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