From fc35cb33d0f58efce3a2a2b58818b7e40631a1cf Mon Sep 17 00:00:00 2001
From: Alice Cecile <alice.i.cecile@gmail.com>
Date: Wed, 20 Nov 2024 19:47:05 -0500
Subject: [PATCH] Release notes for accumulated mouse inputs (#1828)

---
 .../14044_Accumulated_mouse_inputs.md         | 28 +++++++++++++++++++
 .../0.15/release-notes/_release-notes.toml    |  7 +++++
 2 files changed, 35 insertions(+)
 create mode 100644 release-content/0.15/release-notes/14044_Accumulated_mouse_inputs.md

diff --git a/release-content/0.15/release-notes/14044_Accumulated_mouse_inputs.md b/release-content/0.15/release-notes/14044_Accumulated_mouse_inputs.md
new file mode 100644
index 0000000000..34cddcd6de
--- /dev/null
+++ b/release-content/0.15/release-notes/14044_Accumulated_mouse_inputs.md
@@ -0,0 +1,28 @@
+<!-- Accumulated mouse inputs -->
+<!-- https://github.com/bevyengine/bevy/pull/14044 -->
+
+"How much has the player moved their mouse this frame" is a natural question for games when the player is trying to aim or scroll a map.
+Unfortunately, the operating system, and thus [`winit`], only provides us with a stream of events, in the form of individual [`MouseMotion`] events.
+
+To get the summarized information (and the equivalent [`MouseScroll`]) information that most game systems care about, you had to sum them yourself.
+
+```rust
+pub fn accumulate_mouse_motion_system(
+    mut mouse_motion_event: EventReader<MouseMotion>,
+    mut accumulated_mouse_motion: ResMut<AccumulatedMouseMotion>,
+) {
+    let mut delta = Vec2::ZERO;
+    for event in mouse_motion_event.read() {
+        delta += event.delta;
+    }
+    accumulated_mouse_motion.delta = delta;
+}
+```
+
+Bevy now does this for you, exposed in the new [`AccumulatedMouseMotion`] and [`AccumulatedMouseScroll`] resources.
+
+[`winit`]: https://docs.rs/winit/latest/winit/
+[`MouseMotion`]: https://docs.rs/bevy/0.15.0/bevy/input/mouse/struct.MouseMotion.html
+[`MouseScroll`]: https://docs.rs/bevy/0.15.0/bevy/input/mouse/struct.MouseScroll.html
+[`AccumulatedMouseMotion`]: https://docs.rs/bevy/0.15.0/bevy/input/mouse/struct.AccumulatedMouseMotion.html
+[`AccumulatedMouseScroll`]: https://docs.rs/bevy/0.15.0/bevy/input/mouse/struct.AccumulatedMouseScroll.html
diff --git a/release-content/0.15/release-notes/_release-notes.toml b/release-content/0.15/release-notes/_release-notes.toml
index 9a053f61a4..9972d6de68 100644
--- a/release-content/0.15/release-notes/_release-notes.toml
+++ b/release-content/0.15/release-notes/_release-notes.toml
@@ -418,6 +418,13 @@ contributors = ["@IceSentry"]
 prs = [14663]
 file_name = "14663_shader_storage_buffer.md"
 
+[[release_notes]]
+title = "Accumulated mouse inputs"
+authors = ["@Aztro-dev", "@alice-i-cecile"]
+contributors = []
+prs = [14044]
+file_name = "14044_Accumulated_mouse_inputs.md"
+
 [[release_notes]]
 title = "Stable interpolation and smooth following"
 authors = ["@mweatherley"]