chore(ppu): implement IntoIterator and iter() for ObjectBuffer

src/ppu.rs

@@ -196,8 +196,7 @@ impl Ppu {
         // Determine whether we need to enable sprite fetching
         let mut obj_attr = None;
 
-        for i in 0..self.obj_buffer.len() {
+        for attr in self.obj_buffer.iter().flatten() {
-            if let Some(attr) = self.obj_buffer.get(i) {
             if attr.x <= (self.x_pos + 8) {
                 // self.fetcher.obj.resume(); TODO: Try running only when there's a sprite
                 self.fetcher.bg.reset();
@@ -208,7 +207,6 @@ impl Ppu {
                 break;
             }
         }
-        }
 
         if let Some(attr) = obj_attr {
             match self.fetcher.obj.state {
@@ -1012,6 +1010,36 @@ struct ObjectBuffer {
     len: usize,
 }
 
+impl ObjectBuffer {
+    pub fn iter(&self) -> std::slice::Iter<'_, Option<ObjectAttribute>> {
+        self.into_iter()
+    }
+
+    pub fn iter_mut(&mut self) -> &mut std::slice::IterMut<'_, Option<ObjectAttribute>> {
+        todo!("Figure out the lifetimes for ObjectBuffer::iter_mut()");
+    }
+}
+
+impl<'a> IntoIterator for &'a ObjectBuffer {
+    type Item = &'a Option<ObjectAttribute>;
+
+    type IntoIter = std::slice::Iter<'a, Option<ObjectAttribute>>;
+
+    fn into_iter(self) -> Self::IntoIter {
+        self.buf.iter()
+    }
+}
+
+impl<'a> IntoIterator for &'a mut ObjectBuffer {
+    type Item = &'a Option<ObjectAttribute>;
+
+    type IntoIter = std::slice::Iter<'a, Option<ObjectAttribute>>;
+
+    fn into_iter(self) -> Self::IntoIter {
+        self.buf.iter()
+    }
+}
+
 impl ObjectBuffer {
     pub fn is_full(&self) -> bool {
         self.len == OBJECT_LIMIT
@@ -1027,14 +1055,6 @@ impl ObjectBuffer {
         self.len += 1;
     }
 
-    pub fn len(&self) -> usize {
-        self.len
-    }
-
-    pub fn get(&self, index: usize) -> Option<&ObjectAttribute> {
-        self.buf[index].as_ref()
-    }
-
     pub fn remove(&mut self, attr: &ObjectAttribute) {
         let maybe_index = self.buf.iter().position(|maybe_attr| match maybe_attr {
             Some(other_attr) => attr == other_attr,