source/blender/blenkernel/BKE_grease_pencil.hh

@@ -86,6 +86,9 @@ class Drawing : public ::GreasePencilDrawing {
 
   const bke::CurvesGeometry &strokes() const;
   bke::CurvesGeometry &strokes_for_write();
+
+  Array<IndexMask> get_shapes_index_masks(IndexMaskMemory &memory) const;
+
   /**
    * The triangles for all the fills in the geometry.
    */

source/blender/blenkernel/intern/grease_pencil.cc

@@ -29,6 +29,7 @@
 #include "BKE_object_types.hh"
 
 #include "BLI_bounds.hh"
+#include "BLI_delaunay_2d.hh"
 #include "BLI_enumerable_thread_specific.hh"
 #include "BLI_map.hh"
 #include "BLI_math_euler_types.hh"
@@ -366,61 +367,234 @@ Drawing::~Drawing()
   this->runtime = nullptr;
 }
 
-Span<Vector<uint3>> Drawing::triangles() const
+Array<IndexMask> Drawing::get_shapes_index_masks(IndexMaskMemory &memory) const
 {
-  struct LocalMemArena {
+  const CurvesGeometry &curves = this->strokes();
-    MemArena *pf_arena = nullptr;
+  const bke::AttributeAccessor attributes = curves.attributes();
-    LocalMemArena() : pf_arena(BLI_memarena_new(BLI_MEMARENA_STD_BUFSIZE, "Drawing::triangles")) {}
 
-    ~LocalMemArena()
+  const int num_curves = curves.curves_num();
-    {
+
-      if (pf_arena != nullptr) {
+  const VArray<int> shape_ids = *attributes.lookup<int>("shape_id", bke::AttrDomain::Curve);
-        BLI_memarena_free(pf_arena);
+
+  if (!shape_ids) {
+    /* If the attribute does not exist then the default is each shape containing one curve. */
+    Array<IndexMask> data(num_curves);
+    IndexMask::from_groups<int>(
+        IndexMask(num_curves), memory, [&](const int i) { return i; }, data);
+
+    return data;
+  }
+
+  const int max_shape_id = *std::max_element(shape_ids.get_internal_span().begin(),
+                                             shape_ids.get_internal_span().end());
+
+  Array<IndexMask> data(max_shape_id + 1);
+  IndexMask::from_groups<int>(
+      IndexRange(num_curves), memory, [&](const int i) { return shape_ids[i]; }, data);
+
+  return data;
+}
+
+static bool check_self_intersections(Span<float2> projverts)
+{
+  std::atomic<bool> intersect = false;
+  threading::parallel_for(projverts.index_range(), 512, [&](const IndexRange range) {
+    for (const int e2_id : range) {
+      if (intersect) {
+        return;
+      }
+      for (const int e1_id : projverts.index_range().drop_front(e2_id)) {
+        const int p1 = e1_id;
+        const int p2 = (e1_id + 1) % projverts.size();
+        const int p3 = e2_id;
+        const int p4 = (e2_id + 1) % projverts.size();
+        if (p1 == p4) {
+          continue;
+        }
+        if (p2 == p3) {
+          continue;
+        }
+
+        if (isect_seg_seg_v2_simple(projverts[p1], projverts[p2], projverts[p3], projverts[p4])) {
+          intersect.store(true, std::memory_order_relaxed);
+          return;
+        }
+      }
+    };
+  });
+
+  return intersect;
+}
+
+static bool check_other_intersections(Span<float2> projverts1, Span<float2> projverts2)
+{
+  std::atomic<bool> intersect = false;
+
+  threading::parallel_for(projverts1.index_range(), 512, [&](const IndexRange range) {
+    for (const int e1_id : range) {
+      for (const int e2_id : projverts2.index_range()) {
+        const int p11 = e1_id;
+        const int p12 = (e1_id + 1) % projverts1.size();
+        const int p21 = e2_id;
+        const int p22 = (e2_id + 1) % projverts2.size();
+
+        if (isect_seg_seg_v2_simple(
+                projverts1[p11], projverts1[p12], projverts2[p21], projverts2[p22]))
+        {
+          intersect.store(true, std::memory_order_relaxed);
+          return;
+        }
       }
     }
-  };
+  });
+
+  return intersect;
+}
+
+static bool check_valid_curves(Span<float2> projverts, const OffsetIndices<int> points_by_group)
+{
+  std::atomic<bool> intersect = false;
+  /* Check for self intersections. */
+  threading::parallel_for(points_by_group.index_range(), 512, [&](const IndexRange range) {
+    for (const int pos : range) {
+      if (intersect) {
+        return;
+      }
+      const IndexRange point_group = points_by_group[pos];
+      if (check_self_intersections(projverts.slice(point_group))) {
+        intersect.store(true, std::memory_order_relaxed);
+        return;
+      }
+    }
+  });
+
+  if (intersect) {
+    return false;
+  }
+
+  /* Check if other intersect. */
+  threading::parallel_for(points_by_group.index_range(), 512, [&](const IndexRange range1) {
+    for (const int pos1 : range1) {
+      if (intersect) {
+        return;
+      }
+      const IndexRange point_group1 = points_by_group[pos1];
+
+      threading::parallel_for(points_by_group.index_range(), 512, [&](const IndexRange range2) {
+        for (const int pos2 : range2) {
+          if (intersect) {
+            return;
+          }
+          const IndexRange point_group2 = points_by_group[pos2];
+
+          if (pos2 >= pos1) {
+            return;
+          }
+          if (check_other_intersections(projverts.slice(point_group1),
+                                        projverts.slice(point_group2)))
+          {
+            intersect.store(true, std::memory_order_relaxed);
+            return;
+          }
+        }
+      });
+    }
+  });
+
+  if (intersect) {
+    return false;
+  }
+
+  return true;
+}
+
+Span<Vector<uint3>> Drawing::triangles() const
+{
   this->runtime->triangles_cache.ensure([&](Vector<Vector<uint3>> &r_data) {
     const CurvesGeometry &curves = this->strokes();
     const Span<float3> positions = curves.evaluated_positions();
     const Span<float3> normals = this->curve_plane_normals();
     const OffsetIndices<int> points_by_curve = curves.evaluated_points_by_curve();
+    const Array<int> point_to_curve_map = curves.point_to_curve_map();
 
-    r_data.resize(curves.curves_num());
+    IndexMaskMemory memory;
+    const Array<IndexMask> groups = this->get_shapes_index_masks(memory);
+
+    r_data.resize(groups.size() + 1);
+
+    // r_data.resize(curves.curves_num());
     MutableSpan<Vector<uint3>> strokes_triangles = r_data.as_mutable_span();
-    threading::EnumerableThreadSpecific<LocalMemArena> all_local_mem_arenas;
+
-    threading::parallel_for(curves.curves_range(), 32, [&](const IndexRange range) {
+    threading::parallel_for(groups.index_range(), 32, [&](const IndexRange group_range) {
-      MemArena *pf_arena = all_local_mem_arenas.local().pf_arena;
+      for (const int group_id : group_range) {
-      for (const int curve_i : range) {
+        const IndexMask &group = groups[group_id];
-        const IndexRange points = points_by_curve[curve_i];
+
-        if (points.size() < 3) {
+        float3x3 axis_mat;
+        axis_dominant_v3_to_m3(axis_mat.ptr(), normals[group.first()]);
+
+        Array<int> offsets_data(group.size() + 1);
+        offset_indices::gather_group_sizes(
+            points_by_curve, group, offsets_data.as_mutable_span().drop_back(1));
+        offset_indices::accumulate_counts_to_offsets(offsets_data);
+        const OffsetIndices<int> points_by_group = OffsetIndices<int>(offsets_data);
+
+        const int num_points = points_by_group.total_size();
+
+        Array<float2> projverts2(num_points);
+        group.foreach_index(GrainSize(256), [&](const int64_t curve_i, const int64_t pos) {
+          const IndexRange point_group = points_by_group[pos];
+          const IndexRange points = points_by_curve[curve_i];
+          threading::parallel_for(points.index_range(), 512, [&](const IndexRange range) {
+            for (const int p_id : range) {
+              mul_v2_m3v3(projverts2[point_group[p_id]], axis_mat.ptr(), positions[points[p_id]]);
+            }
+          });
+        });
+
+        if (!check_valid_curves(projverts2, points_by_group)) {
           continue;
         }
 
-        const int num_triangles = points.size() - 2;
+        Array<double2> verts(num_points);
-        strokes_triangles[curve_i].resize(num_triangles);
+        Array<std::pair<int, int>> edges(num_points);
-        MutableSpan<uint3> r_tris = strokes_triangles[curve_i];
+        Array<Vector<int>> faces(group.size());
 
-        float(*projverts)[2] = static_cast<float(*)[2]>(
+        Array<int> vert_to_point_map(num_points);
-            BLI_memarena_alloc(pf_arena, sizeof(*projverts) * size_t(points.size())));
 
-        float3x3 axis_mat;
+        group.foreach_index(GrainSize(256), [&](const int64_t curve_i, const int64_t pos) {
-        axis_dominant_v3_to_m3(axis_mat.ptr(), normals[curve_i]);
+          const IndexRange point_group = points_by_group[pos];
+          const IndexRange points = points_by_curve[curve_i];
+          faces[pos].resize(points.size());
+          threading::parallel_for(points.index_range(), 512, [&](const IndexRange range) {
+            for (const int p_id : range) {
+              vert_to_point_map[point_group[p_id]] = points[p_id];
+              verts[point_group[p_id]] = double2(projverts2[point_group[p_id]]);
+              edges[point_group[p_id]] = std::pair<int, int>(
+                  point_group[p_id], point_group[(p_id + 1) % points.size()]);
+              faces[pos][p_id] = point_group[p_id];
+            }
+          });
+        });
 
-        for (const int i : points.index_range()) {
+        meshintersect::CDT_input<double> input;
-          mul_v2_m3v3(projverts[i], axis_mat.ptr(), positions[points[i]]);
+        input.vert = verts;
-        }
+        input.edge = edges;
+        input.face = faces;
+        input.need_ids = false;
 
-        BLI_polyfill_calc_arena(projverts,
+        meshintersect::CDT_result<double> result = delaunay_2d_calc(input, CDT_INSIDE_WITH_HOLES);
-                                points.size(),
-                                0,
-                                reinterpret_cast<uint32_t(*)[3]>(r_tris.data()),
-                                pf_arena);
 
-        for (const int i : r_tris.index_range()) {
+        strokes_triangles[group_id].resize(result.face.size());
-          r_tris[i] += uint3(points.first());
+        MutableSpan<uint3> r_tris = strokes_triangles[group_id];
-        }
 
-        BLI_memarena_clear(pf_arena);
+        threading::parallel_for(result.face.index_range(), 512, [&](const IndexRange range) {
+          for (const int i : range) {
+            BLI_assert(result.face[i].size() == 3);
+            r_tris[i] = uint3(vert_to_point_map[result.face[i][0]],
+                              vert_to_point_map[result.face[i][1]],
+                              vert_to_point_map[result.face[i][2]]);
+          }
+        });
       }
     });
   });

source/blender/draw/engines/gpencil/gpencil_engine_c.cc

@@ -725,24 +725,32 @@ static GPENCIL_tObject *grease_pencil_object_cache_populate(GPENCIL_PrivateData
     IndexMaskMemory memory;
     const IndexMask visible_strokes = ed::greasepencil::retrieve_visible_strokes(
         *ob, info.drawing, memory);
+    const Array<IndexMask> groups = info.drawing.get_shapes_index_masks(memory);
 
     /* Precompute all the triangle and vertex counts.
      * In case the drawing should not be rendered, we need to compute the offset where the next
      * drawing begins. */
-    Array<int> num_triangles_per_stroke(visible_strokes.size());
+    Array<int> num_triangles_per_stroke(groups.size());
     Array<int> num_vertices_per_stroke(visible_strokes.size());
     int total_num_triangles = 0;
     int total_num_vertices = 0;
-    visible_strokes.foreach_index([&](const int stroke_i, const int pos) {
+    int current_curve = 0;
-      const IndexRange points = points_by_curve[stroke_i];
+    for (const int group_id : groups.index_range()) {
-      const int num_stroke_triangles = triangles[stroke_i].size();
+      const IndexMask &group = groups[group_id];
-      const int num_stroke_vertices = (points.size() +
+
-                                       int(cyclic[stroke_i] && (points.size() >= 3)));
+      const int num_stroke_triangles = triangles[group_id].size();
-      num_triangles_per_stroke[pos] = num_stroke_triangles;
+      num_triangles_per_stroke[group_id] = num_stroke_triangles;
-      num_vertices_per_stroke[pos] = num_stroke_vertices;
       total_num_triangles += num_stroke_triangles;
-      total_num_vertices += num_stroke_vertices;
+
-    });
+      group.foreach_index([&](const int curve_i) {
+        const IndexRange points = points_by_curve[curve_i];
+        const int num_stroke_vertices = (points.size() +
+                                         int(cyclic[curve_i] && (points.size() >= 3)));
+        num_vertices_per_stroke[current_curve] = num_stroke_vertices;
+        total_num_vertices += num_stroke_vertices;
+        current_curve++;
+      });
+    }
 
     bool is_layer_used_as_mask = false;
     const bool show_drawing_in_render = use_layer_in_render(
@@ -789,17 +797,21 @@ static GPENCIL_tObject *grease_pencil_object_cache_populate(GPENCIL_PrivateData
                             info.frame_number != pd->cfra && pd->use_multiedit_lines_only;
     const bool is_onion = info.onion_id != 0;
 
-    visible_strokes.foreach_index([&](const int stroke_i, const int pos) {
+    current_curve = 0;
-      const IndexRange points = points_by_curve[stroke_i];
+    for (const int group_id : groups.index_range()) {
+      const IndexMask &group = groups[group_id];
+
+      const int curve_i = group.first();
+
       /* The material index is allowed to be negative as it's stored as a generic attribute. We
-       * clamp it here to avoid crashing in the rendering code. Any stroke with a material < 0 will
+       * clamp it here to avoid crashing in the rendering code. Any stroke with a material < 0
-       * use the first material in the first material slot.*/
+       * will use the first material in the first material slot.*/
-      const int material_index = std::max(stroke_materials[stroke_i], 0);
+      const int material_index = std::max(stroke_materials[curve_i], 0);
       const MaterialGPencilStyle *gp_style = BKE_gpencil_material_settings(ob, material_index + 1);
 
       const bool hide_material = (gp_style->flag & GP_MATERIAL_HIDE) != 0;
       const bool show_stroke = ((gp_style->flag & GP_MATERIAL_STROKE_SHOW) != 0);
-      const bool show_fill = (points.size() >= 3) &&
+      const bool show_fill = (!triangles[group_id].is_empty()) &&
                              ((gp_style->flag & GP_MATERIAL_FILL_SHOW) != 0) &&
                              (!pd->simplify_fill);
       const bool hide_onion = is_onion && ((gp_style->flag & GP_MATERIAL_HIDE_ONIONSKIN) != 0 ||
@@ -808,9 +820,12 @@ static GPENCIL_tObject *grease_pencil_object_cache_populate(GPENCIL_PrivateData
                                (only_lines && !is_onion) || hide_onion;
 
       if (skip_stroke) {
-        t_offset += num_triangles_per_stroke[pos];
+        t_offset += num_triangles_per_stroke[group_id];
-        t_offset += num_vertices_per_stroke[pos] * 2;
+        for (const int i : group.index_range()) {
-        return;
+          t_offset += num_vertices_per_stroke[current_curve + i] * 2;
+        };
+        current_curve += group.size();
+        continue;
       }
 
       GPUUniformBuf *new_ubo_mat;
@@ -855,20 +870,25 @@ static GPENCIL_tObject *grease_pencil_object_cache_populate(GPENCIL_PrivateData
 
       if (show_fill) {
         const int v_first = t_offset * 3;
-        const int v_count = num_triangles_per_stroke[pos] * 3;
+        const int v_count = num_triangles_per_stroke[group_id] * 3;
         drawcall_add(geom, v_first, v_count);
       }
 
-      t_offset += num_triangles_per_stroke[pos];
+      t_offset += num_triangles_per_stroke[group_id];
 
-      if (show_stroke) {
+      group.foreach_index([&](const int curve_i) {
-        const int v_first = t_offset * 3;
+        const IndexRange points = points_by_curve[curve_i];
-        const int v_count = num_vertices_per_stroke[pos] * 2 * 3;
-        drawcall_add(geom, v_first, v_count);
-      }
 
-      t_offset += num_vertices_per_stroke[pos] * 2;
+        if (show_stroke) {
-    });
+          const int v_first = t_offset * 3;
+          const int v_count = num_vertices_per_stroke[current_curve] * 2 * 3;
+          drawcall_add(geom, v_first, v_count);
+        }
+
+        t_offset += num_vertices_per_stroke[current_curve] * 2;
+        current_curve++;
+      });
+    }
   }
 
   drawcall_flush();

source/blender/draw/engines/overlay/overlay_next_grease_pencil.hh

@@ -89,33 +89,32 @@ class GreasePencil {
       IndexMaskMemory memory;
       const IndexMask visible_strokes = ed::greasepencil::retrieve_visible_strokes(
           *ob, info.drawing, memory);
+      const Array<IndexMask> groups = info.drawing.get_shapes_index_masks(memory);
 
       const Span<Vector<uint3>> triangles = info.drawing.triangles();
 
-      visible_strokes.foreach_index([&](const int stroke_i) {
+      const bool hide_onion = info.onion_id != 0;
-        const IndexRange points = points_by_curve[stroke_i];
+
-        const int material_index = stroke_materials[stroke_i];
+      for (const int group_id : groups.index_range()) {
+        const IndexMask &group = groups[group_id];
+
+        const int material_index = stroke_materials[group.first()];
         MaterialGPencilStyle *gp_style = BKE_gpencil_material_settings(ob, material_index + 1);
 
-        const bool hide_onion = info.onion_id != 0;
         const bool hide_material = (gp_style->flag & GP_MATERIAL_HIDE) != 0;
 
-        const int num_stroke_triangles = triangles[stroke_i].size();
+        const int num_stroke_triangles = triangles[group_id].size();
-        const int num_stroke_vertices = (points.size() +
-                                         int(cyclic[stroke_i] && (points.size() >= 3)));
 
         if (hide_material || hide_onion) {
           t_offset += num_stroke_triangles;
-          t_offset += num_stroke_vertices * 2;
-          return;
         }
 
-        blender::gpu::Batch *geom = draw::DRW_cache_grease_pencil_get(scene, ob);
-
         const bool show_stroke = (gp_style->flag & GP_MATERIAL_STROKE_SHOW) != 0;
-        const bool show_fill = (points.size() >= 3) &&
+        const bool show_fill = (num_stroke_triangles != 0) &&
                                (gp_style->flag & GP_MATERIAL_FILL_SHOW) != 0;
 
+        blender::gpu::Batch *geom = draw::DRW_cache_grease_pencil_get(scene, ob);
+
         if (show_fill) {
           int v_first = t_offset * 3;
           int v_count = num_stroke_triangles * 3;
@@ -124,13 +123,25 @@ class GreasePencil {
 
         t_offset += num_stroke_triangles;
 
-        if (show_stroke) {
+        group.foreach_index([&](const int curve_i) {
-          int v_first = t_offset * 3;
+          const IndexRange points = points_by_curve[curve_i];
-          int v_count = num_stroke_vertices * 2 * 3;
+
-          pass.draw(geom, 1, v_count, v_first, res_handle);
+          const int num_stroke_vertices = (points.size() +
-        }
+                                           int(cyclic[curve_i] && (points.size() >= 3)));
-        t_offset += num_stroke_vertices * 2;
+
-      });
+          if (hide_material || hide_onion) {
+            t_offset += num_stroke_vertices * 2;
+            return;
+          }
+
+          if (show_stroke) {
+            int v_first = t_offset * 3;
+            int v_count = num_stroke_vertices * 2 * 3;
+            pass.draw(geom, 1, v_count, v_first, res_handle);
+          }
+          t_offset += num_stroke_vertices * 2;
+        });
+      }
     }
   }
 

source/blender/draw/engines/overlay/overlay_outline.cc

@@ -323,31 +323,26 @@ static void OVERLAY_outline_grease_pencil(OVERLAY_PrivateData *pd, Scene *scene,
     IndexMaskMemory memory;
     const IndexMask visible_strokes = ed::greasepencil::retrieve_visible_strokes(
         *ob, info.drawing, memory);
+    const Array<IndexMask> groups = info.drawing.get_shapes_index_masks(memory);
 
     const Span<Vector<uint3>> triangles = info.drawing.triangles();
 
-    visible_strokes.foreach_index([&](const int stroke_i) {
+    for (const int group_id : groups.index_range()) {
-      const IndexRange points = points_by_curve[stroke_i];
+      const IndexMask &group = groups[group_id];
-      const int material_index = stroke_materials[stroke_i];
+
+      const int material_index = stroke_materials[group.first()];
       MaterialGPencilStyle *gp_style = BKE_gpencil_material_settings(ob, material_index + 1);
 
       const bool hide_onion = info.onion_id != 0;
       const bool hide_material = (gp_style->flag & GP_MATERIAL_HIDE) != 0;
 
-      const int num_stroke_triangles = triangles[stroke_i].size();
+      const int num_stroke_triangles = triangles[group_id].size();
-      const int num_stroke_vertices = (points.size() +
-                                       int(cyclic[stroke_i] && (points.size() >= 3)));
-
-      if (hide_material || hide_onion) {
-        t_offset += num_stroke_triangles;
-        t_offset += num_stroke_vertices * 2;
-        return;
-      }
-
-      blender::gpu::Batch *geom = draw::DRW_cache_grease_pencil_get(scene, ob);
 
       const bool show_stroke = (gp_style->flag & GP_MATERIAL_STROKE_SHOW) != 0;
-      const bool show_fill = (points.size() >= 3) && (gp_style->flag & GP_MATERIAL_FILL_SHOW) != 0;
+      const bool show_fill = (num_stroke_triangles != 0) &&
+                             (gp_style->flag & GP_MATERIAL_FILL_SHOW) != 0;
+
+      blender::gpu::Batch *geom = draw::DRW_cache_grease_pencil_get(scene, ob);
 
       if (show_fill) {
         int v_first = t_offset * 3;
@@ -357,13 +352,24 @@ static void OVERLAY_outline_grease_pencil(OVERLAY_PrivateData *pd, Scene *scene,
 
       t_offset += num_stroke_triangles;
 
-      if (show_stroke) {
+      group.foreach_index([&](const int curve_i) {
-        int v_first = t_offset * 3;
+        const IndexRange points = points_by_curve[curve_i];
-        int v_count = num_stroke_vertices * 2 * 3;
+        const int num_stroke_vertices = (points.size() +
-        DRW_shgroup_call_range(grp, ob, geom, v_first, v_count);
+                                         int(cyclic[curve_i] && (points.size() >= 3)));
-      }
+
-      t_offset += num_stroke_vertices * 2;
+        if (hide_material || hide_onion) {
-    });
+          t_offset += num_stroke_vertices * 2;
+          return;
+        }
+
+        if (show_stroke) {
+          int v_first = t_offset * 3;
+          int v_count = num_stroke_vertices * 2 * 3;
+          DRW_shgroup_call_range(grp, ob, geom, v_first, v_count);
+        }
+        t_offset += num_stroke_vertices * 2;
+      });
+    }
   }
 }
 

source/blender/draw/intern/draw_cache_impl_grease_pencil.cc

@@ -1075,8 +1075,8 @@ static void grease_pencil_geom_batch_ensure(Object &object,
     total_verts_num += num_points + num_cyclic + num_curves * 2;
     total_triangles_num += (num_points + num_cyclic) * 2;
 
-    for (const int curve_i : curves.curves_range()) {
+    for (const int group_id : info.drawing.triangles().index_range()) {
-      total_triangles_num += info.drawing.triangles()[curve_i].size();
+      total_triangles_num += info.drawing.triangles()[group_id].size();
     }
 
     verts_start_offsets_per_visible_drawing.append(std::move(verts_start_offsets));
@@ -1194,70 +1194,80 @@ static void grease_pencil_geom_batch_ensure(Object &object,
       GPU_indexbuf_add_tri_verts(&ibo, v_mat + 2, v_mat + 1, v_mat + 3);
     };
 
-    visible_strokes.foreach_index([&](const int curve_i, const int pos) {
+    const Array<IndexMask> groups = info.drawing.get_shapes_index_masks(memory);
-      const IndexRange points = points_by_curve[curve_i];
+    const Array<int> point_to_curve_map = curves.point_to_curve_map();
-      const bool is_cyclic = cyclic[curve_i] && (points.size() > 2);
-      const int verts_start_offset = verts_start_offsets[pos];
-      const int num_verts = 1 + points.size() + (is_cyclic ? 1 : 0) + 1;
-      const IndexRange verts_range = IndexRange(verts_start_offset, num_verts);
-      MutableSpan<GreasePencilStrokeVert> verts_slice = verts.slice(verts_range);
-      MutableSpan<GreasePencilColorVert> cols_slice = cols.slice(verts_range);
-      const float4x2 texture_matrix = texture_matrices[curve_i] * object_space_to_layer_space;
 
-      const Span<float> lengths = curves.evaluated_lengths_for_curve(curve_i, cyclic[curve_i]);
+    auto point_to_id = [&](uint32_t p) {
+      const int curve_ = point_to_curve_map[p];
+      const IndexRange points_ = points_by_curve[curve_];
+      return (1 + (p - points_.first()) + verts_start_offsets[curve_]) << GP_VERTEX_ID_SHIFT;
+    };
 
-      /* First vertex is not drawn. */
+    for (const int group_id : groups.index_range()) {
-      verts_slice.first().mat = -1;
+      const IndexMask &group = groups[group_id];
+      const Span<uint3> tris_slice = triangles[group_id];
 
-      /* If the stroke has more than 2 points, add the triangle indices to the index buffer. */
+      /* Add the triangle indices to the index buffer. */
-      if (points.size() >= 3) {
+      // if (tris_slice.size() != 0) {
-        const Span<uint3> tris_slice = triangles[curve_i];
+      for (const uint3 tri : tris_slice) {
-        for (const uint3 tri : tris_slice) {
+        const uint3 tri_verts = uint3(point_to_id(tri.x), point_to_id(tri.y), point_to_id(tri.z));
-          GPU_indexbuf_add_tri_verts(
+        GPU_indexbuf_add_tri_verts(&ibo, tri_verts.x, tri_verts.y, tri_verts.z);
-              &ibo,
+      }
-              (verts_range.first() + tri.x - points.first() + 1) << GP_VERTEX_ID_SHIFT,
+      // }
-              (verts_range.first() + tri.y - points.first() + 1) << GP_VERTEX_ID_SHIFT,
+
-              (verts_range.first() + tri.z - points.first() + 1) << GP_VERTEX_ID_SHIFT);
+      group.foreach_index([&](const int curve_i) {
+        const IndexRange points = points_by_curve[curve_i];
+        const bool is_cyclic = cyclic[curve_i] && (points.size() > 2);
+        const int verts_start_offset = verts_start_offsets[curve_i];
+        const int num_verts = 1 + points.size() + (is_cyclic ? 1 : 0) + 1;
+        const IndexRange verts_range = IndexRange(verts_start_offset, num_verts);
+        MutableSpan<GreasePencilStrokeVert> verts_slice = verts.slice(verts_range);
+        MutableSpan<GreasePencilColorVert> cols_slice = cols.slice(verts_range);
+        const float4x2 texture_matrix = texture_matrices[curve_i] * object_space_to_layer_space;
+
+        const Span<float> lengths = curves.evaluated_lengths_for_curve(curve_i, cyclic[curve_i]);
+
+        /* First vertex is not drawn. */
+        verts_slice.first().mat = -1;
+
+        /* Write all the point attributes to the vertex buffers. Create a quad for each point. */
+        const float u_scale = u_scales[curve_i];
+        const float u_translation = u_translations[curve_i];
+        for (const int i : IndexRange(points.size())) {
+          const int idx = i + 1;
+          const float u_stroke = u_scale * (i > 0 ? lengths[i - 1] : 0.0f) + u_translation;
+          populate_point(verts_range,
+                         curve_i,
+                         start_caps[curve_i],
+                         end_caps[curve_i],
+                         points[i],
+                         idx,
+                         u_stroke,
+                         texture_matrix,
+                         verts_slice[idx],
+                         cols_slice[idx]);
         }
-      }
 
-      /* Write all the point attributes to the vertex buffers. Create a quad for each point. */
+        if (is_cyclic) {
-      const float u_scale = u_scales[curve_i];
+          const int idx = points.size() + 1;
-      const float u_translation = u_translations[curve_i];
+          const float u = points.size() > 1 ? lengths[points.size() - 1] : 0.0f;
-      for (const int i : IndexRange(points.size())) {
+          const float u_stroke = u_scale * u + u_translation;
-        const int idx = i + 1;
+          populate_point(verts_range,
-        const float u_stroke = u_scale * (i > 0 ? lengths[i - 1] : 0.0f) + u_translation;
+                         curve_i,
-        populate_point(verts_range,
+                         start_caps[curve_i],
-                       curve_i,
+                         end_caps[curve_i],
-                       start_caps[curve_i],
+                         points[0],
-                       end_caps[curve_i],
+                         idx,
-                       points[i],
+                         u_stroke,
-                       idx,
+                         texture_matrix,
-                       u_stroke,
+                         verts_slice[idx],
-                       texture_matrix,
+                         cols_slice[idx]);
-                       verts_slice[idx],
+        }
-                       cols_slice[idx]);
-      }
 
-      if (is_cyclic) {
+        /* Last vertex is not drawn. */
-        const int idx = points.size() + 1;
+        verts_slice.last().mat = -1;
-        const float u = points.size() > 1 ? lengths[points.size() - 1] : 0.0f;
+      });
-        const float u_stroke = u_scale * u + u_translation;
+    }
-        populate_point(verts_range,
-                       curve_i,
-                       start_caps[curve_i],
-                       end_caps[curve_i],
-                       points[0],
-                       idx,
-                       u_stroke,
-                       texture_matrix,
-                       verts_slice[idx],
-                       cols_slice[idx]);
-      }
-
-      /* Last vertex is not drawn. */
-      verts_slice.last().mat = -1;
-    });
   }
 
   /* Mark last 2 verts as invalid. */