splat-ecs/lib/split-filmstrip-animations.js

A 2D HTML5 Canvas game engine

var clone = require("./clone");

module.exports = function splitFilmStripAnimations(animations) {
  Object.keys(animations).forEach(function(key) {
    var firstFrame = animations[key][0];
    if (firstFrame.filmstripFrames) {
      splitFilmStripAnimation(animations, key);
    }
  });
};

function splitFilmStripAnimation(animations, key) {
  var firstFrame = animations[key][0];
  if (firstFrame.properties.image.sourceWidth % firstFrame.filmstripFrames != 0) {
    console.warn("The \"" + key + "\" animation is " + firstFrame.properties.image.sourceWidth + " pixels wide and that is is not evenly divisible by " + firstFrame.filmstripFrames + " frames.");
  }
  for (var i = 0; i < firstFrame.filmstripFrames; i++) {
    var frameWidth = firstFrame.properties.image.sourceWidth / firstFrame.filmstripFrames;
    var newFrame = clone(firstFrame);
    newFrame.properties.image.sourceX = frameWidth * i;
    newFrame.properties.image.sourceWidth = frameWidth;
    animations[key].push(newFrame);
  }
  animations[key].splice(0,1);
}