RemoteView.cs

/* 
 * Scientific Committee on Advanced Navigation S.C.A.N. Satellite
 * RemoveView: A camera looking at a GameObject, rendering to a texture.
 * 
 * Copyright (c)2013 damny; see LICENSE.txt for licensing details.
 */

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

namespace SCANsat
{
	public class RemoteView {

		private static Camera cam;
		private static GameObject camgo;
		private static Shader edgeDetectShader, grayscaleShader;
		private static Material edgeDetectMaterial, grayscaleMaterial;
		private static AudioClip tick;

		private RenderTexture rt;
		private Rect camRect;
		private int updateFrame, width, height;
		private List<CrashObjectName> cons;
		private Bounds bounds;
		private int activeCon;
		private double switchTime;
		public GameObject lookat;
		public CrashObjectName lookdetail;

		public void setup(int w, int h, GameObject focus) {
			if(edgeDetectShader == null) {
				// simple colour based edge detection that comes with Unity Pro
				edgeDetectShader = Shader.Find("Hidden/Edge Detect X");
				edgeDetectMaterial = new Material(edgeDetectShader);
				edgeDetectMaterial.SetFloat("_Threshold", 0.05f);

				// greyscale shader that comes with Unity Pro
				grayscaleShader = Shader.Find("Hidden/Grayscale Effect");
				grayscaleMaterial = new Material(grayscaleShader);
				Texture2D t = new Texture2D(256, 1, TextureFormat.RGB24, false);
				// ramp texture to render everything in dark shades of Amber,
				// except originally dark lines, which become bright Amber
				for(int i=0; i<256; ++i) t.SetPixel(i, 0, Color.Lerp(Color.black, XKCDColors.Amber, i/1024f));
				for(int i=0; i<10; ++i) t.SetPixel(i, 0, XKCDColors.Amber);
				t.Apply();
				grayscaleMaterial.SetTexture("_RampTex", t);
			}
			if(lookat != focus) {
				switchTime = Time.realtimeSinceStartup;
				lookdetail = null;
				bounds = new Bounds();
				foreach(Collider c in focus.GetComponentsInChildren<Collider>()) {
					if(c.bounds != null) bounds.Encapsulate(c.bounds);
				}
				cons = new List<CrashObjectName>();
				foreach(CrashObjectName con in focus.GetComponentsInChildren<CrashObjectName>()) {
					cons.Add(con);
				}
			}
			lookat = focus;
			width = w;
			height = h;
			camRect = new Rect(0, 0, width, height);
		}

		public void free() {
			GameObject.Destroy(camgo);
			RenderTexture.Destroy(rt);
			cam = null;
			camgo = null;
			rt = null;
		}

		public void updateCamera() {
			if(updateFrame > Time.frameCount - 5) return;
			if(rt == null || rt.width != width || rt.height != height) {
				rt = new RenderTexture(width, height, 32, RenderTextureFormat.RGB565);
				rt.Create();
			}
			if(camgo == null) {
				camgo = new GameObject();
			}
			if(cam == null) {
				cam = camgo.AddComponent<Camera>();
				cam.enabled = false; // so we can render on demand
				cam.targetTexture = rt;
				cam.aspect = width * 1f / height;
				cam.fieldOfView = 90;
			}

			Vector3 pos_target = lookat.transform.position;
			if(lookdetail != null) pos_target = lookdetail.transform.position;
			Vector3 pos_cam = FlightGlobals.ActiveVessel.transform.position;
			Vector3 target_up = (pos_target - FlightGlobals.currentMainBody.transform.position).normalized;
			Vector3 dir = (pos_target - pos_cam).normalized;
			float dist = 100; // TODO: replace with something useful for given object size
			pos_cam = pos_target - dir * dist/2 + target_up * dist/3 ;
			Vector3 cam_up = (pos_cam - FlightGlobals.currentMainBody.transform.position).normalized;

			cam.transform.position = pos_cam;
			cam.transform.LookAt(pos_target, cam_up);
			cam.farClipPlane = dist * 3;

			RenderTexture old = RenderTexture.active;
			RenderTexture.active = rt;
			cam.Render();
			Graphics.Blit(rt, rt, edgeDetectMaterial);
			Graphics.Blit(rt, rt, grayscaleMaterial);

			RenderTexture.active = old;
			updateFrame = Time.frameCount;
		}

		private bool ticking;
		private double lastTick;
		private int tickRate = 10;
		public void drawOverlay(Rect where, GUIStyle style, bool identified) {
			if(tick == null) {
				tick = GameDatabase.Instance.GetAudioClip("Squad/Sounds/sound_click_tick");
			}
			ticking = false;
			int chars = (int)((Time.realtimeSinceStartup - switchTime) * tickRate);
			Rect r = new Rect(0, 0, 200, 20);
			string info = "no structures found";
			if(cons.Count == 1) {
				info = "identified 1 structure";
			} else if(cons.Count > 1) {
				info = "identified " + cons.Count.ToString() + " structures";
			}
			if(!identified) info = "scanning...";
			info = "> " + info;
			if(Math.Round(Time.realtimeSinceStartup) % 2 == 0) info += "_";
			r.x = where.x + 4;
			r.y = where.y + 8;
			GUI.Label(r, left(info, chars), style);
			if(!identified) return;

			r.x = where.x + 4;
			r.y = where.y + where.height - 60;
			string sname = lookat.name;
			Vector3 lookvec = lookat.transform.position;
			if(cons.Count > 0) {
				if(Event.current.type == EventType.ScrollWheel && where.Contains(Event.current.mousePosition)) {
					activeCon += cons.Count + (Event.current.delta.y > 0 ? 1 : -1);
					Event.current.Use();
					switchTime = Time.realtimeSinceStartup;
				}
				activeCon = activeCon % cons.Count;
				lookdetail = cons[activeCon];
				Vector3 pos = cam.WorldToScreenPoint(lookdetail.transform.position);
				lookvec = lookdetail.transform.position;
				sname = lookdetail.objectName;
			}
			if(sname != null) {
				GUI.Label(r, left(sname, chars), style);
				r.y += 30;
				GUI.Label(r, left(distanceString((FlightGlobals.ActiveVessel.transform.position - lookvec).magnitude), chars), style);
			}
			if(ticking) {
				if(Time.realtimeSinceStartup - lastTick > 1f/tickRate) {
					AudioSource.PlayClipAtPoint(tick, Camera.main.transform.position);
					lastTick = Time.realtimeSinceStartup;
				}
			}
		}

		public string left(string s, int cnt) {
			if(cnt >= s.Length) return s;
			ticking = true;
			return s.Substring(0, cnt);
		}

		public string distanceString(double dist) {
			if(dist < 5000) return dist.ToString("N1") + "m";
			return (dist / 1000d).ToString("N3") + "km";
		}

		public Texture getTexture() {
			updateCamera();
			return rt;
		}
	}
}