58 lines
1.6 KiB
C
58 lines
1.6 KiB
C
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/**
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* PANDA 3D SOFTWARE
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* Copyright (c) Carnegie Mellon University. All rights reserved.
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*
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* All use of this software is subject to the terms of the revised BSD
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* license. You should have received a copy of this license along
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* with this source code in a file named "LICENSE."
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*
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* @file lerp_helpers.h
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* @author drose
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* @date 2002-08-27
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*/
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#ifndef LERP_HELPERS_H
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#define LERP_HELPERS_H
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#include "directbase.h"
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// The functions defined here include some trivial template functions for
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// handling basic lerp computations, common to several .cxx files here.
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/**
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* Applies the linear lerp computation for a single parameter.
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*/
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template<class NumericType>
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INLINE void
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lerp_value(NumericType ¤t_value,
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double d,
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const NumericType &starting_value,
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const NumericType &ending_value) {
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current_value = starting_value + d * (ending_value - starting_value);
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}
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/**
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* Applies the linear lerp computation for a single parameter, when the
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* starting value is implicit.
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*
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* This computes the new value based on assuming the prev_value represents the
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* value computed at delta prev_d.
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*/
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template<class NumericType>
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INLINE void
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lerp_value_from_prev(NumericType ¤t_value,
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double d, double prev_d,
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const NumericType &prev_value,
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const NumericType &ending_value) {
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if (prev_d == 1.0) {
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current_value = ending_value;
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} else {
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NumericType starting_value =
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(prev_value - prev_d * ending_value) / (1.0 - prev_d);
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current_value = starting_value + d * (ending_value - starting_value);
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}
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}
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#endif
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