code: def compute_splatting_colors_and_weights_naive(
      pixel_coords_screen, colors, sigma
  ):
      normalizer = float(_get_splat_kernel_normalization(offsets))
      N, H, W, K, _ = colors.shape
      splat_weights_and_colors = torch.zeros((N, H, W, K, 9, 5))
      for n in range(N):
          for h in range(H):
              for w in range(W):
                  for k in range(K):
                      q_xy = pixel_coords_screen[n, h, w, k]
                      q_to_px_center = torch.floor(q_xy) - q_xy + 0.5
                      color = colors[n, h, w, k]
                      alpha = colors[n, h, w, k, 3:4]
                      for d in range(9):
                          dist_p_q = torch.sum(
                              (q_to_px_center + offsets[d]) ** 2
                          )
                          splat_weight = (
                              alpha
                              * torch.exp(-dist_p_q / (2 * sigma**2))
                              * normalizer
                          )
                          splat_color = splat_weight * color
                          splat_weights_and_colors[
                              n, h, w, k, d, :4
                          ] = splat_color
                          splat_weights_and_colors[
                              n, h, w, k, d, 4:5
                          ] = splat_weight
      return splat_weights_and_colors
  
imports: import unittest
  import torch
  from pytorch3d.common.compat import meshgrid_ij
  from pytorch3d.renderer.cameras import FoVPerspectiveCameras
  from pytorch3d.renderer.splatter_blend import _compute_occlusion_layers, _compute_splatted_colors_and_weights, _compute_splatting_colors_and_weights, _get_splat_kernel_normalization, _normalize_and_compose_all_layers, _offset_splats, _precompute, _prepare_pixels_and_colors
  from .common_testing import TestCaseMixin
label_desc: Use image node_id 1 for calling a global function with example usage: compute_splatting_colors_and_weights_naive(pixel_coords_screen, colors, sigma) and returns: splat_weights_and_colors