quadrilateralcowboy/idlib/math/Extrapolate.h
2020-06-12 14:06:25 -07:00

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8.1 KiB
C++

/*
===========================================================================
Doom 3 GPL Source Code
Copyright (C) 1999-2011 id Software LLC, a ZeniMax Media company.
This file is part of the Doom 3 GPL Source Code (?Doom 3 Source Code?).
Doom 3 Source Code is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
Doom 3 Source Code is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with Doom 3 Source Code. If not, see <http://www.gnu.org/licenses/>.
In addition, the Doom 3 Source Code is also subject to certain additional terms. You should have received a copy of these additional terms immediately following the terms and conditions of the GNU General Public License which accompanied the Doom 3 Source Code. If not, please request a copy in writing from id Software at the address below.
If you have questions concerning this license or the applicable additional terms, you may contact in writing id Software LLC, c/o ZeniMax Media Inc., Suite 120, Rockville, Maryland 20850 USA.
===========================================================================
*/
#ifndef __MATH_EXTRAPOLATE_H__
#define __MATH_EXTRAPOLATE_H__
/*
==============================================================================================
Extrapolation
==============================================================================================
*/
typedef enum {
EXTRAPOLATION_NONE = 0x01, // no extrapolation, covered distance = duration * 0.001 * ( baseSpeed )
EXTRAPOLATION_LINEAR = 0x02, // linear extrapolation, covered distance = duration * 0.001 * ( baseSpeed + speed )
EXTRAPOLATION_ACCELLINEAR = 0x04, // linear acceleration, covered distance = duration * 0.001 * ( baseSpeed + 0.5 * speed )
EXTRAPOLATION_DECELLINEAR = 0x08, // linear deceleration, covered distance = duration * 0.001 * ( baseSpeed + 0.5 * speed )
EXTRAPOLATION_ACCELSINE = 0x10, // sinusoidal acceleration, covered distance = duration * 0.001 * ( baseSpeed + sqrt( 0.5 ) * speed )
EXTRAPOLATION_DECELSINE = 0x20, // sinusoidal deceleration, covered distance = duration * 0.001 * ( baseSpeed + sqrt( 0.5 ) * speed )
EXTRAPOLATION_NOSTOP = 0x40 // do not stop at startTime + duration
} extrapolation_t;
template< class type >
class idExtrapolate {
public:
idExtrapolate();
void Init( const float startTime, const float duration, const type &startValue, const type &baseSpeed, const type &speed, const extrapolation_t extrapolationType );
type GetCurrentValue( float time ) const;
type GetCurrentSpeed( float time ) const;
bool IsDone( float time ) const { return ( !( extrapolationType & EXTRAPOLATION_NOSTOP ) && time >= startTime + duration ); }
void SetStartTime( float time ) { startTime = time; currentTime = -1; }
float GetStartTime( void ) const { return startTime; }
float GetEndTime( void ) const { return ( !( extrapolationType & EXTRAPOLATION_NOSTOP ) && duration > 0 ) ? startTime + duration : 0; }
float GetDuration( void ) const { return duration; }
void SetStartValue( const type &value ) { startValue = value; currentTime = -1; }
const type & GetStartValue( void ) const { return startValue; }
const type & GetBaseSpeed( void ) const { return baseSpeed; }
const type & GetSpeed( void ) const { return speed; }
extrapolation_t GetExtrapolationType( void ) const { return extrapolationType; }
private:
extrapolation_t extrapolationType;
float startTime;
float duration;
type startValue;
type baseSpeed;
type speed;
mutable float currentTime;
mutable type currentValue;
};
/*
====================
idExtrapolate::idExtrapolate
====================
*/
template< class type >
ID_INLINE idExtrapolate<type>::idExtrapolate() {
extrapolationType = EXTRAPOLATION_NONE;
startTime = duration = 0.0f;
memset( &startValue, 0, sizeof( startValue ) );
memset( &baseSpeed, 0, sizeof( baseSpeed ) );
memset( &speed, 0, sizeof( speed ) );
currentTime = -1;
currentValue = startValue;
}
/*
====================
idExtrapolate::Init
====================
*/
template< class type >
ID_INLINE void idExtrapolate<type>::Init( const float startTime, const float duration, const type &startValue, const type &baseSpeed, const type &speed, const extrapolation_t extrapolationType ) {
this->extrapolationType = extrapolationType;
this->startTime = startTime;
this->duration = duration;
this->startValue = startValue;
this->baseSpeed = baseSpeed;
this->speed = speed;
currentTime = -1;
currentValue = startValue;
}
/*
====================
idExtrapolate::GetCurrentValue
====================
*/
template< class type >
ID_INLINE type idExtrapolate<type>::GetCurrentValue( float time ) const {
float deltaTime, s;
if ( time == currentTime ) {
return currentValue;
}
currentTime = time;
if ( time < startTime ) {
return startValue;
}
if ( !( extrapolationType & EXTRAPOLATION_NOSTOP ) && ( time > startTime + duration ) ) {
time = startTime + duration;
}
switch( extrapolationType & ~EXTRAPOLATION_NOSTOP ) {
case EXTRAPOLATION_NONE: {
deltaTime = ( time - startTime ) * 0.001f;
currentValue = startValue + deltaTime * baseSpeed;
break;
}
case EXTRAPOLATION_LINEAR: {
deltaTime = ( time - startTime ) * 0.001f;
currentValue = startValue + deltaTime * ( baseSpeed + speed );
break;
}
case EXTRAPOLATION_ACCELLINEAR: {
if ( !duration ) {
currentValue = startValue;
} else {
deltaTime = ( time - startTime ) / duration;
s = ( 0.5f * deltaTime * deltaTime ) * ( duration * 0.001f );
currentValue = startValue + deltaTime * baseSpeed + s * speed;
}
break;
}
case EXTRAPOLATION_DECELLINEAR: {
if ( !duration ) {
currentValue = startValue;
} else {
deltaTime = ( time - startTime ) / duration;
s = ( deltaTime - ( 0.5f * deltaTime * deltaTime ) ) * ( duration * 0.001f );
currentValue = startValue + deltaTime * baseSpeed + s * speed;
}
break;
}
case EXTRAPOLATION_ACCELSINE: {
if ( !duration ) {
currentValue = startValue;
} else {
deltaTime = ( time - startTime ) / duration;
s = ( 1.0f - idMath::Cos( deltaTime * idMath::HALF_PI ) ) * duration * 0.001f * idMath::SQRT_1OVER2;
currentValue = startValue + deltaTime * baseSpeed + s * speed;
}
break;
}
case EXTRAPOLATION_DECELSINE: {
if ( !duration ) {
currentValue = startValue;
} else {
deltaTime = ( time - startTime ) / duration;
s = idMath::Sin( deltaTime * idMath::HALF_PI ) * duration * 0.001f * idMath::SQRT_1OVER2;
currentValue = startValue + deltaTime * baseSpeed + s * speed;
}
break;
}
}
return currentValue;
}
/*
====================
idExtrapolate::GetCurrentSpeed
====================
*/
template< class type >
ID_INLINE type idExtrapolate<type>::GetCurrentSpeed( float time ) const {
float deltaTime, s;
if ( time < startTime || !duration ) {
return ( startValue - startValue );
}
if ( !( extrapolationType & EXTRAPOLATION_NOSTOP ) && ( time > startTime + duration ) ) {
return ( startValue - startValue );
}
switch( extrapolationType & ~EXTRAPOLATION_NOSTOP ) {
case EXTRAPOLATION_NONE: {
return baseSpeed;
}
case EXTRAPOLATION_LINEAR: {
return baseSpeed + speed;
}
case EXTRAPOLATION_ACCELLINEAR: {
deltaTime = ( time - startTime ) / duration;
s = deltaTime;
return baseSpeed + s * speed;
}
case EXTRAPOLATION_DECELLINEAR: {
deltaTime = ( time - startTime ) / duration;
s = 1.0f - deltaTime;
return baseSpeed + s * speed;
}
case EXTRAPOLATION_ACCELSINE: {
deltaTime = ( time - startTime ) / duration;
s = idMath::Sin( deltaTime * idMath::HALF_PI );
return baseSpeed + s * speed;
}
case EXTRAPOLATION_DECELSINE: {
deltaTime = ( time - startTime ) / duration;
s = idMath::Cos( deltaTime * idMath::HALF_PI );
return baseSpeed + s * speed;
}
default: {
return baseSpeed;
}
}
}
#endif /* !__MATH_EXTRAPOLATE_H__ */