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, 9 insertions, 5 deletions

diff --git a/source/blender/modifiers/intern/MOD_uvproject.c b/source/blender/modifiers/intern/MOD_uvproject.c
index 8c9fbefa27a..0da96ba1a38 100644
--- a/source/blender/modifiers/intern/MOD_uvproject.c
+++ b/source/blender/modifiers/intern/MOD_uvproject.c
@@ -125,6 +125,7 @@ typedef struct Projector {
 
 static Mesh *uvprojectModifier_do(
         UVProjectModifierData *umd,
+        const ModifierEvalContext *ctx,
         Object *ob, Mesh *mesh)
 {
 	float (*coords)[3], (*co)[3];
@@ -141,11 +142,14 @@ static Mesh *uvprojectModifier_do(
 	float scay = umd->scaley ? umd->scaley : 1.0f;
 	int free_uci = 0;
 
-	for (i = 0; i < umd->num_projectors; ++i)
-		if (umd->projectors[i])
-			projectors[num_projectors++].ob = umd->projectors[i];
+	for (i = 0; i < umd->num_projectors; ++i) {
+		if (umd->projectors[i] != NULL) {
+			projectors[num_projectors++].ob = DEG_get_evaluated_object(ctx->depsgraph, umd->projectors[i]);
+		}
+	}
 
-	if (num_projectors == 0) return mesh;
+	if (num_projectors == 0)
+		return mesh;
 
 	/* make sure there are UV Maps available */
 
@@ -317,7 +321,7 @@ static Mesh *applyModifier(
 	Mesh *result;
 	UVProjectModifierData *umd = (UVProjectModifierData *) md;
 
-	result = uvprojectModifier_do(umd, ctx->object, mesh);
+	result = uvprojectModifier_do(umd, ctx, ctx->object, mesh);
 
 	return result;
 }