1 files changed, 77 insertions, 0 deletions
diff --git a/source/blender/compositor/operations/COM_LuminanceMatteOperation.cc b/source/blender/compositor/operations/COM_LuminanceMatteOperation.cc
new file mode 100644
index 00000000000..2bd7493625e
--- /dev/null
+++ b/source/blender/compositor/operations/COM_LuminanceMatteOperation.cc
@@ -0,0 +1,77 @@
+/*
+ * 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 2011, Blender Foundation.
+ */
+
+#include "COM_LuminanceMatteOperation.h"
+#include "BLI_math.h"
+
+#include "IMB_colormanagement.h"
+
+LuminanceMatteOperation::LuminanceMatteOperation()
+{
+  addInputSocket(COM_DT_COLOR);
+  addOutputSocket(COM_DT_VALUE);
+
+  this->m_inputImageProgram = nullptr;
+}
+
+void LuminanceMatteOperation::initExecution()
+{
+  this->m_inputImageProgram = this->getInputSocketReader(0);
+}
+
+void LuminanceMatteOperation::deinitExecution()
+{
+  this->m_inputImageProgram = nullptr;
+}
+
+void LuminanceMatteOperation::executePixelSampled(float output[4],
+                                                  float x,
+                                                  float y,
+                                                  PixelSampler sampler)
+{
+  float inColor[4];
+  this->m_inputImageProgram->readSampled(inColor, x, y, sampler);
+
+  const float high = this->m_settings->t1;
+  const float low = this->m_settings->t2;
+  const float luminance = IMB_colormanagement_get_luminance(inColor);
+
+  float alpha;
+
+  /* one line thread-friend algorithm:
+   * output[0] = MIN2(inputValue[3], MIN2(1.0f, MAX2(0.0f, ((luminance - low) / (high - low))));
+   */
+
+  /* test range */
+  if (luminance > high) {
+    alpha = 1.0f;
+  }
+  else if (luminance < low) {
+    alpha = 0.0f;
+  }
+  else { /*blend */
+    alpha = (luminance - low) / (high - low);
+  }
+
+  /* Store matte(alpha) value in [0] to go with
+   * COM_SetAlphaMultiplyOperation and the Value output.
+   */
+
+  /* don't make something that was more transparent less transparent */
+  output[0] = min_ff(alpha, inColor[3]);
+}