"Translation" animation with step=0

[kperry42]

I like the new the "translation" animation feature, it's very nice. One detail, though - it doesn't allow for setting a translation with "step" = 0. This would be helpful if one wants to build several items with computed properties. For instance in this simple example of an expanding row of boxes, where the middle one should stay at the origin:

data = [];
for (let j = -2, j <= 2; j++) {
    data.push(box(1, 1, 1, {translation: {path:'[t, 0, 0]', step: j/10}}));
}

... you don't want to have to write special-case code to remove the translation with step=0.

Currently, threejs-template.js line 421 has:

var step = s.options.translation.step ? s.options.translation.step : .05;

This causes "s.options.translation.step = 0" to map to "step = .05". Using Number.isFinite() here instead would be an improvement:

var step = Number.isFinite(s.options.translation.step) ? s.options.translation.step : .05;

This will map undefined, null, false, and invalid values to the default, but allow 0 as a possible value.

[paulmasson]

@kperry42 I don't have a problem with this change. Would you like to submit a pull request to get credit for the enhancement?