Preview

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

public class BuildSystem : MonoBehaviour
{
    public Demo_ObjectData currentPreview;

    public GameObject selectedPrefab;

    public Material previewMaterial;
    public Material previewDeniedMaterial;

    public Renderer[] renderers;

    public bool allowPlacement = true;

    public GameObject collisionBox;

    void Update()
    {
        UpdatePlacement();
        MovePreview();
    }

    public void UpdatePlacement()
    {
        if (selectedPrefab == null)
        {
            return;
        } else
        {
            if (!PreviewExists())
            {
                CreatePreview(selectedPrefab);
            }
        }
    }

    public void CreatePreview(GameObject prefab)
    {
        currentPreview = Instantiate(prefab).GetComponent<Demo_ObjectData>();
    }

    public void InitializedRenders(GameObject prefab)
    {

    }

    public void MovePreview()
    {
        if (currentPreview != null)
        {
            Ray ray = Camera.main.ScreenPointToRay(new Vector3(Input.mousePosition.x, Input.mousePosition.y, 1.0f));

            int layer_mask = LayerMask.GetMask("Room");

            if (Physics.Raycast(ray, out RaycastHit Hit, Mathf.Infinity, layer_mask, QueryTriggerInteraction.Ignore))
                currentPreview.transform.position = Hit.point;

            collisionBox.transform.parent = currentPreview.transform.GetChild(0);

            float WheelAxis = Input.GetAxis("Mouse ScrollWheel");

            if (Input.GetKey(KeyCode.LeftShift))
            {
                if (WheelAxis > 0)
                    currentPreview.transform.GetChild(0).eulerAngles += new Vector3(currentPreview.transform.localRotation.x, Rotation(currentPreview.transform.GetChild(0).eulerAngles.y), currentPreview.transform.localRotation.z);
                else if (WheelAxis < 0)
                    currentPreview.transform.GetChild(0).eulerAngles += new Vector3(currentPreview.transform.localRotation.x, -NegativeRotation(currentPreview.transform.GetChild(0).eulerAngles.y), currentPreview.transform.localRotation.z);
            }
            else
            {
                if (WheelAxis > 0)
                    currentPreview.transform.GetChild(0).eulerAngles += new Vector3(currentPreview.transform.localRotation.x, currentPreview.smoothRotation, currentPreview.transform.localRotation.z);
                else if (WheelAxis < 0)
                    currentPreview.transform.GetChild(0).eulerAngles += new Vector3(currentPreview.transform.localRotation.x, -currentPreview.smoothRotation, currentPreview.transform.localRotation.z);
            }


            if (allowPlacement)
            {
                renderers = currentPreview.GetComponentsInChildren<Renderer>();

                foreach (var rend in renderers)
                {
                    rend.sharedMaterial = previewMaterial;
                }

                if (Input.GetMouseButtonDown(0))
                {
                    PlacePrefab(currentPreview, currentPreview.transform.position, currentPreview.transform.eulerAngles);
                }
            }
            else
            {
                renderers = currentPreview.GetComponentsInChildren<Renderer>();

                foreach (var rend in renderers)
                {
                    rend.sharedMaterial = previewDeniedMaterial;
                }
            }
        }
    }

    public bool PreviewExists()
    {
        return currentPreview;
    }

    public void PlacePrefab(Demo_ObjectData part, Vector3 position, Vector3 rotation)
    {
        collisionBox.transform.eulerAngles = Vector3.zero;

        collisionBox.transform.parent = null;

        GameObject PlacedTemp = Instantiate(part.gameObject, position, Quaternion.Euler(rotation));

        renderers = PlacedTemp.GetComponentsInChildren<Renderer>();

        foreach (var rend in renderers)
        {
            rend.sharedMaterial = PlacedTemp.GetComponent<Demo_ObjectData>().initialMaterial;
        }

        PlacedTemp.transform.parent = GameMaster.Instance.BuildingManager.currentBuilding.transform;

        GameMaster.Instance.placedParts.Add(PlacedTemp);

        selectedPrefab = null;

        Destroy(currentPreview.gameObject);
        currentPreview = null;
    }

    IEnumerator RotateObject(float angle)
    {
        Quaternion initialRot = currentPreview.transform.GetChild(0).transform.rotation;
        Quaternion endRot = Quaternion.Euler(initialRot.x, initialRot.y + angle, initialRot.z);
        float elapsed = 0.0f;
        while (elapsed < 1f)
        {
            currentPreview.transform.GetChild(0).transform.rotation = Quaternion.Slerp(initialRot, endRot, elapsed / 1f);
            elapsed += Time.deltaTime;
            yield return null;
        }
        currentPreview.transform.GetChild(0).transform.rotation = endRot;
    }

    public float Rotation(float rotationAngle)
    {
        float angle = Mathf.Abs(rotationAngle);
        if (angle == 180)
            angle = 270 - angle;
        if (angle < 90)
            angle = 90 - angle;
        if (angle > 89 && angle < 180)
            angle = 180 - angle;
        if (angle > 179 && angle < 270)
            angle = 270 - angle;
        if (angle > 269)
            angle = 360 - angle;

        return angle;
    }
    public float NegativeRotation(float rotationAngle)
    {
        if (rotationAngle == 180)
            rotationAngle = 90f;
        if (rotationAngle > 89 && rotationAngle < 180)
            rotationAngle = rotationAngle - 90f;
        if (rotationAngle > 179 && rotationAngle < 270)
            rotationAngle = rotationAngle - 180f;
        if (rotationAngle > 269)
            rotationAngle = rotationAngle - 270;

        return rotationAngle;
    }
}