Creating Mirrors Using Viewports (Rendering to Texture) or a Standard Material

using System;
using System.Collections;
using System.Collections.Generic;
using Unigine;

#region Math Variables
#if UNIGINE_DOUBLE
using Vec3 = Unigine.dvec3;
using Mat4 = Unigine.dmat4;
#else
using Vec3 = Unigine.vec3;
using Mat4 = Unigine.mat4;
#endif
#endregion

[Component(PropertyGuid = "AUTOGENERATED_GUID")] // <-- this line is generated automatically for a new component
public class CarMirrorsExample : Component
{
	enum VMode
	{
		MODE_VIEWPORT_SINGLE,   // use a single viewport for multiple cameras
		MODE_VIEWPORT_MULTIPLE  // use a separate viewport for each camera
	};

	// rearview mirror 
	struct Mirror
	{
		public ObjectMeshStatic mesh;                   // mirror mesh
		public String m_type;                           // mirror type (left/right/mid)
		public Texture texture;                         // mirror texture
		public PlayerDummy camera;                      // mirror camera
		public Viewport viewport;                       // mirror viewport
		public Vec3 position;                          // mirror position
	};

	const float MOVING_SPEED = 10.0f;               // speed of objects movement
	const float DELTA_ANGLE = 60.0f;                // delta angle of objects rotation
	const int ASPECT_RATIO = 1;                     // aspect ratio
	const float HFOV = 60;                          // horizontal field of view
	const float VFOV = HFOV / ASPECT_RATIO;         // vertical field of view
	VMode MODE = VMode.MODE_VIEWPORT_MULTIPLE;      // set viewport mode (single/multiple)

	ObjectMeshStatic car_frame;
	ObjectMeshDynamic material_mirror;
	Mirror[] mirrors = new Mirror[3];
	Controls controls;
	float ifps;

	///  Method creating a mirror using a Planar Reflection Probe
	public bool create_top_mirror()
	{
		// creating a reflecting plane for the top mirror 
		// onto which the reflection is to be projected by the probe
		material_mirror = Primitives.CreatePlane(0.8f, 0.3f, 1);

		// creating a planar reflection probe of the same size
		LightPlanarProbe planar_probe = new LightPlanarProbe();
		planar_probe.ProjectionSize = new vec3(1.0f, 0.5f, 1);
		// adding reflection plane and planar probe as children to the car frame
		car_frame.AddChild(material_mirror);
		car_frame.AddChild(planar_probe);
		
		// rotating the reflecting plane by 101 degrees around the X-axis and shifting it to its position
		material_mirror.Transform = MathLib.Translate(new Vec3(0.0f, 0.1f, 2.65)) * MathLib.RotateX(101.0f);

		// putting the planar probe so that it covers the reflecting surface
		planar_probe.Transform = material_mirror.Transform;

		// inheriting a new material from the one assigned
		// to the surface by default in order to tweak it
		// and set metalness and roughness values (metallic and polished)
		Material plane_mat = material_mirror.GetMaterialInherit(0);
		plane_mat.SetParameterFloat("metalness", 1.0f);
		plane_mat.SetParameterFloat("roughness", 0.0f);

		// setting the distance from the camera, up to which 
		// the planar reflection will be visible
		planar_probe.VisibleDistance = 5.0f;

		return true;
	}

	private void Init()
	{
		// setting texture width and height
		int width = 512;
		int height = width / ASPECT_RATIO;

		// creating car body using a mesh and passing it to the Editor
		car_frame = new ObjectMeshStatic("meshes/car_body.mesh");
		car_frame.SetMaterialParameterFloat4("albedo_color", new vec4(1.0f, 0.0f, 0.0f, 1.0f), 0);

		// creating a top rearview mirror a Planar Reflection Probe
		create_top_mirror();

		// setting type and position for all mirrors
		mirrors[0].m_type = "left";
		mirrors[1].m_type = "mid";
		mirrors[2].m_type = "right";
		mirrors[0].position = new Vec3(-1.8f, 1.0f, 1.1f);
		mirrors[1].position = new Vec3(0.0f, 0.35f, 2.45f);
		mirrors[2].position = new Vec3(1.8f, 1.0f, 1.1f);

		// initializing mirrors
		for (int i = 0; i < 3; i++)
		{
			// creating the current mirror and setting its transform
			mirrors[i].mesh = new ObjectMeshStatic("meshes/mirror_plane.mesh");
			mirrors[i].mesh.Transform = new mat4(MathLib.Translate(new Vec3(mirrors[i].position)) * MathLib.RotateX(90.0f));

			// creating and setting materials for the current mirror mesh
			Material mesh_base = Materials.FindManualMaterial("Unigine::mesh_base");
			Material car_mirror = mesh_base.Inherit();
			mirrors[i].mesh.SetMaterial(car_mirror, 0);

			// creating a camera for the current mirror and setting its parameters
			mirrors[i].camera = new PlayerDummy();
			mirrors[i].camera.Projection = MathLib.Perspective(VFOV, 2.0f, 0.05f, 10000.0f) * MathLib.Scale(-1.0f, 1.0f, 1.0f);
			mirrors[i].camera.Position = mirrors[i].position;
			mirrors[i].camera.SetDirection(new vec3(0.0f, -1.0f, 0.0f), vec3.UP);

			// adding mirror mesh and camera as children to the car frame 
			car_frame.AddChild(mirrors[i].mesh);
			car_frame.AddChild(mirrors[i].camera);

			// creating a 2D texture to be set for the mirror material
			mirrors[i].texture = new Texture();

			mirrors[i].texture.Create2D(width, height, Texture.FORMAT_RGBA8, Texture.FORMAT_USAGE_RENDER);

			// checking viewport mode and creating necessary number of viewports
			if (MODE == VMode.MODE_VIEWPORT_MULTIPLE)
			{
				mirrors[i].viewport = new Viewport();
			} else if ((MODE == VMode.MODE_VIEWPORT_SINGLE) && (i == 1))
			{
				mirrors[i].viewport = new Viewport();
			}
		}

		// setting up player and controls
		PlayerSpectator player = new PlayerSpectator();
		car_frame.AddChild(player);
		player.WorldPosition = new Vec3(0.0f, -1.7f, 2.0f);
		player.Controlled = false;
		Game.Player = player;
		Game.Enabled = true;
		player.Fov = 60.0f;
		player.SetDirection(new vec3(0.0f, 1.0f, 0.0f), new vec3(0.0f, 0.0f, 1.0f));
		player.Collision = 0;
		controls = player.Controls;
	}

	private void Update()
	{
		ifps = Engine.IFps;
		// getting the current world transformation matrix of the mesh
		Mat4 transform = car_frame.WorldTransform;

		// getting the direction vector of the mesh from the second column of the transformation matrix
		Vec3 direction = transform.GetColumn3(1);

		// checking controls states and changing car frame transformation
		if ((controls.GetState(Controls.STATE_FORWARD) == 1) || (controls.GetState(Controls.STATE_TURN_UP) == 1))
		{
			car_frame.WorldPosition = car_frame.WorldPosition + direction * MOVING_SPEED * ifps;
		}
		if ((controls.GetState(Controls.STATE_BACKWARD) == 1) || (controls.GetState(Controls.STATE_TURN_DOWN) == 1))
		{
			car_frame.WorldPosition = car_frame.WorldPosition - direction * MOVING_SPEED * ifps;
		}
		if ((controls.GetState(Controls.STATE_MOVE_LEFT) == 1) || (controls.GetState(Controls.STATE_TURN_LEFT) == 1))
		{
			car_frame.SetWorldRotation(car_frame.GetWorldRotation() * new quat(0.0f, 0.0f, DELTA_ANGLE * ifps));
			direction.z += DELTA_ANGLE * ifps;
		}
		if ((controls.GetState(Controls.STATE_MOVE_RIGHT) == 1) || (controls.GetState(Controls.STATE_TURN_RIGHT) == 1))
		{
			car_frame.SetWorldRotation(car_frame.GetWorldRotation() * new quat(0.0f, 0.0f, -DELTA_ANGLE * ifps));
			direction.z -= DELTA_ANGLE * ifps;
		}
	}

	private void PostUpdate()
	{
		Viewport viewport;

		for (int i = 0; i < 3; i++)
		{
			if (MODE == VMode.MODE_VIEWPORT_MULTIPLE)
			{
				// using a separate viewport for each camera
				viewport = mirrors[i].viewport;
			} else
			{
				// using a single viewport for all cameras
				viewport = mirrors[1].viewport;

				// skipping post effects when using a single viewport for multiple cameras to avoid artefacts
				viewport.AppendSkipFlags(Viewport.SKIP_POSTEFFECTS);
			}

			// saving current render state and clearing it 
			RenderState.SaveState();
			RenderState.ClearStates();

			// enabling polygon front mode to correct camera flipping
			RenderState.PolygonFront = 1;

			// rendering and image from the camera of the current mirror to the texture
			viewport.RenderTexture2D(mirrors[i].camera.Camera, mirrors[i].texture);

			// restoring back render state
			RenderState.PolygonFront = 0;
			RenderState.RestoreState();

			Material material = mirrors[i].mesh.GetMaterialInherit(0);
			// setting rendered texture as albedo texture for the material of the current mirror
			material.SetTexture(material.FindTexture("albedo"), mirrors[i].texture);
		}
	}
}