LineArt: Remove custom camera options as this patch doesn't include this function.

Change `reln` to `eln`.

Reviewed By: Sebastian Parborg (zeddb)

Differential Revision: https://developer.blender.org/D11411

source/blender/blenkernel/BKE_gpencil_modifier.h

@@ -294,6 +294,20 @@ bool BKE_gpencil_has_geometry_modifiers(struct Object *ob);
 bool BKE_gpencil_has_time_modifiers(struct Object *ob);
 bool BKE_gpencil_has_transform_modifiers(struct Object *ob);
 
+typedef struct GpencilLineartLimitInfo {
+  char min_level;
+  char max_level;
+  short edge_types;
+} GpencilLineartLimitInfo;
+
+void BKE_gpencil_get_lineart_modifier_limits(struct Object *ob,
+                                             struct GpencilLineartLimitInfo *info);
+
+void BKE_gpencil_set_lineart_modifier_limits(struct GpencilModifierData *md,
+                                             struct GpencilLineartLimitInfo *info,
+                                             bool is_first_lineart);
+bool BKE_gpencil_is_first_lineart_in_stack(struct Object *ob, struct GpencilModifierData *md);
+
 void BKE_gpencil_lattice_init(struct Object *ob);
 void BKE_gpencil_lattice_clear(struct Object *ob);
 

source/blender/blenkernel/intern/gpencil_modifier.c

@@ -55,6 +55,7 @@
 #include "DEG_depsgraph.h"
 #include "DEG_depsgraph_query.h"
 
+#include "MOD_gpencil_lineart.h"
 #include "MOD_gpencil_modifiertypes.h"
 
 #include "BLO_read_write.h"
@@ -202,6 +203,58 @@ bool BKE_gpencil_has_transform_modifiers(Object *ob)
   return false;
 }
 
+void BKE_gpencil_get_lineart_modifier_limits(Object *ob, struct GpencilLineartLimitInfo *info)
+{
+  bool is_first = true;
+  LISTBASE_FOREACH (GpencilModifierData *, md, &ob->greasepencil_modifiers) {
+    if (md->type == eGpencilModifierType_Lineart) {
+      LineartGpencilModifierData *lmd = (LineartGpencilModifierData *)md;
+      if (is_first || (lmd->flags & LRT_GPENCIL_USE_CACHE)) {
+        info->min_level = MIN2(info->min_level, lmd->level_start);
+        info->max_level = MAX2(info->max_level,
+                               (lmd->use_multiple_levels ? lmd->level_end : lmd->level_start));
+        info->edge_types |= lmd->edge_types;
+      }
+    }
+  }
+}
+
+void BKE_gpencil_set_lineart_modifier_limits(GpencilModifierData *md,
+                                             struct GpencilLineartLimitInfo *info,
+                                             bool is_first_lineart)
+{
+  BLI_assert(md->type == eGpencilModifierType_Lineart);
+  LineartGpencilModifierData *lmd = (LineartGpencilModifierData *)md;
+  if (is_first_lineart || lmd->flags & LRT_GPENCIL_USE_CACHE) {
+    lmd->level_start_override = info->min_level;
+    lmd->level_end_override = info->max_level;
+    lmd->edge_types_override = info->edge_types;
+  }
+  else {
+    lmd->level_start_override = lmd->level_start;
+    lmd->level_end_override = lmd->level_end;
+    lmd->edge_types_override = lmd->edge_types;
+  }
+}
+
+bool BKE_gpencil_is_first_lineart_in_stack(Object *ob, GpencilModifierData *md)
+{
+  if (md->type != eGpencilModifierType_Lineart) {
+    return false;
+  }
+  LISTBASE_FOREACH (GpencilModifierData *, gmd, &ob->greasepencil_modifiers) {
+    if (gmd->type == eGpencilModifierType_Lineart) {
+      if (gmd == md) {
+        return true;
+      }
+      else {
+        return false;
+      }
+    }
+  }
+  return false; /* Unlikely. */
+}
+
 /* apply time modifiers */
 static int gpencil_time_modifier(
     Depsgraph *depsgraph, Scene *scene, Object *ob, bGPDlayer *gpl, int cfra, bool is_render)
@@ -771,6 +824,9 @@ void BKE_gpencil_modifiers_calc(Depsgraph *depsgraph, Scene *scene, Object *ob)
   BKE_gpencil_lattice_init(ob);
 
   const bool time_remap = BKE_gpencil_has_time_modifiers(ob);
+  bool is_first_lineart = true;
+  GpencilLineartLimitInfo info = {0};
+  BKE_gpencil_get_lineart_modifier_limits(ob, &info);
 
   LISTBASE_FOREACH (GpencilModifierData *, md, &ob->greasepencil_modifiers) {
 
@@ -781,6 +837,11 @@ void BKE_gpencil_modifiers_calc(Depsgraph *depsgraph, Scene *scene, Object *ob)
         continue;
       }
 
+      if (md->type == eGpencilModifierType_Lineart) {
+        BKE_gpencil_set_lineart_modifier_limits(md, &info, is_first_lineart);
+        is_first_lineart = false;
+      }
+
       /* Apply geometry modifiers (add new geometry). */
       if (mti && mti->generateStrokes) {
         mti->generateStrokes(md, depsgraph, ob);
@@ -806,6 +867,8 @@ void BKE_gpencil_modifiers_calc(Depsgraph *depsgraph, Scene *scene, Object *ob)
 
   /* Clear any lattice data. */
   BKE_gpencil_lattice_clear(ob);
+
+  MOD_lineart_clear_cache(&gpd->runtime.lineart_cache);
 }
 
 void BKE_gpencil_modifier_blend_write(BlendWriter *writer, ListBase *modbase)

source/blender/gpencil_modifiers/MOD_gpencil_lineart.h

@@ -29,3 +29,7 @@ void OBJECT_OT_lineart_clear(struct wmOperatorType *ot);
 void OBJECT_OT_lineart_clear_all(struct wmOperatorType *ot);
 
 void WM_operatortypes_lineart(void);
+
+struct LineartCache;
+
+void MOD_lineart_clear_cache(struct LineartCache **lc);

source/blender/gpencil_modifiers/intern/MOD_gpencillineart.c

@@ -38,6 +38,7 @@
 #include "DNA_scene_types.h"
 #include "DNA_screen_types.h"
 
+#include "MOD_gpencil_lineart.h"
 #include "lineart/MOD_lineart.h"
 
 #include "BKE_collection.h"
@@ -88,7 +89,7 @@ static void generate_strokes_actual(
   }
 
   MOD_lineart_gpencil_generate(
-      lmd->render_buffer,
+      lmd->cache,
       depsgraph,
       ob,
       gpl,
@@ -156,11 +157,31 @@ static void generateStrokes(GpencilModifierData *md, Depsgraph *depsgraph, Objec
     return;
   }
 
-  MOD_lineart_compute_feature_lines(depsgraph, lmd);
+  LineartCache *local_lc = gpd->runtime.lineart_cache;
+  if (!gpd->runtime.lineart_cache) {
+    MOD_lineart_compute_feature_lines(depsgraph, lmd, &gpd->runtime.lineart_cache);
+    MOD_lineart_destroy_render_data(lmd);
+  }
+  else {
+    if (!(lmd->flags & LRT_GPENCIL_USE_CACHE)) {
+      MOD_lineart_compute_feature_lines(depsgraph, lmd, &local_lc);
+      MOD_lineart_destroy_render_data(lmd);
+    }
+    MOD_lineart_chain_clear_picked_flag(local_lc);
+    lmd->cache = local_lc;
+  }
 
   generate_strokes_actual(md, depsgraph, ob, gpl, gpf);
 
-  MOD_lineart_destroy_render_data(lmd);
+  if (!(lmd->flags & LRT_GPENCIL_USE_CACHE)) {
+    /* Clear local cache. */
+    if (local_lc != gpd->runtime.lineart_cache) {
+      MOD_lineart_clear_cache(&local_lc);
+    }
+    /* Restore the original cache pointer so the modifiers below still have access to the "global"
+     * cache. */
+    lmd->cache = gpd->runtime.lineart_cache;
+  }
 
   WM_main_add_notifier(NA_EDITED | NC_GPENCIL, NULL);
 }
@@ -182,11 +203,12 @@ static void bakeModifier(Main *UNUSED(bmain),
     return;
   }
 
-  MOD_lineart_compute_feature_lines(depsgraph, lmd);
+  if (!gpd->runtime.lineart_cache) {
+    MOD_lineart_compute_feature_lines(depsgraph, lmd, &gpd->runtime.lineart_cache);
+    MOD_lineart_destroy_render_data(lmd);
+  }
 
   generate_strokes_actual(md, depsgraph, ob, gpl, gpf);
-
-  MOD_lineart_destroy_render_data(lmd);
 }
 
 static bool isDisabled(GpencilModifierData *md, int UNUSED(userRenderParams))
@@ -258,10 +280,16 @@ static void panel_draw(const bContext *UNUSED(C), Panel *panel)
 
   const int source_type = RNA_enum_get(ptr, "source_type");
   const bool is_baked = RNA_boolean_get(ptr, "is_baked");
+  const bool use_cache = RNA_boolean_get(ptr, "use_cached_result");
+  const bool is_first = BKE_gpencil_is_first_lineart_in_stack(ob_ptr.data, ptr->data);
 
   uiLayoutSetPropSep(layout, true);
   uiLayoutSetEnabled(layout, !is_baked);
 
+  if (!BKE_gpencil_is_first_lineart_in_stack(ob_ptr.data, ptr->data)) {
+    uiItemR(layout, ptr, "use_cached_result", 0, NULL, ICON_NONE);
+  }
+
   uiItemR(layout, ptr, "source_type", 0, NULL, ICON_NONE);
 
   if (source_type == LRT_SOURCE_OBJECT) {
@@ -280,12 +308,17 @@ static void panel_draw(const bContext *UNUSED(C), Panel *panel)
   uiItemR(col, ptr, "use_material", 0, IFACE_("Material Borders"), ICON_NONE);
   uiItemR(col, ptr, "use_edge_mark", 0, IFACE_("Edge Marks"), ICON_NONE);
   uiItemR(col, ptr, "use_intersection", 0, IFACE_("Intersections"), ICON_NONE);
-  uiItemR(col, ptr, "use_crease", 0, IFACE_("Crease"), ICON_NONE);
-  uiLayout *sub = uiLayoutRow(col, true);
-  uiLayoutSetActive(sub, RNA_boolean_get(ptr, "use_crease"));
-  uiLayoutSetPropSep(sub, true);
 
-  uiItemR(sub, ptr, "crease_threshold", UI_ITEM_R_SLIDER, " ", ICON_NONE);
+  uiLayout *sub = uiLayoutRowWithHeading(col, false, IFACE_("Crease"));
+  uiItemR(sub, ptr, "use_crease", 0, "", ICON_NONE);
+  uiLayout *entry = uiLayoutRow(sub, false);
+  uiLayoutSetActive(entry, RNA_boolean_get(ptr, "use_crease") || is_first);
+  if (use_cache && !is_first) {
+    uiItemL(entry, IFACE_("Angle Cached"), ICON_INFO);
+  }
+  else {
+    uiItemR(entry, ptr, "crease_threshold", UI_ITEM_R_SLIDER, " ", ICON_NONE);
+  }
 
   uiItemPointerR(layout, ptr, "target_layer", &obj_data_ptr, "layers", NULL, ICON_GREASEPENCIL);
 
@@ -308,14 +341,33 @@ static void panel_draw(const bContext *UNUSED(C), Panel *panel)
                  NULL,
                  material_valid ? ICON_SHADING_TEXTURE : ICON_ERROR);
 
-  uiItemR(layout, ptr, "use_remove_doubles", 0, NULL, ICON_NONE);
-  uiItemR(layout, ptr, "use_edge_overlap", 0, IFACE_("Overlapping Edges As Contour"), ICON_NONE);
-  uiItemR(layout, ptr, "use_object_instances", 0, NULL, ICON_NONE);
-  uiItemR(layout, ptr, "use_clip_plane_boundaries", 0, NULL, ICON_NONE);
-
   gpencil_modifier_panel_end(layout, ptr);
 }
 
+static void options_panel_draw(const bContext *UNUSED(C), Panel *panel)
+{
+  uiLayout *layout = panel->layout;
+  PointerRNA ob_ptr;
+  PointerRNA *ptr = gpencil_modifier_panel_get_property_pointers(panel, &ob_ptr);
+
+  const bool is_baked = RNA_boolean_get(ptr, "is_baked");
+  const bool use_cache = RNA_boolean_get(ptr, "use_cached_result");
+  const bool is_first = BKE_gpencil_is_first_lineart_in_stack(ob_ptr.data, ptr->data);
+
+  uiLayoutSetPropSep(layout, true);
+  uiLayoutSetEnabled(layout, !is_baked);
+
+  if (!use_cache || is_first) {
+    uiItemR(layout, ptr, "use_remove_doubles", 0, NULL, ICON_NONE);
+    uiItemR(layout, ptr, "use_edge_overlap", 0, IFACE_("Overlapping Edges As Contour"), ICON_NONE);
+    uiItemR(layout, ptr, "use_object_instances", 0, NULL, ICON_NONE);
+    uiItemR(layout, ptr, "use_clip_plane_boundaries", 0, NULL, ICON_NONE);
+  }
+  else {
+    uiItemL(layout, "Cached with the first line art modifier.", ICON_INFO);
+  }
+}
+
 static void style_panel_draw(const bContext *UNUSED(C), Panel *panel)
 {
   uiLayout *layout = panel->layout;
@@ -395,22 +447,30 @@ static void transparency_panel_draw(const bContext *UNUSED(C), Panel *panel)
 
 static void chaining_panel_draw(const bContext *UNUSED(C), Panel *panel)
 {
-  PointerRNA *ptr = gpencil_modifier_panel_get_property_pointers(panel, NULL);
+  PointerRNA ob_ptr;
+  PointerRNA *ptr = gpencil_modifier_panel_get_property_pointers(panel, &ob_ptr);
 
   uiLayout *layout = panel->layout;
 
   const bool is_baked = RNA_boolean_get(ptr, "is_baked");
+  const bool use_cache = RNA_boolean_get(ptr, "use_cached_result");
+  const bool is_first = BKE_gpencil_is_first_lineart_in_stack(ob_ptr.data, ptr->data);
 
   uiLayoutSetPropSep(layout, true);
   uiLayoutSetEnabled(layout, !is_baked);
 
-  uiLayout *col = uiLayoutColumnWithHeading(layout, true, IFACE_("Chain"));
-  uiItemR(col, ptr, "use_fuzzy_intersections", 0, NULL, ICON_NONE);
-  uiItemR(col, ptr, "use_fuzzy_all", 0, NULL, ICON_NONE);
+  if (!use_cache || is_first) {
+    uiLayout *col = uiLayoutColumnWithHeading(layout, true, IFACE_("Chain"));
+    uiItemR(col, ptr, "use_fuzzy_intersections", 0, NULL, ICON_NONE);
+    uiItemR(col, ptr, "use_fuzzy_all", 0, NULL, ICON_NONE);
 
-  uiItemR(layout, ptr, "chaining_image_threshold", 0, NULL, ICON_NONE);
+    uiItemR(layout, ptr, "chaining_image_threshold", 0, NULL, ICON_NONE);
 
-  uiItemR(layout, ptr, "split_angle", UI_ITEM_R_SLIDER, NULL, ICON_NONE);
+    uiItemR(layout, ptr, "split_angle", UI_ITEM_R_SLIDER, NULL, ICON_NONE);
+  }
+  else {
+    uiItemL(layout, "Cached with the first line art modifier.", ICON_INFO);
+  }
 }
 
 static void vgroup_panel_draw(const bContext *UNUSED(C), Panel *panel)
@@ -421,22 +481,30 @@ static void vgroup_panel_draw(const bContext *UNUSED(C), Panel *panel)
   uiLayout *layout = panel->layout;
 
   const bool is_baked = RNA_boolean_get(ptr, "is_baked");
+  const bool use_cache = RNA_boolean_get(ptr, "use_cached_result");
+  const bool is_first = BKE_gpencil_is_first_lineart_in_stack(ob_ptr.data, ptr->data);
 
   uiLayoutSetPropSep(layout, true);
   uiLayoutSetEnabled(layout, !is_baked);
 
-  uiLayout *col = uiLayoutColumn(layout, true);
+  if (!use_cache || is_first) {
+    uiLayout *col = uiLayoutColumn(layout, true);
 
-  uiLayout *row = uiLayoutRow(col, true);
-  uiItemR(row, ptr, "source_vertex_group", 0, IFACE_("Filter Source"), ICON_GROUP_VERTEX);
-  uiItemR(row, ptr, "invert_source_vertex_group", UI_ITEM_R_TOGGLE, "", ICON_ARROW_LEFTRIGHT);
+    uiLayout *row = uiLayoutRow(col, true);
 
-  uiItemR(col, ptr, "use_output_vertex_group_match_by_name", 0, NULL, ICON_NONE);
+    uiItemR(row, ptr, "source_vertex_group", 0, IFACE_("Filter Source"), ICON_GROUP_VERTEX);
+    uiItemR(row, ptr, "invert_source_vertex_group", UI_ITEM_R_TOGGLE, "", ICON_ARROW_LEFTRIGHT);
 
-  const bool match_output = RNA_boolean_get(ptr, "use_output_vertex_group_match_by_name");
-  if (!match_output) {
-    uiItemPointerR(
-        col, ptr, "vertex_group", &ob_ptr, "vertex_groups", IFACE_("Target"), ICON_NONE);
+    uiItemR(col, ptr, "use_output_vertex_group_match_by_name", 0, NULL, ICON_NONE);
+
+    const bool match_output = RNA_boolean_get(ptr, "use_output_vertex_group_match_by_name");
+    if (!match_output) {
+      uiItemPointerR(
+          col, ptr, "vertex_group", &ob_ptr, "vertex_groups", IFACE_("Target"), ICON_NONE);
+    }
+  }
+  else {
+    uiItemL(layout, "Cached with the first line art modifier.", ICON_INFO);
   }
 }
 
@@ -473,6 +541,8 @@ static void panelRegister(ARegionType *region_type)
   PanelType *panel_type = gpencil_modifier_panel_register(
       region_type, eGpencilModifierType_Lineart, panel_draw);
 
+  gpencil_modifier_subpanel_register(
+      region_type, "options", "Options", NULL, options_panel_draw, panel_type);
   gpencil_modifier_subpanel_register(
       region_type, "style", "Style", NULL, style_panel_draw, panel_type);
   PanelType *occlusion_panel = gpencil_modifier_subpanel_register(

source/blender/gpencil_modifiers/intern/lineart/MOD_lineart.h

@@ -250,6 +250,10 @@ typedef struct LineartRenderBuffer {
   ListBase wasted_cuts;
   SpinLock lock_cuts;
 
+  /* This is just a pointer to LineartCache::chain_data_pool, which acts as a cache for line
+   * chains. */
+  LineartStaticMemPool *chain_data_pool;
+
   /*  Render status */
   double view_vector[3];
 
@@ -309,6 +313,18 @@ typedef struct LineartRenderBuffer {
 
 } LineartRenderBuffer;
 
+typedef struct LineartCache {
+  /** Separate memory pool for chain data, this goes to the cache, so when we free the main pool,
+   * chains will still be available. */
+  LineartStaticMemPool chain_data_pool;
+
+  /** A copy of rb->chains so we have that data available after rb has been destroyed. */
+  ListBase chains;
+
+  /** Cache only contains edge types specified in this variable. */
+  char rb_edge_types;
+} LineartCache;
+
 #define DBL_TRIANGLE_LIM 1e-8
 #define DBL_EDGE_LIM 1e-9
 
@@ -563,10 +579,11 @@ void MOD_lineart_chain_discard_short(LineartRenderBuffer *rb, const float thresh
 void MOD_lineart_chain_split_angle(LineartRenderBuffer *rb, float angle_threshold_rad);
 
 int MOD_lineart_chain_count(const LineartEdgeChain *ec);
-void MOD_lineart_chain_clear_picked_flag(struct LineartRenderBuffer *rb);
+void MOD_lineart_chain_clear_picked_flag(LineartCache *lc);
 
 bool MOD_lineart_compute_feature_lines(struct Depsgraph *depsgraph,
-                                       struct LineartGpencilModifierData *lmd);
+                                       struct LineartGpencilModifierData *lmd,
+                                       LineartCache **cached_result);
 
 struct Scene;
 
@@ -579,7 +596,7 @@ LineartBoundingArea *MOD_lineart_get_bounding_area(LineartRenderBuffer *rb, doub
 struct bGPDlayer;
 struct bGPDframe;
 
-void MOD_lineart_gpencil_generate(LineartRenderBuffer *rb,
+void MOD_lineart_gpencil_generate(LineartCache *cache,
                                   struct Depsgraph *depsgraph,
                                   struct Object *ob,
                                   struct bGPDlayer *gpl,

source/blender/gpencil_modifiers/intern/lineart/lineart_chain.c

@@ -74,7 +74,7 @@ static LineartEdge *lineart_line_get_connected(LineartBoundingArea *ba,
 static LineartEdgeChain *lineart_chain_create(LineartRenderBuffer *rb)
 {
   LineartEdgeChain *ec;
-  ec = lineart_mem_acquire(&rb->render_data_pool, sizeof(LineartEdgeChain));
+  ec = lineart_mem_acquire(rb->chain_data_pool, sizeof(LineartEdgeChain));
 
   BLI_addtail(&rb->chains, ec);
 
@@ -119,7 +119,7 @@ static LineartEdgeChainItem *lineart_chain_append_point(LineartRenderBuffer *rb,
     return old_rlci;
   }
 
-  eci = lineart_mem_acquire(&rb->render_data_pool, sizeof(LineartEdgeChainItem));
+  eci = lineart_mem_acquire(rb->chain_data_pool, sizeof(LineartEdgeChainItem));
 
   copy_v2_v2(eci->pos, fbcoord);
   copy_v3_v3(eci->gpos, gpos);
@@ -149,7 +149,7 @@ static LineartEdgeChainItem *lineart_chain_prepend_point(LineartRenderBuffer *rb
     return ec->chain.first;
   }
 
-  eci = lineart_mem_acquire(&rb->render_data_pool, sizeof(LineartEdgeChainItem));
+  eci = lineart_mem_acquire(rb->chain_data_pool, sizeof(LineartEdgeChainItem));
 
   copy_v2_v2(eci->pos, fbcoord);
   copy_v3_v3(eci->gpos, gpos);
@@ -889,12 +889,12 @@ int MOD_lineart_chain_count(const LineartEdgeChain *ec)
   return count;
 }
 
-void MOD_lineart_chain_clear_picked_flag(LineartRenderBuffer *rb)
+void MOD_lineart_chain_clear_picked_flag(LineartCache *lc)
 {
-  if (rb == NULL) {
+  if (lc == NULL) {
     return;
   }
-  LISTBASE_FOREACH (LineartEdgeChain *, ec, &rb->chains) {
+  LISTBASE_FOREACH (LineartEdgeChain *, ec, &lc->chains) {
     ec->picked = 0;
   }
 }

source/blender/gpencil_modifiers/intern/lineart/lineart_cpu.c

@@ -21,6 +21,7 @@
  * \ingroup editors
  */
 
+#include "MOD_gpencil_lineart.h"
 #include "MOD_lineart.h"
 
 #include "BLI_linklist.h"
@@ -42,6 +43,7 @@
 #include "BKE_gpencil_modifier.h"
 #include "BKE_material.h"
 #include "BKE_mesh.h"
+#include "BKE_pointcache.h"
 #include "BKE_scene.h"
 #include "DEG_depsgraph_query.h"
 #include "DNA_camera_types.h"
@@ -107,6 +109,8 @@ static bool lineart_triangle_edge_image_space_occlusion(SpinLock *spl,
 
 static void lineart_add_edge_to_list(LineartRenderBuffer *rb, LineartEdge *e);
 
+static LineartCache *lineart_init_cache(void);
+
 static void lineart_discard_segment(LineartRenderBuffer *rb, LineartEdgeSegment *es)
 {
   BLI_spin_lock(&rb->lock_cuts);
@@ -2771,13 +2775,13 @@ static void lineart_destroy_render_data(LineartRenderBuffer *rb)
 
 void MOD_lineart_destroy_render_data(LineartGpencilModifierData *lmd)
 {
-  LineartRenderBuffer *rb = lmd->render_buffer;
+  LineartRenderBuffer *rb = lmd->render_buffer_ptr;
 
   lineart_destroy_render_data(rb);
 
   if (rb) {
     MEM_freeN(rb);
-    lmd->render_buffer = NULL;
+    lmd->render_buffer_ptr = NULL;
   }
 
   if (G.debug_value == 4000) {
@@ -2785,14 +2789,33 @@ void MOD_lineart_destroy_render_data(LineartGpencilModifierData *lmd)
   }
 }
 
+static LineartCache *lineart_init_cache()
+{
+  LineartCache *lc = MEM_callocN(sizeof(LineartCache), "Lineart Cache");
+  return lc;
+}
+
+void MOD_lineart_clear_cache(struct LineartCache **lc)
+{
+  if (!(*lc)) {
+    return;
+  }
+  lineart_mem_destroy(&((*lc)->chain_data_pool));
+  MEM_freeN(*lc);
+  (*lc) = NULL;
+}
+
 static LineartRenderBuffer *lineart_create_render_buffer(Scene *scene,
-                                                         LineartGpencilModifierData *lmd)
+                                                         LineartGpencilModifierData *lmd,
+                                                         LineartCache *lc)
 {
   LineartRenderBuffer *rb = MEM_callocN(sizeof(LineartRenderBuffer), "Line Art render buffer");
 
-  lmd->render_buffer = rb;
+  lmd->cache = lc;
+  lmd->render_buffer_ptr = rb;
+  lc->rb_edge_types = lmd->edge_types_override;
 
-  if (!scene || !scene->camera) {
+  if (!scene || !scene->camera || !lc) {
     return NULL;
   }
   Camera *c = scene->camera->data;
@@ -2835,11 +2858,15 @@ static LineartRenderBuffer *lineart_create_render_buffer(Scene *scene,
   /* See lineart_edge_from_triangle() for how this option may impact performance. */
   rb->allow_overlapping_edges = (lmd->calculation_flags & LRT_ALLOW_OVERLAPPING_EDGES) != 0;
 
-  rb->use_contour = (lmd->edge_types & LRT_EDGE_FLAG_CONTOUR) != 0;
-  rb->use_crease = (lmd->edge_types & LRT_EDGE_FLAG_CREASE) != 0;
-  rb->use_material = (lmd->edge_types & LRT_EDGE_FLAG_MATERIAL) != 0;
-  rb->use_edge_marks = (lmd->edge_types & LRT_EDGE_FLAG_EDGE_MARK) != 0;
-  rb->use_intersections = (lmd->edge_types & LRT_EDGE_FLAG_INTERSECTION) != 0;
+  int16_t edge_types = lmd->edge_types_override;
+
+  rb->use_contour = (edge_types & LRT_EDGE_FLAG_CONTOUR) != 0;
+  rb->use_crease = (edge_types & LRT_EDGE_FLAG_CREASE) != 0;
+  rb->use_material = (edge_types & LRT_EDGE_FLAG_MATERIAL) != 0;
+  rb->use_edge_marks = (edge_types & LRT_EDGE_FLAG_EDGE_MARK) != 0;
+  rb->use_intersections = (edge_types & LRT_EDGE_FLAG_INTERSECTION) != 0;
+
+  rb->chain_data_pool = &lc->chain_data_pool;
 
   BLI_spin_init(&rb->lock_task);
   BLI_spin_init(&rb->lock_cuts);
@@ -3818,7 +3845,9 @@ static LineartBoundingArea *lineart_bounding_area_next(LineartBoundingArea *this
  *
  * \return True when a change is made.
  */
-bool MOD_lineart_compute_feature_lines(Depsgraph *depsgraph, LineartGpencilModifierData *lmd)
+bool MOD_lineart_compute_feature_lines(Depsgraph *depsgraph,
+                                       LineartGpencilModifierData *lmd,
+                                       LineartCache **cached_result)
 {
   LineartRenderBuffer *rb;
   Scene *scene = DEG_get_evaluated_scene(depsgraph);
@@ -3836,7 +3865,10 @@ bool MOD_lineart_compute_feature_lines(Depsgraph *depsgraph, LineartGpencilModif
     return false;
   }
 
-  rb = lineart_create_render_buffer(scene, lmd);
+  LineartCache *lc = lineart_init_cache();
+  (*cached_result) = lc;
+
+  rb = lineart_create_render_buffer(scene, lmd, lc);
 
   /* Triangle thread testing data size varies depending on the thread count.
    * See definition of LineartTriangleThread for details. */
@@ -3844,7 +3876,9 @@ bool MOD_lineart_compute_feature_lines(Depsgraph *depsgraph, LineartGpencilModif
 
   /* This is used to limit calculation to a certain level to save time, lines who have higher
    * occlusion levels will get ignored. */
-  rb->max_occlusion_level = MAX2(lmd->level_start, lmd->level_end);
+  rb->max_occlusion_level = (lmd->flags & LRT_GPENCIL_USE_CACHE) ?
+                                lmd->level_end_override :
+                                (lmd->use_multiple_levels ? lmd->level_end : lmd->level_start);
 
   /* FIXME(Yiming): See definition of int #LineartRenderBuffer::_source_type for detailed. */
   rb->_source_type = lmd->source_type;
@@ -3907,13 +3941,8 @@ bool MOD_lineart_compute_feature_lines(Depsgraph *depsgraph, LineartGpencilModif
 
     /* Then we connect chains based on the _proximity_ of their end points in image space, here's
      * the place threshold value gets involved. */
-
-    /* do_geometry_space = true. */
     MOD_lineart_chain_connect(rb);
 
-    /* After chaining, we need to clear flags so we don't confuse GPencil generation calls. */
-    MOD_lineart_chain_clear_picked_flag(rb);
-
     float *t_image = &lmd->chaining_image_threshold;
     /* This configuration ensures there won't be accidental lost of short unchained segments. */
     MOD_lineart_chain_discard_short(rb, MIN2(*t_image, 0.001f) - FLT_EPSILON);
@@ -3921,6 +3950,12 @@ bool MOD_lineart_compute_feature_lines(Depsgraph *depsgraph, LineartGpencilModif
     if (rb->angle_splitting_threshold > FLT_EPSILON) {
       MOD_lineart_chain_split_angle(rb, rb->angle_splitting_threshold);
     }
+
+    /* Finally transfer the result list into cache. */
+    memcpy(&lc->chains, &rb->chains, sizeof(ListBase));
+
+    /* At last, we need to clear flags so we don't confuse GPencil generation calls. */
+    MOD_lineart_chain_clear_picked_flag(lc);
   }
 
   if (G.debug_value == 4000) {
@@ -3944,7 +3979,7 @@ static int lineart_rb_edge_types(LineartRenderBuffer *rb)
   return types;
 }
 
-static void lineart_gpencil_generate(LineartRenderBuffer *rb,
+static void lineart_gpencil_generate(LineartCache *cache,
                                      Depsgraph *depsgraph,
                                      Object *gpencil_object,
                                      float (*gp_obmat_inverse)[4],
@@ -3964,9 +3999,9 @@ static void lineart_gpencil_generate(LineartRenderBuffer *rb,
                                      const char *vgname,
                                      int modifier_flags)
 {
-  if (rb == NULL) {
+  if (cache == NULL) {
     if (G.debug_value == 4000) {
-      printf("NULL Lineart rb!\n");
+      printf("NULL Lineart cache!\n");
     }
     return;
   }
@@ -3990,11 +4025,11 @@ static void lineart_gpencil_generate(LineartRenderBuffer *rb,
   float mat[4][4];
   unit_m4(mat);
 
-  int enabled_types = lineart_rb_edge_types(rb);
+  int enabled_types = cache->rb_edge_types;
   bool invert_input = modifier_flags & LRT_GPENCIL_INVERT_SOURCE_VGROUP;
   bool match_output = modifier_flags & LRT_GPENCIL_MATCH_OUTPUT_VGROUP;
 
-  LISTBASE_FOREACH (LineartEdgeChain *, ec, &rb->chains) {
+  LISTBASE_FOREACH (LineartEdgeChain *, ec, &cache->chains) {
 
     if (ec->picked) {
       continue;
@@ -4108,7 +4143,7 @@ static void lineart_gpencil_generate(LineartRenderBuffer *rb,
 /**
  * Wrapper for external calls.
  */
-void MOD_lineart_gpencil_generate(LineartRenderBuffer *rb,
+void MOD_lineart_gpencil_generate(LineartCache *cache,
                                   Depsgraph *depsgraph,
                                   Object *ob,
                                   bGPDlayer *gpl,
@@ -4156,7 +4191,7 @@ void MOD_lineart_gpencil_generate(LineartRenderBuffer *rb,
   }
   float gp_obmat_inverse[4][4];
   invert_m4_m4(gp_obmat_inverse, ob->obmat);
-  lineart_gpencil_generate(rb,
+  lineart_gpencil_generate(cache,
                            depsgraph,
                            ob,
                            gp_obmat_inverse,

source/blender/gpencil_modifiers/intern/lineart/lineart_ops.c

@@ -88,7 +88,12 @@ static void clear_strokes(Object *ob, GpencilModifierData *md, int frame)
   BKE_gpencil_layer_frame_delete(gpl, gpf);
 }
 
-static bool bake_strokes(Object *ob, Depsgraph *dg, GpencilModifierData *md, int frame)
+static bool bake_strokes(Object *ob,
+                         Depsgraph *dg,
+                         LineartCache **lc,
+                         GpencilModifierData *md,
+                         int frame,
+                         bool is_first)
 {
   /* Modifier data sanity check. */
   if (lineart_mod_is_disabled(md)) {
@@ -111,11 +116,22 @@ static bool bake_strokes(Object *ob, Depsgraph *dg, GpencilModifierData *md, int
     /* No greasepencil frame created or found. */
     return false;
   }
-
-  MOD_lineart_compute_feature_lines(dg, lmd);
+  LineartCache *local_lc = *lc;
+  if (!(*lc)) {
+    MOD_lineart_compute_feature_lines(dg, lmd, lc);
+    MOD_lineart_destroy_render_data(lmd);
+  }
+  else {
+    if (is_first || (!(lmd->flags & LRT_GPENCIL_USE_CACHE))) {
+      MOD_lineart_compute_feature_lines(dg, lmd, &local_lc);
+      MOD_lineart_destroy_render_data(lmd);
+    }
+    MOD_lineart_chain_clear_picked_flag(local_lc);
+    lmd->cache = local_lc;
+  }
 
   MOD_lineart_gpencil_generate(
-      lmd->render_buffer,
+      lmd->cache,
       dg,
       ob,
       gpl,
@@ -135,7 +151,15 @@ static bool bake_strokes(Object *ob, Depsgraph *dg, GpencilModifierData *md, int
       lmd->vgname,
       lmd->flags);
 
-  MOD_lineart_destroy_render_data(lmd);
+  if (!(lmd->flags & LRT_GPENCIL_USE_CACHE)) {
+    /* Clear local cache. */
+    if (!is_first) {
+      MOD_lineart_clear_cache(&local_lc);
+    }
+    /* Restore the original cache pointer so the modifiers below still have access to the
+     * "global" cache. */
+    lmd->cache = gpd->runtime.lineart_cache;
+  }
 
   return true;
 }
@@ -174,14 +198,22 @@ static bool lineart_gpencil_bake_single_target(LineartBakeJob *bj, Object *ob, i
     }
   }
 
+  GpencilLineartLimitInfo info = {0};
+  BKE_gpencil_get_lineart_modifier_limits(ob, &info);
+
+  LineartCache *lc = NULL;
+  bool is_first = true;
   LISTBASE_FOREACH (GpencilModifierData *, md, &ob->greasepencil_modifiers) {
     if (md->type != eGpencilModifierType_Lineart) {
       continue;
     }
-    if (bake_strokes(ob, bj->dg, md, frame)) {
+    BKE_gpencil_set_lineart_modifier_limits(md, &info, is_first);
+    if (bake_strokes(ob, bj->dg, &lc, md, frame, is_first)) {
       touched = true;
+      is_first = false;
     }
   }
+  MOD_lineart_clear_cache(&lc);
 
   return touched;
 }

source/blender/makesdna/DNA_gpencil_modifier_types.h

@@ -878,6 +878,7 @@ typedef enum eLineArtGPencilModifierFlags {
   LRT_GPENCIL_MATCH_OUTPUT_VGROUP = (1 << 1),
   LRT_GPENCIL_BINARY_WEIGHTS = (1 << 2) /* Deprecated, this is removed for lack of use case. */,
   LRT_GPENCIL_IS_BAKED = (1 << 3),
+  LRT_GPENCIL_USE_CACHE = (1 << 4),
 } eLineArtGPencilModifierFlags;
 
 typedef enum eLineartGpencilTransparencyFlags {
@@ -886,6 +887,8 @@ typedef enum eLineartGpencilTransparencyFlags {
   LRT_GPENCIL_TRANSPARENCY_MATCH = (1 << 1),
 } eLineartGpencilTransparencyFlags;
 
+struct LineartCache;
+
 typedef struct LineartGpencilModifierData {
   GpencilModifierData modifier;
 
@@ -925,16 +928,24 @@ typedef struct LineartGpencilModifierData {
   /* CPU mode */
   float chaining_image_threshold;
 
-  int _pad;
-
   /* Ported from SceneLineArt flags. */
   int calculation_flags;
 
   /* Additional Switches. */
   int flags;
 
-  /* Runtime only. */
-  void *render_buffer;
+  /* Runtime data. */
+
+  /* Because we can potentially only compute features lines once per modifier stack (Use Cache), we
+   * need to have these override values to ensure that we have the data we need is computed and
+   * stored in the cache. */
+  char level_start_override;
+  char level_end_override;
+  short edge_types_override;
+
+  struct LineartCache *cache;
+  /* Keep a pointer to the render buffer so we can call destroy from ModifierData. */
+  struct LineartRenderBuffer *render_buffer_ptr;
 
 } LineartGpencilModifierData;
 

source/blender/makesdna/DNA_gpencil_types.h

@@ -629,6 +629,7 @@ typedef struct bGPdata_Runtime {
   /** Brush pointer */
   Brush *sbuffer_brush;
   struct GpencilBatchCache *gpencil_cache;
+  struct LineartCache *lineart_cache;
 } bGPdata_Runtime;
 
 /* grid configuration */

source/blender/makesrna/intern/rna_gpencil_modifier.c

@@ -2930,6 +2930,14 @@ static void rna_def_modifier_gpencillineart(BlenderRNA *brna)
   RNA_def_property_ui_text(prop, "Is Baked", "This modifier has baked data");
   RNA_def_property_update(prop, 0, "rna_GpencilModifier_update");
 
+  prop = RNA_def_property(srna, "use_cached_result", PROP_BOOLEAN, PROP_NONE);
+  RNA_def_property_boolean_sdna(prop, NULL, "flags", LRT_GPENCIL_USE_CACHE);
+  RNA_def_property_ui_text(prop,
+                           "Use Cached Result",
+                           "Use cached line art data from the first line art modifier in the "
+                           "stack. Certain settings will be unavailable when using cached data.");
+  RNA_def_property_update(prop, 0, "rna_GpencilModifier_update");
+
   prop = RNA_def_property(srna, "thickness", PROP_INT, PROP_NONE);
   RNA_def_property_ui_text(prop, "Thickness", "The thickness for the generated strokes");
   RNA_def_property_ui_range(prop, 1, 100, 1, 1);