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

// Car.h
#ifndef __CAR_H__
#define __CAR_H__
#include <UnigineEngine.h>
#include <UnigineObjects.h>
#include <UnigineMaterials.h>
#include <UnigineViewport.h>
#include <UnigineEditor.h>
#include <UnigineGame.h>
#include <UnigineRender.h>

enum
{
	MODE_VIEWPORT_SINGLE = 0,				// use a single viewport for multiple cameras
	MODE_VIEWPORT_MULTIPLE					// use a separate viewport for each camera
};

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 = 2;					// aspect ratio
const double HFOV = 60;						// horizontal field of view for mirror cameras
const double VFOV = HFOV / ASPECT_RATIO;	// vertical field of view for mirror cameras




// rearview mirror 
struct Mirror {
	Unigine::ObjectMeshStaticPtr mesh;		// mirror mesh
	Unigine::String m_type;					// mirror type (left/right/mid)
	Unigine::TexturePtr texture;			// mirror texture
	Unigine::PlayerDummyPtr camera;			// mirror camera
	Unigine::ViewportPtr viewport;			// mirror viewport
	Unigine::Math::Vec3 position;			// mirror position
};

class Car 
{
public:
	Car()	{	}
	~Car()	{	}

	int create_top_mirror();
	int init();
	int update();
	int render();
	int shutdown();

	Unigine::ObjectMeshStaticPtr car_frame;
	Unigine::ObjectMeshStaticPtr material_mirror;

	Mirror mirrors[3];
	Unigine::ControlsPtr controls;
};
#endif // __CAR_H__

// Car.cpp

#include "Car.h"
#include <UnigineConsole.h>

using namespace Unigine;
using namespace Math;

// setting viewport mode (single/multiple)
int VMODE = MODE_VIEWPORT_MULTIPLE;

///  method creating a mirror using the mesh_base "planar reflection" option
int Car::create_top_mirror() {

	// creating a mesh with a plane surface for the top mirror
	MeshPtr mesh = Mesh::create();
	mesh->addPlaneSurface("plane", 1.97f, 0.3f, 1.0f);

	// rotating the mesh surface by 108 degrees around the X-axis
	mesh->setSurfaceTransform(rotateX(108.0f));

	// creating a top mirror and setting its position
	material_mirror = ObjectMeshStatic::create(mesh);
	material_mirror->setPosition(Vec3(0.0f, 0.73f, 1.60f));

	car_frame->addChild(material_mirror);

	// creating a new mirror material named "planar_reflector"
	MaterialPtr mesh_base = Materials::findMaterial("mesh_base");
    MaterialPtr reflector_material = mesh_base->inherit("planar_reflector");

	// enabling planar reflections for the mirror material
	reflector_material->setState("planar_reflection", 1);

	// setting metallness and roughness parameters to make the surface look like a mirror
	reflector_material->setParameterSlider(reflector_material->findParameter("metalness"), 1.0f);
	reflector_material->setParameterSlider(reflector_material->findParameter("roughness"), 0.0f);

	// compensating the 108-degree rotation angle of the mesh surface
	reflector_material->setParameter(reflector_material->findParameter("reflection_pivot_rotation"), vec4(108.0f, 0.0f, 0.0f, 0.0f));

	// assigning new mirror material to the surface of the mirror
	material_mirror->setMaterial("planar_reflector", 0);

	// enabling planar reflections rendering using the corresponding console command (render_reflection_dynamic)
	Console::run("render_reflection_dynamic 1");

	return 1;
}

int Car::init()
{
	int width = 512;
	int height = width / ASPECT_RATIO;

	// preparing a mesh for the car body
	MeshPtr bodymesh = Mesh::create();
	bodymesh->addBoxSurface("body", vec3(2.0f, 5.0f, 1.2f));
	bodymesh->addBoxSurface("body", vec3(0.05f, 0.05f, 1.1f));
	bodymesh->setSurfaceTransform(translate(vec3(0.96f, 0.8f, 0.91f)), 1);
	bodymesh->addBoxSurface("body", vec3(0.05f, 0.05f, 1.1f));
	bodymesh->setSurfaceTransform(translate(vec3(-0.96f, 0.8f, 0.91f)), 2);
	bodymesh->addBoxSurface("body", vec3(1.88f, 0.05f, 0.05f));
	bodymesh->setSurfaceTransform(translate(vec3(0.0f, 0.8f, 1.435f)), 3);

	// creating car body using a mesh
	car_frame = ObjectMeshStatic::create(bodymesh);
	car_frame->setMaterial("mesh_base", "*");
	car_frame->setMaterialParameterFloat4("albedo_color", vec4(1.0f, 0.0f, 0.0f, 1.0f), 0);

	// creating a top rearview mirror using the mesh_base material
	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 = Vec3(-1.08f, 0.77f, 0.9f);
	mirrors[1].position = Vec3(0.0f, 0.35f, 1.25f);
	mirrors[2].position = Vec3(1.08f, 0.77f, 0.9f);

	// initializing mirrors
	for (int i = 0; i < 3; i++)
	{
		// creating a mesh for the current mirror
		MeshPtr mesh = Mesh::create();
		mesh->addPlaneSurface("mirror_plane", 0.2f, 0.1f, 1);

		// creating the current mirror and setting its transform
		mirrors[i].mesh = ObjectMeshStatic::create(mesh);
		mirrors[i].mesh->setTransform(Mat4(translate(vec3(mirrors[i].position))*rotateX(90.0f)));

		// creating and setting materials for the current mirror mesh
		String str = String::format("car_mirror_%s", mirrors[i].m_type.get());
		MaterialPtr mesh_base = Materials::findMaterial("mesh_base");
		mesh_base->inherit(str.get());
		mirrors[i].mesh->setMaterial(str.get(), 0);

		// creating a camera for the current mirror and setting its parameters
		mirrors[i].camera = PlayerDummy::create();
		mirrors[i].camera->setProjection(perspective(VFOV, 2.0, 0.05, 10000) * scale(-1.0f, 1.0f, 1.0f));
		mirrors[i].camera->setPosition(mirrors[i].position);
		mirrors[i].camera->setDirection(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 = Texture::create();
		mirrors[i].texture->create2D(width, height, Texture::FORMAT_RGBA8, Texture::USAGE_RENDER);

		// checking viewport mode and creating necessary number of viewports
		if (VMODE == MODE_VIEWPORT_MULTIPLE)
		{
			mirrors[i].viewport = Viewport::create();
		}
		else if ((VMODE == MODE_VIEWPORT_SINGLE) && (i == 1))
		{
			mirrors[i].viewport = Viewport::create();
		}
	}
	
	// setting up player and controls
	PlayerSpectatorPtr player = PlayerSpectator::create();
	
	car_frame->addChild(player);
	player->setWorldPosition(Vec3(0.0f, -0.5f, 1.1f));
	player->setControlled(0);
	Game::setPlayer(player);
	Game::setEnabled(1);
	player->setFov(60.0f);
	player->setDirection(vec3(0.0f, 1.0f, 0.0f), vec3(0.0f, 0.0f, -1.0f));
	player->setCollision(0);
	controls = player->getControls();

	return 1;
}

float ifps;

int Car::update()
{
	ifps = Game::getIFps();
	// get the current world transformation matrix of the mesh
	Mat4 transform = car_frame->getWorldTransform();

	// get 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) || controls->getState(Controls::STATE_TURN_UP))
	{
		car_frame->setWorldPosition(car_frame->getWorldPosition() + direction * MOVING_SPEED*ifps);
	}
	if (controls->getState(Controls::STATE_BACKWARD) || controls->getState(Controls::STATE_TURN_DOWN))
	{
		car_frame->setWorldPosition(car_frame->getWorldPosition() - direction * MOVING_SPEED*ifps);
	}
	if (controls->getState(Controls::STATE_MOVE_LEFT) || controls->getState(Controls::STATE_TURN_LEFT))
	{
		car_frame->setWorldRotation(car_frame->getWorldRotation() * quat(0.0f, 0.0f, DELTA_ANGLE*ifps));
		direction.z += DELTA_ANGLE*ifps;
	}
	if (controls->getState(Controls::STATE_MOVE_RIGHT) || controls->getState(Controls::STATE_TURN_RIGHT))
	{
		car_frame->setWorldRotation(car_frame->getWorldRotation() * quat(0.0f, 0.0f, -DELTA_ANGLE*ifps));
		direction.z -= DELTA_ANGLE*ifps;
	}

	return 1;
}

int Car::render()
{
	ViewportPtr viewport;

	for (int i = 0; i < 3; i++)
	{
		MaterialPtr material = mirrors[i].mesh->getMaterialInherit(0);
		
		if (VMODE == MODE_VIEWPORT_MULTIPLE)
		{
			// using a separate viewport for each camera
			viewport = mirrors[i].viewport;
		}
		else if (VMODE == MODE_VIEWPORT_SINGLE)
		{
			// using a single viewport for all cameras
			viewport = mirrors[1].viewport;

			// skipping post effects when using a single viewport for multiple cameras
			viewport->appendSkipFlags(Viewport::SKIP_POSTEFFECTS);
		}

		// rendering

		// saving current render state and clearing it 
		RenderState::saveState();
		RenderState::clearStates();
		
		// enabling polygon front mode to correct camera flipping
		RenderState::setPolygonFront(1);
		
		// rendering and image from the camera of the current mirror to the texture
		viewport->renderTexture2D(mirrors[i].camera->getCamera(), mirrors[i].texture);

		// restoring back render state
		RenderState::setPolygonFront(0);
		RenderState::restoreState();

		// setting rendered texture as albedo texture for the material of the current mirror
		material->setTexture(material->findTexture("albedo"), mirrors[i].texture);

	}

	return 1;
}

int Car::shutdown()
{
	car_frame.clear();

	for (int i = 0; i < 3; i++)
	{
		mirrors[i].mesh.clear();
		mirrors[i].texture.clear();
		mirrors[i].camera.clear();
	}

	return 1;
}

// AppWorldLogic.h
#ifndef __APP_WORLD_LOGIC_H__
#define __APP_WORLD_LOGIC_H__

#include <UnigineLogic.h>
#include <UnigineStreams.h>
#include "car.h"

class AppWorldLogic : public Unigine::WorldLogic {
	
public:

	/* .. */

	Car car;
};

#endif // __APP_WORLD_LOGIC_H__

// AppWorldLogic.cpp

#include "AppWorldLogic.h"

/* .. */


int AppWorldLogic::init() {
	
	// creating and initializing a car
	car.init();
    
	return 1;
}

// start of the main loop
int AppWorldLogic::update() {

	// calling car update
	car.update();

	return 1;
}

int AppWorldLogic::postUpdate() {
	
	// calling car render
	car.render();

	return 1;
}

int AppWorldLogic::shutdown() {

	// calling car shutdown
	car.shutdown();

	return 1;
}

/* .. */