mat4-interpolator
Builds an interpolator that acts on two 4x4 matrices, using algorithms from W3C Spec to produce consistent results with CSS animations. Translation, scale, skew and perspective are interpolated linearly, and rotation is interpolated with spherical interpolation.
var start = mat4var end = mat4var out = mat4 //create the interpolatorvar lerp = start end if !lerp //returns false is the matrices cannot be inverted //in this case you need to fall back to your own animation method lerp = discreteAnimator //.. in your render loop { //interpolate based on alpha, storing results in 'out' matrix }
Note: mat4-interpolate is recommended for most use cases, but this module may be useful to avoid decomposing static matrices every frame.
You can run the demo on RequireBin:
http://requirebin.com/?gist=1347c3e7fd430a191545
Usage
lerp = createInterpolator(start, end)
Creates an interpolator function that acts on the target start and end matrices. This will decompose the two matrices into components. If either matrix is non-invertible (i.e. scale or perspective W of zero), this method returns false
. W3C suggests falling back to discrete animations in this case.
lerp(out, alpha)
The returned function accepts an out
matrix for storing the interpolated results, and an alpha
for how much to interpolate.
Returns the out
matrix.
License
MIT, see LICENSE.md for details.