enable grid in 3d views, some tweaks, make alpha picker always show up

crates/store/re_types/definitions/rerun/blueprint/components/plane_orientation.fbs

@@ -8,9 +8,9 @@ enum PlaneOrientation: ubyte (
     Invalid = 0,
 
     /// Plane spanned by X and Z axis.
-    Xz (default),
+    Xz,
     /// Plane spanned by Y and Z axis.
     Yz,
     /// Plane spanned by X and Y axis.
-    Xy,
+    Xy (default), // we default to RFU cameras in the view.
 }

crates/viewer/re_component_ui/src/color.rs

@@ -19,9 +19,8 @@ fn edit_rgba32_impl(ui: &mut egui::Ui, color: &mut MaybeMutRef<'_, Rgba32>) -> e
         let response = egui::color_picker::color_edit_button_srgba(
             ui,
             &mut edit_color,
-            // TODO(#1611): No transparency supported right now.
-            // Once we do we probably need to be more explicit about the component semantics.
-            egui::color_picker::Alpha::Opaque,
+            // TODO(#1611): Most of the time this doesn't do anything. Would be great to distinguish that.
+            egui::color_picker::Alpha::OnlyBlend,
         );
         *color = edit_color.into();
         response

crates/viewer/re_renderer/shader/world_grid.wgsl

@@ -18,7 +18,7 @@ struct WorldGridUniformBuffer {
 var<uniform> config: WorldGridUniformBuffer;
 
 struct VertexOutput {
-    @builtin(position)W
+    @builtin(position)
     position: vec4f,
 
     @location(0)

crates/viewer/re_space_view_spatial/src/ui_3d.rs

@@ -13,7 +13,12 @@ use re_space_view::controls::{
     ROTATE3D_BUTTON, SPEED_UP_3D_MODIFIER, TRACKED_OBJECT_RESTORE_KEY,
 };
 use re_types::{
-    blueprint::archetypes::Background, components::ViewCoordinates, view_coordinates::SignedAxis3,
+    blueprint::{
+        archetypes::{Background, LineGrid3D},
+        components::{GridSpacing, PlaneOrientation, UiRadius, Visible},
+    },
+    components::ViewCoordinates,
+    view_coordinates::SignedAxis3,
 };
 use re_ui::{ContextExt, ModifiersMarkdown, MouseButtonMarkdown};
 use re_viewer_context::{
@@ -667,6 +672,16 @@ impl SpatialSpaceView3D {
             view_builder.queue_draw(draw_data);
         }
 
+        // Optional 3D line grid.
+        let grid_config = ViewProperty::from_archetype::<LineGrid3D>(
+            ctx.blueprint_db(),
+            ctx.blueprint_query,
+            query.space_view_id,
+        );
+        if let Some(draw_data) = self.setup_grid_3d(ctx, &grid_config, state)? {
+            view_builder.queue_draw(draw_data);
+        }
+
         // Commit ui induced lines.
         view_builder.queue_draw(line_builder.into_draw_data()?);
 
@@ -701,6 +716,45 @@ impl SpatialSpaceView3D {
 
         Ok(())
     }
+
+    fn setup_grid_3d(
+        &self,
+        ctx: &ViewerContext<'_>,
+        grid_config: &ViewProperty,
+        state: &SpatialSpaceViewState,
+    ) -> Result<Option<re_renderer::renderer::WorldGridDrawData>, SpaceViewSystemExecutionError>
+    {
+        if !**grid_config.component_or_fallback::<Visible>(ctx, self, state)? {
+            return Ok(None);
+        }
+
+        let spacing = **grid_config.component_or_fallback::<GridSpacing>(ctx, self, state)?;
+        let thickness_ui =
+            (**grid_config.component_or_fallback::<UiRadius>(ctx, self, state)?) * 2.0;
+        let color =
+            grid_config.component_or_fallback::<re_types::components::Color>(ctx, self, state)?;
+        let orientation =
+            grid_config.component_or_fallback::<PlaneOrientation>(ctx, self, state)?;
+        let plane = match orientation {
+            PlaneOrientation::Xy => re_math::Plane3::XY,
+            PlaneOrientation::Yz => re_math::Plane3::YZ,
+            PlaneOrientation::Xz => re_math::Plane3::ZX,
+        };
+
+        let Some(render_ctx) = ctx.render_ctx else {
+            return Ok(None);
+        };
+
+        Ok(Some(re_renderer::renderer::WorldGridDrawData::new(
+            render_ctx,
+            &re_renderer::renderer::WorldGridConfiguration {
+                color: color.into(),
+                plane,
+                spacing,
+                thickness_ui,
+            },
+        )))
+    }
 }
 
 /// Show center of orbit camera when interacting with camera (it's quite helpful).

crates/viewer/re_space_view_spatial/src/view_3d_properties.rs

@@ -16,7 +16,7 @@ impl TypedComponentFallbackProvider<Color> for SpatialSpaceView3D {
         if ctx.archetype_name == Some(Background::name()) {
             Color::WHITE
         } else if ctx.archetype_name == Some(LineGrid3D::name()) {
-            Color::from_unmultiplied_rgba(200, 200, 200, 200)
+            Color::from_unmultiplied_rgba(128, 128, 128, 128)
         } else {
             Color::default()
         }

crates/viewer/re_viewport_blueprint/src/view_properties.rs

@@ -83,7 +83,7 @@ impl ViewProperty {
     /// Get the value of a specific component or its fallback if the component is not present.
     // TODO(andreas): Unfortunately we can't use TypedComponentFallbackProvider here because it may not be implemented for all components of interest.
     // This sadly means that there's a bit of unnecessary back and forth between arrow array and untyped that could be avoided otherwise.
-    pub fn component_or_fallback<C: re_types::Component + Default>(
+    pub fn component_or_fallback<C: re_types::Component>(
         &self,
         ctx: &ViewerContext<'_>,
         fallback_provider: &dyn ComponentFallbackProvider,
@@ -96,7 +96,7 @@ impl ViewProperty {
     }
 
     /// Get the component array for a given type or its fallback if the component is not present or empty.
-    pub fn component_array_or_fallback<C: re_types::Component + Default>(
+    pub fn component_array_or_fallback<C: re_types::Component>(
         &self,
         ctx: &ViewerContext<'_>,
         fallback_provider: &dyn ComponentFallbackProvider,