1 files changed, 66 insertions, 0 deletions
diff --git a/stockton-render/src/draw/draw_passes/cons.rs b/stockton-render/src/draw/draw_passes/cons.rs
new file mode 100644
index 0000000..274bd76
--- /dev/null
+++ b/stockton-render/src/draw/draw_passes/cons.rs
@@ -0,0 +1,66 @@
+//! Code for using multiple draw passes in place of just one
+//! Note that this can be extended to an arbitrary amount of draw passes.
+
+use super::{DrawPass, DrawPassInput};
+use crate::{draw::queue_negotiator::QueueNegotiator, types::*};
+use anyhow::Result;
+
+/// One draw pass, then another.
+struct ConsDrawPass<A: DrawPass, B: DrawPass> {
+    a: A,
+    b: B,
+}
+
+impl<A: DrawPass, B: DrawPass> DrawPass for ConsDrawPass<A, B> {
+    type Input = ConsDrawPassInput<A::Input, B::Input>;
+
+    fn queue_draw(&self, input: &Self::Input, cmd_buffer: &mut CommandBufferT) -> Result<()> {
+        self.a.queue_draw(&input.a, cmd_buffer)?;
+        self.b.queue_draw(&input.b, cmd_buffer)?;
+
+        Ok(())
+    }
+
+    fn find_aux_queues<'a>(
+        adapter: &'a Adapter,
+        queue_negotiator: &mut QueueNegotiator,
+    ) -> Result<Vec<(&'a QueueFamilyT, Vec<f32>)>> {
+        let mut vec = Vec::new();
+
+        vec.extend(A::find_aux_queues(adapter, queue_negotiator)?);
+        vec.extend(B::find_aux_queues(adapter, queue_negotiator)?);
+
+        Ok(vec)
+    }
+}
+
+/// Input for a ConsDrawPass.
+struct ConsDrawPassInput<A, B> {
+    pub a: A,
+    pub b: B,
+}
+
+impl<A: DrawPassInput, B: DrawPassInput> DrawPassInput for ConsDrawPassInput<A, B> {}
+
+/// A draw pass that does nothing. Can be used at the end of sequences if there's an odd number of draw passes.
+struct NilDrawPass;
+
+impl DrawPass for NilDrawPass {
+    type Input = NilDrawPassInput;
+
+    fn queue_draw(&self, _input: &Self::Input, _cmd_buffer: &mut CommandBufferT) -> Result<()> {
+        Ok(())
+    }
+
+    fn find_aux_queues<'a>(
+        _adapter: &'a Adapter,
+        _queue_negotiator: &mut QueueNegotiator,
+    ) -> Result<Vec<(&'a QueueFamilyT, Vec<f32>)>> {
+        Ok(vec![])
+    }
+}
+
+/// Input for a NilDrawPass.
+struct NilDrawPassInput;
+
+impl DrawPassInput for NilDrawPassInput {}