1 files changed, 109 insertions, 0 deletions
diff --git a/source/blender/compositor/operations/COM_KeyingOperation.cc b/source/blender/compositor/operations/COM_KeyingOperation.cc
new file mode 100644
index 00000000000..94e65181207
--- /dev/null
+++ b/source/blender/compositor/operations/COM_KeyingOperation.cc
@@ -0,0 +1,109 @@
+/*
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * Copyright 2012, Blender Foundation.
+ */
+
+#include "COM_KeyingOperation.h"
+
+#include "MEM_guardedalloc.h"
+
+#include "BLI_listbase.h"
+#include "BLI_math.h"
+
+static float get_pixel_saturation(const float pixelColor[4],
+                                  float screen_balance,
+                                  int primary_channel)
+{
+  const int other_1 = (primary_channel + 1) % 3;
+  const int other_2 = (primary_channel + 2) % 3;
+
+  const int min_channel = MIN2(other_1, other_2);
+  const int max_channel = MAX2(other_1, other_2);
+
+  const float val = screen_balance * pixelColor[min_channel] +
+                    (1.0f - screen_balance) * pixelColor[max_channel];
+
+  return (pixelColor[primary_channel] - val) * fabsf(1.0f - val);
+}
+
+KeyingOperation::KeyingOperation()
+{
+  this->addInputSocket(COM_DT_COLOR);
+  this->addInputSocket(COM_DT_COLOR);
+  this->addOutputSocket(COM_DT_VALUE);
+
+  this->m_screenBalance = 0.5f;
+
+  this->m_pixelReader = nullptr;
+  this->m_screenReader = nullptr;
+}
+
+void KeyingOperation::initExecution()
+{
+  this->m_pixelReader = this->getInputSocketReader(0);
+  this->m_screenReader = this->getInputSocketReader(1);
+}
+
+void KeyingOperation::deinitExecution()
+{
+  this->m_pixelReader = nullptr;
+  this->m_screenReader = nullptr;
+}
+
+void KeyingOperation::executePixelSampled(float output[4], float x, float y, PixelSampler sampler)
+{
+  float pixel_color[4];
+  float screen_color[4];
+
+  this->m_pixelReader->readSampled(pixel_color, x, y, sampler);
+  this->m_screenReader->readSampled(screen_color, x, y, sampler);
+
+  const int primary_channel = max_axis_v3(screen_color);
+  const float min_pixel_color = min_fff(pixel_color[0], pixel_color[1], pixel_color[2]);
+
+  if (min_pixel_color > 1.0f) {
+    /* overexposure doesn't happen on screen itself and usually happens
+     * on light sources in the shot, this need to be checked separately
+     * because saturation and falloff calculation is based on the fact
+     * that pixels are not overexposed
+     */
+    output[0] = 1.0f;
+  }
+  else {
+    float saturation = get_pixel_saturation(pixel_color, this->m_screenBalance, primary_channel);
+    float screen_saturation = get_pixel_saturation(
+        screen_color, this->m_screenBalance, primary_channel);
+
+    if (saturation < 0) {
+      /* means main channel of pixel is different from screen,
+       * assume this is completely a foreground
+       */
+      output[0] = 1.0f;
+    }
+    else if (saturation >= screen_saturation) {
+      /* matched main channels and higher saturation on pixel
+       * is treated as completely background
+       */
+      output[0] = 0.0f;
+    }
+    else {
+      /* nice alpha falloff on edges */
+      float distance = 1.0f - saturation / screen_saturation;
+
+      output[0] = distance;
+    }
+  }
+}