Add OpenImageDenoise thirdparty library

thirdparty/oidn/core/transfer_function.cpp

@@ -0,0 +1,103 @@
+// ======================================================================== //
+// 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