New option for taking account of face smoothness in view map calculation.

With this option disabled, the smoothness of faces is ignored and
jagged feature edges (when seen from a three-dimensional viewpoint)
are generated.  If the new option is enabled, face smoothness is taken
into account during the view map calculation, resulting in smooth
feature edges in 3D.  This generally leads to more stable strokes, and
also permits more stylization possibilities relying on the feature
edge smoothness in 3D.  The downside of smooth feature edges is that
the visibility is mathematically not well-defined and may cause some
artefact in rendering results.  The new option is thus intended to
allow users to try both jagged and smooth feature edges and see which
ones would fit individual application needs.  This option is disabled
by default.

4 files changed, 60 insertions, 30 deletions

diff --git a/source/blender/freestyle/intern/blender_interface/BlenderFileLoader.cpp b/source/blender/freestyle/intern/blender_interface/BlenderFileLoader.cpp
index 3bf6ceb70f8..e146a8673ef 100644
--- a/source/blender/freestyle/intern/blender_interface/BlenderFileLoader.cpp
+++ b/source/blender/freestyle/intern/blender_interface/BlenderFileLoader.cpp
@@ -9,6 +9,7 @@ BlenderFileLoader::BlenderFileLoader(Render *re, SceneRenderLayer* srl)
 	_Scene = NULL;
 	_numFacesRead = 0;
 	_minEdgeSize = DBL_MAX;
+	_smooth = (srl->freestyleConfig.flags & FREESTYLE_FACE_SMOOTHNESS_FLAG) != 0;
 }
 
 BlenderFileLoader::~BlenderFileLoader()
@@ -123,38 +124,49 @@ void BlenderFileLoader::clipLine(float v1[3], float v2[3], float c[3], float z)
 // clip the triangle (V1, V2, V3) by the near and far clipping plane and
 // obtain a set of vertices after the clipping.  The number of vertices
 // is at most 5.
-void BlenderFileLoader::clipTriangle(int numTris, float triCoords[][3], float v1[3], float v2[3], float v3[3], int clip[3])
+void BlenderFileLoader::clipTriangle(int numTris, float triCoords[][3], float v1[3], float v2[3], float v3[3],
+									 float triNormals[][3], float n1[3], float n2[3], float n3[3], int clip[3])
 {
-	float *v[3];
+	float *v[3], *n[3];
 	int i, j, k;
 
-	v[0] = v1;
-	v[1] = v2;
-	v[2] = v3;
+	v[0] = v1; n[0] = n1;
+	v[1] = v2; n[1] = n2;
+	v[2] = v3; n[2] = n3;
 	k = 0;
 	for (i = 0; i < 3; i++) {
 		j = (i + 1) % 3;
 		if (clip[i] == NOT_CLIPPED) {
-			copy_v3_v3(triCoords[k++], v[i]);
+			copy_v3_v3(triCoords[k], v[i]);
+			copy_v3_v3(triNormals[k], n[i]);
+			k++;
 			if (clip[j] != NOT_CLIPPED) {
-				clipLine(v[i], v[j], triCoords[k++], (clip[j] == CLIPPED_BY_NEAR) ? _z_near : _z_far);
+				clipLine(v[i], v[j], triCoords[k], (clip[j] == CLIPPED_BY_NEAR) ? _z_near : _z_far);
+				copy_v3_v3(triNormals[k], n[j]);
+				k++;
 			}
 		} else if (clip[i] != clip[j]) {
 			if (clip[j] == NOT_CLIPPED) {
-				clipLine(v[i], v[j], triCoords[k++], (clip[i] == CLIPPED_BY_NEAR) ? _z_near : _z_far);
+				clipLine(v[i], v[j], triCoords[k], (clip[i] == CLIPPED_BY_NEAR) ? _z_near : _z_far);
+				copy_v3_v3(triNormals[k], n[i]);
+				k++;
 			} else {
-				clipLine(v[i], v[j], triCoords[k++], (clip[i] == CLIPPED_BY_NEAR) ? _z_near : _z_far);
-				clipLine(v[i], v[j], triCoords[k++], (clip[j] == CLIPPED_BY_NEAR) ? _z_near : _z_far);
+				clipLine(v[i], v[j], triCoords[k], (clip[i] == CLIPPED_BY_NEAR) ? _z_near : _z_far);
+				copy_v3_v3(triNormals[k], n[i]);
+				k++;
+				clipLine(v[i], v[j], triCoords[k], (clip[j] == CLIPPED_BY_NEAR) ? _z_near : _z_far);
+				copy_v3_v3(triNormals[k], n[j]);
+				k++;
 			}
 		}
 	}
 	assert (k == 2 + numTris);
 }
 
-void BlenderFileLoader::addTriangle(struct LoaderState *ls, float v1[3], float v2[3], float v3[3])
+void BlenderFileLoader::addTriangle(struct LoaderState *ls, float v1[3], float v2[3], float v3[3],
+									float n1[3], float n2[3], float n3[3])
 {
-	float v12[3], v13[3], n[3];
-	float *fv[3], len;
+	float *fv[3], *fn[3], len;
 	unsigned i, j;
 
 	// initialize the bounding box by the first vertex
@@ -163,19 +175,13 @@ void BlenderFileLoader::addTriangle(struct LoaderState *ls, float v1[3], float v
 		copy_v3_v3(ls->maxBBox, v1);
 	}
 
-	// compute the normal of the triangle
-	sub_v3_v3v3(v12, v1, v2);
-	sub_v3_v3v3(v13, v1, v3);
-	cross_v3_v3v3(n, v12, v13);
-	normalize_v3(n);
-
-	fv[0] = v1;
-	fv[1] = v2;
-	fv[2] = v3;
+	fv[0] = v1; fn[0] = n1;
+	fv[1] = v2; fn[1] = n2;
+	fv[2] = v3; fn[2] = n3;
 	for (i = 0; i < 3; i++) {
 
 		copy_v3_v3(ls->pv, fv[i]);
-		copy_v3_v3(ls->pn, n);
+		copy_v3_v3(ls->pn, fn[i]);
 
 		// update the bounding box
 		for (j = 0; j < 3; j++)
@@ -215,6 +221,7 @@ void BlenderFileLoader::insertShapeNode(ObjectInstanceRen *obi, int id)
 	VlakRen *vlr;
 	unsigned numFaces = 0;
 	float v1[3], v2[3], v3[3], v4[3];
+	float n1[3], n2[3], n3[3], n4[3], facenormal[3];
 	int clip_1[3], clip_2[3];
 	int wire_material = 0;
 	for(int a=0; a < obr->totvlak; a++) {
@@ -302,6 +309,18 @@ void BlenderFileLoader::insertShapeNode(ObjectInstanceRen *obi, int id)
 				mul_m4_v3(obi->mat, v3);
 				if (vlr->v4) mul_m4_v3(obi->mat, v4);
 			}
+			if (_smooth && (vlr->flag & R_SMOOTH)) {
+				copy_v3_v3(n1, vlr->v1->n);
+				copy_v3_v3(n2, vlr->v2->n);
+				copy_v3_v3(n3, vlr->v3->n);
+				if (vlr->v4) copy_v3_v3(n4, vlr->v4->n);
+			} else {
+				RE_vlakren_get_normal(_re, obi, vlr, facenormal);
+				copy_v3_v3(n1, facenormal);
+				copy_v3_v3(n2, facenormal);
+				copy_v3_v3(n3, facenormal);
+				if (vlr->v4) copy_v3_v3(n4, facenormal);
+			}
 
 			unsigned numTris_1, numTris_2;
 			numTris_1 = countClippedFaces(v1, v2, v3, clip_1);
@@ -347,20 +366,22 @@ void BlenderFileLoader::insertShapeNode(ObjectInstanceRen *obi, int id)
 		    	}
 	  		}
 
-			float triCoords[5][3];
+			float triCoords[5][3], triNormals[5][3];
 
 			if (numTris_1 > 0) {
-				clipTriangle(numTris_1, triCoords, v1, v2, v3, clip_1);
+				clipTriangle(numTris_1, triCoords, v1, v2, v3, triNormals, n1, n2, n3, clip_1);
 				for (i = 0; i < numTris_1; i++) {
-					addTriangle(&ls, triCoords[0], triCoords[i+1], triCoords[i+2]);
+					addTriangle(&ls, triCoords[0], triCoords[i+1], triCoords[i+2],
+						triNormals[0], triNormals[i+1], triNormals[i+2]);
 					_numFacesRead++;
 				}
 			}
 
 			if (numTris_2 > 0) {
-				clipTriangle(numTris_2, triCoords, v1, v3, v4, clip_2);
+				clipTriangle(numTris_2, triCoords, v1, v3, v4, triNormals, n1, n3, n4, clip_2);
 				for (i = 0; i < numTris_2; i++) {
-					addTriangle(&ls, triCoords[0], triCoords[i+1], triCoords[i+2]);
+					addTriangle(&ls, triCoords[0], triCoords[i+1], triCoords[i+2],
+						triNormals[0], triNormals[i+1], triNormals[i+2]);
 					_numFacesRead++;
 				}
 			}
diff --git a/source/blender/freestyle/intern/blender_interface/BlenderFileLoader.h b/source/blender/freestyle/intern/blender_interface/BlenderFileLoader.h
index 038f4bdd6c8..adf3e4eb7b1 100644
--- a/source/blender/freestyle/intern/blender_interface/BlenderFileLoader.h
+++ b/source/blender/freestyle/intern/blender_interface/BlenderFileLoader.h
@@ -65,8 +65,10 @@ protected:
 	void insertShapeNode(ObjectInstanceRen *obi, int id);
 	int countClippedFaces(float v1[3], float v2[3], float v3[3], int clip[3]);
 	void clipLine(float v1[3], float v2[3], float c[3], float z);
-	void clipTriangle(int numTris, float triCoords[][3], float v1[3], float v2[3], float v3[3], int clip[3]);
-	void addTriangle(struct LoaderState *ls, float v1[3], float v2[3], float v3[3]);
+	void clipTriangle(int numTris, float triCoords[][3], float v1[3], float v2[3], float v3[3],
+		float triNormals[][3], float n1[3], float n2[3], float n3[3], int clip[3]);
+	void addTriangle(struct LoaderState *ls, float v1[3], float v2[3], float v3[3],
+		float n1[3], float n2[3], float n3[3]);
 
 protected:
 	Render* _re;
@@ -74,6 +76,7 @@ protected:
 	NodeGroup* _Scene;
 	unsigned _numFacesRead;
 	real _minEdgeSize;
+	bool _smooth; /* if true, face smoothness is taken into account */
 	float _viewplane_left;
 	float _viewplane_right;
 	float _viewplane_bottom;
diff --git a/source/blender/makesdna/DNA_freestyle_types.h b/source/blender/makesdna/DNA_freestyle_types.h
index 08980afec89..391bf825eb3 100644
--- a/source/blender/makesdna/DNA_freestyle_types.h
+++ b/source/blender/makesdna/DNA_freestyle_types.h
@@ -39,6 +39,7 @@ struct FreestyleLineStyle;
 #define FREESTYLE_SUGGESTIVE_CONTOURS_FLAG  1
 #define FREESTYLE_RIDGES_AND_VALLEYS_FLAG   2
 #define FREESTYLE_MATERIAL_BOUNDARIES_FLAG  4
+#define FREESTYLE_FACE_SMOOTHNESS_FLAG      8
 
 /* FreestyleConfig::mode */
 #define FREESTYLE_CONTROL_SCRIPT_MODE  1
diff --git a/source/blender/makesrna/intern/rna_scene.c b/source/blender/makesrna/intern/rna_scene.c
index c21e7bfdfce..b12e8552ef6 100644
--- a/source/blender/makesrna/intern/rna_scene.c
+++ b/source/blender/makesrna/intern/rna_scene.c
@@ -1827,6 +1827,11 @@ static void rna_def_freestyle_settings(BlenderRNA *brna)
 	RNA_def_property_ui_text(prop, "Material Boundaries", "Enable material boundaries.");
 	RNA_def_property_update(prop, NC_SCENE, NULL);
 
+	prop= RNA_def_property(srna, "use_smoothness", PROP_BOOLEAN, PROP_NONE);
+	RNA_def_property_boolean_sdna(prop, NULL, "flags", FREESTYLE_FACE_SMOOTHNESS_FLAG);
+	RNA_def_property_ui_text(prop, "Face Smoothness", "Take face smoothness into account in view map calculation.");
+	RNA_def_property_update(prop, NC_SCENE, NULL);
+
 	prop= RNA_def_property(srna, "sphere_radius", PROP_FLOAT, PROP_NONE);
 	RNA_def_property_float_sdna(prop, NULL, "sphere_radius");
 	RNA_def_property_range(prop, 0.0, 1000.0);