68 lines
1.7 KiB
C++
68 lines
1.7 KiB
C++
/* SPDX-FileCopyrightText: 2011-2022 Blender Foundation
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*
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* SPDX-License-Identifier: Apache-2.0 */
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#include "scene/curves.h"
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#include "device/device.h"
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#include "scene/mesh.h"
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#include "scene/object.h"
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#include "scene/scene.h"
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#include "util/foreach.h"
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#include "util/map.h"
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#include "util/progress.h"
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#include "util/vector.h"
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CCL_NAMESPACE_BEGIN
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/* Curve functions */
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void curvebounds(float *lower, float *upper, float3 *p, int dim)
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{
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float *p0 = &p[0].x;
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float *p1 = &p[1].x;
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float *p2 = &p[2].x;
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float *p3 = &p[3].x;
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/* Catmull-Rom weights. */
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float curve_coef[4];
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curve_coef[0] = p1[dim];
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curve_coef[1] = 0.5f * (-p0[dim] + p2[dim]);
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curve_coef[2] = 0.5f * (2 * p0[dim] - 5 * p1[dim] + 4 * p2[dim] - p3[dim]);
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curve_coef[3] = 0.5f * (-p0[dim] + 3 * p1[dim] - 3 * p2[dim] + p3[dim]);
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float discroot = curve_coef[2] * curve_coef[2] - 3 * curve_coef[3] * curve_coef[1];
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float ta = -1.0f;
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float tb = -1.0f;
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if (discroot >= 0 && curve_coef[3] != 0.0f) {
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discroot = sqrtf(discroot);
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ta = (-curve_coef[2] - discroot) / (3 * curve_coef[3]);
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tb = (-curve_coef[2] + discroot) / (3 * curve_coef[3]);
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ta = (ta > 1.0f || ta < 0.0f) ? -1.0f : ta;
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tb = (tb > 1.0f || tb < 0.0f) ? -1.0f : tb;
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}
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*upper = max(p1[dim], p2[dim]);
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*lower = min(p1[dim], p2[dim]);
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float exa = p1[dim];
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float exb = p2[dim];
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if (ta >= 0.0f) {
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float t2 = ta * ta;
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float t3 = t2 * ta;
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exa = curve_coef[3] * t3 + curve_coef[2] * t2 + curve_coef[1] * ta + curve_coef[0];
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}
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if (tb >= 0.0f) {
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float t2 = tb * tb;
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float t3 = t2 * tb;
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exb = curve_coef[3] * t3 + curve_coef[2] * t2 + curve_coef[1] * tb + curve_coef[0];
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}
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*upper = max(*upper, max(exa, exb));
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*lower = min(*lower, min(exa, exb));
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}
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CCL_NAMESPACE_END
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