3D 씬의 실시간 2D 픽셀 아트화 (Low-Res RenderTexture & Point Upscaling)

using UnityEngine;
using UnityEngine.UI;

[RequireComponent(typeof(Camera))]
public class PixelArtRenderFeatureController : MonoBehaviour
{
    [Header("타겟 저해상도 (레트로 해상도)")]
    [SerializeField] private int targetWidth = 320;
    [SerializeField] private int targetHeight = 180;

    [Header("출력 캔버스 RawImage (전체 화면)")]
    [SerializeField] private RawImage displayScreen;

    private RenderTexture _pixelRenderTexture;
    private Camera _camera;

    private void Awake()
    {
        _camera = GetComponent<Camera>();
        CreatePixelRenderTexture();
    }

    private void CreatePixelRenderTexture()
    {
        // 1. 기존 텍스처 해제
        if (_pixelRenderTexture != null)
        {
            _camera.targetTexture = null;
            _pixelRenderTexture.Release();
        }

        // 2. 도트 느낌을 위한 핵심: FilterMode.Point (바이리니어 블러 제거)
        _pixelRenderTexture = new RenderTexture(targetWidth, targetHeight, 24, RenderTextureFormat.ARGB32)
        {
            filterMode = FilterMode.Point,
            antiAliasing = 1, // 안티앨리어싱을 꺼야 도트 경계가 살아남
            useMipMap = false
        };
        _pixelRenderTexture.Create();

        // 3. 카메라 타겟 바인딩
        _camera.targetTexture = _pixelRenderTexture;

        // 4. UI 캔버스 RawImage로 풀스크린 전송
        if (displayScreen != null)
        {
            displayScreen.texture = _pixelRenderTexture;
        }
    }

    private void OnDestroy()
    {
        if (_pixelRenderTexture != null)
        {
            _pixelRenderTexture.Release();
            Destroy(_pixelRenderTexture);
        }
    }
}