fix(text): show selection highlight

Render tinted SDF glyphs in the final xray pass so base text and wipeouts cannot occlude them.\n\nRefs #479

src/scene/pipeline/mod.rs

@@ -102,6 +102,8 @@ pub struct Pipeline {
     /// SDF text-quad pipeline (Phase 2b): draws per-glyph quads sampling the
     /// shared glyph atlas. Fed only when `OCS_TEXT_SDF` is set (else no verts).
     text_pipeline: wgpu::RenderPipeline,
+    /// Depth-independent variant used by selection / rollover highlighting.
+    text_highlight_pipeline: wgpu::RenderPipeline,
     mesh_pipeline: wgpu::RenderPipeline,
     /// Depth-write-disabled variant of `mesh_pipeline` for non-opaque solids.
     mesh_transparent_pipeline: wgpu::RenderPipeline,
@@ -1602,8 +1604,8 @@ impl Pipeline {
 
         // ── Text (SDF glyph quads) ─────────────────────────────────────────
         let text_atlas_bgl = text_gpu::TextAtlasGpu::bind_group_layout(device);
-        let text_pipeline =
-            text_gpu::create_pipeline(device, &frame_bgl, &text_atlas_bgl, format, MSAA_SAMPLES);
+        let (text_pipeline, text_highlight_pipeline) =
+            text_gpu::create_pipelines(device, &frame_bgl, &text_atlas_bgl, format, MSAA_SAMPLES);
 
         let viewcube = ViewCubePipeline::new(device, queue, format);
 
@@ -1745,6 +1747,7 @@ impl Pipeline {
             hatch_compat_pipeline,
             image_pipeline,
             text_pipeline,
+            text_highlight_pipeline,
             text_atlas_bgl,
             text_atlas_gpu: None,
             text_vbuf: None,
@@ -3619,14 +3622,13 @@ impl Pipeline {
         }
 
         // ── Pass 5c: SDF text quads (drawn over wires) ────────────────────
-        // The highlight buffer (selected / hovered text, tinted) is drawn in
-        // the same pass right after the base text so it recolours those glyphs.
+        // Selection / rollover text is drawn later with the selected-wire xray
+        // overlay, after wipeouts, so normal text cannot hide its own tint.
         if let Some(atlas) = &self.text_atlas_gpu {
             let have_base = self.text_vbuf.is_some() && self.text_vcount > 0;
-            let have_hl = self.text_highlight_vbuf.is_some() && self.text_highlight_vcount > 0;
             let have_preview =
                 self.text_preview_vbuf.is_some() && self.text_preview_vcount > 0;
-            if have_base || have_hl || have_preview {
+            if have_base || have_preview {
                 let mut pass = encoder.begin_render_pass(&wgpu::RenderPassDescriptor {
                     label: Some("text.render_pass"),
                     color_attachments: &[Some(wgpu::RenderPassColorAttachment {
@@ -3660,12 +3662,6 @@ impl Pipeline {
                         pass.draw(0..self.text_vcount, 0..1);
                     }
                 }
-                if let Some(hlbuf) = &self.text_highlight_vbuf {
-                    if self.text_highlight_vcount > 0 {
-                        pass.set_vertex_buffer(0, hlbuf.slice(..));
-                        pass.draw(0..self.text_highlight_vcount, 0..1);
-                    }
-                }
                 // Grip-drag / command-preview glyphs, drawn over the base text.
                 if let Some(pbuf) = &self.text_preview_vbuf {
                     if self.text_preview_vcount > 0 {
@@ -3714,12 +3710,14 @@ impl Pipeline {
             }
         }
 
-        // ── Pass 7: selected wire overlay pass ───────────────────────────
-        // Redraws selected wires with depth_compare=Always so they appear on
-        // top of all other geometry at full brightness.
-        if !self.gpu_selected_wires.is_empty() {
+        // ── Pass 7: selection overlay pass ───────────────────────────────
+        // Redraws selected wires and text with depth_compare=Always so both
+        // appear on top of all other geometry at full brightness.
+        let have_text_highlight =
+            self.text_highlight_vbuf.is_some() && self.text_highlight_vcount > 0;
+        if !self.gpu_selected_wires.is_empty() || have_text_highlight {
             let mut pass = encoder.begin_render_pass(&wgpu::RenderPassDescriptor {
-                label: Some("wire_xray.render_pass"),
+                label: Some("selection_xray.render_pass"),
                 color_attachments: &[Some(wgpu::RenderPassColorAttachment {
                     view: msaa,
                     depth_slice: None,
@@ -3741,19 +3739,31 @@ impl Pipeline {
                 occlusion_query_set: None,
             });
             pass.set_viewport(0.0, 0.0, vp.width as f32, vp.height as f32, 0.0, 1.0);
-            pass.set_pipeline(&self.wire_xray_pipeline);
             pass.set_bind_group(0, &self.uniform_bind_group, &[]);
             pass.set_stencil_reference(stencil_ref);
-            for wire in &self.gpu_selected_wires {
-                if wire.instance_count > 0 {
-                    if let Some(bg) = &wire.const_bind_group {
-                        pass.set_bind_group(1, bg.as_ref(), &[]);
+            if !self.gpu_selected_wires.is_empty() {
+                pass.set_pipeline(&self.wire_xray_pipeline);
+                for wire in &self.gpu_selected_wires {
+                    if wire.instance_count > 0 {
+                        if let Some(bg) = &wire.const_bind_group {
+                            pass.set_bind_group(1, bg.as_ref(), &[]);
+                        }
+                        pass.set_vertex_buffer(0, wire.instance_buffer.slice(..));
+                        pass.draw(
+                            0..6,
+                            wire.first_instance..wire.first_instance + wire.instance_count,
+                        );
                     }
-                    pass.set_vertex_buffer(0, wire.instance_buffer.slice(..));
-                    pass.draw(
-                        0..6,
-                        wire.first_instance..wire.first_instance + wire.instance_count,
-                    );
+                }
+            }
+            if let (Some(atlas), Some(hlbuf)) =
+                (&self.text_atlas_gpu, &self.text_highlight_vbuf)
+            {
+                if self.text_highlight_vcount > 0 {
+                    pass.set_pipeline(&self.text_highlight_pipeline);
+                    pass.set_bind_group(1, &atlas.bind_group, &[]);
+                    pass.set_vertex_buffer(0, hlbuf.slice(..));
+                    pass.draw(0..self.text_highlight_vcount, 0..1);
                 }
             }
         }

src/scene/pipeline/text_gpu.rs

@@ -250,16 +250,17 @@ impl TextAtlasGpu {
 
 // ── Pipeline ─────────────────────────────────────────────────────────────────
 
-/// Build the text render pipeline. Mirrors the image pipeline: alpha blending,
-/// `LessEqual` depth with write, 4x MSAA. `frame_bgl` is group 0 (shared
-/// uniforms), `atlas_bgl` is group 1 (the atlas).
-pub fn create_pipeline(
+/// Build the base and highlight text pipelines. The base mirrors the image
+/// pipeline (`LessEqual` depth with write); the highlight variant always draws
+/// without changing depth, matching the selected-wire xray overlay.
+/// `frame_bgl` is group 0 (shared uniforms), `atlas_bgl` is group 1 (the atlas).
+pub fn create_pipelines(
     device: &wgpu::Device,
     frame_bgl: &wgpu::BindGroupLayout,
     atlas_bgl: &wgpu::BindGroupLayout,
     color_format: wgpu::TextureFormat,
     sample_count: u32,
-) -> wgpu::RenderPipeline {
+) -> (wgpu::RenderPipeline, wgpu::RenderPipeline) {
     let shader = device.create_shader_module(wgpu::ShaderModuleDescriptor {
         label: Some("text.wgsl"),
         source: wgpu::ShaderSource::Wgsl(include_str!("../../shaders/text.wgsl").into()),
@@ -269,44 +270,54 @@ pub fn create_pipeline(
         bind_group_layouts: &[frame_bgl, atlas_bgl],
         push_constant_ranges: &[],
     });
-    device.create_render_pipeline(&wgpu::RenderPipelineDescriptor {
-        label: Some("text.pipeline"),
-        layout: Some(&layout),
-        vertex: wgpu::VertexState {
-            module: &shader,
-            entry_point: Some("vs_main"),
-            buffers: &[TextVertex::layout()],
-            compilation_options: Default::default(),
-        },
-        fragment: Some(wgpu::FragmentState {
-            module: &shader,
-            entry_point: Some("fs_main"),
-            targets: &[Some(wgpu::ColorTargetState {
-                format: color_format,
-                blend: Some(wgpu::BlendState::ALPHA_BLENDING),
-                write_mask: wgpu::ColorWrites::ALL,
-            })],
-            compilation_options: Default::default(),
-        }),
-        primitive: wgpu::PrimitiveState {
-            topology: wgpu::PrimitiveTopology::TriangleList,
-            ..Default::default()
-        },
-        depth_stencil: Some(wgpu::DepthStencilState {
-            format: wgpu::TextureFormat::Depth24PlusStencil8,
-            depth_write_enabled: true,
-            depth_compare: wgpu::CompareFunction::LessEqual,
-            stencil: wgpu::StencilState::default(),
-            bias: wgpu::DepthBiasState::default(),
-        }),
-        multisample: wgpu::MultisampleState {
-            count: sample_count,
-            mask: !0,
-            alpha_to_coverage_enabled: false,
-        },
-        multiview: None,
-        cache: None,
-    })
+    let create = |label, depth_write_enabled, depth_compare| {
+        device.create_render_pipeline(&wgpu::RenderPipelineDescriptor {
+            label: Some(label),
+            layout: Some(&layout),
+            vertex: wgpu::VertexState {
+                module: &shader,
+                entry_point: Some("vs_main"),
+                buffers: &[TextVertex::layout()],
+                compilation_options: Default::default(),
+            },
+            fragment: Some(wgpu::FragmentState {
+                module: &shader,
+                entry_point: Some("fs_main"),
+                targets: &[Some(wgpu::ColorTargetState {
+                    format: color_format,
+                    blend: Some(wgpu::BlendState::ALPHA_BLENDING),
+                    write_mask: wgpu::ColorWrites::ALL,
+                })],
+                compilation_options: Default::default(),
+            }),
+            primitive: wgpu::PrimitiveState {
+                topology: wgpu::PrimitiveTopology::TriangleList,
+                ..Default::default()
+            },
+            depth_stencil: Some(wgpu::DepthStencilState {
+                format: wgpu::TextureFormat::Depth24PlusStencil8,
+                depth_write_enabled,
+                depth_compare,
+                stencil: wgpu::StencilState::default(),
+                bias: wgpu::DepthBiasState::default(),
+            }),
+            multisample: wgpu::MultisampleState {
+                count: sample_count,
+                mask: !0,
+                alpha_to_coverage_enabled: false,
+            },
+            multiview: None,
+            cache: None,
+        })
+    };
+    (
+        create("text.pipeline", true, wgpu::CompareFunction::LessEqual),
+        create(
+            "text.highlight.pipeline",
+            false,
+            wgpu::CompareFunction::Always,
+        ),
+    )
 }
 
 /// Upload a finished vertex list; `None` if empty.