Use RenderStartup in bevy_gizmos. (#19898)

# Objective

- Progress towards #19887.

## Solution

- Convert `FromWorld` impls into systems that run in `RenderStartup`.
- Add an ordering constraint to ensure that necessary resources exist.

## Testing

- Ran `2d_gizmos` and `3d_gizmos` examples and it still worked.

crates/bevy_gizmos/src/lib.rs

@@ -124,7 +124,7 @@ use {
         },
         renderer::RenderDevice,
         sync_world::{MainEntity, TemporaryRenderEntity},
-        Extract, ExtractSchedule, Render, RenderApp, RenderSystems,
+        Extract, ExtractSchedule, Render, RenderApp, RenderStartup, RenderSystems,
     },
     bytemuck::cast_slice,
 };
@@ -176,6 +176,8 @@ impl Plugin for GizmoPlugin {
 
         #[cfg(feature = "bevy_render")]
         if let Some(render_app) = app.get_sub_app_mut(RenderApp) {
+            render_app.add_systems(RenderStartup, init_line_gizmo_uniform_bind_group_layout);
+
             render_app.add_systems(
                 Render,
                 prepare_line_gizmo_bind_group.in_set(RenderSystems::PrepareBindGroups),
@@ -199,26 +201,6 @@ impl Plugin for GizmoPlugin {
             tracing::warn!("bevy_render feature is enabled but RenderApp was not detected. Are you sure you loaded GizmoPlugin after RenderPlugin?");
         }
     }
-
-    #[cfg(feature = "bevy_render")]
-    fn finish(&self, app: &mut App) {
-        let Some(render_app) = app.get_sub_app_mut(RenderApp) else {
-            return;
-        };
-
-        let render_device = render_app.world().resource::<RenderDevice>();
-        let line_layout = render_device.create_bind_group_layout(
-            "LineGizmoUniform layout",
-            &BindGroupLayoutEntries::single(
-                ShaderStages::VERTEX,
-                uniform_buffer::<LineGizmoUniform>(true),
-            ),
-        );
-
-        render_app.insert_resource(LineGizmoUniformBindgroupLayout {
-            layout: line_layout,
-        });
-    }
 }
 
 /// A extension trait adding `App::init_gizmo_group` and `App::insert_gizmo_config`.
@@ -415,6 +397,24 @@ fn update_gizmo_meshes<Config: GizmoConfigGroup>(
     }
 }
 
+#[cfg(feature = "bevy_render")]
+fn init_line_gizmo_uniform_bind_group_layout(
+    mut commands: Commands,
+    render_device: Res<RenderDevice>,
+) {
+    let line_layout = render_device.create_bind_group_layout(
+        "LineGizmoUniform layout",
+        &BindGroupLayoutEntries::single(
+            ShaderStages::VERTEX,
+            uniform_buffer::<LineGizmoUniform>(true),
+        ),
+    );
+
+    commands.insert_resource(LineGizmoUniformBindgroupLayout {
+        layout: line_layout,
+    });
+}
+
 #[cfg(feature = "bevy_render")]
 fn extract_gizmo_data(
     mut commands: Commands,

crates/bevy_gizmos/src/pipeline_2d.rs

@@ -1,23 +1,21 @@
 use crate::{
     config::{GizmoLineJoint, GizmoLineStyle, GizmoMeshConfig},
-    line_gizmo_vertex_buffer_layouts, line_joint_gizmo_vertex_buffer_layouts, DrawLineGizmo,
+    init_line_gizmo_uniform_bind_group_layout, line_gizmo_vertex_buffer_layouts,
-    DrawLineJointGizmo, GizmoRenderSystems, GpuLineGizmo, LineGizmoUniformBindgroupLayout,
+    line_joint_gizmo_vertex_buffer_layouts, DrawLineGizmo, DrawLineJointGizmo, GizmoRenderSystems,
-    SetLineGizmoBindGroup,
+    GpuLineGizmo, LineGizmoUniformBindgroupLayout, SetLineGizmoBindGroup,
 };
 use bevy_app::{App, Plugin};
-use bevy_asset::{load_embedded_asset, Handle};
+use bevy_asset::{load_embedded_asset, AssetServer, Handle};
 use bevy_core_pipeline::core_2d::{Transparent2d, CORE_2D_DEPTH_FORMAT};
 
 use bevy_ecs::{
     prelude::Entity,
     resource::Resource,
     schedule::IntoScheduleConfigs,
-    system::{Query, Res, ResMut},
+    system::{Commands, Query, Res, ResMut},
-    world::{FromWorld, World},
 };
 use bevy_image::BevyDefault as _;
 use bevy_math::FloatOrd;
-use bevy_render::sync_world::MainEntity;
 use bevy_render::{
     render_asset::{prepare_assets, RenderAssets},
     render_phase::{
@@ -28,6 +26,7 @@ use bevy_render::{
     view::{ExtractedView, Msaa, RenderLayers, ViewTarget},
     Render, RenderApp, RenderSystems,
 };
+use bevy_render::{sync_world::MainEntity, RenderStartup};
 use bevy_sprite::{Mesh2dPipeline, Mesh2dPipelineKey, SetMesh2dViewBindGroup};
 use bevy_utils::default;
 use tracing::error;
@@ -55,6 +54,10 @@ impl Plugin for LineGizmo2dPlugin {
                         bevy_sprite::queue_material2d_meshes::<bevy_sprite::ColorMaterial>,
                     ),
             )
+            .add_systems(
+                RenderStartup,
+                init_line_gizmo_pipelines.after(init_line_gizmo_uniform_bind_group_layout),
+            )
             .add_systems(
                 Render,
                 (queue_line_gizmos_2d, queue_line_joint_gizmos_2d)
@@ -62,15 +65,6 @@ impl Plugin for LineGizmo2dPlugin {
                     .after(prepare_assets::<GpuLineGizmo>),
             );
     }
-
-    fn finish(&self, app: &mut App) {
-        let Some(render_app) = app.get_sub_app_mut(RenderApp) else {
-            return;
-        };
-
-        render_app.init_resource::<LineGizmoPipeline>();
-        render_app.init_resource::<LineJointGizmoPipeline>();
-    }
 }
 
 #[derive(Clone, Resource)]
@@ -80,17 +74,22 @@ struct LineGizmoPipeline {
     shader: Handle<Shader>,
 }
 
-impl FromWorld for LineGizmoPipeline {
+fn init_line_gizmo_pipelines(
-    fn from_world(render_world: &mut World) -> Self {
+    mut commands: Commands,
-        LineGizmoPipeline {
+    mesh_2d_pipeline: Res<Mesh2dPipeline>,
-            mesh_pipeline: render_world.resource::<Mesh2dPipeline>().clone(),
+    uniform_bind_group_layout: Res<LineGizmoUniformBindgroupLayout>,
-            uniform_layout: render_world
+    asset_server: Res<AssetServer>,
-                .resource::<LineGizmoUniformBindgroupLayout>()
+) {
-                .layout
+    commands.insert_resource(LineGizmoPipeline {
-                .clone(),
+        mesh_pipeline: mesh_2d_pipeline.clone(),
-            shader: load_embedded_asset!(render_world, "lines.wgsl"),
+        uniform_layout: uniform_bind_group_layout.layout.clone(),
-        }
+        shader: load_embedded_asset!(asset_server.as_ref(), "lines.wgsl"),
-    }
+    });
+    commands.insert_resource(LineJointGizmoPipeline {
+        mesh_pipeline: mesh_2d_pipeline.clone(),
+        uniform_layout: uniform_bind_group_layout.layout.clone(),
+        shader: load_embedded_asset!(asset_server.as_ref(), "line_joints.wgsl"),
+    });
 }
 
 #[derive(PartialEq, Eq, Hash, Clone)]
@@ -178,19 +177,6 @@ struct LineJointGizmoPipeline {
     shader: Handle<Shader>,
 }
 
-impl FromWorld for LineJointGizmoPipeline {
-    fn from_world(render_world: &mut World) -> Self {
-        LineJointGizmoPipeline {
-            mesh_pipeline: render_world.resource::<Mesh2dPipeline>().clone(),
-            uniform_layout: render_world
-                .resource::<LineGizmoUniformBindgroupLayout>()
-                .layout
-                .clone(),
-            shader: load_embedded_asset!(render_world, "line_joints.wgsl"),
-        }
-    }
-}
-
 #[derive(PartialEq, Eq, Hash, Clone)]
 struct LineJointGizmoPipelineKey {
     mesh_key: Mesh2dPipelineKey,

crates/bevy_gizmos/src/pipeline_3d.rs

@@ -1,11 +1,11 @@
 use crate::{
     config::{GizmoLineJoint, GizmoLineStyle, GizmoMeshConfig},
-    line_gizmo_vertex_buffer_layouts, line_joint_gizmo_vertex_buffer_layouts, DrawLineGizmo,
+    init_line_gizmo_uniform_bind_group_layout, line_gizmo_vertex_buffer_layouts,
-    DrawLineJointGizmo, GizmoRenderSystems, GpuLineGizmo, LineGizmoUniformBindgroupLayout,
+    line_joint_gizmo_vertex_buffer_layouts, DrawLineGizmo, DrawLineJointGizmo, GizmoRenderSystems,
-    SetLineGizmoBindGroup,
+    GpuLineGizmo, LineGizmoUniformBindgroupLayout, SetLineGizmoBindGroup,
 };
 use bevy_app::{App, Plugin};
-use bevy_asset::{load_embedded_asset, Handle};
+use bevy_asset::{load_embedded_asset, AssetServer, Handle};
 use bevy_core_pipeline::{
     core_3d::{Transparent3d, CORE_3D_DEPTH_FORMAT},
     oit::OrderIndependentTransparencySettings,
@@ -17,12 +17,10 @@ use bevy_ecs::{
     query::Has,
     resource::Resource,
     schedule::IntoScheduleConfigs,
-    system::{Query, Res, ResMut},
+    system::{Commands, Query, Res, ResMut},
-    world::{FromWorld, World},
 };
 use bevy_image::BevyDefault as _;
 use bevy_pbr::{MeshPipeline, MeshPipelineKey, SetMeshViewBindGroup};
-use bevy_render::sync_world::MainEntity;
 use bevy_render::{
     render_asset::{prepare_assets, RenderAssets},
     render_phase::{
@@ -33,6 +31,7 @@ use bevy_render::{
     view::{ExtractedView, Msaa, RenderLayers, ViewTarget},
     Render, RenderApp, RenderSystems,
 };
+use bevy_render::{sync_world::MainEntity, RenderStartup};
 use bevy_utils::default;
 use tracing::error;
 
@@ -53,6 +52,10 @@ impl Plugin for LineGizmo3dPlugin {
                 Render,
                 GizmoRenderSystems::QueueLineGizmos3d.in_set(RenderSystems::Queue),
             )
+            .add_systems(
+                RenderStartup,
+                init_line_gizmo_pipelines.after(init_line_gizmo_uniform_bind_group_layout),
+            )
             .add_systems(
                 Render,
                 (queue_line_gizmos_3d, queue_line_joint_gizmos_3d)
@@ -60,15 +63,6 @@ impl Plugin for LineGizmo3dPlugin {
                     .after(prepare_assets::<GpuLineGizmo>),
             );
     }
-
-    fn finish(&self, app: &mut App) {
-        let Some(render_app) = app.get_sub_app_mut(RenderApp) else {
-            return;
-        };
-
-        render_app.init_resource::<LineGizmoPipeline>();
-        render_app.init_resource::<LineJointGizmoPipeline>();
-    }
 }
 
 #[derive(Clone, Resource)]
@@ -78,17 +72,22 @@ struct LineGizmoPipeline {
     shader: Handle<Shader>,
 }
 
-impl FromWorld for LineGizmoPipeline {
+fn init_line_gizmo_pipelines(
-    fn from_world(render_world: &mut World) -> Self {
+    mut commands: Commands,
-        LineGizmoPipeline {
+    mesh_pipeline: Res<MeshPipeline>,
-            mesh_pipeline: render_world.resource::<MeshPipeline>().clone(),
+    uniform_bind_group_layout: Res<LineGizmoUniformBindgroupLayout>,
-            uniform_layout: render_world
+    asset_server: Res<AssetServer>,
-                .resource::<LineGizmoUniformBindgroupLayout>()
+) {
-                .layout
+    commands.insert_resource(LineGizmoPipeline {
-                .clone(),
+        mesh_pipeline: mesh_pipeline.clone(),
-            shader: load_embedded_asset!(render_world, "lines.wgsl"),
+        uniform_layout: uniform_bind_group_layout.layout.clone(),
-        }
+        shader: load_embedded_asset!(asset_server.as_ref(), "lines.wgsl"),
-    }
+    });
+    commands.insert_resource(LineJointGizmoPipeline {
+        mesh_pipeline: mesh_pipeline.clone(),
+        uniform_layout: uniform_bind_group_layout.layout.clone(),
+        shader: load_embedded_asset!(asset_server.as_ref(), "line_joints.wgsl"),
+    });
 }
 
 #[derive(PartialEq, Eq, Hash, Clone)]
@@ -173,19 +172,6 @@ struct LineJointGizmoPipeline {
     shader: Handle<Shader>,
 }
 
-impl FromWorld for LineJointGizmoPipeline {
-    fn from_world(render_world: &mut World) -> Self {
-        LineJointGizmoPipeline {
-            mesh_pipeline: render_world.resource::<MeshPipeline>().clone(),
-            uniform_layout: render_world
-                .resource::<LineGizmoUniformBindgroupLayout>()
-                .layout
-                .clone(),
-            shader: load_embedded_asset!(render_world, "line_joints.wgsl"),
-        }
-    }
-}
-
 #[derive(PartialEq, Eq, Hash, Clone)]
 struct LineJointGizmoPipelineKey {
     view_key: MeshPipelineKey,