From 16be3cf028caa15f91b03c18953586f564d2fff3 Mon Sep 17 00:00:00 2001
From: "Spencer C. Imbleau" <spencer@imbleau.com>
Date: Sun, 4 Aug 2024 15:05:04 -0400
Subject: [PATCH] fix: runtime swapping of render settings

---
 CHANGELOG.md          |  1 +
 src/render/mod.rs     | 10 ++++------
 src/render/plugin.rs  |  5 ++++-
 src/render/systems.rs |  3 ++-
 4 files changed, 11 insertions(+), 8 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 9ccb586..e811896 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -22,6 +22,7 @@ Subheadings to categorize changes are `added, changed, deprecated, removed, fixe
 
 - `VelloPlugin` now has configuration. To retain previous behavior, use `VelloPlugin::default()`.
 - `VelloRenderer` is now a resource.
+- The `VelloRenderer` will attempt CPU fallback if it cannot obtain a GPU.
 - The font API has changed significantly. Please visit `examples/text` for further usage. This is to prepare for additional text features such as linebreak behavior, bounded text, and text justification.
   - `VelloText` has been renamed to `VelloTextSection`.
   - `VelloText.content` has been renamed to `VelloText.value`.
diff --git a/src/render/mod.rs b/src/render/mod.rs
index f6556ae..9fbddc0 100644
--- a/src/render/mod.rs
+++ b/src/render/mod.rs
@@ -76,11 +76,8 @@ impl VelloRenderer {
             vello::RendererOptions {
                 surface_format: None,
                 use_cpu: settings.use_cpu,
-                antialiasing_support: AaSupport {
-                    area: settings.antialiasing == AaConfig::Area,
-                    msaa8: settings.antialiasing == AaConfig::Msaa8,
-                    msaa16: settings.antialiasing == AaConfig::Msaa16,
-                },
+                // TODO: Vello doesn't currently allow adding additional AA support after initialization, so we need to use all support modes here instead.
+                antialiasing_support: AaSupport::all(),
                 num_init_threads: None,
             },
         )
@@ -98,10 +95,11 @@ impl FromWorld for VelloRenderer {
         ) {
             Ok(r) => r,
             Err(e) => {
-                error!("Attempting CPU fallback, failed to initialize renderer: {e:}");
+                error!("Attempting safe-mode fallback, failed to initialize renderer: {e:}");
                 {
                     let mut settings = world.get_resource_mut::<VelloRenderSettings>().unwrap();
                     settings.use_cpu = true;
+                    settings.antialiasing = AaConfig::Area;
                 }
                 match VelloRenderer::try_new(
                     world.get_resource::<RenderDevice>().unwrap().wgpu_device(),
diff --git a/src/render/plugin.rs b/src/render/plugin.rs
index 6b0b828..0fb258c 100644
--- a/src/render/plugin.rs
+++ b/src/render/plugin.rs
@@ -51,7 +51,10 @@ impl Plugin for VelloRenderPlugin {
         render_app
             .insert_resource(self.render_settings.clone())
             .insert_resource(ExtractedPixelScale(1.0))
-            .add_systems(Update, systems::render_settings_change_detection)
+            .add_systems(
+                Render,
+                systems::render_settings_change_detection.in_set(RenderSet::Cleanup),
+            )
             .add_systems(
                 ExtractSchedule,
                 (
diff --git a/src/render/systems.rs b/src/render/systems.rs
index 1ecf3ab..4afab4e 100644
--- a/src/render/systems.rs
+++ b/src/render/systems.rs
@@ -336,8 +336,9 @@ pub fn render_settings_change_detection(
     mut commands: Commands,
     render_settings: Res<VelloRenderSettings>,
 ) {
-    if render_settings.is_changed() {
+    if render_settings.is_changed() && !render_settings.is_added() {
         // Replace renderer
+        info!("Render settings changed, re-initializing vello...");
         commands.remove_resource::<VelloRenderer>();
         commands.init_resource::<VelloRenderer>();
     }