124 lines
2.7 KiB
C++
124 lines
2.7 KiB
C++
/*
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* Copyright 2011-2013 Blender Foundation
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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/* Parts adapted from code in the public domain in NVidia Mesh Tools. */
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#include "mesh.h"
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#include "subd_patch.h"
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#include "util_math.h"
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#include "util_types.h"
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CCL_NAMESPACE_BEGIN
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/* De Casteljau Evaluation */
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static void decasteljau_cubic(float3 *P, float3 *dt, float t, const float3 cp[4])
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{
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float3 d0 = cp[0] + t*(cp[1] - cp[0]);
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float3 d1 = cp[1] + t*(cp[2] - cp[1]);
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float3 d2 = cp[2] + t*(cp[3] - cp[2]);
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d0 += t*(d1 - d0);
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d1 += t*(d2 - d1);
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*P = d0 + t*(d1 - d0);
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if(dt) *dt = d1 - d0;
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}
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static void decasteljau_bicubic(float3 *P, float3 *du, float3 *dv, const float3 cp[16], float u, float v)
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{
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float3 ucp[4], utn[4];
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/* interpolate over u */
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decasteljau_cubic(ucp+0, utn+0, u, cp);
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decasteljau_cubic(ucp+1, utn+1, u, cp+4);
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decasteljau_cubic(ucp+2, utn+2, u, cp+8);
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decasteljau_cubic(ucp+3, utn+3, u, cp+12);
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/* interpolate over v */
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decasteljau_cubic(P, dv, v, ucp);
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if(du) decasteljau_cubic(du, NULL, v, utn);
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}
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/* Linear Quad Patch */
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void LinearQuadPatch::eval(float3 *P, float3 *dPdu, float3 *dPdv, float u, float v)
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{
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float3 d0 = interp(hull[0], hull[1], u);
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float3 d1 = interp(hull[2], hull[3], u);
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*P = interp(d0, d1, v);
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if(dPdu && dPdv) {
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*dPdu = interp(hull[1] - hull[0], hull[3] - hull[2], v);
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*dPdv = interp(hull[2] - hull[0], hull[3] - hull[1], u);
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}
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}
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BoundBox LinearQuadPatch::bound()
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{
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BoundBox bbox = BoundBox::empty;
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for(int i = 0; i < 4; i++)
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bbox.grow(hull[i]);
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return bbox;
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}
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/* Linear Triangle Patch */
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void LinearTrianglePatch::eval(float3 *P, float3 *dPdu, float3 *dPdv, float u, float v)
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{
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*P = u*hull[0] + v*hull[1] + (1.0f - u - v)*hull[2];
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if(dPdu && dPdv) {
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*dPdu = hull[0] - hull[2];
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*dPdv = hull[1] - hull[2];
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}
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}
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BoundBox LinearTrianglePatch::bound()
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{
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BoundBox bbox = BoundBox::empty;
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for(int i = 0; i < 3; i++)
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bbox.grow(hull[i]);
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return bbox;
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}
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/* Bicubic Patch */
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void BicubicPatch::eval(float3 *P, float3 *dPdu, float3 *dPdv, float u, float v)
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{
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decasteljau_bicubic(P, dPdu, dPdv, hull, u, v);
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}
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BoundBox BicubicPatch::bound()
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{
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BoundBox bbox = BoundBox::empty;
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for(int i = 0; i < 16; i++)
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bbox.grow(hull[i]);
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return bbox;
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}
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CCL_NAMESPACE_END
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