Fixed last commit, make NearestNeighbour extraction work with the 8UC4 isomap

include/eos/render/texture_extraction.hpp

@@ -245,7 +245,13 @@ inline cv::Mat extract_texture(Mesh mesh, cv::Mat affine_camera_matrix, cv::Mat
 						Vec2f src_texel = Mat(warp_mat_org_inv * Mat(homogenous_dst_coord));
 
 						if ((cvRound(src_texel[1]) < image.rows) && (cvRound(src_texel[0]) < image.cols) && cvRound(src_texel[0]) > 0 && cvRound(src_texel[1]) > 0)
-							isomap.at<cv::Vec3b>(y, x) = image.at<cv::Vec3b>(cvRound(src_texel[1]), cvRound(src_texel[0]));
+						{
+							cv::Vec4b isomap_pixel;
+							isomap.at<cv::Vec4b>(y, x)[0] = image.at<Vec3b>(cvRound(src_texel[1]), cvRound(src_texel[0]))[0];
+							isomap.at<cv::Vec4b>(y, x)[1] = image.at<Vec3b>(cvRound(src_texel[1]), cvRound(src_texel[0]))[1];
+							isomap.at<cv::Vec4b>(y, x)[2] = image.at<Vec3b>(cvRound(src_texel[1]), cvRound(src_texel[0]))[2];
+							isomap.at<cv::Vec4b>(y, x)[3] = static_cast<uchar>(255); // pixel is visible
+						}
 					}
 				}
 			}