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126bd9e1a4
This patch was generated automatically by the "modeline.py" script, available here: https://github.com/amccreight/moz-source-tools/blob/master/modeline.py For every file that is modified in this patch, the changes are as follows: (1) The patch changes the file to use the exact C++ mode lines from the Mozilla coding style guide, available here: https://developer.mozilla.org/en-US/docs/Mozilla/Developer_guide/Coding_Style#Mode_Line (2) The patch deletes any blank lines between the mode line & the MPL boilerplate comment. (3) If the file previously had the mode lines and MPL boilerplate in a single contiguous C++ comment, then the patch splits them into separate C++ comments, to match the boilerplate in the coding style. MozReview-Commit-ID: 77D61xpSmIl --HG-- extra : rebase_source : c6162fa3cf539a07177a19838324bf368faa162b
87 lines
2.3 KiB
C++
87 lines
2.3 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim: set ts=8 sts=2 et sw=2 tw=80: */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#ifndef mozilla_layers_AxisPhysicsMSDModel_h
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#define mozilla_layers_AxisPhysicsMSDModel_h
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#include "AxisPhysicsModel.h"
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namespace mozilla {
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namespace layers {
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/**
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* AxisPhysicsMSDModel encapsulates a 1-dimensional MSD (Mass-Spring-Damper)
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* model. A unit mass is assumed.
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*/
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class AxisPhysicsMSDModel : public AxisPhysicsModel {
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public:
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AxisPhysicsMSDModel(double aInitialPosition, double aInitialDestination,
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double aInitialVelocity, double aSpringConstant,
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double aDampingRatio);
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~AxisPhysicsMSDModel();
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/**
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* Gets the raw destination of this axis at this moment.
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*/
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double GetDestination() const;
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/**
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* Sets the raw destination of this axis at this moment.
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*/
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void SetDestination(double aDestination);
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/**
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* Returns true when the position is close to the destination and the
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* velocity is low.
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*/
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bool IsFinished(double aSmallestVisibleIncrement);
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protected:
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virtual double Acceleration(const State &aState);
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private:
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/**
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* mDestination represents the target position and the resting position of
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* the simulated spring.
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*/
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double mDestination;
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/**
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* Greater values of mSpringConstant result in a stiffer / stronger spring.
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*/
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double mSpringConstant;
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/**
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* mSpringConstantSqrtTimesTwo is calculated from mSpringConstant to reduce
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* calculations performed in the inner loop.
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*/
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double mSpringConstantSqrtXTwo;
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/**
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* Damping Ratio: http://en.wikipedia.org/wiki/Damping_ratio
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*
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* When mDampingRatio < 1.0, this is an under damped system.
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* - Overshoots destination and oscillates with the amplitude gradually
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* decreasing to zero.
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*
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* When mDampingRatio == 1.0, this is a critically damped system.
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* - Reaches destination as quickly as possible without oscillating.
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*
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* When mDampingRatio > 1.0, this is an over damped system.
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* - Reaches destination (exponentially decays) without oscillating.
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*/
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double mDampingRatio;
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};
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} // namespace layers
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} // namespace mozilla
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#endif
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