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

1 files changed, 138 insertions, 0 deletions

diff --git a/source/blender/blenloader/intern/versioning_280.c b/source/blender/blenloader/intern/versioning_280.c
index cc9a23dbf68..2e81372aab6 100644
--- a/source/blender/blenloader/intern/versioning_280.c
+++ b/source/blender/blenloader/intern/versioning_280.c
@@ -1750,6 +1750,144 @@ void do_versions_after_linking_280(Main *bmain, ReportList *UNUSED(reports))
     }
   }
 
+  if (!MAIN_VERSION_ATLEAST(bmain, 290, 0)) {
+    /* Patch old grease pencil modifiers material filter. */
+    LISTBASE_FOREACH (Object *, ob, &bmain->objects) {
+      LISTBASE_FOREACH (GpencilModifierData *, md, &ob->greasepencil_modifiers) {
+        switch (md->type) {
+          case eGpencilModifierType_Array: {
+            ArrayGpencilModifierData *gpmd = (ArrayGpencilModifierData *)md;
+            if (gpmd->materialname[0] != '\0') {
+              gpmd->material = BLI_findstring(
+                  &bmain->materials, gpmd->materialname, offsetof(ID, name) + 2);
+              gpmd->materialname[0] = '\0';
+            }
+            break;
+          }
+          case eGpencilModifierType_Color: {
+            ColorGpencilModifierData *gpmd = (ColorGpencilModifierData *)md;
+            if (gpmd->materialname[0] != '\0') {
+              gpmd->material = BLI_findstring(
+                  &bmain->materials, gpmd->materialname, offsetof(ID, name) + 2);
+              gpmd->materialname[0] = '\0';
+            }
+            break;
+          }
+          case eGpencilModifierType_Hook: {
+            HookGpencilModifierData *gpmd = (HookGpencilModifierData *)md;
+            if (gpmd->materialname[0] != '\0') {
+              gpmd->material = BLI_findstring(
+                  &bmain->materials, gpmd->materialname, offsetof(ID, name) + 2);
+              gpmd->materialname[0] = '\0';
+            }
+            break;
+          }
+          case eGpencilModifierType_Lattice: {
+            LatticeGpencilModifierData *gpmd = (LatticeGpencilModifierData *)md;
+            if (gpmd->materialname[0] != '\0') {
+              gpmd->material = BLI_findstring(
+                  &bmain->materials, gpmd->materialname, offsetof(ID, name) + 2);
+              gpmd->materialname[0] = '\0';
+            }
+            break;
+          }
+          case eGpencilModifierType_Mirror: {
+            MirrorGpencilModifierData *gpmd = (MirrorGpencilModifierData *)md;
+            if (gpmd->materialname[0] != '\0') {
+              gpmd->material = BLI_findstring(
+                  &bmain->materials, gpmd->materialname, offsetof(ID, name) + 2);
+              gpmd->materialname[0] = '\0';
+            }
+            break;
+          }
+          case eGpencilModifierType_Multiply: {
+            MultiplyGpencilModifierData *gpmd = (MultiplyGpencilModifierData *)md;
+            if (gpmd->materialname[0] != '\0') {
+              gpmd->material = BLI_findstring(
+                  &bmain->materials, gpmd->materialname, offsetof(ID, name) + 2);
+              gpmd->materialname[0] = '\0';
+            }
+            break;
+          }
+          case eGpencilModifierType_Noise: {
+            NoiseGpencilModifierData *gpmd = (NoiseGpencilModifierData *)md;
+            if (gpmd->materialname[0] != '\0') {
+              gpmd->material = BLI_findstring(
+                  &bmain->materials, gpmd->materialname, offsetof(ID, name) + 2);
+              gpmd->materialname[0] = '\0';
+            }
+            break;
+          }
+          case eGpencilModifierType_Offset: {
+            OffsetGpencilModifierData *gpmd = (OffsetGpencilModifierData *)md;
+            if (gpmd->materialname[0] != '\0') {
+              gpmd->material = BLI_findstring(
+                  &bmain->materials, gpmd->materialname, offsetof(ID, name) + 2);
+              gpmd->materialname[0] = '\0';
+            }
+            break;
+          }
+          case eGpencilModifierType_Opacity: {
+            OpacityGpencilModifierData *gpmd = (OpacityGpencilModifierData *)md;
+            if (gpmd->materialname[0] != '\0') {
+              gpmd->material = BLI_findstring(
+                  &bmain->materials, gpmd->materialname, offsetof(ID, name) + 2);
+              gpmd->materialname[0] = '\0';
+            }
+            break;
+          }
+          case eGpencilModifierType_Simplify: {
+            SimplifyGpencilModifierData *gpmd = (SimplifyGpencilModifierData *)md;
+            if (gpmd->materialname[0] != '\0') {
+              gpmd->material = BLI_findstring(
+                  &bmain->materials, gpmd->materialname, offsetof(ID, name) + 2);
+              gpmd->materialname[0] = '\0';
+            }
+            break;
+          }
+          case eGpencilModifierType_Smooth: {
+            SmoothGpencilModifierData *gpmd = (SmoothGpencilModifierData *)md;
+            if (gpmd->materialname[0] != '\0') {
+              gpmd->material = BLI_findstring(
+                  &bmain->materials, gpmd->materialname, offsetof(ID, name) + 2);
+              gpmd->materialname[0] = '\0';
+            }
+            break;
+          }
+          case eGpencilModifierType_Subdiv: {
+            SubdivGpencilModifierData *gpmd = (SubdivGpencilModifierData *)md;
+            if (gpmd->materialname[0] != '\0') {
+              gpmd->material = BLI_findstring(
+                  &bmain->materials, gpmd->materialname, offsetof(ID, name) + 2);
+              gpmd->materialname[0] = '\0';
+            }
+            break;
+          }
+          case eGpencilModifierType_Texture: {
+            TextureGpencilModifierData *gpmd = (TextureGpencilModifierData *)md;
+            if (gpmd->materialname[0] != '\0') {
+              gpmd->material = BLI_findstring(
+                  &bmain->materials, gpmd->materialname, offsetof(ID, name) + 2);
+              gpmd->materialname[0] = '\0';
+            }
+            break;
+          }
+          case eGpencilModifierType_Thick: {
+            ThickGpencilModifierData *gpmd = (ThickGpencilModifierData *)md;
+            if (gpmd->materialname[0] != '\0') {
+              gpmd->material = BLI_findstring(
+                  &bmain->materials, gpmd->materialname, offsetof(ID, name) + 2);
+              gpmd->materialname[0] = '\0';
+            }
+            break;
+          }
+          default:
+            break;
+        }
+      }
+    }
+  }
+
   /**
    * Versioning code until next subversion bump goes here.
    *