Code sample for doing wave spring physics

WavePhys.hx

//Note: This does _not_ compile, it's just to demonstrate the relevant physics bits

class Main extends luxe.Game {
	var fieldWidth:Int = 60;
	var fieldDepth:Int = 60;
	var physTimeStep:Float = 1 / 60;
	var physTimeCounter:Float = 0;
	
	var springK:Float = 100;
	var springDampening:Float = 0.00;
	var springSpread:Float = 600;
	var startHeight:Float = -1500;
	var heightTintRange:Float = 10;
	
	var physStepCounter:Int = 0;
	var maxPhysSteps:Int = 20;
	
	var fieldVertices:Array<Vertex>;
	var springVelocities:Array<Float>;
	
	override function update(dt:Float) {
		if (dt > 1) {
			return;
		}
		
		physTimeCounter += dt;
		physStepCounter = 0;
		while (physTimeCounter >= physTimeStep && physStepCounter < maxPhysSteps) {
			updateSprings(physTimeStep);
			physTimeCounter -= physTimeStep;
			physStepCounter++;
		}
    } //update
	
	function updateSprings(dt:Float):Void {
		
		for (x in 0...fieldWidth) {
			for (y in 0...fieldDepth) {
				runHooke(x, y, dt);
			}
		}
		
		var avgHeight:Float = 0;
		var heightDiff:Float = 0;
		for (x in 0...fieldWidth) {
			for (y in 0...fieldDepth) {
				avgHeight = getNeighborAverage(x, y);
				heightDiff = fieldVertices[x * fieldWidth + y].pos.z - avgHeight;
				
				springVelocities[x * fieldWidth + y] += -springSpread * heightDiff * dt; //Effectively another hooke's law, springSpread is k
				//springVelocities[x * fieldWidth + y] -= springDampening * springVelocities[x * fieldWidth + y];
			}
		}
		
	}
	
	function runHooke(x:Int, y:Int, dt:Float):Void {
		//0 represents rest height
		springVelocities[x * fieldWidth + y] += -springK * (fieldVertices[x * fieldWidth + y].pos.z - 0) * dt;
		springVelocities[x * fieldWidth + y] -= springDampening * springVelocities[x * fieldWidth + y];
		fieldVertices[x * fieldWidth + y].pos.z += springVelocities[x * fieldWidth + y] * dt;
	}
	
	function getNeighborAverage(x:Int, y:Int):Float {
		var sum:Float = 0;
		var springCounter:Int = 0;
		var xStart:Int = x - 1;
		var xEnd:Int = x + 1;
		var yStart:Int = y - 1;
		var yEnd:Int = y + 1;
		if (xStart < 0) {
			xStart = 0;
		}
		if (xEnd > fieldWidth - 1) {
			xEnd = fieldWidth - 1;
		}
		if (yStart < 0) {
			yStart = 0;
		}
		if (yEnd > fieldDepth - 1) {
			yEnd = fieldDepth - 1;
		}
		var springCounter:Int = 0;
		for (_x in xStart...xEnd + 1) {
			for (_y in yStart...yEnd + 1) {
				if (!(_x == x && _y == y)) {
					if ((_x == xStart || _x == xEnd) && (_y == yStart || _y == yEnd)) {
						sum += fieldVertices[_x * fieldWidth + _y].pos.z * 0.7071067811865475;// 1 / sqrt(2), adjusting distance to neighbour by dividing by sart(1^2 + 1^@)
					}
					else {
						sum += fieldVertices[_x * fieldWidth + _y].pos.z;
					}
					springCounter++;
				}
			}
		}
		if (springCounter != 0) {
			sum /= springCounter;
		}
		return sum;
	}
} //Main