From de7da82022ddb9a6a740ad5b757c215a817b2272 Mon Sep 17 00:00:00 2001
From: hypercube <0hypercube@gmail.com>
Date: Mon, 10 Nov 2025 20:09:05 +0000
Subject: [PATCH] Reverse the loop level input to instance_index node

---
 node-graph/gcore/src/context.rs                    | 10 +++++-----
 node-graph/gcore/src/vector/algorithms/instance.rs |  3 ++-
 2 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/node-graph/gcore/src/context.rs b/node-graph/gcore/src/context.rs
index ba4836d04d..0a4ebc545f 100644
--- a/node-graph/gcore/src/context.rs
+++ b/node-graph/gcore/src/context.rs
@@ -27,7 +27,7 @@ pub trait ExtractAnimationTime {
 }
 
 pub trait ExtractIndex {
-	fn try_index(&self) -> Option<impl Iterator<Item = usize>>;
+	fn try_index(&self) -> Option<impl DoubleEndedIterator<Item = usize>>;
 }
 
 // Consider returning a slice or something like that
@@ -175,7 +175,7 @@ impl<T: ExtractAnimationTime + Sync> ExtractAnimationTime for Option<T> {
 	}
 }
 impl<T: ExtractIndex> ExtractIndex for Option<T> {
-	fn try_index(&self) -> Option<impl Iterator<Item = usize>> {
+	fn try_index(&self) -> Option<impl DoubleEndedIterator<Item = usize>> {
 		self.as_ref().and_then(|x| x.try_index())
 	}
 }
@@ -212,7 +212,7 @@ impl<T: ExtractAnimationTime + Sync> ExtractAnimationTime for Arc<T> {
 	}
 }
 impl<T: ExtractIndex> ExtractIndex for Arc<T> {
-	fn try_index(&self) -> Option<impl Iterator<Item = usize>> {
+	fn try_index(&self) -> Option<impl DoubleEndedIterator<Item = usize>> {
 		(**self).try_index()
 	}
 }
@@ -268,7 +268,7 @@ impl ExtractRealTime for ContextImpl<'_> {
 	}
 }
 impl ExtractIndex for ContextImpl<'_> {
-	fn try_index(&self) -> Option<impl Iterator<Item = usize>> {
+	fn try_index(&self) -> Option<impl DoubleEndedIterator<Item = usize>> {
 		self.index.clone().map(|x| x.into_iter())
 	}
 }
@@ -304,7 +304,7 @@ impl ExtractAnimationTime for OwnedContextImpl {
 	}
 }
 impl ExtractIndex for OwnedContextImpl {
-	fn try_index(&self) -> Option<impl Iterator<Item = usize>> {
+	fn try_index(&self) -> Option<impl DoubleEndedIterator<Item = usize>> {
 		self.index.clone().map(|x| x.into_iter())
 	}
 }
diff --git a/node-graph/gcore/src/vector/algorithms/instance.rs b/node-graph/gcore/src/vector/algorithms/instance.rs
index 9e40093bc0..d550f72f9f 100644
--- a/node-graph/gcore/src/vector/algorithms/instance.rs
+++ b/node-graph/gcore/src/vector/algorithms/instance.rs
@@ -109,7 +109,8 @@ async fn instance_position(ctx: impl Ctx + ExtractVarArgs) -> DVec2 {
 async fn instance_index(ctx: impl Ctx + ExtractIndex, _primary: (), loop_level: u32) -> f64 {
 	let Some(index_iter) = ctx.try_index() else { return 0. };
 	let mut last = 0;
-	for (i, index) in index_iter.enumerate() {
+	// Index zero should be the top most index for some reason https://github.com/GraphiteEditor/Graphite/issues/3360
+	for (i, index) in index_iter.rev().enumerate() {
 		if i == loop_level as usize {
 			return index as f64;
 		}