Add Chromium-only Blender WebEngine parity work

blender-5.2.0/intern/cycles/subd/patch.cpp

@@ -0,0 +1,119 @@
+/* SPDX-FileCopyrightText: 2011-2022 Blender Foundation
+ *
+ * SPDX-License-Identifier: Apache-2.0 */
+
+/* Parts adapted from code in the public domain in NVidia Mesh Tools. */
+
+#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, const float t, const float3 cp[4])
+{
+  float3 d0 = cp[0] + t * (cp[1] - cp[0]);
+  float3 d1 = cp[1] + t * (cp[2] - cp[1]);
+  const 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, const float v)
+{
+  float3 ucp[4];
+  float3 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, nullptr, v, utn);
+  }
+}
+
+/* Linear Quad Patch */
+
+void LinearQuadPatch::eval(
+    float3 *P, float3 *dPdu, float3 *dPdv, float3 *N, const float u, float v) const
+{
+  const float3 d0 = interp(hull[0], hull[1], u);
+  const float3 d1 = interp(hull[2], hull[3], u);
+
+  *P = interp(d0, d1, v);
+
+  if (N || (dPdu && dPdv)) {
+    const float3 dPdu_ = interp(hull[1] - hull[0], hull[3] - hull[2], v);
+    const float3 dPdv_ = interp(hull[2] - hull[0], hull[3] - hull[1], u);
+
+    if (dPdu && dPdv) {
+      *dPdu = dPdu_;
+      *dPdv = dPdv_;
+    }
+
+    if (N) {
+      *N = normalize(cross(dPdu_, dPdv_));
+    }
+  }
+}
+
+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, const float u, const float v) const
+{
+  if (N) {
+    float3 dPdu_;
+    float3 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