Fix initialization panic with GL backend

crates/fj-viewer/src/graphics/drawables.rs

@@ -5,13 +5,16 @@ use super::{
 
 pub struct Drawables<'r> {
     pub model: Drawable<'r>,
-    pub mesh: Drawable<'r>,
+    pub mesh: Option<Drawable<'r>>,
 }
 
 impl<'r> Drawables<'r> {
     pub fn new(geometries: &'r Geometries, pipelines: &'r Pipelines) -> Self {
         let model = Drawable::new(&geometries.mesh, &pipelines.model);
-        let mesh = Drawable::new(&geometries.mesh, &pipelines.mesh);
+        let mesh = pipelines
+            .mesh
+            .as_ref()
+            .map(|pipeline| Drawable::new(&geometries.mesh, pipeline));
 
         Self { model, mesh }
     }

crates/fj-viewer/src/graphics/pipelines.rs

@@ -9,15 +9,15 @@ use super::{
 #[derive(Debug)]
 pub struct Pipelines {
     pub model: Pipeline,
-    pub mesh: Pipeline,
-    pub lines: Pipeline,
+    pub mesh: Option<Pipeline>,
 }
 
 impl Pipelines {
     pub fn new(
         device: &wgpu::Device,
         bind_group_layout: &wgpu::BindGroupLayout,
         color_format: wgpu::TextureFormat,
+        features: wgpu::Features,
     ) -> Self {
         let pipeline_layout =
             device.create_pipeline_layout(&wgpu::PipelineLayoutDescriptor {
@@ -28,32 +28,32 @@ impl Pipelines {
 
         let shaders = Shaders::new(device);
 
-        Self {
-            model: Pipeline::new(
-                device,
-                &pipeline_layout,
-                shaders.model(),
-                wgpu::PrimitiveTopology::TriangleList,
-                wgpu::PolygonMode::Fill,
-                color_format,
-            ),
-            mesh: Pipeline::new(
+        let model = Pipeline::new(
+            device,
+            &pipeline_layout,
+            shaders.model(),
+            wgpu::PrimitiveTopology::TriangleList,
+            wgpu::PolygonMode::Fill,
+            color_format,
+        );
+
+        let mesh = if features.contains(wgpu::Features::POLYGON_MODE_LINE) {
+            // We need this feature, otherwise initializing the pipeline will
+            // panic.
+
+            Some(Pipeline::new(
                 device,
                 &pipeline_layout,
                 shaders.mesh(),
                 wgpu::PrimitiveTopology::TriangleList,
                 wgpu::PolygonMode::Line,
                 color_format,
-            ),
-            lines: Pipeline::new(
-                device,
-                &pipeline_layout,
-                shaders.lines(),
-                wgpu::PrimitiveTopology::LineList,
-                wgpu::PolygonMode::Line,
-                color_format,
-            ),
-        }
+            ))
+        } else {
+            None
+        };
+
+        Self { model, mesh }
     }
 }
 

crates/fj-viewer/src/graphics/renderer.rs

@@ -20,7 +20,6 @@ use super::{
 #[derive(Debug)]
 pub struct Renderer {
     surface: wgpu::Surface,
-    features: wgpu::Features,
     device: wgpu::Device,
     queue: wgpu::Queue,
 
@@ -188,14 +187,13 @@ impl Renderer {
 
         let geometries = Geometries::new(&device, &Vertices::empty());
         let pipelines =
-            Pipelines::new(&device, &bind_group_layout, color_format);
+            Pipelines::new(&device, &bind_group_layout, color_format, features);
 
         let navigation_cube_renderer =
             NavigationCubeRenderer::new(&device, &queue, &surface_config);
 
         Ok(Self {
             surface,
-            features,
             device,
             queue,
 
@@ -311,8 +309,10 @@ impl Renderer {
                 drawables.model.draw(&mut render_pass);
             }
 
-            if self.is_line_drawing_available() && config.draw_mesh {
-                drawables.mesh.draw(&mut render_pass);
+            if let Some(drawable) = drawables.mesh {
+                if config.draw_mesh {
+                    drawable.draw(&mut render_pass);
+                }
             }
         }
 
@@ -376,11 +376,6 @@ impl Renderer {
 
         texture.create_view(&wgpu::TextureViewDescriptor::default())
     }
-
-    /// Returns true if the renderer's adapter can draw lines
-    pub fn is_line_drawing_available(&self) -> bool {
-        self.features.contains(wgpu::Features::POLYGON_MODE_LINE)
-    }
 }
 
 /// Error describing the set of render surface initialization errors

crates/fj-viewer/src/graphics/shader.wgsl

@@ -56,10 +56,3 @@ fn frag_mesh(in: VertexOutput) -> FragmentOutput {
     out.color = vec4<f32>(1.0 - in.color.rgb, in.color.a);
     return out;
 }
-
-@fragment
-fn frag_lines(in: VertexOutput) -> FragmentOutput {
-    var out: FragmentOutput;
-    out.color = vec4<f32>(in.color.rgb, in.color.a);
-    return out;
-}

crates/fj-viewer/src/graphics/shaders.rs

@@ -28,13 +28,6 @@ impl Shaders {
             frag_entry: "frag_mesh",
         }
     }
-
-    pub fn lines(&self) -> Shader {
-        Shader {
-            module: &self.0,
-            frag_entry: "frag_lines",
-        }
-    }
 }
 
 #[derive(Clone, Copy)]

crates/fj-viewer/src/viewer.rs

@@ -47,9 +47,7 @@ impl Viewer {
 
     /// Toggle the "draw mesh" setting
     pub fn toggle_draw_mesh(&mut self) {
-        if self.renderer.is_line_drawing_available() {
-            self.draw_config.draw_mesh = !self.draw_config.draw_mesh;
-        }
+        self.draw_config.draw_mesh = !self.draw_config.draw_mesh;
     }
 
     /// Handle the model being updated