AnalyzeStars.cs

using UnityEngine;
using System.Globalization;

/*
    THIS SCRIPT IS WRITTEN BY
    THOMAS KOLE
    www.thomaskole.com

    THIS SCRIPT IS RELEASED UNDER A
    Creative Commons Attribution-NonCommercial
    LISENCE, MEANING THAT YOU CAN USE IT AS LONG
    AS YOU ATTRIBUTE ME.

    FOR COMMERCIAL USE, PLEASE CONTACT ME.

    ----

    THIS SCRIPT READS FROM THE HYG DATABASE
    http://astronexus.com/node/34
    A PROCESSED VERSION CAN BE FOUND IN THE
    .unitypackage,
    OR ON MY WEBSITE
    https://thomaskole.wordpress.com/
    FOR IT'S USAGE, PLEASE SEE THE ASTRONEXUS WEBSITE.

    ----

    PLEASE FEEL FREE TO MODIFY ANY PART OF THIS SCRIPT
    AS MUCH AS YOU WANT!

    Modified by HJ.
*/

namespace sp1
{
    public class AnalyzeStars : MonoBehaviour
    {
        // Public

        public int maxParticles = 100;
        public TextAsset starCSV;
        public Material matVertex;

        // Private

        private Vector3[] points;
        private Color[] colors;

        private GameObject pointGroup;
        Camera thisCamera;

        private bool IsStarInitialized;
        void Awake()
        {
        }

        void Start()
        {
            IsStarInitialized = false;
            float farClipPlane = 30000.0f;  // hard-coded for now, problem with Camera.main not defined
            Tools.Log("reading star files...");
            string[] lines = starCSV.text.Split('\n');

            int lineCount = lines.Length-1;
            if (lineCount < maxParticles)
                maxParticles = lineCount - 1;

            points = new Vector3[maxParticles];
            colors = new Color[maxParticles];

            for (int i = 0; i < maxParticles; i++)
            {
                string[] components = lines[i].Split(',');

                points[i] = new Vector3(float.Parse(components[1], CultureInfo.InvariantCulture),
                                                        float.Parse(components[3], CultureInfo.InvariantCulture),
                                                        float.Parse(components[2], CultureInfo.InvariantCulture)).normalized * farClipPlane * 0.5f;
                float magnitude = float.Parse(components[0], CultureInfo.InvariantCulture);
                float intensity = (1.0f - ((magnitude + 1.44f) / 16.0f));
                colors[i] = Color.white * intensity;
            }

            InstantiateMesh(maxParticles);
        }

        public void OnEnable()
        {
            // register the callback when enabling object
            Camera.onPreRender += MyPreRender;
            MSCameraController.OnCameraChange += OnCameraChange;
        }

        public void MyPreRender(Camera cam)
        {
            Debug.Log("PreRender " + gameObject.name + " from camera " + cam.gameObject.name);
            thisCamera = cam;
            Camera.onPreRender -= MyPreRender;
        }

        public void OnCameraChange(CameraType cam)
        {
            //Debug.Log("OnCameraChange " + gameObject.name + " from camera " + cam._camera.name);
            thisCamera = cam._camera;
        }

        void Update()
        {
            if (IsStarInitialized)
            {
                //
                // make the stars blink a bit
                //
                pointGroup.GetComponent<Renderer>().material.SetFloat("_AnimationTime", Time.frameCount / 10.0f);
                //
                // Update the positions of the star cloud ; it remains centered on the camera view
                //
                if (pointGroup != null && thisCamera != null)
                    pointGroup.transform.SetPositionAndRotation(thisCamera.transform.position, Quaternion.identity);
            }
        }


        private void InstantiateMesh(int nPoints)
        {
            // Create Mesh
            pointGroup = new GameObject("StarField");
            pointGroup.AddComponent<MeshFilter>();
            pointGroup.AddComponent<MeshRenderer>();
            pointGroup.GetComponent<Renderer>().material = matVertex;
            pointGroup.GetComponent<MeshFilter>().mesh = CreateMesh(nPoints);
            pointGroup.SetActive(true);
            IsStarInitialized = true;
        }


        private Mesh CreateMesh(int nPoints)
        {
            
            Mesh mesh = new Mesh();

            int[] indecies = new int[nPoints];

            for (int i = 0; i < nPoints; ++i)
            {
                indecies[i] = i;
            }

            mesh.vertices = points;
            mesh.colors = colors;
            mesh.SetIndices(indecies, MeshTopology.Points, 0);
            mesh.uv = new Vector2[nPoints];
            mesh.normals = new Vector3[nPoints];

            return mesh;
        }
    }
}