mat4-interpolate

Interpolates between two 4x4 matrices, using algorithms from W3C Spec to produce consistent results with CSS animations. Like mat4-interpolator but does the decomposition in place.

Translation, scale, skew and perspective are interpolated linearly, and rotation is interpolated with spherical interpolation.

1var mat4 = require('gl-mat4')
2var start = mat4.create()
3var end = mat4.fromRotationTranslation([], [0,1,0,0], [20, 50, -10])
4var out = mat4.create()
5
6//the matrix interpolator
7var interpolate = require('mat4-interpolate')
8
9
10//.. in your render loop
11function render() {
12    //interpolate based on alpha, storing results in 'out' matrix
13    var vlid = interpolate(out, start, end, alpha)
14    
15    if (!valid) {
16        //could not interpolate, you need to animate yourself somehow   
17    }
18}

Usage

valid = interpolate(out, start, end, alpha)

Interpolates between start and end matrices (16 floats in an array) and stores the result in out, using alpha for interpolation. This will decompose the two matrices into components, lerp/slerp, and then recompose.

Returns true is the interpolation succeeded, or false if either matrix is non-invertible (i.e. scale or perspective W of zero). W3C suggests falling back to discrete animations in this case.

License

MIT, see LICENSE.md for details.