ProjectBall.Unity/Assets/Scripts/WaterField.cs

using UnityEngine;
using System.Collections;
using System.Collections.Generic;

public class WaterField : MonoBehaviour {
	public List<GameObject> capturedObjects = new List<GameObject>();
	public bool enableDrag = true;
	float maxDrag = 0.0f;
	float vel = 0.0f;

	// Use this for initialization
	void Start () {
		if (collider == null) {
			var c = gameObject.AddComponent<BoxCollider>();
			c.center = new Vector3(0, -0.5f,  0);
			c.isTrigger = true;
		}
	}
	
	// Update is called once per frame
	void FixedUpdate () {

		float envDensity = AdvancedPhysics.Matters.Water.Density;



		Plane p = new Plane(transform.up, transform.position);

		foreach (var obj in capturedObjects) {
			if(obj.collider is SphereCollider){
				float objDensity = AdvancedPhysics.Matters.Water.Density * 1.05f;
				Vector3 sphereCenter;
				float sphereRadius;
				SphereCollider c = obj.collider as SphereCollider;
				if(c != null){
					sphereCenter = c.transform.position;
					sphereRadius = c.radius;
				}else{
					sphereCenter = obj.collider.bounds.center;
					Vector3 ext = obj.collider.bounds.extents;
					
					sphereRadius = ext.x > ext.y ? ext.x : (ext.y > ext.z ? ext.y : ext.z);
				}
				
				
				float underwaterVolume = SphereVolumeUnderPlane(p, sphereCenter, sphereRadius);
				
				float forceMagnitude = AdvancedMath.BuoyantForce(underwaterVolume, objDensity, envDensity, Physics.gravity.magnitude);
				
				Vector3 force = Physics.gravity.normalized * -forceMagnitude;
				
				Vector3 sphereDragForce = -obj.rigidbody.velocity.normalized * AdvancedMath.SphereDrag(envDensity, obj.rigidbody.velocity.magnitude, sphereRadius);
				
				float sphereVolume = AdvancedMath.SphereVolume(sphereRadius);
				Vector3 speedForce = Vector3.zero;
				if(underwaterVolume < sphereVolume){
					if(underwaterVolume > 0.0f)
						speedForce  = Vector3.Cross(obj.rigidbody.angularVelocity, transform.up) * 30;
				}else{
					speedForce  = Vector3.Cross(obj.rigidbody.angularVelocity, transform.up) * 10;
					
				}

				obj.rigidbody.AddForce(force + sphereDragForce + speedForce);

			}if(obj.collider is BoxCollider){
				float objDensity = AdvancedPhysics.Matters.Water.Density * 1.05f;
				var mat = obj.GetComponent<AdvancedPhysicsMaterial>();
				if(mat != null){
					objDensity = mat.matter.Density;
				}

				var tf = obj.transform.localToWorldMatrix;
				
				Vector3[] vertices;
				int[] indices;

				var mf = obj.GetComponent<MeshFilter>();
				if(mf != null && mf.sharedMesh != null){
					vertices = mf.mesh.vertices;
					indices = mf.mesh.triangles;
					int cnt = vertices.Length;
					for(int i = 0; i < cnt; ++i){
						vertices[i] = tf.MultiplyPoint3x4(vertices[i]);
					}
				}else{
					AdvancedUtils.CreateMeshCube (obj.transform.localToWorldMatrix, out vertices, out indices);
				}



				List<Vector3> cuttedTriangles = AdvancedUtils.CutMesh (vertices, indices, p);

				//AdvancedGizmo.DrawMesh(cuttedTriangles.ToArray(), true);

				float totalVolume = 0;
				Vector3 totalBuoyantForce = Vector3.zero;

				for (int i = 0; i < cuttedTriangles.Count; i+=3) {
					Vector3 v0 = cuttedTriangles[i + 0];
					Vector3 v1 = cuttedTriangles[i + 1];
					Vector3 v2 = cuttedTriangles[i + 2];
					Vector3 normal = AdvancedMath.TriangleNormal(v0, v1, v2);

					float dot = Vector3.Dot (normal, p.normal);
					if(Mathf.Abs(dot) >= 0.0001f){
						float sign = Mathf.Sign(dot);
						
						float h0 = p.GetDistanceToPoint(v0);
						float h1 = p.GetDistanceToPoint(v1);
						float h2 = p.GetDistanceToPoint(v2);
						float avgH = (h0 + h1 + h2) / 3.0f;
						
						Vector3 vp0 = v0 - p.normal * h0;
						Vector3 vp1 = v1 - p.normal * h1;
						Vector3 vp2 = v2 - p.normal * h2;
						
						float triangleSquare = AdvancedMath.TriangleSquare(vp0, vp1, vp2);
						float prismVolume = AdvancedMath.PrismVolume(triangleSquare, avgH) * sign;
						float prismBuoyantMagnitude = AdvancedMath.BuoyantForce(prismVolume, objDensity, envDensity, Physics.gravity.magnitude);
						Vector3 prismBuoyantForce = Physics.gravity.normalized * -prismBuoyantMagnitude;
		
						totalBuoyantForce += prismBuoyantForce;
						totalVolume += prismVolume;
						Vector3 com = AdvancedMath.PrismCenterOfMass(vp0, vp1, vp2, p.normal, h0, h1, h2);
						obj.rigidbody.AddForceAtPosition(prismBuoyantForce, com, ForceMode.Force);
						//obj.rigidbody.d
						//Physics.
					}
				}
				if(obj.name == "CubeTest"){
				//	Debug.Log("Total underwater volume: " + totalVolume);
					//Debug.Log("Total buoyant force: " + totalBuoyantForce);
				}



				Vector3 ext = obj.collider.bounds.extents;
				float sphereRadius = ext.x > ext.y ? ext.x : (ext.y > ext.z ? ext.y : ext.z);

				float v = obj.rigidbody.velocity.magnitude;

				float dragMagnitude = AdvancedMath.Drag(envDensity, v, 1.02f, Mathf.PI * sphereRadius * sphereRadius);
				if(v < 0.01f){
					dragMagnitude = 0.0f;
				}

				if(	dragMagnitude > v*v*obj.rigidbody.mass){
					dragMagnitude = v*v*obj.rigidbody.mass;
				}
			/*	if(dragMagnitude > obj.rigidbody.velocity.magnitude){
					dragMagnitude = obj.rigidbody.velocity.magnitude;
				}*/

				if(enableDrag){
					Vector3 sphereDragForce = -obj.rigidbody.velocity.normalized * dragMagnitude;
					obj.rigidbody.AddForce(sphereDragForce, ForceMode.Force);
					Debug.DrawRay(obj.transform.position,obj.rigidbody.velocity, Color.green); 
					Debug.DrawRay(obj.transform.position,sphereDragForce, Color.red);
					if(obj.name == "CubeTest"){
						if(maxDrag < dragMagnitude){
							maxDrag = dragMagnitude;
							vel = v;
						}
					}

				}
			

			//	obj.rigidbody.velocity -= (sphereDragForce / obj.rigidbody.mass) * Time.fixedDeltaTime;
	




				AdvancedGizmo.DrawMesh(cuttedTriangles.ToArray(), true);
			}
		}
	}

	void OnGUI(){
		GUI.Label (new Rect(0,0,100,100), "Max drag = " + maxDrag);
		GUI.Label (new Rect(0,30,100,100), "Vel = " + vel);
	}

	void OnDrawGizmos(){
		Gizmos.matrix = transform.localToWorldMatrix;

		Gizmos.DrawWireCube (new Vector3 (0, -0.5f, 0), Vector3.one);
		Gizmos.matrix = Matrix4x4.identity;

		//AdvancedGizmo.DrawGrid (transform.position, width, height);

		int waveLineCount = 5;
		int wavesCount = 7;

		float hLineOffset = (1.0f / (float)(waveLineCount + 1));
		for (int i = 0; i < waveLineCount; ++i) {
			float hOffset = -hLineOffset * (float)(i + 1);

			AdvancedGizmo.Plot2D (Mathf.Sin, transform.localToWorldMatrix, new Vector3(-0.5f, 0, 0.5f + hOffset), Vector3.right, Vector3.forward, 1, Mathf.PI * wavesCount, 0.05f, 40, Color.blue);
		}
	}

	float SphereVolumeUnderPlane(Plane p, Vector3 sphereCenter, float r){
		float distance = p.GetDistanceToPoint (sphereCenter);
		if (distance >= r) {
				return 0;
		} else if (distance <= -r) {
				return AdvancedMath.SphereVolume (r);
		} else {
			float h = Mathf.Abs(distance - r);
			return AdvancedMath.SphereSegmentVolume(r, h);
		}
	}

	void OnTriggerEnter(Collider other){
		if (other.rigidbody != null && !other.rigidbody.isKinematic) {
			capturedObjects.Add(other.gameObject);
		}
	}
	
	void OnTriggerExit(Collider other){
		if (other.rigidbody != null && !other.rigidbody.isKinematic) {
			capturedObjects.Remove(other.gameObject);
		}
	}
}