1 files changed, 33 insertions, 20 deletions

diff --git a/intern/cycles/subd/subd_dice.cpp b/intern/cycles/subd/subd_dice.cpp
index 44bab066dde..a5dfcd21ceb 100644
--- a/intern/cycles/subd/subd_dice.cpp
+++ b/intern/cycles/subd/subd_dice.cpp
@@ -58,10 +58,9 @@ void EdgeDice::reserve(int num_verts, int num_tris)
 
 int EdgeDice::add_vert(Patch *patch, float2 uv)
 {
-	float3 P, N, dPdu, dPdv;
+	float3 P, N;
 
-	patch->eval(&P, &dPdu, &dPdv, uv.x, uv.y);
-	N = normalize(cross(dPdu, dPdv));
+	patch->eval(&P, NULL, NULL, &N, uv.x, uv.y);
 
 	assert(vert_offset < params.mesh->verts.size());
 
@@ -81,7 +80,7 @@ int EdgeDice::add_vert(Patch *patch, float2 uv)
 
 void EdgeDice::add_triangle(Patch *patch, int v0, int v1, int v2)
 {
-	params.mesh->add_triangle(v0, v1, v2, params.shader, params.smooth);
+	params.mesh->add_triangle(v0, v1, v2, params.shader, params.smooth, false);
 
 	if(params.ptex) {
 		Attribute *attr_ptex_face_id = params.mesh->attributes.add(ATTR_STD_PTEX_FACE_ID);
@@ -159,7 +158,7 @@ float3 QuadDice::eval_projected(SubPatch& sub, float u, float v)
 	float2 uv = map_uv(sub, u, v);
 	float3 P;
 
-	sub.patch->eval(&P, NULL, NULL, uv.x, uv.y);
+	sub.patch->eval(&P, NULL, NULL, NULL, uv.x, uv.y);
 	if(params.camera)
 		P = transform_perspective(&params.camera->worldtoraster, P);
 
@@ -260,17 +259,10 @@ float QuadDice::scale_factor(SubPatch& sub, EdgeFactors& ef, int Mu, int Mv)
 void QuadDice::add_corners(SubPatch& sub)
 {
 	/* add verts for patch corners */
-	if(sub.patch->is_triangle()) {
-		add_vert(sub, 0.0f, 0.0f);
-		add_vert(sub, 1.0f, 0.0f);
-		add_vert(sub, 0.0f, 1.0f);
-	}
-	else {
-		add_vert(sub, 0.0f, 0.0f);
-		add_vert(sub, 1.0f, 0.0f);
-		add_vert(sub, 0.0f, 1.0f);
-		add_vert(sub, 1.0f, 1.0f);
-	}
+	add_vert(sub, 0.0f, 0.0f);
+	add_vert(sub, 1.0f, 0.0f);
+	add_vert(sub, 0.0f, 1.0f);
+	add_vert(sub, 1.0f, 1.0f);
 }
 
 void QuadDice::add_grid(SubPatch& sub, int Mu, int Mv, int offset)
@@ -305,7 +297,12 @@ void QuadDice::dice(SubPatch& sub, EdgeFactors& ef)
 	int Mu = max(ef.tu0, ef.tu1);
 	int Mv = max(ef.tv0, ef.tv1);
 
+#if 0 /* Doesnt work very well, especially at grazing angles. */
 	float S = scale_factor(sub, ef, Mu, Mv);
+#else
+	float S = 1.0f;
+#endif
+
 	Mu = max((int)ceil(S*Mu), 2); // XXX handle 0 & 1?
 	Mv = max((int)ceil(S*Mv), 2); // XXX handle 0 & 1?
 
@@ -454,15 +451,21 @@ void TriangleDice::add_grid(SubPatch& sub, EdgeFactors& ef, int M)
 		add_triangle(sub.patch, outer_w[0], outer_u[0], outer_v[0]);
 	}
 	else {
-		/* center vertex + 6 triangles */
+		/* center vertex + up to 6 triangles */
 		int center = add_vert(sub, make_float2(1.0f/3.0f, 1.0f/3.0f));
 
 		add_triangle(sub.patch, outer_w[0], outer_w[1], center);
-		add_triangle(sub.patch, outer_w[1], outer_w[2], center);
+		/* if this is false then there is only one triangle on this side */
+		if(outer_w.size() > 2)
+			add_triangle(sub.patch, outer_w[1], outer_w[2], center);
+
 		add_triangle(sub.patch, outer_u[0], outer_u[1], center);
-		add_triangle(sub.patch, outer_u[1], outer_u[2], center);
+		if(outer_u.size() > 2)
+			add_triangle(sub.patch, outer_u[1], outer_u[2], center);
+
 		add_triangle(sub.patch, outer_v[0], outer_v[1], center);
-		add_triangle(sub.patch, outer_v[1], outer_v[2], center);
+		if(outer_v.size() > 2)
+			add_triangle(sub.patch, outer_v[1], outer_v[2], center);
 	}
 }
 
@@ -471,6 +474,16 @@ void TriangleDice::dice(SubPatch& sub, EdgeFactors& ef)
 	/* todo: handle 2 1 1 resolution */
 	int M = max(ef.tu, max(ef.tv, ef.tw));
 
+	/* Due to the "slant" of the edges of a triangle compared to a quad, the internal
+	 * triangles end up smaller, causing over-tessellation. This is to correct for this
+	 * difference in area. Technically its only correct for equilateral triangles, but
+	 * its better than how it was.
+	 *
+	 * (2*cos(radians(30))/3)**0.5
+	 */
+	float S = 0.7598356856515927f;
+	M = max((int)ceil(S*M), 1);
+
 	reserve(ef, M);
 	add_grid(sub, ef, M);