Disable button labels for the many_buttons stress text by default (#20636)

# Objective

The `many_buttons` benchmark isn't a good measure of UI performance
because it's dominated by the text layout and rendering for the button
labels. The button labels should be disabled by default, we have other
text specific stress tests.

## Solution

1. Rename the `no_text` commandline parameter to `text`. The buttons are
no longer shown by default, to run the example with labels you need to
use:
  ```
  cargo run --example many_buttons --release -- --text
  ```
2. Add a second button icon image, this is to break up the batches
during rendering without text.
3. Spawn every button with an icon.

Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>

Author: ickshonpe

examples/stress_tests/many_buttons.rs

@@ -15,9 +15,9 @@ const FONT_SIZE: f32 = 7.0;
 #[derive(FromArgs, Resource)]
 /// `many_buttons` general UI benchmark that stress tests layouting, text, interaction and rendering
 struct Args {
-    /// whether to add text to each button
+    /// whether to add labels to each button
     #[argh(switch)]
-    no_text: bool,
+    text: bool,
 
     /// whether to add borders to each button
     #[argh(switch)]
@@ -27,15 +27,15 @@ struct Args {
     #[argh(switch)]
     relayout: bool,
 
-    /// whether to recompute all text each frame
+    /// whether to recompute all text each frame (if text enabled)
     #[argh(switch)]
     recompute_text: bool,
 
     /// how many buttons per row and column of the grid.
     #[argh(option, default = "110")]
     buttons: usize,
 
-    /// give every nth button an image
+    /// change the button icon every nth button, if `0` no icons are added.
     #[argh(option, default = "4")]
     image_freq: usize,
 
@@ -153,8 +153,11 @@ fn button_system(
 }
 
 fn setup_flex(mut commands: Commands, asset_server: Res<AssetServer>, args: Res<Args>) {
-    let image = if 0 < args.image_freq {
-        Some(asset_server.load("branding/icon.png"))
+    let images = if 0 < args.image_freq {
+        Some(vec![
+            asset_server.load("branding/icon.png"),
+            asset_server.load("textures/Game Icons/wrench.png"),
+        ])
     } else {
         None
     };
@@ -193,13 +196,12 @@ fn setup_flex(mut commands: Commands, asset_server: Res<AssetServer>, args: Res<
                             buttons_f,
                             column,
                             row,
-                            !args.no_text,
+                            args.text,
                             border,
                             border_color,
-                            image
-                                .as_ref()
-                                .filter(|_| (column + row) % args.image_freq == 0)
-                                .cloned(),
+                            images.as_ref().map(|images| {
+                                images[((column + row) / args.image_freq) % images.len()].clone()
+                            }),
                         );
                     }
                 });
@@ -208,8 +210,11 @@ fn setup_flex(mut commands: Commands, asset_server: Res<AssetServer>, args: Res<
 }
 
 fn setup_grid(mut commands: Commands, asset_server: Res<AssetServer>, args: Res<Args>) {
-    let image = if 0 < args.image_freq {
-        Some(asset_server.load("branding/icon.png"))
+    let images = if 0 < args.image_freq {
+        Some(vec![
+            asset_server.load("branding/icon.png"),
+            asset_server.load("textures/Game Icons/wrench.png"),
+        ])
     } else {
         None
     };
@@ -246,13 +251,12 @@ fn setup_grid(mut commands: Commands, asset_server: Res<AssetServer>, args: Res<
                         buttons_f,
                         column,
                         row,
-                        !args.no_text,
+                        args.text,
                         border,
                         border_color,
-                        image
-                            .as_ref()
-                            .filter(|_| (column + row) % args.image_freq == 0)
-                            .cloned(),
+                        images.as_ref().map(|images| {
+                            images[((column + row) / args.image_freq) % images.len()].clone()
+                        }),
                     );
                 }
             }
@@ -322,8 +326,11 @@ fn despawn_ui(mut commands: Commands, root_node: Single<Entity, (With<Node>, Wit
 }
 
 fn setup_many_cameras(mut commands: Commands, asset_server: Res<AssetServer>, args: Res<Args>) {
-    let image = if 0 < args.image_freq {
-        Some(asset_server.load("branding/icon.png"))
+    let images = if 0 < args.image_freq {
+        Some(vec![
+            asset_server.load("branding/icon.png"),
+            asset_server.load("textures/Game Icons/wrench.png"),
+        ])
     } else {
         None
     };
@@ -381,13 +388,13 @@ fn setup_many_cameras(mut commands: Commands, asset_server: Res<AssetServer>, ar
                                 buttons_f,
                                 column,
                                 row,
-                                !args.no_text,
+                                args.text,
                                 border,
                                 border_color,
-                                image
-                                    .as_ref()
-                                    .filter(|_| (column + row) % args.image_freq == 0)
-                                    .cloned(),
+                                images.as_ref().map(|images| {
+                                    images[((column + row) / args.image_freq) % images.len()]
+                                        .clone()
+                                }),
                             );
                         });
                 });