9cfc7967dd
* Replace license text in headers with SPDX identifiers. * Remove specific license info from outdated readme.txt, instead leave details to the source files. * Add list of SPDX license identifiers used, and corresponding license texts. * Update copyright dates while we're at it. Ref D14069, T95597
109 lines
2.3 KiB
C++
109 lines
2.3 KiB
C++
/* SPDX-License-Identifier: Apache-2.0
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* Copyright 2011-2022 Blender Foundation */
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/* Parts adapted from code in the public domain in NVidia Mesh Tools. */
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#include "scene/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)
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*dt = d1 - d0;
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}
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static void decasteljau_bicubic(
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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)
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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, float3 *N, 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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if (N) {
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*N = normalize(
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interp(interp(normals[0], normals[1], u), interp(normals[2], normals[3], u), v));
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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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/* Bicubic Patch */
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void BicubicPatch::eval(float3 *P, float3 *dPdu, float3 *dPdv, float3 *N, float u, float v)
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{
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if (N) {
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float3 dPdu_, dPdv_;
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decasteljau_bicubic(P, &dPdu_, &dPdv_, hull, u, v);
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if (dPdu && dPdv) {
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*dPdu = dPdu_;
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*dPdv = dPdv_;
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}
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*N = normalize(cross(dPdu_, dPdv_));
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}
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else {
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decasteljau_bicubic(P, dPdu, dPdv, hull, u, v);
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}
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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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