Provide GlobalsUniform in UiMaterial shaders (#10739)

# Objective

`GlobalsUniform` provides the current time to shaders, which is useful
for animations. `UiMaterial` is an abstraction that makes it easier to
write custom shaders for UI elements.
This PR makes it possible to use the `GlobalsUniform` in `UiMaterial`
shaders.

## Solution

The `GlobalsUniform` is bound to `@group(0) @binding(1)`. It is
accessible in shaders with:
```wgsl
#import bevy_render::globals::Globals

@group(0) @binding(1)
var<uniform> globals: Globals;
```

---

## Changelog

Added `GlobalsUniform` in `UiMaterial` shaders

## Discussion

Should I modify the existing ui_material example to showcase this?

crates/bevy_ui/src/render/ui_material.wgsl

@@ -1,8 +1,13 @@
-#import bevy_render::view::View
+#import bevy_render::{
+    view::View,
+    globals::Globals,
+}
 #import bevy_ui::ui_vertex_output::UiVertexOutput
 
 @group(0) @binding(0)
 var<uniform> view: View;
+@group(0) @binding(1)
+var<uniform> globals: Globals;
 
 @vertex
 fn vertex(

crates/bevy_ui/src/render/ui_material_pipeline.rs

@@ -15,6 +15,7 @@ use bevy_ecs::{
 use bevy_math::{Mat4, Rect, Vec2, Vec4Swizzles};
 use bevy_render::{
     extract_component::ExtractComponentPlugin,
+    globals::{GlobalsBuffer, GlobalsUniform},
     render_asset::RenderAssets,
     render_phase::*,
     render_resource::{binding_types::uniform_buffer, *},
@@ -225,11 +226,15 @@ impl<M: UiMaterial> FromWorld for UiMaterialPipeline<M> {
 
         let view_layout = render_device.create_bind_group_layout(
             "ui_view_layout",
-            &BindGroupLayoutEntries::single(
+            &BindGroupLayoutEntries::sequential(
                 ShaderStages::VERTEX_FRAGMENT,
-                uniform_buffer::<ViewUniform>(true),
+                (
+                    uniform_buffer::<ViewUniform>(true),
+                    uniform_buffer::<GlobalsUniform>(false),
+                ),
             ),
         );
+
         UiMaterialPipeline {
             ui_layout,
             view_layout,
@@ -430,18 +435,22 @@ pub fn prepare_uimaterial_nodes<M: UiMaterial>(
     mut ui_meta: ResMut<UiMaterialMeta<M>>,
     mut extracted_uinodes: ResMut<ExtractedUiMaterialNodes<M>>,
     view_uniforms: Res<ViewUniforms>,
+    globals_buffer: Res<GlobalsBuffer>,
     ui_material_pipeline: Res<UiMaterialPipeline<M>>,
     mut phases: Query<&mut RenderPhase<TransparentUi>>,
     mut previous_len: Local<usize>,
 ) {
-    if let Some(view_binding) = view_uniforms.uniforms.binding() {
+    if let (Some(view_binding), Some(globals_binding)) = (
+        view_uniforms.uniforms.binding(),
+        globals_buffer.buffer.binding(),
+    ) {
         let mut batches: Vec<(Entity, UiMaterialBatch<M>)> = Vec::with_capacity(*previous_len);
 
         ui_meta.vertices.clear();
         ui_meta.view_bind_group = Some(render_device.create_bind_group(
             "ui_material_view_bind_group",
             &ui_material_pipeline.view_layout,
-            &BindGroupEntries::single(view_binding),
+            &BindGroupEntries::sequential((view_binding, globals_binding)),
         ));
         let mut index = 0;
 

crates/bevy_ui/src/ui_material.rs

@@ -67,7 +67,8 @@ use bevy_render::render_resource::{AsBindGroup, RenderPipelineDescriptor, Shader
 ///
 /// If you only use the fragment shader make sure to import `UiVertexOutput` from
 /// `bevy_ui::ui_vertex_output` in your wgsl shader.
-/// Also note that bind group 0 is always bound to the [`View Uniform`](bevy_render::view::ViewUniform).
+/// Also note that bind group 0 is always bound to the [`View Uniform`](bevy_render::view::ViewUniform)
+/// and the [`Globals Uniform`](bevy_render::globals::GlobalsUniform).
 ///
 /// ```wgsl
 /// #import bevy_ui::ui_vertex_output UiVertexOutput