Add Custom Loop Normals to Data Transfer.

Titles says everything, just two notes:
* We have to actually transfer plain *normals*, not 'compressed' clnors,
  so had to add pre/post process to transfer to make the conversions.
* Also added interpolation and advanced copy/mixing to CD_NORMAL, for same reasons.

1 files changed, 45 insertions, 1 deletions

diff --git a/source/blender/blenkernel/intern/customdata.c b/source/blender/blenkernel/intern/customdata.c
index 0c437f6e02f..0436ec0ef22 100644
--- a/source/blender/blenkernel/intern/customdata.c
+++ b/source/blender/blenkernel/intern/customdata.c
@@ -300,6 +300,49 @@ static void layerInterp_mdeformvert(void **sources, const float *weights,
 	}
 }
 
+static void layerInterp_normal(void **sources, const float *weights,
+                               const float *UNUSED(sub_weights), int count, void *dest)
+{
+	float no[3] = {0.0f};
+
+	while (count--) {
+		madd_v3_v3fl(no, (float *)sources[count], weights[count]);
+	}
+
+	copy_v3_v3((float *)dest, no);
+}
+
+static void layerCopyValue_normal(const void *source, void *dest, const int mixmode, const float mixfactor)
+{
+	const float *no_src = source;
+	float *no_dst = dest;
+	float no_tmp[3];
+
+	if (ELEM(mixmode, CDT_MIX_NOMIX, CDT_MIX_REPLACE_ABOVE_THRESHOLD, CDT_MIX_REPLACE_BELOW_THRESHOLD)) {
+		/* Above/below threshold modes are not supported here, fallback to nomix (just in case). */
+		copy_v3_v3(no_dst, no_src);
+	}
+	else {  /* Modes that support 'real' mix factor. */
+		/* Since we normalize in the end, MIX and ADD are the same op here. */
+		if (ELEM(mixmode, CDT_MIX_MIX, CDT_MIX_ADD)) {
+			add_v3_v3v3(no_tmp, no_dst, no_src);
+			normalize_v3(no_tmp);
+		}
+		else if (mixmode == CDT_MIX_SUB) {
+			sub_v3_v3v3(no_tmp, no_dst, no_src);
+			normalize_v3(no_tmp);
+		}
+		else if (mixmode == CDT_MIX_MUL) {
+			mul_v3_v3v3(no_tmp, no_dst, no_src);
+			normalize_v3(no_tmp);
+		}
+		else {
+			copy_v3_v3(no_tmp, no_src);
+		}
+		interp_v3_v3v3_slerp_safe(no_dst, no_dst, no_tmp, mixfactor);
+	}
+}
+
 static void layerCopy_tface(const void *source, void *dest, int count)
 {
 	const MTFace *source_tf = (const MTFace *)source;
@@ -1165,7 +1208,8 @@ static const LayerTypeInfo LAYERTYPEINFO[CD_NUMTYPES] = {
 	{sizeof(int), "", 0, NULL, NULL, NULL, NULL, NULL, layerDefault_origindex},
 	/* 8: CD_NORMAL */
 	/* 3 floats per normal vector */
-	{sizeof(float) * 3, "vec3f", 1, NULL, NULL, NULL, NULL, NULL, NULL},
+	{sizeof(float) * 3, "vec3f", 1, NULL, NULL, NULL, layerInterp_normal, NULL, NULL,
+	 NULL, NULL, NULL, NULL, NULL, layerCopyValue_normal},
 	/* 9: CD_POLYINDEX (deprecated) */
 	{sizeof(int), "", 0, NULL, NULL, NULL, NULL, NULL, NULL},
 	/* 10: CD_PROP_FLT */