Fix T37486: Displacement bake from multires crashes when preview level is on 0

Revert "Code cleanup: remove unused block from multire baker"

This reverts commit 63b01f6beee8eced14ff013ca93732f5c176ad10.

Multires displacement baker in fact uses level 0 for the
original subdivided mesh. Missed this when was making an
original commit.

1 files changed, 19 insertions, 16 deletions

diff --git a/source/blender/render/intern/source/multires_bake.c b/source/blender/render/intern/source/multires_bake.c
index a920306732d..3ae075b4936 100644
--- a/source/blender/render/intern/source/multires_bake.c
+++ b/source/blender/render/intern/source/multires_bake.c
@@ -611,9 +611,6 @@ static void get_ccgdm_data(DerivedMesh *lodm, DerivedMesh *hidm,
 	float crn_x, crn_y;
 	int grid_size, S, face_side;
 	int *grid_offset, g_index;
-	int side, grid_index, loc_offs, cell_index, cell_side, row, col;
-
-	BLI_assert(lvl > 0);
 
 	lodm->getTessFace(lodm, face_index, &mface);
 
@@ -624,19 +621,25 @@ static void get_ccgdm_data(DerivedMesh *lodm, DerivedMesh *hidm,
 
 	face_side = (grid_size << 1) - 1;
 
-	side = (1 << (lvl - 1)) + 1;
-	grid_index = DM_origindex_mface_mpoly(index_mf_to_mpoly, index_mp_to_orig, face_index);
-	loc_offs = face_index % (1 << (2 * lvl));
-	cell_index = loc_offs % ((side - 1) * (side - 1));
-	cell_side = (grid_size - 1) / (side - 1);
-	row = cell_index / (side - 1);
-	col = cell_index % (side - 1);
-
-	S = face_index / (1 << (2 * (lvl - 1))) - grid_offset[grid_index];
-	g_index = grid_offset[grid_index];
-
-	crn_y = (row * cell_side) + u * cell_side;
-	crn_x = (col * cell_side) + v * cell_side;
+	if (lvl == 0) {
+		g_index = grid_offset[face_index];
+		S = mdisp_rot_face_to_crn(mface.v4 ? 4 : 3, face_side, u * (face_side - 1), v * (face_side - 1), &crn_x, &crn_y);
+	}
+	else {
+		int side = (1 << (lvl - 1)) + 1;
+		int grid_index = DM_origindex_mface_mpoly(index_mf_to_mpoly, index_mp_to_orig, face_index);
+		int loc_offs = face_index % (1 << (2 * lvl));
+		int cell_index = loc_offs % ((side - 1) * (side - 1));
+		int cell_side = (grid_size - 1) / (side - 1);
+		int row = cell_index / (side - 1);
+		int col = cell_index % (side - 1);
+
+		S = face_index / (1 << (2 * (lvl - 1))) - grid_offset[grid_index];
+		g_index = grid_offset[grid_index];
+
+		crn_y = (row * cell_side) + u * cell_side;
+		crn_x = (col * cell_side) + v * cell_side;
+	}
 
 	CLAMP(crn_x, 0.0f, grid_size);
 	CLAMP(crn_y, 0.0f, grid_size);