refactor(render): slight leveldrawpass refactors

1 files changed, 41 insertions, 0 deletions

diff --git a/stockton-render/src/draw/draw_passes/util.rs b/stockton-render/src/draw/draw_passes/util.rs
new file mode 100644
index 0000000..a42f870
--- /dev/null
+++ b/stockton-render/src/draw/draw_passes/util.rs
@@ -0,0 +1,41 @@
+//! Utility structs & functions
+
+use anyhow::Result;
+
+/// Keeps a given resource for each swapchain image
+pub struct TargetSpecificResources<T> {
+    elements: Vec<T>,
+    next_idx: usize,
+}
+
+impl<T> TargetSpecificResources<T> {
+    /// Create a new set of resources, given a function to generate them and the count
+    /// In most cases, count should be swapchain_properties.image_count
+    pub fn new<F>(generator: F, count: usize) -> Result<Self>
+    where
+        F: FnMut() -> Result<T>,
+    {
+        let mut elements = Vec::with_capacity(count);
+        for _ in 0..count {
+            elements.push(generator()?);
+        }
+
+        Ok(TargetSpecificResources {
+            elements,
+            next_idx: 0,
+        })
+    }
+
+    /// Get the next resource, wrapping around if necessary.
+    pub fn get_next<'a>(&'a mut self) -> &'a T {
+        let el = &self.elements[self.next_idx];
+        self.next_idx = (self.next_idx + 1) % self.elements.len();
+        el
+    }
+
+    /// Dissolve the resource set, returning an iterator over each item.
+    /// In most cases, each item will need deactivated.
+    pub fn dissolve(self) -> impl Iterator<Item = T> {
+        self.elements.into_iter()
+    }
+}