Animation scale does not use linear interpolation between keyframes

Partner Rank:

2

Partner Team Reporting:

Pathway Studios

Verification builds and Platforms:

Minecraft-Release_UAP_x64_2760493 - 1.13.0.5

Minecraft-Publish_UAP_x64_3227708 - 1.13.0.25

Minecraft-Publish_UAP_x64_3240615 - 1.14.0.1 RC0

Summary:

In custom entity animations "scale" is not linearly interpolated between keyframes.

Impact:

Causes animations to behave in an unexpected manner, e.g., growing and shrinking instead of growing and staying the same size.

Repro Steps:

1. Open the attached world and observe the entity on the ground

Observed Results:

The entity grows and then shrinks before growing again.

Expected Results:

The entity should grow linearly, stay the same size for a moment, then grow linearly again.

Screenshot/Video?

Yes.

Regression Builds:

None.  Could not find a version with the current custom entity syntax where the bug did not occur, tried R12-R14 builds.

Notes:

The animation file for the world and video has the following keyframes.  Based on these keyframes should never shrink (until the animation loops and restarts).

"scale": {
  "0.7667": [1, 1, 1],
  "1.2333": [1.6, 0.8, 1.6],
  "1.3667": [1.6, 0.8, 1.6],
  "1.9667": [2, 0.6, 2],
  "2.0833": [2, 0.6, 2],
  "2.6833": [2.5, 0.4, 2.5],
  "2.8": [2.5, 0.4, 2.5],
  "3.4": [3, 0.2, 3]
}