1 files changed, 85 insertions, 0 deletions
diff --git a/source/blender/compositor/operations/COM_DifferenceMatteOperation.cc b/source/blender/compositor/operations/COM_DifferenceMatteOperation.cc
new file mode 100644
index 00000000000..cca99a42c0c
--- /dev/null
+++ b/source/blender/compositor/operations/COM_DifferenceMatteOperation.cc
@@ -0,0 +1,85 @@
+/*
+ * 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_DifferenceMatteOperation.h"
+#include "BLI_math.h"
+
+DifferenceMatteOperation::DifferenceMatteOperation()
+{
+  addInputSocket(COM_DT_COLOR);
+  addInputSocket(COM_DT_COLOR);
+  addOutputSocket(COM_DT_VALUE);
+
+  this->m_inputImage1Program = nullptr;
+  this->m_inputImage2Program = nullptr;
+}
+
+void DifferenceMatteOperation::initExecution()
+{
+  this->m_inputImage1Program = this->getInputSocketReader(0);
+  this->m_inputImage2Program = this->getInputSocketReader(1);
+}
+void DifferenceMatteOperation::deinitExecution()
+{
+  this->m_inputImage1Program = nullptr;
+  this->m_inputImage2Program = nullptr;
+}
+
+void DifferenceMatteOperation::executePixelSampled(float output[4],
+                                                   float x,
+                                                   float y,
+                                                   PixelSampler sampler)
+{
+  float inColor1[4];
+  float inColor2[4];
+
+  const float tolerance = this->m_settings->t1;
+  const float falloff = this->m_settings->t2;
+  float difference;
+  float alpha;
+
+  this->m_inputImage1Program->readSampled(inColor1, x, y, sampler);
+  this->m_inputImage2Program->readSampled(inColor2, x, y, sampler);
+
+  difference = (fabsf(inColor2[0] - inColor1[0]) + fabsf(inColor2[1] - inColor1[1]) +
+                fabsf(inColor2[2] - inColor1[2]));
+
+  /* average together the distances */
+  difference = difference / 3.0f;
+
+  /* make 100% transparent */
+  if (difference <= tolerance) {
+    output[0] = 0.0f;
+  }
+  /*in the falloff region, make partially transparent */
+  else if (difference <= falloff + tolerance) {
+    difference = difference - tolerance;
+    alpha = difference / falloff;
+    /*only change if more transparent than before */
+    if (alpha < inColor1[3]) {
+      output[0] = alpha;
+    }
+    else { /* leave as before */
+      output[0] = inColor1[3];
+    }
+  }
+  else {
+    /* foreground object */
+    output[0] = inColor1[3];
+  }
+}