perf(render): instance block geometry

Share source buffers across block placements and render nested content with GPU instance transforms.\n\nChunk silhouettes and compact mesh material data so large drawings stay under device buffer limits and remain responsive.

src/scene/mod.rs

@@ -1224,25 +1224,6 @@ fn transform_block_mesh_lod_set(
     use acadrust::types::Vector3;
     let mut out = set.clone();
     out.instance_transform = Some(*xform);
-    let origin = xform.apply(Vector3::ZERO);
-    let vectors = [
-        xform.apply_rotation(Vector3::UNIT_X),
-        xform.apply_rotation(Vector3::UNIT_Y),
-        xform.apply_rotation(Vector3::UNIT_Z),
-    ];
-    out.curved_gens.retain_mut(|generator| {
-        let transformed = cadkernel::brep::mesh::transform_silhouette_affine(
-            &generator.source,
-            vectors.map(|vector| [vector.x, vector.y, vector.z]),
-            [origin.x, origin.y, origin.z],
-        );
-        if let Some(source) = transformed {
-            generator.source = source;
-            true
-        } else {
-            false
-        }
-    });
     let mut min_x = f32::INFINITY;
     let mut min_y = f32::INFINITY;
     let mut max_x = f32::NEG_INFINITY;
@@ -3214,6 +3195,7 @@ impl Scene {
         let ((x0, y0), (x1, y1)) = self.paper_limits()?;
         let (x0, y0, x1, y1) = (x0 as f32, y0 as f32, x1 as f32, y1 as f32);
         Some(HatchModel {
+            render_instance: None,
             world_origin: [0.0, 0.0],
             boundary: Arc::new(vec![[x0, y0], [x1, y0], [x1, y1], [x0, y1], [x0, y0]]),
             boundary_wcs: None,
@@ -5841,6 +5823,7 @@ impl Scene {
         )
         .with_viewport(viewport);
         let mut models = Vec::new();
+        let mut image_sources = rustc_hash::FxHashMap::default();
         let root = if self.block_edit_block.is_none() {
             viewport.map(|viewport| render_graph::SceneRoot::Viewport {
                 paper_block: self.current_layout_block_handle(),
@@ -5898,6 +5881,21 @@ impl Scene {
                             (point.z - vertex.pos[2] as f64) as f32,
                         ];
                     }
+                    let matrix = &context.transform.matrix.m;
+                    let linear = [
+                        matrix[0][0].to_bits(), matrix[0][1].to_bits(), matrix[0][2].to_bits(),
+                        matrix[1][0].to_bits(), matrix[1][1].to_bits(), matrix[1][2].to_bits(),
+                        matrix[2][0].to_bits(), matrix[2][1].to_bits(), matrix[2][2].to_bits(),
+                    ];
+                    let source_id = *image_sources
+                        .entry((handle.value(), linear))
+                        .or_insert_with(crate::scene::model::instance_model::next_source_id);
+                    placed.render_instance = Some(
+                        crate::scene::model::instance_model::RenderInstance {
+                            source_id,
+                            translation: [matrix[0][3], matrix[1][3], matrix[2][3]],
+                        },
+                    );
                 }
                 placed.draw_depth = context.draw_depth(handle, depth_map.as_ref());
                 models.push(placed);