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File:Debug-Information.PNG

Screenshot Showing the Debug-Information

The debug screen is triggered when the F3 key is pressed (Fn+F3 on Macs and some laptops). It shows the chunk cache, the memory usage, the map seed, various parameters, the player's map coordinates and a graph that measures the game's current frame rate. It can be very useful for telling other players your map location and monitoring performance. Pressing ⇧ Shift+F3 brings up the debug screen but without the graphs, as of 1.2.4.

Legend

Name Description[1][2]
C Number of chunks rendered over total number of chunks. Counts all render passes: if a chunk is rendered twice (because it contains both water and normal blocks, for example) then it will be counted twice.
F Number of chunks loaded outside the viewing distance. Counts all render passes.
O Number of chunks removed through occlusion culling. Counts all render passes.
E (first row) Number of empty chunks. These chunks are skipped for one of two reasons: Either the chunk has not yet been loaded and rendered into polygons, or the chunk has nothing to draw in the current render pass. Counts all renderpasses.
E (second row) Number of rendered entities over total entities
B Unused, always 0. May previously have been the number of entities removed due to hidden chunks
I Number of invisible entities
P Number of particles on screen
T Unknown. Currently displays "All:" followed by the number of loaded entities.
MultiplayerChunkCache
ChunkCache
The most chunks that will be loaded
x Player's location in blocks East of 0,0
y Player's altitude in blocks (62 is overworld sea level, 10 is overworld lava flood level, 31 is nether lava sea). Coordinate is taken from eye level, not foot level.
z Player's location in blocks South of 0,0
f Player's facing (0-3: south, west, north, east)
lc Max section height for the chunk you are in (Uses cubic chunk sections, so heights will display in multiples of 16 minus 1.)
b Shows you what Biome you are in
bl Shows the light level from other blocks besides the sun and moon.
sl Shows the light level from the sun and moon.
rl Shows the total light level to where you are standing

Rendering Graph

The graph at the bottom screen displays rendering performance information. The height of each bar indicates the time taken to render each frame.

Green bars represent a frame rate higher than or equal to 60 frames per second, and red for less than 60. Once the graph has moved all the way to the right of the graph area, it will return to the left and begin to overwrite older bars.

The speed at which the graph writes new bars is dependent on the current frame rate, as one bar is written per frame.

Profiler Graph

Pie charts in the lower right of the debug screen display real time profiling information. More detailed information about one section can be displayed by using the keys 1-9. Press 0 to go back to the previous section.

History

In Indev, Infdev, and early Alpha versions, the debug screen only had what we recognize as "the top part with all the numbers". This debug screen was not activated with F3, but as a toggle in the options. In Alpha 1.1.0, the debug screen was no longer listed as an option and required F3 to be held down to activate. In Alpha 1.2.3, the coordinates were added.

In Beta 1.3, the debug screen, along with other F# controls, became a toggle. Also, between Beta 1.3 and Beta 1.7, when you activated the debug screen, it would show numbers above every mob; these numbers being the mob's Entity ID. These would be visible through blocks, hence making F3 a very useful mob-finder, which also was considered cheating and took away from the game. Because of this, the Entity ID label was removed in Beta 1.8.

In Beta 1.7, the "f" coordinate was made visible in the debug screen (facing direction).

In Beta 1.8, the ability to see the level's seed was added.

In 1.2, information about the biome and light level of the player's location were added. The seed in multiplayer is now always zero.

Bugs

  • Opening a chest or opening the Achievements screen with the debug screen on turns the debugging area grey. The text does not turn grey, however. This will not crash the game.
  • If you quit while it says "respawn", press f3 and then log in again, it will show you the coordinates of your death.
  • At very low frame rates the graph can rise high enough so that it will cover values like the coordinates. A mod to fix this can be found here.

References

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