/
hdr_merge.rs
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/
hdr_merge.rs
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/*
* Copyright (C) 2014 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.
*/
#pragma version(1)
#pragma rs java_package_name(com.example.android.hdrviewfinder)
#pragma rs_fp_relaxed
rs_allocation gCurrentFrame;
rs_allocation gPrevFrame;
int gCutPointX = 0;
int gDoMerge = 0;
int gFrameCounter = 0;
uchar4 __attribute__((kernel)) mergeHdrFrames(uchar4 prevPixel, uint32_t x, uint32_t y) {
// Read in pixel values from latest frame - YUV color space
uchar4 curPixel;
curPixel.r = rsGetElementAtYuv_uchar_Y(gCurrentFrame, x, y);
curPixel.g = rsGetElementAtYuv_uchar_U(gCurrentFrame, x, y);
curPixel.b = rsGetElementAtYuv_uchar_V(gCurrentFrame, x, y);
curPixel.a = 255;
uchar4 mergedPixel;
if (gDoMerge == 1) {
// Complex HDR fusion technique
mergedPixel = curPixel / 2 + prevPixel / 2;
/* Experimental color saturation boosting merge
mergedPixel.r = curPixel.r / 2 + prevPixel.r / 2;
uchar saturationCurrent = abs(curPixel.g - 128) + abs(curPixel.b - 128);
uchar saturationPrev = abs(prevPixel.g - 128) + abs(prevPixel.b - 128);
mergedPixel.g = saturationCurrent > saturationPrev ? curPixel.g : prevPixel.g;
mergedPixel.b = saturationCurrent > saturationPrev ? curPixel.b : prevPixel.b;
*/
} else if (gCutPointX > 0) {
// Composite side by side
mergedPixel = ((x < gCutPointX) ^ (gFrameCounter & 0x1)) ?
curPixel : prevPixel;
} else {
// Straight passthrough
mergedPixel = curPixel;
}
// Convert YUV to RGB, JFIF transform with fixed-point math
// R = Y + 1.402 * (V - 128)
// G = Y - 0.34414 * (U - 128) - 0.71414 * (V - 128)
// B = Y + 1.772 * (U - 128)
int4 rgb;
rgb.r = mergedPixel.r +
mergedPixel.b * 1436 / 1024 - 179;
rgb.g = mergedPixel.r -
mergedPixel.g * 46549 / 131072 + 44 -
mergedPixel.b * 93604 / 131072 + 91;
rgb.b = mergedPixel.r +
mergedPixel.g * 1814 / 1024 - 227;
rgb.a = 255;
// Store current pixel for next frame
rsSetElementAt_uchar4(gPrevFrame, curPixel, x, y);
// Write out merged HDR result
uchar4 out = convert_uchar4(clamp(rgb, 0, 255));
return out;
}