1 /* 2 * Copyright (C) 2010 Google Inc. All rights reserved. 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY 15 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 16 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 17 * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY 18 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 19 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 20 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND 21 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 23 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 24 */ 25 26 #include "config.h" 27 28 #if ENABLE(WEB_AUDIO) 29 30 #include "AudioParam.h" 31 32 #include <wtf/MathExtras.h> 33 34 namespace WebCore { 35 36 const double AudioParam::DefaultSmoothingConstant = 0.05; 37 const double AudioParam::SnapThreshold = 0.001; 38 39 void AudioParam::setValue(float value) 40 { 41 // Check against JavaScript giving us bogus floating-point values. 42 // Don't ASSERT, since this can happen if somebody writes bad JS. 43 if (!isnan(value) && !isinf(value)) 44 m_value = value; 45 } 46 47 bool AudioParam::smooth() 48 { 49 if (m_smoothedValue == m_value) { 50 // Smoothed value has already approached and snapped to value. 51 return true; 52 } 53 54 // Exponential approach 55 m_smoothedValue += (m_value - m_smoothedValue) * m_smoothingConstant; 56 57 // If we get close enough then snap to actual value. 58 if (fabs(m_smoothedValue - m_value) < SnapThreshold) // FIXME: the threshold needs to be adjustable depending on range - but this is OK general purpose value. 59 m_smoothedValue = m_value; 60 61 return false; 62 } 63 64 } // namespace WebCore 65 66 #endif // ENABLE(WEB_AUDIO) 67
