GPencil: Replace material name with material pointer for Modifiers filter

Before, the material name was used to filter the effect of the stroke, but after the last changes in the ID code, now it's not working.

After talking with @severin, we agreed to replace the material name with a pointer. Also, this fix a design issue when the materials were linked.

Related to T76594

Differential Revision: https://developer.blender.org/D7681  with some minor changes

17 files changed, 187 insertions, 50 deletions

diff --git a/source/blender/gpencil_modifiers/intern/MOD_gpencil_util.c b/source/blender/gpencil_modifiers/intern/MOD_gpencil_util.c
index f7b51b08c44..f7929b58650 100644
--- a/source/blender/gpencil_modifiers/intern/MOD_gpencil_util.c
+++ b/source/blender/gpencil_modifiers/intern/MOD_gpencil_util.c
@@ -79,7 +79,7 @@ void gpencil_modifier_type_init(GpencilModifierTypeInfo *types[])
 /* verify if valid layer, material and pass index */
 bool is_stroke_affected_by_modifier(Object *ob,
                                     char *mlayername,
-                                    char *mmaterialname,
+                                    Material *material,
                                     const int mpassindex,
                                     const int gpl_passindex,
                                     const int minpoints,
@@ -106,15 +106,15 @@ bool is_stroke_affected_by_modifier(Object *ob,
       }
     }
   }
-  /* omit if filter by material */
-  if (mmaterialname[0] != '\0') {
+  /* Omit if filter by material. */
+  if (material != NULL) {
     if (inv4 == false) {
-      if (!STREQ(mmaterialname, ma->id.name + 2)) {
+      if (material != ma) {
         return false;
       }
     }
     else {
-      if (STREQ(mmaterialname, ma->id.name + 2)) {
+      if (material == ma) {
         return false;
       }
     }
diff --git a/source/blender/gpencil_modifiers/intern/MOD_gpencil_util.h b/source/blender/gpencil_modifiers/intern/MOD_gpencil_util.h
index fc4522bc028..5cc3750639b 100644
--- a/source/blender/gpencil_modifiers/intern/MOD_gpencil_util.h
+++ b/source/blender/gpencil_modifiers/intern/MOD_gpencil_util.h
@@ -34,7 +34,7 @@ struct bGPDstroke;
 
 bool is_stroke_affected_by_modifier(struct Object *ob,
                                     char *mlayername,
-                                    char *mmaterialname,
+                                    struct Material *material,
                                     const int mpassindex,
                                     const int gpl_passindex,
                                     const int minpoints,
diff --git a/source/blender/gpencil_modifiers/intern/MOD_gpencilarray.c b/source/blender/gpencil_modifiers/intern/MOD_gpencilarray.c
index 5aa3f70d940..18de9c1cf83 100644
--- a/source/blender/gpencil_modifiers/intern/MOD_gpencilarray.c
+++ b/source/blender/gpencil_modifiers/intern/MOD_gpencilarray.c
@@ -77,6 +77,8 @@ static void initData(GpencilModifierData *md)
   gpmd->object = NULL;
   gpmd->flag |= GP_ARRAY_USE_RELATIVE;
   gpmd->seed = 1;
+  gpmd->layername[0] = '\0';
+  gpmd->material = NULL;
 }
 
 static void copyData(const GpencilModifierData *md, GpencilModifierData *target)
@@ -163,7 +165,7 @@ static void generate_geometry(GpencilModifierData *md,
     LISTBASE_FOREACH (bGPDstroke *, gps, &gpf->strokes) {
       if (is_stroke_affected_by_modifier(ob,
                                          mmd->layername,
-                                         mmd->materialname,
+                                         mmd->material,
                                          mmd->pass_index,
                                          mmd->layer_pass,
                                          1,
@@ -320,6 +322,15 @@ static void foreachObjectLink(GpencilModifierData *md,
   walk(userData, ob, &mmd->object, IDWALK_CB_NOP);
 }
 
+static void foreachIDLink(GpencilModifierData *md, Object *ob, IDWalkFunc walk, void *userData)
+{
+  ArrayGpencilModifierData *mmd = (ArrayGpencilModifierData *)md;
+
+  walk(userData, ob, (ID **)&mmd->material, IDWALK_CB_USER);
+
+  foreachObjectLink(md, ob, (ObjectWalkFunc)walk, userData);
+}
+
 GpencilModifierTypeInfo modifierType_Gpencil_Array = {
     /* name */ "Array",
     /* structName */ "ArrayGpencilModifierData",
@@ -340,6 +351,6 @@ GpencilModifierTypeInfo modifierType_Gpencil_Array = {
     /* updateDepsgraph */ updateDepsgraph,
     /* dependsOnTime */ NULL,
     /* foreachObjectLink */ foreachObjectLink,
-    /* foreachIDLink */ NULL,
+    /* foreachIDLink */ foreachIDLink,
     /* foreachTexLink */ NULL,
 };
diff --git a/source/blender/gpencil_modifiers/intern/MOD_gpencilcolor.c b/source/blender/gpencil_modifiers/intern/MOD_gpencilcolor.c
index d1c17e2b392..fa084936682 100644
--- a/source/blender/gpencil_modifiers/intern/MOD_gpencilcolor.c
+++ b/source/blender/gpencil_modifiers/intern/MOD_gpencilcolor.c
@@ -37,8 +37,10 @@
 #include "BKE_colortools.h"
 #include "BKE_gpencil.h"
 #include "BKE_gpencil_modifier.h"
+#include "BKE_lib_query.h"
 #include "BKE_main.h"
 #include "BKE_material.h"
+#include "BKE_modifier.h"
 
 #include "DEG_depsgraph.h"
 
@@ -51,7 +53,7 @@ static void initData(GpencilModifierData *md)
   gpmd->pass_index = 0;
   ARRAY_SET_ITEMS(gpmd->hsv, 0.5f, 1.0f, 1.0f);
   gpmd->layername[0] = '\0';
-  gpmd->materialname[0] = '\0';
+  gpmd->material = NULL;
   gpmd->modify_color = GP_MODIFY_COLOR_BOTH;
 
   gpmd->curve_intensity = BKE_curvemapping_add(1, 0.0f, 0.0f, 1.0f, 1.0f);
@@ -91,7 +93,7 @@ static void deformStroke(GpencilModifierData *md,
 
   if (!is_stroke_affected_by_modifier(ob,
                                       mmd->layername,
-                                      mmd->materialname,
+                                      mmd->material,
                                       mmd->pass_index,
                                       mmd->layer_pass,
                                       1,
@@ -178,6 +180,13 @@ static void freeData(GpencilModifierData *md)
   }
 }
 
+static void foreachIDLink(GpencilModifierData *md, Object *ob, IDWalkFunc walk, void *userData)
+{
+  ColorGpencilModifierData *mmd = (ColorGpencilModifierData *)md;
+
+  walk(userData, ob, (ID **)&mmd->material, IDWALK_CB_USER);
+}
+
 GpencilModifierTypeInfo modifierType_Gpencil_Color = {
     /* name */ "Hue/Saturation",
     /* structName */ "ColorGpencilModifierData",
@@ -198,6 +207,6 @@ GpencilModifierTypeInfo modifierType_Gpencil_Color = {
     /* updateDepsgraph */ NULL,
     /* dependsOnTime */ NULL,
     /* foreachObjectLink */ NULL,
-    /* foreachIDLink */ NULL,
+    /* foreachIDLink */ foreachIDLink,
     /* foreachTexLink */ NULL,
 };
diff --git a/source/blender/gpencil_modifiers/intern/MOD_gpencilhook.c b/source/blender/gpencil_modifiers/intern/MOD_gpencilhook.c
index c664f755f2f..acbf3f7a4d6 100644
--- a/source/blender/gpencil_modifiers/intern/MOD_gpencilhook.c
+++ b/source/blender/gpencil_modifiers/intern/MOD_gpencilhook.c
@@ -78,7 +78,7 @@ static void initData(GpencilModifierData *md)
   HookGpencilModifierData *gpmd = (HookGpencilModifierData *)md;
   gpmd->pass_index = 0;
   gpmd->layername[0] = '\0';
-  gpmd->materialname[0] = '\0';
+  gpmd->material = NULL;
   gpmd->vgname[0] = '\0';
   gpmd->object = NULL;
   gpmd->force = 0.5f;
@@ -208,7 +208,7 @@ static void deformStroke(GpencilModifierData *md,
 
   if (!is_stroke_affected_by_modifier(ob,
                                       mmd->layername,
-                                      mmd->materialname,
+                                      mmd->material,
                                       mmd->pass_index,
                                       mmd->layer_pass,
                                       1,
@@ -338,6 +338,15 @@ static void foreachObjectLink(GpencilModifierData *md,
   walk(userData, ob, &mmd->object, IDWALK_CB_NOP);
 }
 
+static void foreachIDLink(GpencilModifierData *md, Object *ob, IDWalkFunc walk, void *userData)
+{
+  HookGpencilModifierData *mmd = (HookGpencilModifierData *)md;
+
+  walk(userData, ob, (ID **)&mmd->material, IDWALK_CB_USER);
+
+  foreachObjectLink(md, ob, (ObjectWalkFunc)walk, userData);
+}
+
 GpencilModifierTypeInfo modifierType_Gpencil_Hook = {
     /* name */ "Hook",
     /* structName */ "HookGpencilModifierData",
@@ -358,6 +367,6 @@ GpencilModifierTypeInfo modifierType_Gpencil_Hook = {
     /* updateDepsgraph */ updateDepsgraph,
     /* dependsOnTime */ NULL,
     /* foreachObjectLink */ foreachObjectLink,
-    /* foreachIDLink */ NULL,
+    /* foreachIDLink */ foreachIDLink,
     /* foreachTexLink */ NULL,
 };
diff --git a/source/blender/gpencil_modifiers/intern/MOD_gpencillattice.c b/source/blender/gpencil_modifiers/intern/MOD_gpencillattice.c
index 2c91db3a4fa..ec1b5d6e34f 100644
--- a/source/blender/gpencil_modifiers/intern/MOD_gpencillattice.c
+++ b/source/blender/gpencil_modifiers/intern/MOD_gpencillattice.c
@@ -56,7 +56,7 @@ static void initData(GpencilModifierData *md)
   LatticeGpencilModifierData *gpmd = (LatticeGpencilModifierData *)md;
   gpmd->pass_index = 0;
   gpmd->layername[0] = '\0';
-  gpmd->materialname[0] = '\0';
+  gpmd->material = NULL;
   gpmd->vgname[0] = '\0';
   gpmd->object = NULL;
   gpmd->cache_data = NULL;
@@ -80,7 +80,7 @@ static void deformStroke(GpencilModifierData *md,
 
   if (!is_stroke_affected_by_modifier(ob,
                                       mmd->layername,
-                                      mmd->materialname,
+                                      mmd->material,
                                       mmd->pass_index,
                                       mmd->layer_pass,
                                       1,
@@ -200,6 +200,15 @@ static void foreachObjectLink(GpencilModifierData *md,
   walk(userData, ob, &mmd->object, IDWALK_CB_NOP);
 }
 
+static void foreachIDLink(GpencilModifierData *md, Object *ob, IDWalkFunc walk, void *userData)
+{
+  LatticeGpencilModifierData *mmd = (LatticeGpencilModifierData *)md;
+
+  walk(userData, ob, (ID **)&mmd->material, IDWALK_CB_USER);
+
+  foreachObjectLink(md, ob, (ObjectWalkFunc)walk, userData);
+}
+
 GpencilModifierTypeInfo modifierType_Gpencil_Lattice = {
     /* name */ "Lattice",
     /* structName */ "LatticeGpencilModifierData",
@@ -220,6 +229,6 @@ GpencilModifierTypeInfo modifierType_Gpencil_Lattice = {
     /* updateDepsgraph */ updateDepsgraph,
     /* dependsOnTime */ NULL,
     /* foreachObjectLink */ foreachObjectLink,
-    /* foreachIDLink */ NULL,
+    /* foreachIDLink */ foreachIDLink,
     /* foreachTexLink */ NULL,
 };
diff --git a/source/blender/gpencil_modifiers/intern/MOD_gpencilmirror.c b/source/blender/gpencil_modifiers/intern/MOD_gpencilmirror.c
index 64d008bde18..4b3104fe9bf 100644
--- a/source/blender/gpencil_modifiers/intern/MOD_gpencilmirror.c
+++ b/source/blender/gpencil_modifiers/intern/MOD_gpencilmirror.c
@@ -57,7 +57,7 @@ static void initData(GpencilModifierData *md)
   MirrorGpencilModifierData *gpmd = (MirrorGpencilModifierData *)md;
   gpmd->pass_index = 0;
   gpmd->layername[0] = '\0';
-  gpmd->materialname[0] = '\0';
+  gpmd->material = NULL;
   gpmd->object = NULL;
   gpmd->flag |= GP_MIRROR_AXIS_X;
 }
@@ -130,7 +130,7 @@ static void generate_geometry(GpencilModifierData *md, Object *ob, bGPDlayer *gp
       for (i = 0, gps = gpf->strokes.first; i < tot_strokes; i++, gps = gps->next) {
         if (is_stroke_affected_by_modifier(ob,
                                            mmd->layername,
-                                           mmd->materialname,
+                                           mmd->material,
                                            mmd->pass_index,
                                            mmd->layer_pass,
                                            1,
@@ -213,6 +213,15 @@ static void foreachObjectLink(GpencilModifierData *md,
   walk(userData, ob, &mmd->object, IDWALK_CB_NOP);
 }
 
+static void foreachIDLink(GpencilModifierData *md, Object *ob, IDWalkFunc walk, void *userData)
+{
+  MirrorGpencilModifierData *mmd = (MirrorGpencilModifierData *)md;
+
+  walk(userData, ob, (ID **)&mmd->material, IDWALK_CB_USER);
+
+  foreachObjectLink(md, ob, (ObjectWalkFunc)walk, userData);
+}
+
 GpencilModifierTypeInfo modifierType_Gpencil_Mirror = {
     /* name */ "Mirror",
     /* structName */ "MirrorGpencilModifierData",
@@ -233,6 +242,6 @@ GpencilModifierTypeInfo modifierType_Gpencil_Mirror = {
     /* updateDepsgraph */ updateDepsgraph,
     /* dependsOnTime */ NULL,
     /* foreachObjectLink */ foreachObjectLink,
-    /* foreachIDLink */ NULL,
+    /* foreachIDLink */ foreachIDLink,
     /* foreachTexLink */ NULL,
 };
diff --git a/source/blender/gpencil_modifiers/intern/MOD_gpencilmultiply.c b/source/blender/gpencil_modifiers/intern/MOD_gpencilmultiply.c
index dcf541c26d0..bd84d90d5df 100644
--- a/source/blender/gpencil_modifiers/intern/MOD_gpencilmultiply.c
+++ b/source/blender/gpencil_modifiers/intern/MOD_gpencilmultiply.c
@@ -71,6 +71,8 @@ static void initData(GpencilModifierData *md)
   mmd->fading_center = 0.5f;
   mmd->fading_thickness = 0.5f;
   mmd->fading_opacity = 0.5f;
+  mmd->layername[0] = '\0';
+  mmd->material = NULL;
 }
 
 static void copyData(const GpencilModifierData *md, GpencilModifierData *target)
@@ -211,7 +213,7 @@ static void bakeModifier(Main *UNUSED(bmain),
       for (gps = gpf->strokes.first; gps; gps = gps->next) {
         if (!is_stroke_affected_by_modifier(ob,
                                             mmd->layername,
-                                            mmd->materialname,
+                                            mmd->material,
                                             mmd->pass_index,
                                             mmd->layer_pass,
                                             1,
@@ -252,7 +254,7 @@ static void generate_geometry(GpencilModifierData *md, Object *ob, bGPDlayer *gp
   for (gps = gpf->strokes.first; gps; gps = gps->next) {
     if (!is_stroke_affected_by_modifier(ob,
                                         mmd->layername,
-                                        mmd->materialname,
+                                        mmd->material,
                                         mmd->pass_index,
                                         mmd->layer_pass,
                                         1,
@@ -297,6 +299,13 @@ static void generateStrokes(GpencilModifierData *md, Depsgraph *depsgraph, Objec
   }
 }
 
+static void foreachIDLink(GpencilModifierData *md, Object *ob, IDWalkFunc walk, void *userData)
+{
+  MultiplyGpencilModifierData *mmd = (MultiplyGpencilModifierData *)md;
+
+  walk(userData, ob, (ID **)&mmd->material, IDWALK_CB_USER);
+}
+
 GpencilModifierTypeInfo modifierType_Gpencil_Multiply = {
     /* name */ "Multiple Strokes",
     /* structName */ "MultiplyGpencilModifierData",
@@ -317,6 +326,6 @@ GpencilModifierTypeInfo modifierType_Gpencil_Multiply = {
     /* updateDepsgraph */ NULL,
     /* dependsOnTime */ NULL,
     /* foreachObjectLink */ NULL,
-    /* foreachIDLink */ NULL,
+    /* foreachIDLink */ foreachIDLink,
     /* foreachTexLink */ NULL,
 };
diff --git a/source/blender/gpencil_modifiers/intern/MOD_gpencilnoise.c b/source/blender/gpencil_modifiers/intern/MOD_gpencilnoise.c
index cc9dfa81b3c..cc38fa8bc87 100644
--- a/source/blender/gpencil_modifiers/intern/MOD_gpencilnoise.c
+++ b/source/blender/gpencil_modifiers/intern/MOD_gpencilnoise.c
@@ -44,6 +44,8 @@
 #include "BKE_gpencil.h"
 #include "BKE_gpencil_geom.h"
 #include "BKE_gpencil_modifier.h"
+#include "BKE_lib_query.h"
+#include "BKE_modifier.h"
 #include "BKE_object.h"
 
 #include "DEG_depsgraph.h"
@@ -60,7 +62,7 @@ static void initData(GpencilModifierData *md)
   gpmd->flag |= GP_NOISE_USE_RANDOM;
   gpmd->factor = 0.5f;
   gpmd->layername[0] = '\0';
-  gpmd->materialname[0] = '\0';
+  gpmd->material = NULL;
   gpmd->vgname[0] = '\0';
   gpmd->step = 4;
   gpmd->seed = 1;
@@ -135,7 +137,7 @@ static void deformStroke(GpencilModifierData *md,
 
   if (!is_stroke_affected_by_modifier(ob,
                                       mmd->layername,
-                                      mmd->materialname,
+                                      mmd->material,
                                       mmd->pass_index,
                                       mmd->layer_pass,
                                       1,
@@ -259,6 +261,13 @@ static void bakeModifier(struct Main *UNUSED(bmain),
   }
 }
 
+static void foreachIDLink(GpencilModifierData *md, Object *ob, IDWalkFunc walk, void *userData)
+{
+  NoiseGpencilModifierData *mmd = (NoiseGpencilModifierData *)md;
+
+  walk(userData, ob, (ID **)&mmd->material, IDWALK_CB_USER);
+}
+
 GpencilModifierTypeInfo modifierType_Gpencil_Noise = {
     /* name */ "Noise",
     /* structName */ "NoiseGpencilModifierData",
@@ -279,6 +288,6 @@ GpencilModifierTypeInfo modifierType_Gpencil_Noise = {
     /* updateDepsgraph */ NULL,
     /* dependsOnTime */ dependsOnTime,
     /* foreachObjectLink */ NULL,
-    /* foreachIDLink */ NULL,
+    /* foreachIDLink */ foreachIDLink,
     /* foreachTexLink */ NULL,
 };
diff --git a/source/blender/gpencil_modifiers/intern/MOD_gpenciloffset.c b/source/blender/gpencil_modifiers/intern/MOD_gpenciloffset.c
index ddf65ede02a..aa1893912b5 100644
--- a/source/blender/gpencil_modifiers/intern/MOD_gpenciloffset.c
+++ b/source/blender/gpencil_modifiers/intern/MOD_gpenciloffset.c
@@ -38,6 +38,8 @@
 #include "BKE_deform.h"
 #include "BKE_gpencil_geom.h"
 #include "BKE_gpencil_modifier.h"
+#include "BKE_lib_query.h"
+#include "BKE_modifier.h"
 
 #include "DEG_depsgraph.h"
 
@@ -49,7 +51,7 @@ static void initData(GpencilModifierData *md)
   OffsetGpencilModifierData *gpmd = (OffsetGpencilModifierData *)md;
   gpmd->pass_index = 0;
   gpmd->layername[0] = '\0';
-  gpmd->materialname[0] = '\0';
+  gpmd->material = NULL;
   gpmd->vgname[0] = '\0';
   ARRAY_SET_ITEMS(gpmd->loc, 0.0f, 0.0f, 0.0f);
   ARRAY_SET_ITEMS(gpmd->rot, 0.0f, 0.0f, 0.0f);
@@ -77,7 +79,7 @@ static void deformStroke(GpencilModifierData *md,
 
   if (!is_stroke_affected_by_modifier(ob,
                                       mmd->layername,
-                                      mmd->materialname,
+                                      mmd->material,
                                       mmd->pass_index,
                                       mmd->layer_pass,
                                       1,
@@ -129,6 +131,13 @@ static void bakeModifier(struct Main *UNUSED(bmain),
   }
 }
 
+static void foreachIDLink(GpencilModifierData *md, Object *ob, IDWalkFunc walk, void *userData)
+{
+  OffsetGpencilModifierData *mmd = (OffsetGpencilModifierData *)md;
+
+  walk(userData, ob, (ID **)&mmd->material, IDWALK_CB_USER);
+}
+
 GpencilModifierTypeInfo modifierType_Gpencil_Offset = {
     /* name */ "Offset",
     /* structName */ "OffsetGpencilModifierData",
@@ -149,6 +158,6 @@ GpencilModifierTypeInfo modifierType_Gpencil_Offset = {
     /* updateDepsgraph */ NULL,
     /* dependsOnTime */ NULL,
     /* foreachObjectLink */ NULL,
-    /* foreachIDLink */ NULL,
+    /* foreachIDLink */ foreachIDLink,
     /* foreachTexLink */ NULL,
 };
diff --git a/source/blender/gpencil_modifiers/intern/MOD_gpencilopacity.c b/source/blender/gpencil_modifiers/intern/MOD_gpencilopacity.c
index ac6f3d04719..91d2c7c862e 100644
--- a/source/blender/gpencil_modifiers/intern/MOD_gpencilopacity.c
+++ b/source/blender/gpencil_modifiers/intern/MOD_gpencilopacity.c
@@ -38,8 +38,10 @@
 #include "BKE_deform.h"
 #include "BKE_gpencil.h"
 #include "BKE_gpencil_modifier.h"
+#include "BKE_lib_query.h"
 #include "BKE_main.h"
 #include "BKE_material.h"
+#include "BKE_modifier.h"
 
 #include "DEG_depsgraph.h"
 
@@ -53,7 +55,7 @@ static void initData(GpencilModifierData *md)
   gpmd->factor = 1.0f;
   gpmd->hardeness = 1.0f;
   gpmd->layername[0] = '\0';
-  gpmd->materialname[0] = '\0';
+  gpmd->material = NULL;
   gpmd->vgname[0] = '\0';
   gpmd->modify_color = GP_MODIFY_COLOR_BOTH;
   gpmd->curve_intensity = BKE_curvemapping_add(1, 0.0f, 0.0f, 1.0f, 1.0f);
@@ -92,7 +94,7 @@ static void deformStroke(GpencilModifierData *md,
 
   if (!is_stroke_affected_by_modifier(ob,
                                       mmd->layername,
-                                      mmd->materialname,
+                                      mmd->material,
                                       mmd->pass_index,
                                       mmd->layer_pass,
                                       1,
@@ -189,6 +191,13 @@ static void freeData(GpencilModifierData *md)
   }
 }
 
+static void foreachIDLink(GpencilModifierData *md, Object *ob, IDWalkFunc walk, void *userData)
+{
+  OpacityGpencilModifierData *mmd = (OpacityGpencilModifierData *)md;
+
+  walk(userData, ob, (ID **)&mmd->material, IDWALK_CB_USER);
+}
+
 GpencilModifierTypeInfo modifierType_Gpencil_Opacity = {
     /* name */ "Opacity",
     /* structName */ "OpacityGpencilModifierData",
@@ -209,6 +218,6 @@ GpencilModifierTypeInfo modifierType_Gpencil_Opacity = {
     /* updateDepsgraph */ NULL,
     /* dependsOnTime */ NULL,
     /* foreachObjectLink */ NULL,
-    /* foreachIDLink */ NULL,
+    /* foreachIDLink */ foreachIDLink,
     /* foreachTexLink */ NULL,
 };
diff --git a/source/blender/gpencil_modifiers/intern/MOD_gpencilsimplify.c b/source/blender/gpencil_modifiers/intern/MOD_gpencilsimplify.c
index 29f26d49668..b63d52e2f45 100644
--- a/source/blender/gpencil_modifiers/intern/MOD_gpencilsimplify.c
+++ b/source/blender/gpencil_modifiers/intern/MOD_gpencilsimplify.c
@@ -34,6 +34,8 @@
 
 #include "BKE_gpencil_geom.h"
 #include "BKE_gpencil_modifier.h"
+#include "BKE_lib_query.h"
+#include "BKE_modifier.h"
 
 #include "DEG_depsgraph.h"
 
@@ -49,7 +51,7 @@ static void initData(GpencilModifierData *md)
   gpmd->length = 0.1f;
   gpmd->distance = 0.1f;
   gpmd->layername[0] = '\0';
-  gpmd->materialname[0] = '\0';
+  gpmd->material = NULL;
 }
 
 static void copyData(const GpencilModifierData *md, GpencilModifierData *target)
@@ -68,7 +70,7 @@ static void deformStroke(GpencilModifierData *md,
 
   if (!is_stroke_affected_by_modifier(ob,
                                       mmd->layername,
-                                      mmd->materialname,
+                                      mmd->material,
                                       mmd->pass_index,
                                       mmd->layer_pass,
                                       mmd->mode == GP_SIMPLIFY_SAMPLE ? 3 : 4,
@@ -123,6 +125,13 @@ static void bakeModifier(struct Main *UNUSED(bmain),
   }
 }
 
+static void foreachIDLink(GpencilModifierData *md, Object *ob, IDWalkFunc walk, void *userData)
+{
+  SimplifyGpencilModifierData *mmd = (SimplifyGpencilModifierData *)md;
+
+  walk(userData, ob, (ID **)&mmd->material, IDWALK_CB_USER);
+}
+
 GpencilModifierTypeInfo modifierType_Gpencil_Simplify = {
     /* name */ "Simplify",
     /* structName */ "SimplifyGpencilModifierData",
@@ -143,6 +152,6 @@ GpencilModifierTypeInfo modifierType_Gpencil_Simplify = {
     /* updateDepsgraph */ NULL,
     /* dependsOnTime */ NULL,
     /* foreachObjectLink */ NULL,
-    /* foreachIDLink */ NULL,
+    /* foreachIDLink */ foreachIDLink,
     /* foreachTexLink */ NULL,
 };
diff --git a/source/blender/gpencil_modifiers/intern/MOD_gpencilsmooth.c b/source/blender/gpencil_modifiers/intern/MOD_gpencilsmooth.c
index be9260da225..8487283d848 100644
--- a/source/blender/gpencil_modifiers/intern/MOD_gpencilsmooth.c
+++ b/source/blender/gpencil_modifiers/intern/MOD_gpencilsmooth.c
@@ -35,6 +35,8 @@
 #include "BKE_deform.h"
 #include "BKE_gpencil_geom.h"
 #include "BKE_gpencil_modifier.h"
+#include "BKE_lib_query.h"
+#include "BKE_modifier.h"
 
 #include "DEG_depsgraph.h"
 
@@ -48,7 +50,7 @@ static void initData(GpencilModifierData *md)
   gpmd->flag |= GP_SMOOTH_MOD_LOCATION;
   gpmd->factor = 0.5f;
   gpmd->layername[0] = '\0';
-  gpmd->materialname[0] = '\0';
+  gpmd->material = NULL;
   gpmd->vgname[0] = '\0';
   gpmd->step = 1;
 
@@ -88,7 +90,7 @@ static void deformStroke(GpencilModifierData *md,
 
   if (!is_stroke_affected_by_modifier(ob,
                                       mmd->layername,
-                                      mmd->materialname,
+                                      mmd->material,
                                       mmd->pass_index,
                                       mmd->layer_pass,
                                       3,
@@ -167,6 +169,13 @@ static void freeData(GpencilModifierData *md)
   }
 }
 
+static void foreachIDLink(GpencilModifierData *md, Object *ob, IDWalkFunc walk, void *userData)
+{
+  SmoothGpencilModifierData *mmd = (SmoothGpencilModifierData *)md;
+
+  walk(userData, ob, (ID **)&mmd->material, IDWALK_CB_USER);
+}
+
 GpencilModifierTypeInfo modifierType_Gpencil_Smooth = {
     /* name */ "Smooth",
     /* structName */ "SmoothGpencilModifierData",
@@ -187,6 +196,6 @@ GpencilModifierTypeInfo modifierType_Gpencil_Smooth = {
     /* updateDepsgraph */ NULL,
     /* dependsOnTime */ NULL,
     /* foreachObjectLink */ NULL,
-    /* foreachIDLink */ NULL,
+    /* foreachIDLink */ foreachIDLink,
     /* foreachTexLink */ NULL,
 };
diff --git a/source/blender/gpencil_modifiers/intern/MOD_gpencilsubdiv.c b/source/blender/gpencil_modifiers/intern/MOD_gpencilsubdiv.c
index ec0f5789238..0b00bcaf3ff 100644
--- a/source/blender/gpencil_modifiers/intern/MOD_gpencilsubdiv.c
+++ b/source/blender/gpencil_modifiers/intern/MOD_gpencilsubdiv.c
@@ -36,6 +36,8 @@
 
 #include "BKE_gpencil_geom.h"
 #include "BKE_gpencil_modifier.h"
+#include "BKE_lib_query.h"
+#include "BKE_modifier.h"
 
 #include "DEG_depsgraph.h"
 
@@ -48,7 +50,7 @@ static void initData(GpencilModifierData *md)
   gpmd->pass_index = 0;
   gpmd->level = 1;
   gpmd->layername[0] = '\0';
-  gpmd->materialname[0] = '\0';
+  gpmd->material = NULL;
 }
 
 static void copyData(const GpencilModifierData *md, GpencilModifierData *target)
@@ -72,7 +74,7 @@ static void deformStroke(GpencilModifierData *md,
 
   if (!is_stroke_affected_by_modifier(ob,
                                       mmd->layername,
-                                      mmd->materialname,
+                                      mmd->material,
                                       mmd->pass_index,
                                       mmd->layer_pass,
                                       minimum_vert,
@@ -104,6 +106,13 @@ static void bakeModifier(struct Main *UNUSED(bmain),
   }
 }
 
+static void foreachIDLink(GpencilModifierData *md, Object *ob, IDWalkFunc walk, void *userData)
+{
+  SubdivGpencilModifierData *mmd = (SubdivGpencilModifierData *)md;
+
+  walk(userData, ob, (ID **)&mmd->material, IDWALK_CB_USER);
+}
+
 GpencilModifierTypeInfo modifierType_Gpencil_Subdiv = {
     /* name */ "Subdivide",
     /* structName */ "SubdivGpencilModifierData",
@@ -124,6 +133,6 @@ GpencilModifierTypeInfo modifierType_Gpencil_Subdiv = {
     /* updateDepsgraph */ NULL,
     /* dependsOnTime */ NULL,
     /* foreachObjectLink */ NULL,
-    /* foreachIDLink */ NULL,
+    /* foreachIDLink */ foreachIDLink,
     /* foreachTexLink */ NULL,
 };
diff --git a/source/blender/gpencil_modifiers/intern/MOD_gpenciltexture.c b/source/blender/gpencil_modifiers/intern/MOD_gpenciltexture.c
index c3733c981ae..27b1ba8c9cd 100644
--- a/source/blender/gpencil_modifiers/intern/MOD_gpenciltexture.c
+++ b/source/blender/gpencil_modifiers/intern/MOD_gpenciltexture.c
@@ -38,6 +38,8 @@
 #include "BKE_gpencil.h"
 #include "BKE_gpencil_geom.h"
 #include "BKE_gpencil_modifier.h"
+#include "BKE_lib_query.h"
+#include "BKE_modifier.h"
 
 #include "DEG_depsgraph.h"
 
@@ -56,7 +58,7 @@ static void initData(GpencilModifierData *md)
   gpmd->uv_scale = 1.0f;
   gpmd->pass_index = 0;
   gpmd->layername[0] = '\0';
-  gpmd->materialname[0] = '\0';
+  gpmd->material = NULL;
   gpmd->vgname[0] = '\0';
 }
 
@@ -78,7 +80,7 @@ static void deformStroke(GpencilModifierData *md,
 
   if (!is_stroke_affected_by_modifier(ob,
                                       mmd->layername,
-                                      mmd->materialname,
+                                      mmd->material,
                                       mmd->pass_index,
                                       mmd->layer_pass,
                                       1,
@@ -140,6 +142,13 @@ static void bakeModifier(struct Main *UNUSED(bmain),
   }
 }
 
+static void foreachIDLink(GpencilModifierData *md, Object *ob, IDWalkFunc walk, void *userData)
+{
+  TextureGpencilModifierData *mmd = (TextureGpencilModifierData *)md;
+
+  walk(userData, ob, (ID **)&mmd->material, IDWALK_CB_USER);
+}
+
 GpencilModifierTypeInfo modifierType_Gpencil_Texture = {
     /* name */ "Texture Mapping",
     /* structName */ "TextureGpencilModifierData",
@@ -160,6 +169,6 @@ GpencilModifierTypeInfo modifierType_Gpencil_Texture = {
     /* updateDepsgraph */ NULL,
     /* dependsOnTime */ NULL,
     /* foreachObjectLink */ NULL,
-    /* foreachIDLink */ NULL,
+    /* foreachIDLink */ foreachIDLink,
     /* foreachTexLink */ NULL,
 };
diff --git a/source/blender/gpencil_modifiers/intern/MOD_gpencilthick.c b/source/blender/gpencil_modifiers/intern/MOD_gpencilthick.c
index 776cc1792f9..1e21cd05a02 100644
--- a/source/blender/gpencil_modifiers/intern/MOD_gpencilthick.c
+++ b/source/blender/gpencil_modifiers/intern/MOD_gpencilthick.c
@@ -37,6 +37,8 @@
 #include "BKE_deform.h"
 #include "BKE_gpencil.h"
 #include "BKE_gpencil_modifier.h"
+#include "BKE_lib_query.h"
+#include "BKE_modifier.h"
 
 #include "DEG_depsgraph.h"
 
@@ -50,7 +52,7 @@ static void initData(GpencilModifierData *md)
   gpmd->thickness_fac = 1.0f;
   gpmd->thickness = 30;
   gpmd->layername[0] = '\0';
-  gpmd->materialname[0] = '\0';
+  gpmd->material = NULL;
   gpmd->vgname[0] = '\0';
   gpmd->curve_thickness = BKE_curvemapping_add(1, 0.0f, 0.0f, 1.0f, 1.0f);
   if (gpmd->curve_thickness) {
@@ -95,7 +97,7 @@ static void deformStroke(GpencilModifierData *md,
 
   if (!is_stroke_affected_by_modifier(ob,
                                       mmd->layername,
-                                      mmd->materialname,
+                                      mmd->material,
                                       mmd->pass_index,
                                       mmd->layer_pass,
                                       1,
@@ -159,6 +161,13 @@ static void bakeModifier(struct Main *UNUSED(bmain),
   }
 }
 
+static void foreachIDLink(GpencilModifierData *md, Object *ob, IDWalkFunc walk, void *userData)
+{
+  ThickGpencilModifierData *mmd = (ThickGpencilModifierData *)md;
+
+  walk(userData, ob, (ID **)&mmd->material, IDWALK_CB_USER);
+}
+
 GpencilModifierTypeInfo modifierType_Gpencil_Thick = {
     /* name */ "Thickness",
     /* structName */ "ThickGpencilModifierData",
@@ -179,6 +188,6 @@ GpencilModifierTypeInfo modifierType_Gpencil_Thick = {
     /* updateDepsgraph */ NULL,
     /* dependsOnTime */ NULL,
     /* foreachObjectLink */ NULL,
-    /* foreachIDLink */ NULL,
+    /* foreachIDLink */ foreachIDLink,
     /* foreachTexLink */ NULL,
 };
diff --git a/source/blender/gpencil_modifiers/intern/MOD_gpenciltint.c b/source/blender/gpencil_modifiers/intern/MOD_gpenciltint.c
index 8f1edb2e73f..a5fc9fe6808 100644
--- a/source/blender/gpencil_modifiers/intern/MOD_gpenciltint.c
+++ b/source/blender/gpencil_modifiers/intern/MOD_gpenciltint.c
@@ -62,7 +62,7 @@ static void initData(GpencilModifierData *md)
   TintGpencilModifierData *gpmd = (TintGpencilModifierData *)md;
   gpmd->pass_index = 0;
   gpmd->layername[0] = '\0';
-  gpmd->materialname[0] = '\0';
+  gpmd->material = NULL;
   gpmd->vgname[0] = '\0';
   gpmd->object = NULL;
   gpmd->radius = 1.0f;
@@ -130,7 +130,7 @@ static void deformStroke(GpencilModifierData *md,
 
   if (!is_stroke_affected_by_modifier(ob,
                                       mmd->layername,
-                                      mmd->materialname,
+                                      mmd->material,
                                       mmd->pass_index,
                                       mmd->layer_pass,
                                       1,
@@ -323,6 +323,15 @@ static void foreachObjectLink(GpencilModifierData *md,
   walk(userData, ob, &mmd->object, IDWALK_CB_NOP);
 }
 
+static void foreachIDLink(GpencilModifierData *md, Object *ob, IDWalkFunc walk, void *userData)
+{
+  TintGpencilModifierData *mmd = (TintGpencilModifierData *)md;
+
+  walk(userData, ob, (ID **)&mmd->material, IDWALK_CB_USER);
+
+  foreachObjectLink(md, ob, (ObjectWalkFunc)walk, userData);
+}
+
 GpencilModifierTypeInfo modifierType_Gpencil_Tint = {
     /* name */ "Tint",
     /* structName */ "TintGpencilModifierData",
@@ -343,6 +352,6 @@ GpencilModifierTypeInfo modifierType_Gpencil_Tint = {
     /* updateDepsgraph */ updateDepsgraph,
     /* dependsOnTime */ NULL,
     /* foreachObjectLink */ foreachObjectLink,
-    /* foreachIDLink */ NULL,
+    /* foreachIDLink */ foreachIDLink,
     /* foreachTexLink */ NULL,
 };