From bebe7c405da5e7aec3db0915e367b4ff04a49b1c Mon Sep 17 00:00:00 2001
From: JMS55 <47158642+JMS55@users.noreply.github.com>
Date: Mon, 9 Jun 2025 13:05:58 -0700
Subject: [PATCH] Make camera controller not trigger change detection every
 frame (#19547)

Split off from https://github.com/bevyengine/bevy/pull/19058
---
 examples/helpers/camera_controller.rs | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/examples/helpers/camera_controller.rs b/examples/helpers/camera_controller.rs
index 07f0f31b11..a60aa69a5e 100644
--- a/examples/helpers/camera_controller.rs
+++ b/examples/helpers/camera_controller.rs
@@ -198,7 +198,7 @@ fn run_camera_controller(
     }
     let cursor_grab = *mouse_cursor_grab || *toggle_cursor_grab;
 
-    // Apply movement update
+    // Update velocity
     if axis_input != Vec3::ZERO {
         let max_speed = if key_input.pressed(controller.key_run) {
             controller.run_speed
@@ -213,11 +213,15 @@ fn run_camera_controller(
             controller.velocity = Vec3::ZERO;
         }
     }
-    let forward = *transform.forward();
-    let right = *transform.right();
-    transform.translation += controller.velocity.x * dt * right
-        + controller.velocity.y * dt * Vec3::Y
-        + controller.velocity.z * dt * forward;
+
+    // Apply movement update
+    if controller.velocity != Vec3::ZERO {
+        let forward = *transform.forward();
+        let right = *transform.right();
+        transform.translation += controller.velocity.x * dt * right
+            + controller.velocity.y * dt * Vec3::Y
+            + controller.velocity.z * dt * forward;
+    }
 
     // Handle cursor grab
     if cursor_grab_change {