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// ======================================================================== //
// Copyright 2009-2019 Intel Corporation //
// //
// 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 "transfer_function.h"
namespace oidn {
const float LogTransferFunction::xScale = 1.f / log(LogTransferFunction::yMax + 1.f);
const float PQXTransferFunction::xScale = 1.f / PQXTransferFunction::pqxForward(PQXTransferFunction::yMax * PQXTransferFunction::yScale);
float AutoexposureNode::autoexposure(const Image& color)
{
assert(color.format == Format::Float3);
constexpr float key = 0.18f;
constexpr float eps = 1e-8f;
constexpr int K = 16; // downsampling amount
// Downsample the image to minimize sensitivity to noise
const int H = color.height; // original height
const int W = color.width; // original width
const int HK = (H + K/2) / K; // downsampled height
const int WK = (W + K/2) / K; // downsampled width
// Compute the average log luminance of the downsampled image
using Sum = std::pair<float, int>;
// -- GODOT start --
// Sum sum =
// tbb::parallel_reduce(
// tbb::blocked_range2d<int>(0, HK, 0, WK),
// Sum(0.f, 0),
// [&](const tbb::blocked_range2d<int>& r, Sum sum) -> Sum
// {
// // Iterate over blocks
// for (int i = r.rows().begin(); i != r.rows().end(); ++i)
// {
// for (int j = r.cols().begin(); j != r.cols().end(); ++j)
// {
Sum sum = Sum(0.0f, 0);
for (int i = 0; i != HK; ++i)
{
for (int j = 0; j != WK; ++j)
{
// Compute the average luminance in the current block
const int beginH = int(ptrdiff_t(i) * H / HK);
const int beginW = int(ptrdiff_t(j) * W / WK);
const int endH = int(ptrdiff_t(i+1) * H / HK);
const int endW = int(ptrdiff_t(j+1) * W / WK);
float L = 0.f;
for (int h = beginH; h < endH; ++h)
{
for (int w = beginW; w < endW; ++w)
{
const float* rgb = (const float*)color.get(h, w);
const float r = maxSafe(rgb[0], 0.f);
const float g = maxSafe(rgb[1], 0.f);
const float b = maxSafe(rgb[2], 0.f);
L += luminance(r, g, b);
}
}
L /= (endH - beginH) * (endW - beginW);
// Accumulate the log luminance
if (L > eps)
{
sum.first += log2(L);
sum.second++;
}
}
}
// return sum;
// },
// [](Sum a, Sum b) -> Sum { return Sum(a.first+b.first, a.second+b.second); },
// tbb::static_partitioner()
// );
// -- GODOT end --
return (sum.second > 0) ? (key / exp2(sum.first / float(sum.second))) : 1.f;
}
} // namespace oidn
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