Bug In GLTF Animation Export

mrlooi · January 22, 2021, 10:53am

FYI:

BabylonJS/Babylon.js/blob/master/serializers/src/glTF/2.0/glTFAnimation.ts#L564


let prevKeyFrame: Nullable<IAnimationKey> = null;
let endFrame: Nullable<number> = null;
minMaxFrames.min = Tools.FloatRound(minFrame / fps);

let keyFrames = animation.getKeys();

for (let i = 0, length = keyFrames.length; i < length; ++i) {
    endFrame = null;
    currKeyFrame = keyFrames[i];

    if (i + 1 < length) {
        nextKeyFrame = keyFrames[i + 1];
        if (currKeyFrame.value.equals && currKeyFrame.value.equals(nextKeyFrame.value) || currKeyFrame.value === nextKeyFrame.value) {
            if (i === 0) { // set the first frame to itself
                endFrame = currKeyFrame.frame;
            }
            else {
                continue;
            }
        }
        else {

(i + 1 < length) is buggy behavior
Imagine if i = 0 and length = 1, this will evaluate to false, which will go to the else statement where
prevKeyFrame = keyFrames[i - 1] → prevKeyFrame will be null, and therefore prevKeyFrame.value will throw an error

Noticed this after it broke a GLTF export on my side

Evgeni_Popov · January 22, 2021, 12:29pm

Adding @Drigax

Drigax · January 22, 2021, 4:49pm

@mrlooi thanks for discovering this!

Would you like to make a PR to address this?

Topic		Replies	Views
Maya Exporter Bug - Second Animation Group Incorrect Length Content creation (3dsMax, Maya, Blender, glTF)	6	686	September 28, 2019
GLTF Bug: FreeCamera animation not being exported Bugs	13	612	August 5, 2022
GLTF importer errors on load Bugs gltf	7	2376	April 26, 2021
Animations lost when exported with GLTF2Export.GLBAsync Questions	8	661	July 25, 2019
GLTF2Exporter seem like having some bug Bugs gltf2export	6	496	February 4, 2023

Bug In GLTF Animation Export

Related Topics