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Diffstat (limited to 'intern/cycles/subd/patch.cpp')
-rw-r--r-- | intern/cycles/subd/patch.cpp | 121 |
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 |