99 lines
4.0 KiB
C++
99 lines
4.0 KiB
C++
/*
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* Copyright (C) 2020 The Android Open Source Project
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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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#include <camutils/Bookmark.h>
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#include <camutils/Manipulator.h>
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#include <math/scalar.h>
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#include <math/vec3.h>
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using namespace filament::math;
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namespace filament {
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namespace camutils {
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template <typename FLOAT>
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Bookmark<FLOAT> Bookmark<FLOAT>::interpolate(Bookmark<FLOAT> a, Bookmark<FLOAT> b, double t) {
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Bookmark<FLOAT> result;
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using float3 = filament::math::vec3<FLOAT>;
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if (a.mode == Mode::MAP) {
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assert(b.mode == Mode::MAP);
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const double rho = sqrt(2.0);
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const double rho2 = 2, rho4 = 4;
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const double ux0 = a.map.center.x, uy0 = a.map.center.y, w0 = a.map.extent;
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const double ux1 = b.map.center.x, uy1 = b.map.center.y, w1 = b.map.extent;
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const double dx = ux1 - ux0, dy = uy1 - uy0, d2 = dx * dx + dy * dy, d1 = sqrt(d2);
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const double b0 = (w1 * w1 - w0 * w0 + rho4 * d2) / (2.0 * w0 * rho2 * d1);
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const double b1 = (w1 * w1 - w0 * w0 - rho4 * d2) / (2.0 * w1 * rho2 * d1);
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const double r0 = log(sqrt(b0 * b0 + 1.0) - b0);
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const double r1 = log(sqrt(b1 * b1 + 1) - b1);
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const double dr = r1 - r0;
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const int valid = !std::isnan(dr) && dr != 0;
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const double S = (valid ? dr : log(w1 / w0)) / rho;
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const double s = t * S;
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// This performs Van Wijk interpolation to animate between two waypoints on a map.
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if (valid) {
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const double coshr0 = cosh(r0);
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const double u = w0 / (rho2 * d1) * (coshr0 * tanh(rho * s + r0) - sinh(r0));
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Bookmark<FLOAT> result;
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result.map.center.x = ux0 + u * dx;
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result.map.center.y = uy0 + u * dy;
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result.map.extent = w0 * coshr0 / cosh(rho * s + r0);
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return result;
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}
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// For degenerate cases, fall back to a simplified interpolation method.
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result.map.center.x = ux0 + t * dx;
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result.map.center.y = uy0 + t * dy;
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result.map.extent = w0 * exp(rho * s);
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return result;
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}
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assert(b.mode == Mode::ORBIT);
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result.orbit.phi = lerp(a.orbit.phi, b.orbit.phi, FLOAT(t));
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result.orbit.theta = lerp(a.orbit.theta, b.orbit.theta, FLOAT(t));
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result.orbit.distance = lerp(a.orbit.distance, b.orbit.distance, FLOAT(t));
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result.orbit.pivot = lerp(a.orbit.pivot, b.orbit.pivot, float3(t));
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return result;
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}
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// Uses the Van Wijk method to suggest a duration for animating between two waypoints on a map.
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// This does not have units, so just use it as a multiplier.
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template <typename FLOAT>
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double Bookmark<FLOAT>::duration(Bookmark<FLOAT> a, Bookmark<FLOAT> b) {
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assert(a.mode == Mode::ORBIT && b.mode == Mode::ORBIT);
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const double rho = sqrt(2.0);
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const double rho2 = 2, rho4 = 4;
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const double ux0 = a.map.center.x, uy0 = a.map.center.y, w0 = a.map.extent;
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const double ux1 = b.map.center.x, uy1 = b.map.center.y, w1 = b.map.extent;
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const double dx = ux1 - ux0, dy = uy1 - uy0, d2 = dx * dx + dy * dy, d1 = sqrt(d2);
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const double b0 = (w1 * w1 - w0 * w0 + rho4 * d2) / (2.0 * w0 * rho2 * d1);
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const double b1 = (w1 * w1 - w0 * w0 - rho4 * d2) / (2.0 * w1 * rho2 * d1);
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const double r0 = log(sqrt(b0 * b0 + 1.0) - b0);
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const double r1 = log(sqrt(b1 * b1 + 1) - b1);
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const double dr = r1 - r0;
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const int valid = !std::isnan(dr) && dr != 0;
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const double S = (valid ? dr : log(w1 / w0)) / rho;
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return fabs(S);
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}
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template class Bookmark<float>;
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} // namespace camutils
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} // namespace filament
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