1 files changed, 121 insertions, 0 deletions
diff --git a/intern/cycles/subd/patch.cpp b/intern/cycles/subd/patch.cpp
new file mode 100644
index 00000000000..4d73f334c1b
--- /dev/null
+++ b/intern/cycles/subd/patch.cpp
@@ -0,0 +1,121 @@
+/*
+ * Copyright 2011-2013 Blender Foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/* Parts adapted from code in the public domain in NVidia Mesh Tools. */
+
+#include "scene/mesh.h"
+
+#include "subd/patch.h"
+
+#include "util/math.h"
+#include "util/types.h"
+
+CCL_NAMESPACE_BEGIN
+
+/* De Casteljau Evaluation */
+
+static void decasteljau_cubic(float3 *P, float3 *dt, float t, const float3 cp[4])
+{
+  float3 d0 = cp[0] + t * (cp[1] - cp[0]);
+  float3 d1 = cp[1] + t * (cp[2] - cp[1]);
+  float3 d2 = cp[2] + t * (cp[3] - cp[2]);
+
+  d0 += t * (d1 - d0);
+  d1 += t * (d2 - d1);
+
+  *P = d0 + t * (d1 - d0);
+  if (dt)
+    *dt = d1 - d0;
+}
+
+static void decasteljau_bicubic(
+    float3 *P, float3 *du, float3 *dv, const float3 cp[16], float u, float v)
+{
+  float3 ucp[4], utn[4];
+
+  /* interpolate over u */
+  decasteljau_cubic(ucp + 0, utn + 0, u, cp);
+  decasteljau_cubic(ucp + 1, utn + 1, u, cp + 4);
+  decasteljau_cubic(ucp + 2, utn + 2, u, cp + 8);
+  decasteljau_cubic(ucp + 3, utn + 3, u, cp + 12);
+
+  /* interpolate over v */
+  decasteljau_cubic(P, dv, v, ucp);
+  if (du)
+    decasteljau_cubic(du, NULL, v, utn);
+}
+
+/* Linear Quad Patch */
+
+void LinearQuadPatch::eval(float3 *P, float3 *dPdu, float3 *dPdv, float3 *N, float u, float v)
+{
+  float3 d0 = interp(hull[0], hull[1], u);
+  float3 d1 = interp(hull[2], hull[3], u);
+
+  *P = interp(d0, d1, v);
+
+  if (dPdu && dPdv) {
+    *dPdu = interp(hull[1] - hull[0], hull[3] - hull[2], v);
+    *dPdv = interp(hull[2] - hull[0], hull[3] - hull[1], u);
+  }
+
+  if (N) {
+    *N = normalize(
+        interp(interp(normals[0], normals[1], u), interp(normals[2], normals[3], u), v));
+  }
+}
+
+BoundBox LinearQuadPatch::bound()
+{
+  BoundBox bbox = BoundBox::empty;
+
+  for (int i = 0; i < 4; i++)
+    bbox.grow(hull[i]);
+
+  return bbox;
+}
+
+/* Bicubic Patch */
+
+void BicubicPatch::eval(float3 *P, float3 *dPdu, float3 *dPdv, float3 *N, float u, float v)
+{
+  if (N) {
+    float3 dPdu_, dPdv_;
+    decasteljau_bicubic(P, &dPdu_, &dPdv_, hull, u, v);
+
+    if (dPdu && dPdv) {
+      *dPdu = dPdu_;
+      *dPdv = dPdv_;
+    }
+
+    *N = normalize(cross(dPdu_, dPdv_));
+  }
+  else {
+    decasteljau_bicubic(P, dPdu, dPdv, hull, u, v);
+  }
+}
+
+BoundBox BicubicPatch::bound()
+{
+  BoundBox bbox = BoundBox::empty;
+
+  for (int i = 0; i < 16; i++)
+    bbox.grow(hull[i]);
+
+  return bbox;
+}
+
+CCL_NAMESPACE_END