MegaBagar/FreeCam/Assets/BlockSpawner.cs

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

public class BlockSpawner : MonoBehaviour
{

    [SerializeField]
    private GameObject _blockToPlace;
    public GameObject BlockToPlace
    {
        get
        {
            return _blockToPlace;
        }
        set
        {
            DisablePreviewMode();
            _blockToPlace = value;
        }
    }

    public float spawnDistance = 3f;

    public Shader previewShader;
    private GameObject _blockInstance;


    private bool _isPreview = false;
    private Shader _initialShader;

    public void OnPlaceBlock()
    {
        if (!_isPreview) return;
        _blockInstance.transform.SetParent(null);
        SwitchToDefaultRender();
        _blockInstance = null;
        DisablePreviewMode();
    }

    public void OnTogglePreviewMode(InputValue value)
    {
        float valueAsFloat = value.Get<float>();

        if (valueAsFloat == 1f) EnablePreviewMode();
        else DisablePreviewMode();
    }

    private void EnablePreviewMode()
    {
        if (_blockToPlace == null) return;

        Vector3 spawnPos = Vector3.forward * spawnDistance;
        _blockInstance = Instantiate(_blockToPlace, spawnPos, Quaternion.identity);
        _blockInstance.transform.SetParent(this.transform, false);
        _isPreview = true;
        SwitchToMeshRender();
    }

    private void DisablePreviewMode()
    {
        if (_blockInstance != null) Destroy(_blockInstance);
        _isPreview = false;
    }

    private void SwitchToMeshRender()
    {
        MeshRenderer vRenderer = _blockInstance.GetComponent<MeshRenderer>();
        Material vMaterial = vRenderer.material;
        _initialShader = vMaterial.shader;
        vMaterial.shader = previewShader;
    }

    private void SwitchToDefaultRender()
    {
        MeshRenderer vRenderer = _blockInstance.GetComponent<MeshRenderer>();
        Material vMaterial = vRenderer.material;
        vMaterial.shader = _initialShader;
    }
}