| import { ZeroCurvatureEnding, WrapAroundEnding, ZeroSlopeEnding } from '../../constants.js'; |
| import { Interpolant } from '../Interpolant.js'; |
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| class CubicInterpolant extends Interpolant { |
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| constructor( parameterPositions, sampleValues, sampleSize, resultBuffer ) { |
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| super( parameterPositions, sampleValues, sampleSize, resultBuffer ); |
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| this._weightPrev = - 0; |
| this._offsetPrev = - 0; |
| this._weightNext = - 0; |
| this._offsetNext = - 0; |
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| this.DefaultSettings_ = { |
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| endingStart: ZeroCurvatureEnding, |
| endingEnd: ZeroCurvatureEnding |
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| }; |
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| } |
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| intervalChanged_( i1, t0, t1 ) { |
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| const pp = this.parameterPositions; |
| let iPrev = i1 - 2, |
| iNext = i1 + 1, |
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| tPrev = pp[ iPrev ], |
| tNext = pp[ iNext ]; |
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| if ( tPrev === undefined ) { |
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| switch ( this.getSettings_().endingStart ) { |
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| case ZeroSlopeEnding: |
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| iPrev = i1; |
| tPrev = 2 * t0 - t1; |
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| break; |
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| case WrapAroundEnding: |
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| iPrev = pp.length - 2; |
| tPrev = t0 + pp[ iPrev ] - pp[ iPrev + 1 ]; |
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| break; |
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| default: |
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| iPrev = i1; |
| tPrev = t1; |
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| } |
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| } |
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| if ( tNext === undefined ) { |
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| switch ( this.getSettings_().endingEnd ) { |
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| case ZeroSlopeEnding: |
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| iNext = i1; |
| tNext = 2 * t1 - t0; |
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| break; |
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| case WrapAroundEnding: |
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| iNext = 1; |
| tNext = t1 + pp[ 1 ] - pp[ 0 ]; |
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| break; |
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| default: |
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| iNext = i1 - 1; |
| tNext = t0; |
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| } |
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| } |
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| const halfDt = ( t1 - t0 ) * 0.5, |
| stride = this.valueSize; |
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| this._weightPrev = halfDt / ( t0 - tPrev ); |
| this._weightNext = halfDt / ( tNext - t1 ); |
| this._offsetPrev = iPrev * stride; |
| this._offsetNext = iNext * stride; |
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| } |
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| interpolate_( i1, t0, t, t1 ) { |
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| const result = this.resultBuffer, |
| values = this.sampleValues, |
| stride = this.valueSize, |
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| o1 = i1 * stride, o0 = o1 - stride, |
| oP = this._offsetPrev, oN = this._offsetNext, |
| wP = this._weightPrev, wN = this._weightNext, |
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| p = ( t - t0 ) / ( t1 - t0 ), |
| pp = p * p, |
| ppp = pp * p; |
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| const sP = - wP * ppp + 2 * wP * pp - wP * p; |
| const s0 = ( 1 + wP ) * ppp + ( - 1.5 - 2 * wP ) * pp + ( - 0.5 + wP ) * p + 1; |
| const s1 = ( - 1 - wN ) * ppp + ( 1.5 + wN ) * pp + 0.5 * p; |
| const sN = wN * ppp - wN * pp; |
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| for ( let i = 0; i !== stride; ++ i ) { |
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| result[ i ] = |
| sP * values[ oP + i ] + |
| s0 * values[ o0 + i ] + |
| s1 * values[ o1 + i ] + |
| sN * values[ oN + i ]; |
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| } |
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| return result; |
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| } |
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| } |
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| export { CubicInterpolant }; |
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|
