a Threshold Switch gives it as a percentage with a redstone output at a level you set, and a Display Link puts either the mode or the charge on a Display Board.

Fixed before release, both found by looking at the block in-game and neither catchable by anything that was running at the time:

• Goggle overlay lines rendered as raw translation keys. Catnip resolves a LangBuilder key as <namespace>.<key> and the lang file had them unprefixed. tools/check_lang.py now resolves every key the code asks for, in CI.
• The first section of cable below the battery rendered almost black. Light is read from the block a segment hangs in, and the topmost segment hangs less than a block down by design, so truncating its offset sampled the light inside the battery itself.
• The weight jumped, usually upward and by up to a whole block, whenever the shaft stopped or reversed. Create's actuator re-grids the offset on a sign change using an integer division, so it truncates to a whole block instead of snapping to a sixteenth, and signum(0) == 0 makes "stopped" count as a sign change. Since a battery's offset is its charge, flicking the drive on and off was a way to charge it for nothing.
• Weights may not contain machinery. Create's actors — drills, saws, harvesters, deployers — stall a contraption while they work, which freezes it in place, and a battery paid by the tick rather than by the block would earn its full rating standing still. A battery now refuses such a weight and says so on its own face; cut the shaft with a Rope Pulley first, which is the block for it.
• Letting go of a weight snapped it to the nearest whole block, which lifted it by up to half a block for nothing — chargeable by winding to just under a half and toggling. It now settles downward, so the snap can only ever cost a fraction rather than pay one.
• Clearing the blocks under a descending weight left it stopped at the old limit, reporting itself spent over an open shaft. The measured drop is the charge scale; whether the weight may move is now asked of the block actually below it, and the measurement is re-taken when the two disagree.
• A battery carried off by another contraption deleted the weight it was holding: the block left the world without going through its own removal, so the weight's entity found no controller and discarded itself. Batteries are now in Create's non_movable tag — breaking one still returns its weight, as it always did.
• A battery that was given rotation with nothing hung under it walked down the shaft, tore the first solid block it found out of the world, and kept it. Rotation may now only take a weight that is flush against the battery's underside; reaching down the shaft is offered only to a player who right-clicks, who is looking at the block and can undo it with a second click.
• The comparator output never updated. Declaring hasAnalogOutputSignal is only half of an analog output — nothing polls it — so the reading a comparator latched when it was placed stayed there for ever. It now follows the charge.
• The overlay quoted a Stress figure while winding up and nothing at all while letting down. LinearActuatorBlockEntity is not a GeneratingKineticBlockEntity, so the inherited overlay only ever reported stress impact; the generator half had to be transcribed too.
• The goggle overlay was too busy: a charge percentage, a paid-out-of-total and a seconds-remaining countdown are all the same fact, and all three flickered. It is now a status line, a charge bar in Create's own idiom, and the weight — calibrated against Create's Boiler, which is the densest overlay Create ships.
• The shaft spinning through the middle of the battery rendered almost black. Same symptom, different cause: the block was missing noOcclusion(), and a block entity renderer is handed the light level at its block's own position — zero, inside a full-cube occluder. That also blocked all light from reaching anything below the battery and had neighbours cull faces you can see through.