Pixel-Composer/scripts/__path/__path.gml

function Path() constructor {
	lengthTotal = 0;
	lengths     = [];
	lengthAccs  = [];
	boundary    = new BoundingBox();
	loop		= false;
	
	static getBoundary		= function() { return boundary; }
	static getAccuLength	= function() { return lengthAccs; }
	static getLength		= function() { return lengthTotal; }
	static getSegmentCount  = function() { return 1; }
	static getLineCount     = function() { return 1; }
	
	static getTangentRatio  = function(_rat) { return 0; }
	static getPointDistance = function(_seg) { return new __vec2(0, 0); }
	static getPointSegment  = function(_seg) { return new __vec2(0, 0); }
	static getPointRatio    = function(_rat) { return new __vec2(0, 0); }
}

function PathSegment() : Path() constructor {
	segments = [];
	
	static getBoundary		= function() { 
		if(getSegmentCount() == 0) return new BoundingBox( 0, 0, 0, 0 );
		
		var minx = segments[0].x, maxx = segments[0].x;
		var miny = segments[0].y, maxy = segments[0].y;
		
		for( var i = 0, n = array_length(segments); i < n; i++ ) {
			var s = segments[i];
			
			minx = min(minx, s.x);
			maxx = max(maxx, s.x);
			miny = min(miny, s.y);
			maxy = max(maxy, s.y);
		}
		return new BoundingBox( minx, miny, maxx, maxy ); 
	}
	static getSegmentCount  = function() { return array_length(segments); }
	static getLineCount		= function() { return 1; }
	
	static setSegment = function(segment) {
		self.segments = segment;
		lengths		= [];
		lengthAccs  = [];
		lengthTotal = 0;
		
		var op, np;
		for( var i = 0, n = array_length(segment); i < n; i++ ) {
			np = segment[i];
			
			if(i) {
				lengths[i]    = point_distance(op.x, op.y, np.x, np.y);
				lengthTotal  += lengths[i];
				lengthAccs[i] = lengthTotal;
			}
			
			op = np;
		}
	}
	
	static getPointDistance = function(_dist) {
		for( var i = 1; i < array_length(lengths); i += 1 ) {
			if(_dist <= lengths[i]) {
				var rat = _dist / lengths[i];
				return segments[i - 1].lerpTo(segments[i], rat);
			}
			
			_dist -= lengths[i];
		}
		
		return new __vec2(0, 0);
	}
	
	static getPointSegment = function(_seg) {
		var fr = (floor(_seg)) % getSegmentCount();
		var to = (fr + 1) % getSegmentCount();
		var st = frac(_seg);
		
		return segments[fr].lerpTo(segments[to], st);
	}
	
	static getPointRatio = function(_rat) {
		return getPointSegment(frac(_rat) * lengthTotal);
	}
	
	static getTangentRatio = function(_rat) {
		_rat = frac(_rat);
		var l = _rat * lengthTotal;
		
		for( var i = 1; i < array_length(lengths); i += 1 ) {
			if(l <= lengths[i]) {
				var rat = l / lengths[i];
				return segments[i - 1].directionTo(segments[i]);
			}
			
			l -= lengths[i];
		}
		
		return 0;
	}
}