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If you hit F3 while playing Minecraft, an overlay appears. Some of the items, such as fps, x, y, and z are obvious, but I'm curious about some of the other values. What do they all represent?

Debug screen

  • If you press SIFT + F3 the graghs disappear.(FYI) – user29947 Jul 25 '12 at 3:57
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Debug numbers

  • C is the number of renderers* being rendered over total number loaded
  • F is number of renderers being clipped (i.e. not viewable)
  • O is the number of renderers removed through occlusion culling
  • E (first line) is the number of renderers skipped
  • E (second line) is the number of rendered entities over total entities
  • B is the number of entities hidden
  • I is the number of individually removed entities (the remainder of B and the numerator of E combined)
  • P is the number of particles
  • T: All is the total number of entities
  • MultiplayerChunkCache is the number of chunks currently loaded into memory
  • x and z are your current coordinates along the horizontal plane
  • y (feet pos) is the current coordinate along the vertical plane of the floor you're walking on
  • y (eyes pos) is the current coordinate along the vertical plane of your eye level (Steve's eyes being 1.620 blocks above the ground)
  • f is the orientation of Steve: 0 is west, 1 is north, 2 is east, 3 is south
  • lc is the height level of the highest non-air block within the current chunk
  • b is the name of the biome you're currently in
  • bl is the light level of the block your head is in, from block-based lights like torches
  • sl is the level of sunlight/moonlight on the block your head is in (independent of the current time of day)
  • rl is the maximum of bl and sl
  • ws is your walk speed
  • fs is your flying speed
  • g is whether your feet are on the ground (true if you are, false otherwise)

Graphs

The bar graph charts frame rate over time inversely (e.g., higher spikes = lower frame rate). Green plots are when your frame rate is 60 FPS or higher.

The pie graph charts the distribution of CPU time across different parts of Minecraft:

  • [0] root (white) is essentially a sanity check: should always be 100%
  • [? probably 1]unspecified (green) is the time spent on things not already enumerated
  • [2] render (blue) is the time spent on rendering the world
  • [3] tick (purple) is the time spent on the game clock (heartbeat)
  • [4] sound (yellow) is the time spent on the sound engine
  • [5] updatelights (salmon) is the time spent on updating the lighting engine (usually at sunset and sunrise)

Pressing the 1-9 keys will show sub-divisions of the numbered slices of the pie chart (in addition to switching items as usual), and pressing 0 will go back up.

Notes

  • A chunk, if you're not familiar with the term, is a section of the world, equal to 16x128x16 blocks.
  • Given the context in which it appears in RenderGlobal.java, I believe "renderers" refers to a single block.
  • Under the Minecraft coordinate system, X and Z are the horizontal axes and Y is the vertical axis, which confuses players used to other coordinate systems.
  • I'm curious -- what is occlusion referring to in this sense? – Raven Dreamer Jan 20 '11 at 3:27
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    @Raven: Hidden surface determination. – user3389 Jan 20 '11 at 3:34
  • Awesome. A +1 to your comment. – Raven Dreamer Jan 20 '11 at 4:04
  • And what is that fancy graphic at the bottom? – Denilson Sá Maia Mar 4 '11 at 11:16
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    Red on the graph represents lost frames, or when your game runs under 60 FPS. – Kevin Yap Apr 13 '11 at 22:43
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There is a very good video I have of this. It explains the F3 menu / debug screen.

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    Welcome to Arqade! Whilst this video may answer the question, it would be preferable to quote the essential parts of the answer here, and provide the link for reference. – Jupotter Jul 13 '13 at 11:43

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