Duality-BackgroundScroller-Example/Source/Code/CorePlugin/BackgroundScroller.cs

using Duality;
using Duality.Components;
using Duality.Components.Renderers;
using Duality.Resources;

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;


namespace BackGroundScroller_Example
{
    //BackgroundScroller - Maintains/Creates/Moves layerss
    public class BackgroundScroller : Component, ICmpInitializable
    {

        //vertical offset can be defined
        private float z_PosFront;
        private float z_PosMid;
        private float z_PosBack;

        public float zOffsetFront
        {
            get { return this.z_PosFront; }
            set { this.z_PosFront = value; }
        }

        public float zOffsetMid
        {
            get { return this.z_PosMid; }
            set { this.z_PosMid = value; }
        }

        public float zOffsetBack
        {
            get { return this.z_PosBack; }
            set { this.z_PosBack = value; }
        }

        //due to vertical offset some layers might need a upscale
        private float scaleFront;
        private float scaleMid;
        private float scaleBack;

        public float ScaleFrontLayer
        {
            get { return this.scaleFront; }
            set { this.scaleFront = value; }
        }

        public float ScaleMidLayer
        {
            get { return this.scaleMid; }
            set { this.scaleMid = value; }
        }

        public float ScaleBackLayer
        {
            get { return this.scaleBack; }
            set { this.scaleBack = value; }
        }

        //Load Prefabs used to generate the spawning background -> further in developement this will be removed for
        //an automation which pics the created prefab due to a master level plan given by the level handler
        private ContentRef<Prefab> frontLayerPrefab;
        private ContentRef<Prefab> midLayerPrefab;
        private ContentRef<Prefab> backLayerPrefab;

        public ContentRef<Prefab> FrontLayerPrefab
        {
            get { return this.frontLayerPrefab; }
            set { this.frontLayerPrefab = value; }
        }

        public ContentRef<Prefab> MidLayerPrefab
        {
            get { return this.midLayerPrefab; }
            set { this.midLayerPrefab = value; }
        }

        public ContentRef<Prefab> BackLayerPrefab
        {
            get { return this.backLayerPrefab; }
            set { this.backLayerPrefab = value; }
        }

        

        //Layerlists to maintain and iterate through all on a certain z-level
        Dictionary<GameObject, ContentRef<Prefab>> FrontLayers;
        Dictionary<GameObject, ContentRef<Prefab>> MidLayers;
        Dictionary<GameObject, ContentRef<Prefab>> BackLayers;

        public void OnInit(InitContext context)
        {
            FrontLayers = new Dictionary<GameObject, ContentRef<Prefab>>();
            MidLayers = new Dictionary<GameObject, ContentRef<Prefab>>();
            BackLayers = new Dictionary<GameObject, ContentRef<Prefab>>();
        }

        public void OnShutdown(ShutdownContext context)
        {

        }


        public void Update(float camSpeed, Camera mainCam)
        {

            //Copy of bluebrints given by levelHandler to enable on the fly prefab changing
            //Check if LayerList is empty, if yes startscreen has to be initialized
            if (BackLayers.Count == 0 && MidLayers.Count == 0 && FrontLayers.Count == 0)
            {
                Vector3 tmpPos = new Vector3();
                GameObject tmpLayer;
                float textureWidth;
                float tmpScale;

                //The startconstellation is a mainscreen, a 1 x left offscreen layer and 1 x rightoffscreen layer

                //FrontLayers Preset (3 : 1 x LeftOffscreen, 1 x Mainscreen, 1 x RightOffscreen)
                GameObject newFront = FrontLayerPrefab.Res.Instantiate();
                textureWidth = newFront.GetComponent<SpriteRenderer>().SharedMaterial.Res.MainTexture.Res.Size.X;
                tmpScale = scaleFront;
                tmpPos.Z = zOffsetFront;

                //LeftOffscreen-Front
                tmpPos.X = -textureWidth * tmpScale;
                tmpLayer = createLayer(FrontLayerPrefab, tmpPos,tmpScale, "Front");
                FrontLayers.Add(tmpLayer, FrontLayerPrefab);

                //MainScreen-Front
                tmpPos.X = 0;
                tmpLayer = createLayer(FrontLayerPrefab, tmpPos, tmpScale, "Front");
                FrontLayers.Add(tmpLayer, FrontLayerPrefab);

                //RightOffscreen-Front
                tmpPos.X = textureWidth * tmpScale;
                tmpLayer = createLayer(FrontLayerPrefab, tmpPos, tmpScale, "Front");
                FrontLayers.Add(tmpLayer, FrontLayerPrefab);

                //MidLayers Preset (3 : 1 x LeftOffscreen, 1 x Mainscreen, 1 x RightOffscreen)
                GameObject newMid = MidLayerPrefab.Res.Instantiate();
                textureWidth = newMid.GetComponent<SpriteRenderer>().SharedMaterial.Res.MainTexture.Res.Size.X;
                tmpScale = scaleMid;
                tmpPos.Z = zOffsetMid;

                //LeftOffscreen-Mid
                tmpPos.X = -textureWidth * tmpScale;
                tmpLayer = createLayer(MidLayerPrefab, tmpPos, tmpScale, "Mid");
                MidLayers.Add(tmpLayer, MidLayerPrefab);

                //MainScreen-Mid
                tmpPos.X = 0;
                tmpLayer = createLayer(MidLayerPrefab, tmpPos, tmpScale, "Mid");
                MidLayers.Add(tmpLayer, MidLayerPrefab);

                //RightOffscreen-Mid
                tmpPos.X = textureWidth * tmpScale;
                tmpLayer = createLayer(MidLayerPrefab, tmpPos, tmpScale, "Mid");
                MidLayers.Add(tmpLayer, MidLayerPrefab);

                //BackLayers Preset (3 : 1 x LeftOffscreen, 1 x Mainscreen, 1 x RightOffscreen)
                GameObject newBack = BackLayerPrefab.Res.Instantiate();
                textureWidth = newBack.GetComponent<SpriteRenderer>().SharedMaterial.Res.MainTexture.Res.Size.X;
                tmpPos.Z = zOffsetBack;
                tmpScale = scaleBack;

                //LeftOffscreen-Back
                tmpPos.X = -textureWidth * tmpScale;
                tmpLayer = createLayer(BackLayerPrefab, tmpPos, tmpScale, "Back");
                BackLayers.Add(tmpLayer, BackLayerPrefab);

                //MainScreen-Back
                tmpPos.X = 0;
                tmpLayer = createLayer(BackLayerPrefab, tmpPos, tmpScale, "Back");
                BackLayers.Add(tmpLayer, BackLayerPrefab);

                //RightOffscreen-Back
                tmpPos.X = textureWidth * tmpScale;
                tmpLayer = createLayer(BackLayerPrefab, tmpPos, tmpScale, "Back");
                BackLayers.Add(tmpLayer, BackLayerPrefab);

            }

            // check if layers need to be killed/created by iterating through 
            //them and check their position relativ to the cam
            UpdatePosition(mainCam, camSpeed);

        }

        // Mechanisms to instantiate from the given prefabs and to add the new objects to the handled lists
        private GameObject createLayer(ContentRef<Prefab> Prefab, Vector3 StartPos,float scale, string LayerName)
        {
            GameObject newLayer = Prefab.Res.Instantiate();
            newLayer.Transform.MoveToAbs(StartPos*scale);
            newLayer.Transform.Scale = scale;
            newLayer.Parent = this.GameObj.ChildByName(LayerName);
            return newLayer;
        }


        private void UpdatePosition(Camera cam, float speed)
        {
            //temporal list to still be able to delete objects while iterating through
            Dictionary<GameObject, ContentRef<Prefab>> LayersToMove = new Dictionary<GameObject, ContentRef<Prefab>>();

            //Enlist all layers from all lists to prepare for iteration
            foreach (KeyValuePair<GameObject, ContentRef<Prefab>> KeyPair in BackLayers)
            {
                if (KeyPair.Key != null)
                {
                    LayersToMove.Add(KeyPair.Key, KeyPair.Value);
                }
            }

            foreach (KeyValuePair<GameObject, ContentRef<Prefab>> KeyPair in MidLayers)
            {
                if (KeyPair.Key != null)
                {
                    LayersToMove.Add(KeyPair.Key, KeyPair.Value);
                }
            }

            foreach (KeyValuePair<GameObject, ContentRef<Prefab>> KeyPair in FrontLayers)
            {
                if (KeyPair.Key != null)
                {
                    LayersToMove.Add(KeyPair.Key, KeyPair.Value);
                }
            }

            //Dictionary of layers is iterated and each is checked for leaving visible area + extra safety screen
            foreach (KeyValuePair<GameObject, ContentRef<Prefab>> KeyPair in LayersToMove)
            {

                //Calculate the spritesize for the recreation process
                float screenWidth = 1366f; //has to be the actual screensize
                float textureWidth;
                float tmpZOffset = 0f;
                float tmpScale = 1f;
                string layerName = "";

                //if offscreen the object is erased from the list and disposed at the next cicle
                if (KeyPair.Key.Transform.Pos.X <= cam.GameObj.Transform.Pos.X - (2 * screenWidth * KeyPair.Key.Transform.Scale) ||
                    KeyPair.Key.Transform.Pos.X >= cam.GameObj.Transform.Pos.X + (2 * screenWidth * KeyPair.Key.Transform.Scale))
                {

                    KeyPair.Key.DisposeLater();

                    //Create new Layer based on destructed one
                    Vector3 tmpPos = new Vector3();
                    textureWidth = KeyPair.Key.GetComponent<SpriteRenderer>().SharedMaterial.Res.MainTexture.Res.Size.X *
                                   KeyPair.Key.GetComponent<Transform>().Scale;
                     
                    //Find type of layer in the whole list and set its config to create a similar layer
                    if (BackLayers.ContainsKey(KeyPair.Key))
                    {
                        BackLayers.Remove(KeyPair.Key);
                        layerName = "Back";
                        tmpZOffset = z_PosBack;
                        tmpScale = scaleBack;
                    }

                    if (MidLayers.ContainsKey(KeyPair.Key))
                    {
                        MidLayers.Remove(KeyPair.Key);
                        layerName = "Mid";
                        tmpZOffset = z_PosMid;
                        tmpScale = scaleMid;
                    }

                    if (FrontLayers.ContainsKey(KeyPair.Key))
                    {
                        FrontLayers.Remove(KeyPair.Key);
                        layerName = "Front";
                        tmpZOffset = z_PosFront;
                        tmpScale = scaleFront;
                    }

                    //Determine which side the layer has to be knitted onto
                    if (KeyPair.Key.Transform.Pos.X <= cam.GameObj.Transform.Pos.X - (2 * screenWidth * tmpScale))
                        tmpPos.X = KeyPair.Key.Transform.Pos.X + 3 * textureWidth * tmpScale;
                    else
                        tmpPos.X = KeyPair.Key.Transform.Pos.X - 3 * textureWidth * tmpScale;

                    tmpPos.Z = tmpZOffset;

                    //Temporary GameObject for Instantiation and temporary Keypair for adding to the dictionary
                    GameObject tmpLayer;
                    tmpLayer = createLayer(KeyPair.Value, tmpPos, tmpScale, layerName);
                    KeyValuePair<GameObject, ContentRef<Prefab>> tmpKeyPair = new KeyValuePair<GameObject, ContentRef<Prefab>>(tmpLayer, KeyPair.Value);

                    switch (layerName)
                    {
                        case "Front": FrontLayers.Add(tmpKeyPair.Key, tmpKeyPair.Value); break;
                        case "Mid": MidLayers.Add(tmpKeyPair.Key, tmpKeyPair.Value); break;
                        case "Back": BackLayers.Add(tmpKeyPair.Key, tmpKeyPair.Value); break;
                    }
                }
            }
        }
    }
}