Index: binaries/data/mods/public/maps/random/rmgen/DensityConstraint.js
===================================================================
--- binaries/data/mods/public/maps/random/rmgen/DensityConstraint.js
+++ binaries/data/mods/public/maps/random/rmgen/DensityConstraint.js
@@ -0,0 +1,70 @@
+/*
+ * Density constraint
+ */
+function DensityConstraint(density)
+{
+	this.density = density;
+	if (this.density.step === undefined)
+	{
+		this.density.step = (t) => t;
+	}
+}
+
+DensityConstraint.prototype.allows = function(position)
+{
+	const value = this.density.probability(position);
+	if (value >= 0 && value <= 1)
+	{
+		const height = g_Map.getHeight(position);
+		const probability = this.density.step(value, height, position);
+		const randomValue = randFloat(0, 1);
+		return randomValue <= probability;
+	}
+	return false;
+};
+
+/*
+ * Density radius function
+ */
+function DensityRadius(center, radius, stepDensityFunction = undefined)
+{
+	this.step = stepDensityFunction;
+	this.center = center;
+	this.radius = radius;
+}
+
+DensityRadius.prototype.probability = function(position)
+{
+	const distance = this.center.distanceTo(position);
+	return distance / this.radius;
+};
+
+/*
+ * Density direction function
+ */
+function DensityDirection(position, direction, maxDistance, stepDensityFunction = undefined)
+{
+	this.step = stepDensityFunction;
+	this.position = position;
+	this.positionEnd = direction.clone().rotate(Math.PI / 2).add(this.position);
+	this.maxDistance = maxDistance;
+}
+
+DensityDirection.prototype.probability = function(position)
+{
+	const distance = distanceOfPointFromLine(this.position, this.positionEnd, position);
+	return distance / this.maxDistance;
+};
+
+/*
+ * Density custom defiend function
+ */
+function DensityCustom(customFunction, stepDensityFunction = undefined)
+{
+	this.customFunction = cusotmFuntion;
+}
+
+DensityCustom.prototype.probability = function(position)
+{
+	return this.customFunction(position);
+};
\ No newline at end of file