| /* |
| * Copyright 2017 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 "LinearRamp.h" |
| |
| bool LinearRamp::isRamping() { |
| float target = mTarget.load(); |
| if (target != mLevelTo) { |
| // Update target. Continue from previous level. |
| mLevelTo = target; |
| mRemaining = mLengthInFrames; |
| return true; |
| } else { |
| return mRemaining > 0; |
| } |
| } |
| |
| bool LinearRamp::nextSegment(int32_t frames, float *levelFrom, float *levelTo) { |
| bool ramping = isRamping(); |
| *levelFrom = mLevelFrom; |
| if (ramping) { |
| float level; |
| if (frames >= mRemaining) { |
| level = mLevelTo; |
| mRemaining = 0; |
| } else { |
| // Interpolate to a point along the full ramp. |
| level = mLevelFrom + (frames * (mLevelTo - mLevelFrom) / mRemaining); |
| mRemaining -= frames; |
| } |
| mLevelFrom = level; // for next ramp |
| *levelTo = level; |
| } else { |
| *levelTo = mLevelTo; |
| } |
| return ramping; |
| } |