Fix modifiers evaluation outside of depsgraph/CoW context.

Fix T58237: Exporters: Curve Modifier not applied when "apply modifiers" are selected.
Fix T58856: Python: "to_mesh" broken in 2.8.

...And many other cases... ;)

Thing is, we need target IDs to always be evaluated ones (at least I
cannot see any case where having orig ones is desired effect here).
Depsgraph/Cow system ensures us that when modifiers are evaluated by it,
but they can also be called outside of this context, e.g. when doing
binding, or object conversion...

So we need to ensure in modifiers code that we actually are always
working with eval data for those targets.

Note that I did not touch to physics modifiers, those are a bit touchy
and rather not 'fix' something there until proven broken!

1 files changed, 18 insertions, 9 deletions

diff --git a/source/blender/modifiers/intern/MOD_normal_edit.c b/source/blender/modifiers/intern/MOD_normal_edit.c
index d7126113fe8..5e5621ae717 100644
--- a/source/blender/modifiers/intern/MOD_normal_edit.c
+++ b/source/blender/modifiers/intern/MOD_normal_edit.c
@@ -42,6 +42,8 @@
 #include "BKE_mesh.h"
 #include "BKE_deform.h"
 
+#include "DEG_depsgraph_query.h"
+
 #include "MOD_util.h"
 
 
@@ -193,13 +195,16 @@ static bool polygons_check_flip(
 }
 
 static void normalEditModifier_do_radial(
-        NormalEditModifierData *enmd, Object *ob, Mesh *mesh,
+        NormalEditModifierData *enmd, const ModifierEvalContext *ctx,
+        Object *ob, Mesh *mesh,
         short (*clnors)[2], float (*loopnors)[3], float (*polynors)[3],
         const short mix_mode, const float mix_factor, const float mix_limit,
         MDeformVert *dvert, const int defgrp_index, const bool use_invert_vgroup,
         MVert *mvert, const int num_verts, MEdge *medge, const int num_edges,
         MLoop *mloop, const int num_loops, MPoly *mpoly, const int num_polys)
 {
+	Object *ob_target = DEG_get_evaluated_object(ctx->depsgraph, enmd->target);
+
 	const bool do_polynors_fix = (enmd->flag & MOD_NORMALEDIT_NO_POLYNORS_FIX) == 0;
 	int i;
 
@@ -209,7 +214,7 @@ static void normalEditModifier_do_radial(
 
 	BLI_bitmap *done_verts = BLI_BITMAP_NEW((size_t)num_verts, __func__);
 
-	generate_vert_coordinates(mesh, ob, enmd->target, enmd->offset, num_verts, cos, size);
+	generate_vert_coordinates(mesh, ob, ob_target, enmd->offset, num_verts, cos, size);
 
 	/**
 	 * size gives us our spheroid coefficients ``(A, B, C)``.
@@ -294,13 +299,16 @@ static void normalEditModifier_do_radial(
 }
 
 static void normalEditModifier_do_directional(
-        NormalEditModifierData *enmd, Object *ob, Mesh *mesh,
+        NormalEditModifierData *enmd, const ModifierEvalContext *ctx,
+        Object *ob, Mesh *mesh,
         short (*clnors)[2], float (*loopnors)[3], float (*polynors)[3],
         const short mix_mode, const float mix_factor, const float mix_limit,
         MDeformVert *dvert, const int defgrp_index, const bool use_invert_vgroup,
         MVert *mvert, const int num_verts, MEdge *medge, const int num_edges,
         MLoop *mloop, const int num_loops, MPoly *mpoly, const int num_polys)
 {
+	Object *ob_target = DEG_get_evaluated_object(ctx->depsgraph, enmd->target);
+
 	const bool do_polynors_fix = (enmd->flag & MOD_NORMALEDIT_NO_POLYNORS_FIX) == 0;
 	const bool use_parallel_normals = (enmd->flag & MOD_NORMALEDIT_USE_DIRECTION_PARALLEL) != 0;
 
@@ -313,7 +321,7 @@ static void normalEditModifier_do_directional(
 	float mat[4][4];
 
 	invert_m4_m4(mat, ob->obmat);
-	mul_m4_m4m4(mat, mat, enmd->target->obmat);
+	mul_m4_m4m4(mat, mat, ob_target->obmat);
 	copy_v3_v3(target_co, mat[3]);
 
 	if (use_parallel_normals) {
@@ -328,7 +336,7 @@ static void normalEditModifier_do_directional(
 	}
 	else {
 		float (*cos)[3] = MEM_malloc_arrayN((size_t)num_verts, sizeof(*cos), __func__);
-		generate_vert_coordinates(mesh, ob, enmd->target, NULL, num_verts, cos, NULL);
+		generate_vert_coordinates(mesh, ob, ob_target, NULL, num_verts, cos, NULL);
 
 		BLI_bitmap *done_verts = BLI_BITMAP_NEW((size_t)num_verts, __func__);
 		MLoop *ml;
@@ -380,7 +388,8 @@ static bool is_valid_target(NormalEditModifierData *enmd)
 	return false;
 }
 
-static Mesh *normalEditModifier_do(NormalEditModifierData *enmd, Object *ob, Mesh *mesh)
+static Mesh *normalEditModifier_do(
+        NormalEditModifierData *enmd, const ModifierEvalContext *ctx, Object *ob, Mesh *mesh)
 {
 	const bool use_invert_vgroup = ((enmd->flag & MOD_NORMALEDIT_INVERT_VGROUP) != 0);
 	const bool use_current_clnors = !((enmd->mix_mode == MOD_NORMALEDIT_MIX_COPY) &&
@@ -474,13 +483,13 @@ static Mesh *normalEditModifier_do(NormalEditModifierData *enmd, Object *ob, Mes
 
 	if (enmd->mode == MOD_NORMALEDIT_MODE_RADIAL) {
 		normalEditModifier_do_radial(
-		            enmd, ob, result, clnors, loopnors, polynors,
+		            enmd, ctx, ob, result, clnors, loopnors, polynors,
 		            enmd->mix_mode, enmd->mix_factor, enmd->mix_limit, dvert, defgrp_index, use_invert_vgroup,
 		            mvert, num_verts, medge, num_edges, mloop, num_loops, mpoly, num_polys);
 	}
 	else if (enmd->mode == MOD_NORMALEDIT_MODE_DIRECTIONAL) {
 		normalEditModifier_do_directional(
-		            enmd, ob, result, clnors, loopnors, polynors,
+		            enmd, ctx, ob, result, clnors, loopnors, polynors,
 		            enmd->mix_mode, enmd->mix_factor, enmd->mix_limit, dvert, defgrp_index, use_invert_vgroup,
 		            mvert, num_verts, medge, num_edges, mloop, num_loops, mpoly, num_polys);
 	}
@@ -542,7 +551,7 @@ static void updateDepsgraph(ModifierData *md, const ModifierUpdateDepsgraphConte
 
 static Mesh *applyModifier(ModifierData *md, const ModifierEvalContext *ctx, Mesh *mesh)
 {
-	return normalEditModifier_do((NormalEditModifierData *)md, ctx->object, mesh);
+	return normalEditModifier_do((NormalEditModifierData *)md, ctx, ctx->object, mesh);
 }
 
 ModifierTypeInfo modifierType_NormalEdit = {