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Diffstat (limited to 'Source/WebCore/webaudio/WaveShaperDSPKernel.cpp')
-rw-r--r-- | Source/WebCore/webaudio/WaveShaperDSPKernel.cpp | 76 |
1 files changed, 76 insertions, 0 deletions
diff --git a/Source/WebCore/webaudio/WaveShaperDSPKernel.cpp b/Source/WebCore/webaudio/WaveShaperDSPKernel.cpp new file mode 100644 index 000000000..5f3cf3476 --- /dev/null +++ b/Source/WebCore/webaudio/WaveShaperDSPKernel.cpp @@ -0,0 +1,76 @@ +/* + * Copyright (C) 2011, Google Inc. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' AND ANY + * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED + * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE + * DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS BE LIABLE FOR ANY + * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES + * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; + * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON + * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS + * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +#include "config.h" + +#if ENABLE(WEB_AUDIO) + +#include "WaveShaperDSPKernel.h" + +#include "WaveShaperProcessor.h" +#include <algorithm> + +using namespace std; + +namespace WebCore { + +void WaveShaperDSPKernel::process(const float* source, float* destination, size_t framesToProcess) +{ + ASSERT(source && destination && waveShaperProcessor()); + + Float32Array* curve = waveShaperProcessor()->curve(); + if (!curve) { + // Act as "straight wire" pass-through if no curve is set. + memcpy(destination, source, sizeof(float) * framesToProcess); + return; + } + + float* curveData = curve->data(); + int curveLength = curve->length(); + + ASSERT(curveData); + + if (!curveData || !curveLength) { + memcpy(destination, source, sizeof(float) * framesToProcess); + return; + } + + // Apply waveshaping curve. + for (unsigned i = 0; i < framesToProcess; ++i) { + const float input = source[i]; + + // Calculate an index based on input -1 -> +1 with 0 being at the center of the curve data. + int index = (curveLength * (input + 1)) / 2; + + // Clip index to the input range of the curve. + // This takes care of input outside of nominal range -1 -> +1 + index = max(index, 0); + index = min(index, curveLength - 1); + destination[i] = curveData[index]; + } +} + +} // namespace WebCore + +#endif // ENABLE(WEB_AUDIO) |