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/*
* Copyright (C) 2020 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <cstring>
#include <math.h>
#include <vibrator/ExternalVibrationUtils.h>
namespace android::os {
namespace {
static constexpr float HAPTIC_SCALE_VERY_LOW_RATIO = 2.0f / 3.0f;
static constexpr float HAPTIC_SCALE_LOW_RATIO = 3.0f / 4.0f;
static constexpr float HAPTIC_MAX_AMPLITUDE_FLOAT = 1.0f;
float getHapticScaleGamma(HapticScale scale) {
switch (scale) {
case HapticScale::VERY_LOW:
return 2.0f;
case HapticScale::LOW:
return 1.5f;
case HapticScale::HIGH:
return 0.5f;
case HapticScale::VERY_HIGH:
return 0.25f;
default:
return 1.0f;
}
}
float getHapticMaxAmplitudeRatio(HapticScale scale) {
switch (scale) {
case HapticScale::VERY_LOW:
return HAPTIC_SCALE_VERY_LOW_RATIO;
case HapticScale::LOW:
return HAPTIC_SCALE_LOW_RATIO;
case HapticScale::NONE:
case HapticScale::HIGH:
case HapticScale::VERY_HIGH:
return 1.0f;
default:
return 0.0f;
}
}
} // namespace
bool isValidHapticScale(HapticScale scale) {
switch (scale) {
case HapticScale::MUTE:
case HapticScale::VERY_LOW:
case HapticScale::LOW:
case HapticScale::NONE:
case HapticScale::HIGH:
case HapticScale::VERY_HIGH:
return true;
}
return false;
}
void scaleHapticData(float* buffer, size_t length, HapticScale scale) {
if (!isValidHapticScale(scale) || scale == HapticScale::NONE) {
return;
}
if (scale == HapticScale::MUTE) {
memset(buffer, 0, length * sizeof(float));
return;
}
float gamma = getHapticScaleGamma(scale);
float maxAmplitudeRatio = getHapticMaxAmplitudeRatio(scale);
for (size_t i = 0; i < length; i++) {
float sign = buffer[i] >= 0 ? 1.0 : -1.0;
buffer[i] = powf(fabsf(buffer[i] / HAPTIC_MAX_AMPLITUDE_FLOAT), gamma)
* maxAmplitudeRatio * HAPTIC_MAX_AMPLITUDE_FLOAT * sign;
}
}
} // namespace android::os