Add helper to validate (and fix) material indices of meshes' polygons, curves' splines and texts' letters.

Useful especially for importer addons.

Reviewers: campbellbarton

Reviewed By: campbellbarton

Differential Revision: https://developer.blender.org/D650

source/blender/blenkernel/BKE_curve.h

@@ -87,6 +87,7 @@ bool BKE_curve_center_bounds(struct Curve *cu, float cent[3]);
 void BKE_curve_translate(struct Curve *cu, float offset[3], const bool do_keys);
 void BKE_curve_material_index_remove(struct Curve *cu, int index);
 void BKE_curve_material_index_clear(struct Curve *cu);
+int BKE_curve_material_index_validate(struct Curve *cu);
 
 ListBase    *BKE_curve_nurbs_get(struct Curve *cu);
 

source/blender/blenkernel/BKE_mesh.h

@@ -287,6 +287,7 @@ void BKE_mesh_calc_relative_deform(
 
 int BKE_mesh_validate(struct Mesh *me, const int do_verbose);
 void BKE_mesh_cd_validate(struct Mesh *me);
+int BKE_mesh_validate_material_indices(struct Mesh *me);
 
 bool BKE_mesh_validate_arrays(
         struct Mesh *me,

source/blender/blenkernel/intern/curve.c

@@ -52,6 +52,7 @@
 
 #include "BKE_animsys.h"
 #include "BKE_curve.h"
+#include "BKE_depsgraph.h"
 #include "BKE_displist.h"
 #include "BKE_font.h"
 #include "BKE_global.h"
@@ -4230,6 +4231,45 @@ void BKE_curve_material_index_clear(Curve *cu)
 	}
 }
 
+int BKE_curve_material_index_validate(Curve *cu)
+{
+	const int curvetype = BKE_curve_type_get(cu);
+	bool is_valid = true;
+
+	if (curvetype == OB_FONT) {
+		CharInfo *info = cu->strinfo;
+		const int max_idx = max_ii(0, cu->totcol);  /* OB_FONT use 1 as first mat index, not 0!!! */
+		int i;
+		for (i = cu->len_wchar - 1; i >= 0; i--, info++) {
+			if (info->mat_nr > max_idx) {
+				info->mat_nr = 0;
+				is_valid = false;
+			}
+		}
+	}
+	else {
+		Nurb *nu;
+		const int max_idx = max_ii(0, cu->totcol - 1);
+		for (nu = cu->nurb.first; nu; nu = nu->next) {
+			if (nu->mat_nr > max_idx) {
+				nu->mat_nr = 0;
+				if (curvetype == OB_CURVE) {
+					nu->charidx = 0;
+				}
+				is_valid = false;
+			}
+		}
+	}
+
+	if (!is_valid) {
+		DAG_id_tag_update(&cu->id, OB_RECALC_DATA);
+		return true;
+	}
+	else {
+		return false;
+	}
+}
+
 void BKE_curve_rect_from_textbox(const struct Curve *cu, const struct TextBox *tb, struct rctf *r_rect)
 {
 	r_rect->xmin = cu->xof + tb->x;

source/blender/blenkernel/intern/mesh_validate.c

@@ -909,8 +909,6 @@ static bool mesh_validate_customdata(CustomData *data, CustomDataMask mask,
 	return is_valid;
 }
 
-#undef PRINT
-
 /**
  * \returns is_valid.
  */
@@ -1052,8 +1050,36 @@ void BKE_mesh_cd_validate(Mesh *me)
 		}
 	}
 }
-/** \} */
 
+/**
+ * Check all material indices of polygons are valid, invalid ones are set to 0.
+ * \returns is_valid.
+ */
+int BKE_mesh_validate_material_indices(Mesh *me)
+{
+	MPoly *mp;
+	const int max_idx = max_ii(0, me->totcol - 1);
+	const int totpoly = me->totpoly;
+	int i;
+	bool is_valid = true;
+
+	for (mp = me->mpoly, i = 0; i < totpoly; i++, mp++) {
+		if (mp->mat_nr > max_idx) {
+			mp->mat_nr = 0;
+			is_valid = false;
+		}
+	}
+
+	if (!is_valid) {
+		DAG_id_tag_update(&me->id, OB_RECALC_DATA);
+		return true;
+	}
+	else {
+		return false;
+	}
+}
+
+/** \} */
 
 
 /* -------------------------------------------------------------------- */

source/blender/makesrna/intern/rna_curve_api.c

@@ -58,6 +58,12 @@ void RNA_api_curve(StructRNA *srna)
 	RNA_def_function_ui_description(func, "Transform curve by a matrix");
 	parm = RNA_def_float_matrix(func, "matrix", 4, 4, NULL, 0.0f, 0.0f, "", "Matrix", 0.0f, 0.0f);
 	RNA_def_property_flag(parm, PROP_REQUIRED);
+
+	func = RNA_def_function(srna, "validate_material_indices", "BKE_curve_material_index_validate");
+	RNA_def_function_ui_description(func, "Validate material indices of splines or letters, return True when the curve "
+	                                "has had invalid indices corrected (to default 0)");
+	parm = RNA_def_boolean(func, "result", 0, "Result", "");
+	RNA_def_function_return(func, parm);
 }
 
 #endif

source/blender/makesrna/intern/rna_mesh_api.c

@@ -206,11 +206,17 @@ void RNA_api_mesh(StructRNA *srna)
 	RNA_def_function_return(func, parm);
 
 	func = RNA_def_function(srna, "validate", "BKE_mesh_validate");
-	RNA_def_function_ui_description(func, "validate geometry, return True when the mesh has had "
+	RNA_def_function_ui_description(func, "Validate geometry, return True when the mesh has had "
 	                                "invalid geometry corrected/removed");
 	RNA_def_boolean(func, "verbose", 0, "Verbose", "Output information about the errors found");
 	parm = RNA_def_boolean(func, "result", 0, "Result", "");
 	RNA_def_function_return(func, parm);
+
+	func = RNA_def_function(srna, "validate_material_indices", "BKE_mesh_validate_material_indices");
+	RNA_def_function_ui_description(func, "Validate material indices of polygons, return True when the mesh has had "
+	                                "invalid indices corrected (to default 0)");
+	parm = RNA_def_boolean(func, "result", 0, "Result", "");
+	RNA_def_function_return(func, parm);
 }
 
 #endif