This is my mod here: https://mods.factorio.com/mod/RenaiTransportation
and this is the report: https://mods.factorio.com/mod/RenaiTran ... 1d8601a94e
The mod has train ramps that you place on rails and then trains can hit the ramp, jump into the air, and land back on the rail. The ramp itself is a simple-entity-with-owner that has the "train-layer" collision mask and it essentially works like this:
1. Train collides with ramp, triggering on_entity_damaged
2. From on_entity_damaged, properties about the train are recorded in global variables before it is destroyed. The game tick it will land, the train's air time, and other things are arbitrarily calculated based on how fast the train was going when it collided with the ramp
3. An invisible, intangible, frictionless, belt-immune car is spawned at the train's position, it is given the speed the train had during collision. If there was a player in the train, they are placed inside the car as the rider
4. I set the car.destructible() = false and create some sprites of the train and train mask where the car is the target, meaning if the car is destroyed so will the sprites.
5. on_tick, while the game.tick is less than the calculated landing tick, the car moves under the speed of the initial "push" in step 3, and the sprites are manipulated to look like a train is jumping
6. on_tick, when the game.tick == the landing tick and if there is rail under the car, the car is destroyed, the train is reformed, and it goes on.
There is a different "magnetic" version of the train ramp that recalculates all the air time and landing tick stuff so that the train always lands at a certain spot, this is what user Legowaffles was using in the crash report
I recreated the setup here: .
You should only need my mod and the Creative Mod to recreate https://mods.factorio.com/mod/creative-mod.
Manually drive the train towards the ramp however you like. Sometimes mid-jump the game will crash, sometimes it wont. I would say 4/5 times it crashes, the slower you go the more likely. But bizarrely, if you connect the gap in the rails where the train jumps, it will almost never crash no matter how slow you are going.
By the error message, I traced the issue to be that the sprite of the train that the code is trying to animate during the jump suddenly went missing. I gave the car a visible image just to test and I found that for whatever reason the car sometimes just disappears, which takes the sprites with it, and thus causing the crash. When the game crashes, the player character is visible on the ground too, so it was kicked out of the car when it disappeared. The only time in the code I destroy the car is when the game.tick == the landing tick, and I set the car.destructible() = false so nothing should be damaging it. I also don't believe I am miscalculating anything about the landing tick or air time because this issue only came up recently (crash posted 2 weeks ago, ramp existed for 7 months), and it wouldn't explain why connecting the gap in the rails would prevent the crash. I checked the changelog, the car prototype, and various areas in the mod code but couldn't find anything that might be causing the car to sometimes disappear and sometimes not
