In 1.7.10 and earlier, TNT will immediately collide with the ceiling and just fall straight down if it's triggered when there's a block above it. This no longer happens and it ignores ceiling collision when triggered.
Example gfy: http://gfycat.com/LimitedAppropriateAmurminnow
Edit: Bonus info, taken from comment below by Dan Shemp
PrimedTNT now has its "centre" at the bottom of the entity, which means the block code for TNT summons the entity 0.5 of a block too high. When "+ 0.5f" is removed from the y-argument for PrimedTNT's constructor call, this bug is resolved. Dispensers also had this problem but it was fixed in separate code.
Somewhat related: Ender Crystal entity spawning 1 block too low
Related issues
Comments
trazlander
migrated
Perhaps some of the code dealing with the TNT affects both this ticket and MC-64025, but this ticket is definitely not a direct duplicate. At the very most, it Relates (and that's stretching it).
This ticket simply describes the lack of TNT ceiling collision. I tested, and it is indeed present in 14w32d, but absent in 1.7.10
migrated
Still no ceiling collision in 14w34d.
trazlander
Confirmed in 1.8.1-pre3
galaxy_2alex
You can add affecting versions yourself by the way 😉
trazlander
Oh duh I reported this one myself
trazlander
Updated Gif to http://gfycat.com/LimitedAppropriateAmurminnow
trazlander
migrated
Is this only visual thing?
trazlander
Could be. But I don't think so. Pressing the button and quickly logging out and checking the entity in mcedit shows it popping up into the block http://i.imgur.com/rYyKBOS.png
Though I've seen weird issues where things like this may only happen in a single player world and may work properly on a server. But I haven't tested that.
migrated
Dupe of MC-8565.
trazlander
Dupe of MC-8565.
Nope. That one is about dispensing TNT directly into a block.
This is new with 1.8, it has to do with the "hop" when you trigger a tnt block not factoring in ceiling collision.
migrated
PrimedTNT now has its "centre" at the bottom of the entity, which means the block code for TNT summons the entity 0.5 of a block too high. When "+ 0.5f" is removed from the y-argument for PrimedTNT's constructor call, this bug is resolved. Dispensers also had this problem but it was fixed in separate code.
Somewhat related: Ender Crystal entity spawning 1 block too low
migrated
Not fixed in 1.8.3.
migrated
Cannot confirm broken in 1.8.3. I literally triple-checked before posting.
michael
Do you just not read reports anymore or do you just guess what it says from their keywords. This was immediately marked as a duplicate of a bug (MC-64025) that the only similar word between them is "TNT". This has to do with tnt not colliding with a ceiling when activated, and MC-64025 has to do with a visual glitch when tnt is dispensed inside of another block.