Provide GlobalsUniform in UiMaterial shaders (bevyengine#10739)

`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.

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

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

---

Added `GlobalsUniform` in `UiMaterial` shaders

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::*,
@@ -222,16 +223,28 @@ impl<M: UiMaterial> FromWorld for UiMaterialPipeline<M> {
  let ui_layout = M::bind_group_layout(render_device);
 
  let view_layout = render_device.create_bind_group_layout(&BindGroupLayoutDescriptor {
- entries: &[BindGroupLayoutEntry {
- binding: 0,
- visibility: ShaderStages::VERTEX | ShaderStages::FRAGMENT,
- ty: BindingType::Buffer {
- ty: BufferBindingType::Uniform,
- has_dynamic_offset: true,
- min_binding_size: Some(ViewUniform::min_size()),
+ entries: &[
+ BindGroupLayoutEntry {
+ binding: 0,
+ visibility: ShaderStages::VERTEX | ShaderStages::FRAGMENT,
+ ty: BindingType::Buffer {
+ ty: BufferBindingType::Uniform,
+ has_dynamic_offset: true,
+ min_binding_size: Some(ViewUniform::min_size()),
+ },
+ count: None,
+ },
+ BindGroupLayoutEntry {
+ binding: 1,
+ visibility: ShaderStages::VERTEX | ShaderStages::FRAGMENT,
+ ty: BindingType::Buffer {
+ ty: BufferBindingType::Uniform,
+ has_dynamic_offset: false,
+ min_binding_size: Some(GlobalsUniform::min_size()),
+ },
+ count: None,
  },
- count: None,
- }],
+ ],
  label: Some("ui_view_layout"),
  });
  UiMaterialPipeline {
@@ -432,18 +445,22 @@ pub fn prepare_uimaterial_nodes<M: UiMaterial>(
  mut ui_meta: ResMut<UiMaterialMeta>,
  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