[Merged by Bors] - 0.7 migration guide

content/learn/book/migration-guides/0.6-0.7/_index.md

@@ -0,0 +1,197 @@
++++
+title = "0.6 to 0.7"
+weight = 1
+sort_by = "weight"
+template = "book-section.html"
+page_template = "book-section.html"
+insert_anchor_links = "right"
+[extra]
+long_title = "Migration Guide: 0.6 to 0.7"
++++
+
+<!-- Github filter used to find the relevant PRs "is:pr label:C-Breaking-Change closed:>2022-02-01 [Merged by Bors]" -->
+
+### AliasedMutability
+
+<https://github.com/bevyengine/bevy/pull/4298>
+
+The `QueryEntityError` enum now has a `AliasedMutability` variant, and returns the offending entity.
+
+### Remove margins.rs
+
+<https://github.com/bevyengine/bevy/pull/4284>
+
+The `Margins` type was removed. To migrate, replace of `Margins` with `UiRect`.
+
+### Remove face_toward.rs
+
+<https://github.com/bevyengine/bevy/pull/4277>
+
+The `FaceToward` trait was removed. To migrate, replace every occurrence of `Mat4::face_toward` to `Mat4::look_at_rh`.
+
+### `World::entities_mut` is now unsafe
+
+<https://github.com/bevyengine/bevy/pull/4093>
+
+```rs
+// 0.6
+world.entities_mut()
+
+// 0.7
+unsafe { world.entities_mut() }
+```
+
+### Mesh vertex buffer layouts
+
+<https://github.com/bevyengine/bevy/pull/3959>
+
+TODO
+
+### Remove the need for 'IntoSystem::into_system()' when using run criteria piping
+
+<https://github.com/bevyengine/bevy/pull/3923>
+
+```rs
+// 0.6
+.with_run_criteria(RunCriteria::pipe(
+    "is_done_label",
+    IntoSystem::into_system(inverse),
+))
+
+// 0.7
+.with_run_criteria(RunCriteria::pipe("is_done_label", inverse))
+```
+
+### Obviate the need for RunSystem, and remove it
+
+<https://github.com/bevyengine/bevy/pull/3817>
+
+TODO
+
+### Replace VSync with PresentMode
+
+https://github.com/bevyengine/bevy/pull/3812
+
+Instead of using a boolean flag for vsync we switched to using a [`PresentMode`] enum with multiple variants.
+
+```rs
+// 0.6
+App::new()
+    .insert_resource(WindowDescriptor {
+        vsync: false,
+        ..Default::default()
+    })
+
+// 0.7
+App::new()
+    .insert_resource(WindowDescriptor {
+        present_mode: PresentMode::Mailbox,
+        ..Default::default()
+    })
+```
+
+<!-- TODO update to 0.7 link -->
+[`PresentMode`]: http://dev-docs.bevyengine.org/bevy/window/enum.PresentMode.html
+
+### Fix mul_vec3 tranformation order
+
+<https://github.com/bevyengine/bevy/pull/3811>
+
+Transforms are now consistently applied in the standard scale -> rotate -> translate. This doesn't require any code changes, but it means SpriteBundle will behave as expected when rotating.
+
+### Use marker components for cameras instead of name strings
+
+<https://github.com/bevyengine/bevy/pull/3635>
+
+TODO
+
+### Remove the config api
+
+<https://github.com/bevyengine/bevy/pull/3633>
+
+TODO
+
+### Cameras now point at RenderTarget rather than Window
+
+<https://github.com/bevyengine/bevy/pull/3412>
+
+This change was made to support rendering to textures. Users working with multiple windows may be affected.
+
+```rs
+// 0.6
+commands.spawn_bundle(PerspectiveCameraBundle {
+    camera: Camera {
+        window: window_id,
+        ..Default::default()
+    },
+    ..Default::default()
+});
+
+// 0.7
+commands.spawn_bundle(PerspectiveCameraBundle {
+    camera: Camera {
+        target: RenderTarget::Window(window_id),
+        ..Default::default()
+    },
+    ..Default::default()
+});
+```
+
+### Implement init_resource for Commands and World
+
+<https://github.com/bevyengine/bevy/pull/3079>
+
+```rs
+#[derive(Default)]
+struct Scoreboard {
+    current_score: u32,
+    high_score: u32,
+}
+
+// 0.6
+commands.insert_resource(Scoreboard::Default());
+
+// 0.7
+commands.init_resource::<Scoreboard>();
+```
+
+### ParamSet for conflicting SystemParam
+
+<https://github.com/bevyengine/bevy/pull/2765>
+
+```rs
+// 0.6
+fn system(
+    mut transforms: QuerySet<(
+        QueryState<&mut Transform, With<Marker>>,
+        QueryState<&Transform>,
+    )>,
+) {
+    for transform in transforms.q1().iter() {
+        // ...
+    }
+}
+// 0.7
+fn system(
+    mut transforms: ParamSet<(
+        Query<&mut Transform, With<Marker>>,
+        Query<&Transform>
+    )>,
+) {
+    for transform in transforms.p1().iter() {
+        // ...
+    }
+}
+```
+
+### Infallabile resource getters
+
+<https://github.com/bevyengine/bevy/pull/4047>
+
+```rs
+// 0.6
+let score = world.get_resource::<Score>().unwrap();
+
+// 0.7
+let score = world.resource::<Score>();
+```