got a good obj file, finally

resources/texture-test-1.obj

@@ -0,0 +1,18 @@
+# Blender v2.93.1 OBJ File: ''
+# www.blender.org
+mtllib texture-test-1.mtl
+o Plane_Plane.001
+v -1.000000 0.000000 1.000000
+v 1.000000 0.000000 1.000000
+v -1.000000 0.000000 -1.000000
+v 1.000000 0.000000 -1.000000
+vt 1.000000 0.000000
+vt 0.000000 1.000000
+vt 0.000000 0.000000
+vt 1.000000 1.000000
+vn 0.0000 1.0000 0.0000
+g Plane_Plane.001_Material.002
+usemtl Material.002
+s off
+f 2/1/1 3/2/1 1/3/1
+f 2/1/1 4/4/1 3/2/1