examples: add .obj viewer as a sokol example (#9456)

examples/sokol/06_obj_viewer/obj/util.v

@@ -0,0 +1,43 @@
+module obj
+import os
+
+// read a file as single lines
+pub fn read_lines_from_file(file_path string) []string {
+	mut path := ""
+	mut rows := []string{}
+	$if android {
+		path = "models/"+file_path
+		bts := os.read_apk_asset(path) or {
+			eprintln("File [$path] NOT FOUND!")
+			return rows
+		}
+		rows = bts.bytestr().split_into_lines()
+	} $else {
+		path = "assets/models/"+file_path
+		rows = os.read_lines(path) or {
+			eprintln("File [$path] NOT FOUND!")
+			return rows
+		}
+	}
+	return rows
+}
+
+// read a file as []byte
+pub fn read_bytes_from_file(file_path string) []byte {
+	mut path := ""
+	mut buffer := []byte{}
+	$if android {
+		path = "models/"+file_path
+		buffer = os.read_apk_asset(path) or {
+			eprintln("Texure file: [$path] NOT FOUND!")
+			exit(0)
+		}
+	} $else {
+		path = "assets/models/"+file_path
+		buffer = os.read_bytes(path) or {
+			eprintln("Texure file: [$path] NOT FOUND!")
+			exit(0)
+		}
+	}
+	return buffer
+}