So I spawned a spawner minecart with a command block. The command was the following:
/summon spawner_minecart ~ ~6 ~.1 {SpawnRange:0,MinSpawnDelay:3,MaxSpawnDelay:3,SpawnData:{id:"minecraft:falling_block",Block:redstone_block,Time:1,DropItem:0},SpawnCount:1}This creates a spawner minecart with a SpawnRange of 0 that spawns redstone blocks, so I expected it to spawn redstone block in the block the spawner minecart is in.
However, the spawner minecart spawns the blocks in the block it is in as well as the block above that, and also the block underneath the block the spawner minecart is standing on.
From 14w06a on, some of the spawned blocks are invisible. They become visible again after relogging.
The weird thing though is, that the spawner minecart doesn't drop blocks below the floor when it is at an exact coordinate. (In the command it said: ~ ~6 ~.1 If you replace the .1 with a 1 it doesn't spawn blocks below the floor, but it still does spawn above the block the spawner minecart is in.)
How to reproduce
Use the following command
/setblock ~ ~4 ~ spawner{SpawnRange:0s,MinSpawnDelay:3s,MaxSpawnDelay:3s,SpawnData:{entity: {id: "minecraft:armor_stand", NoGravity:1b}},SpawnCount:1s} destroy→ All armor stands are spawned at the same x and y position because
SpawnRangeis 0, but their y position varies
Code analysis
Code analysis by @unknown can be found in this comment.
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Yes, this bug does still occur in version 13w48b.
Is this still a concern in the latest Minecraft version 14w03b? If so, please update the affected versions in order to best aid Mojang ensuring bugs are still valid in the latest releases/pre-releases.
Yes, in fact, the bug become worse, besides a spawnerminecart, the commandblock now also summons a fake Pig.
As you can see, redstoneblocks were spawned underneath the platform. They also got spawned in and above the minecart but you can't see those, because of another bug causing the spawned blocks to be invisible. As well as that, you can also see a fake pig, it will disappear after relogging. Reloggin will also make the other redstoneblocks visible, and it will fix the fake hole that the minecart created.
Spawners are supposed to spawn entities in range you gave, SpawnRange only affects the x and z range. This works as intended, Not sure about the pig though.
Can you change the up- and downwards spawnrange of spawners? And if so, how?
There is a new bug that prevents this bug from being tested; if you spawn in the spawnerminecart, minecraft crashes.
Confirmed for
1.8.6
Confirmed for
15w40b
The reason for that is that the height is not affected by the SpawnRange:
MobSpawnerBaseLogic.class (1.8)
double var8 = (double)(var1.getY() + this.getSpawnerWorld().rand.nextInt(3) - 1);(I hope it is alright that I added this code snippet)
var8 seems to be the y coordinate for the entity to spawn, var1 is the position of the mob spawner..rand.nextInt(3) means a random integer between 0 and 2 (see Java - Random)
This means that is always spawns the entity either one block above, at the same position or one block below the spawner.
Possible fix (1.8)
double var8 = (double)(var1.getY() + (this.getSpawnerWorld().rand.nextDouble() - this.getSpawnerWorld().rand.nextDouble()) * Math.min((double)this.spawnRange, 1) + 0.5D);Where 1 represents the random value between -1 and 1
Confirmed for
1.9-pre2
Confirmed in 1.15.2 and 20w22a.
Can confirm in 20w51a.
Can confirm in 21w03a.
Can confirm in 21w05b.
Can confirm in 21w06a.
Can confirm in 21w07a.
Video attached.
Affects 21w18a
I can reproduce this in 1.20.4 and 24w07a with the following command:
/setblock ~ ~4 ~ spawner{SpawnRange:0s,MinSpawnDelay:3s,MaxSpawnDelay:3s,SpawnData:{entity: {id: "minecraft:armor_stand", NoGravity:1b}},SpawnCount:1s} destroy
Is this still a concern in the latest Minecraft version 13w48b? If so, please update the affected versions in order to best aid Mojang ensuring bugs are still valid in the latest releases/pre-releases.