feat(engine): add support for Wavefront obj usemtl & mtllib

1 files changed, 38 insertions, 2 deletions

diff --git a/engine/src/file_format/wavefront/common.rs b/engine/src/file_format/wavefront/common.rs
index 0c5ac33..2e27bcb 100644
--- a/engine/src/file_format/wavefront/common.rs
+++ b/engine/src/file_format/wavefront/common.rs
@@ -218,11 +218,19 @@ impl Value
             })?));
         }
 
-        if value.contains('/') {
+        if value.contains('/')
+            && value
+                .chars()
+                .all(|character| character.is_ascii_digit() || character == '/')
+        {
             return Ok(Self::Triplet(Triplet::parse::<KeywordT>(value, line_no)?));
         }
 
-        if value.contains(|character: char| character.is_ascii_digit()) {
+        if !value.is_empty()
+            && value
+                .chars()
+                .all(|character: char| character.is_ascii_digit())
+        {
             return Ok(Self::Integer(value.parse().map_err(|err| {
                 ParsingError::InvalidIntegerValue {
                     err,
@@ -238,6 +246,18 @@ impl Value
 
         Err(ParsingError::UnknownValueType(value.to_string()))
     }
+
+    pub fn to_text(
+        &self,
+        argument_index: usize,
+        line_no: usize,
+    ) -> Result<&str, ParsingError>
+    {
+        match self {
+            Value::Text(value) => Ok(value),
+            _ => Err(ParsingError::UnexpectedArgumentType { argument_index, line_no }),
+        }
+    }
 }
 
 #[derive(Debug)]
@@ -265,6 +285,22 @@ impl<KeywordT: Keyword> Statement<KeywordT>
         }
     }
 
+    pub fn get_text_arg(&self, index: usize, line_no: usize)
+        -> Result<&str, ParsingError>
+    {
+        match self.arguments.get(index) {
+            Some(Value::Text(value)) => Ok(value),
+            Some(_) => Err(ParsingError::UnexpectedArgumentType {
+                argument_index: index,
+                line_no,
+            }),
+            None => Err(ParsingError::MissingArgument {
+                keyword: self.keyword.to_string(),
+                line_no,
+            }),
+        }
+    }
+
     pub fn get_triplet_arg(
         &self,
         index: usize,