mat4-interpolate

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.

var mat4 = require('gl-mat4')
var start = mat4.create()
var end = mat4.fromRotationTranslation([], [0,1,0,0], [20, 50, -10])
var out = mat4.create()

//the matrix interpolator
var interpolate = require('mat4-interpolate')


//.. in your render loop
function render() {
    //interpolate based on alpha, storing results in 'out' matrix
    var vlid = interpolate(out, start, end, alpha)
    
    if (!valid) {
        //could not interpolate, you need to animate yourself somehow   
    }
}

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.