VR PROJECTS / FOLLOW THE COACH / STUDY 01

How time selects a pose

Start with one part of the system: time → pose number → pose data → drawing. This exercise imports a snapshot of the game's pose table and timing function.

QuestTracks headset and controllers
→
WebXRExposes their poses to the page
→
Game logicSelects poses, targets, and results
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OutputUpdates visuals, sound, and partner view

Selected pose

Pose 1 / 8
Front view of the selected Coach pose Hand a is orange; hand b is blue. Moving the time slider changes the pose. a b
a: left side of this front view b: right side of this front view

This drawing isolates pose selection. The VR scene also places each target in 3D relative to the player.

Control time

Paused
Beat length
0.60 s
Pose number k
0
Table index
0
Time per pose
1.20 s

Change the formula

Local experiment only

This is the function that selects a pose number. Change 2 * beat to 4 * beat, run it, and move the time slider. Each pose should remain selected longer. Your edit does not change the VR game.

Using the original game formula.

Game code snapshots: Pose table and timing · VR scene

Three things to understand

  1. beat is the length of one beat in seconds. Dance uses 0.6 seconds.
  2. k = Math.floor(time / (2 * beat)) advances the pose every two beats. Math.floor rounds down to an integer.
  3. The table contains eight poses. k % 8 loops back to table index 0 after index 7.

Try this: set Dance mode to 2.5 seconds. Predict k and the table index before checking the numbers.

The exercise starts at time 0 to make the calculation visible. The game uses a shared clock, so k is usually much larger; the modulo loop is the same.