77 lines
3.6 KiB
C++
77 lines
3.6 KiB
C++
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/**************************************************************************/
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/* transform_interpolator.cpp */
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/**************************************************************************/
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/* This file is part of: */
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/* GODOT ENGINE */
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/* https://godotengine.org */
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/**************************************************************************/
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/* Copyright (c) 2014-present Godot Engine contributors (see AUTHORS.md). */
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/* Copyright (c) 2007-2014 Juan Linietsky, Ariel Manzur. */
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/* */
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/* Permission is hereby granted, free of charge, to any person obtaining */
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/* a copy of this software and associated documentation files (the */
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/* "Software"), to deal in the Software without restriction, including */
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/* without limitation the rights to use, copy, modify, merge, publish, */
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/* distribute, sublicense, and/or sell copies of the Software, and to */
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/* permit persons to whom the Software is furnished to do so, subject to */
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/* the following conditions: */
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/* */
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/* The above copyright notice and this permission notice shall be */
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/* included in all copies or substantial portions of the Software. */
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/* */
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/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, */
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/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF */
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/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. */
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/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY */
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/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, */
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/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE */
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/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
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/**************************************************************************/
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#include "transform_interpolator.h"
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#include "core/math/transform_2d.h"
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void TransformInterpolator::interpolate_transform_2d(const Transform2D &p_prev, const Transform2D &p_curr, Transform2D &r_result, real_t p_fraction) {
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// Extract parameters.
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Vector2 p1 = p_prev.get_origin();
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Vector2 p2 = p_curr.get_origin();
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// Special case for physics interpolation, if flipping, don't interpolate basis.
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// If the determinant polarity changes, the handedness of the coordinate system changes.
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if (_sign(p_prev.determinant()) != _sign(p_curr.determinant())) {
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r_result.columns[0] = p_curr.columns[0];
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r_result.columns[1] = p_curr.columns[1];
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r_result.set_origin(p1.lerp(p2, p_fraction));
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return;
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}
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real_t r1 = p_prev.get_rotation();
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real_t r2 = p_curr.get_rotation();
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Size2 s1 = p_prev.get_scale();
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Size2 s2 = p_curr.get_scale();
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// Slerp rotation.
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Vector2 v1(Math::cos(r1), Math::sin(r1));
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Vector2 v2(Math::cos(r2), Math::sin(r2));
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real_t dot = v1.dot(v2);
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dot = CLAMP(dot, -1, 1);
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Vector2 v;
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if (dot > 0.9995f) {
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v = v1.lerp(v2, p_fraction).normalized(); // Linearly interpolate to avoid numerical precision issues.
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} else {
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real_t angle = p_fraction * Math::acos(dot);
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Vector2 v3 = (v2 - v1 * dot).normalized();
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v = v1 * Math::cos(angle) + v3 * Math::sin(angle);
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}
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// Construct matrix.
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r_result = Transform2D(Math::atan2(v.y, v.x), p1.lerp(p2, p_fraction));
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r_result.scale_basis(s1.lerp(s2, p_fraction));
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}
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