From ab8792cc7b809a5004f7989b9228f231dee2c1bc Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bart=C5=82omiej=20Karwacki?= <b.karwacki@gmail.com>
Date: Tue, 2 May 2023 12:03:01 +0200
Subject: [PATCH] Add vertex color support to OBJ importer

---
 editor/import/resource_importer_obj.cpp | 23 ++++++++++++++++++++++-
 1 file changed, 22 insertions(+), 1 deletion(-)

diff --git a/editor/import/resource_importer_obj.cpp b/editor/import/resource_importer_obj.cpp
index 6207ef0bf06..fcd3793c706 100644
--- a/editor/import/resource_importer_obj.cpp
+++ b/editor/import/resource_importer_obj.cpp
@@ -214,6 +214,7 @@ static Error _parse_obj(const String &p_path, List<Ref<Mesh>> &r_meshes, bool p_
 	Vector<Vector3> vertices;
 	Vector<Vector3> normals;
 	Vector<Vector2> uvs;
+	Vector<Color> colors;
 	String name;
 
 	Map<String, Map<String, Ref<SpatialMaterial>>> material_map;
@@ -244,6 +245,19 @@ static Error _parse_obj(const String &p_path, List<Ref<Mesh>> &r_meshes, bool p_
 			vtx.y = v[2].to_float() * scale_mesh.y + offset_mesh.y;
 			vtx.z = v[3].to_float() * scale_mesh.z + offset_mesh.z;
 			vertices.push_back(vtx);
+			//vertex colors
+			if (v.size() >= 7) {
+				while (colors.size() < vertices.size() - 1) {
+					colors.push_back(Color(1.0, 1.0, 1.0));
+				}
+				Color c;
+				c.r = v[4].to_float();
+				c.g = v[5].to_float();
+				c.b = v[6].to_float();
+				colors.push_back(c);
+			} else if (!colors.empty()) {
+				colors.push_back(Color(1.0, 1.0, 1.0));
+			}
 		} else if (l.begins_with("vt ")) {
 			//uv
 			Vector<String> v = l.split(" ", false);
@@ -312,6 +326,9 @@ static Error _parse_obj(const String &p_path, List<Ref<Mesh>> &r_meshes, bool p_
 					ERR_FAIL_INDEX_V(vtx, vertices.size(), ERR_FILE_CORRUPT);
 
 					Vector3 vertex = vertices[vtx];
+					if (!colors.empty()) {
+						surf_tool->add_color(colors[vtx]);
+					}
 					//if (weld_vertices)
 					//	vertex.snap(Vector3(weld_tolerance, weld_tolerance, weld_tolerance));
 					surf_tool->add_vertex(vertex);
@@ -344,7 +361,11 @@ static Error _parse_obj(const String &p_path, List<Ref<Mesh>> &r_meshes, bool p_
 				print_verbose("OBJ: Current material " + current_material + " has " + itos(material_map.has(current_material_library) && material_map[current_material_library].has(current_material)));
 
 				if (material_map.has(current_material_library) && material_map[current_material_library].has(current_material)) {
-					surf_tool->set_material(material_map[current_material_library][current_material]);
+					Ref<SpatialMaterial> &material = material_map[current_material_library][current_material];
+					if (!colors.empty()) {
+						material->set_flag(SpatialMaterial::FLAG_SRGB_VERTEX_COLOR, true);
+					}
+					surf_tool->set_material(material);
 				}
 
 				mesh = surf_tool->commit(mesh, p_compress_flags);