1 files changed, 109 insertions, 0 deletions
diff --git a/source/blender/compositor/operations/COM_ChromaMatteOperation.cc b/source/blender/compositor/operations/COM_ChromaMatteOperation.cc
new file mode 100644
index 00000000000..52de0198a00
--- /dev/null
+++ b/source/blender/compositor/operations/COM_ChromaMatteOperation.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 2011, Blender Foundation.
+ */
+
+#include "COM_ChromaMatteOperation.h"
+#include "BLI_math.h"
+
+ChromaMatteOperation::ChromaMatteOperation()
+{
+  addInputSocket(COM_DT_COLOR);
+  addInputSocket(COM_DT_COLOR);
+  addOutputSocket(COM_DT_VALUE);
+
+  this->m_inputImageProgram = nullptr;
+  this->m_inputKeyProgram = nullptr;
+}
+
+void ChromaMatteOperation::initExecution()
+{
+  this->m_inputImageProgram = this->getInputSocketReader(0);
+  this->m_inputKeyProgram = this->getInputSocketReader(1);
+}
+
+void ChromaMatteOperation::deinitExecution()
+{
+  this->m_inputImageProgram = nullptr;
+  this->m_inputKeyProgram = nullptr;
+}
+
+void ChromaMatteOperation::executePixelSampled(float output[4],
+                                               float x,
+                                               float y,
+                                               PixelSampler sampler)
+{
+  float inKey[4];
+  float inImage[4];
+
+  const float acceptance = this->m_settings->t1; /* in radians */
+  const float cutoff = this->m_settings->t2;     /* in radians */
+  const float gain = this->m_settings->fstrength;
+
+  float x_angle, z_angle, alpha;
+  float theta, beta;
+  float kfg;
+
+  this->m_inputKeyProgram->readSampled(inKey, x, y, sampler);
+  this->m_inputImageProgram->readSampled(inImage, x, y, sampler);
+
+  /* Store matte(alpha) value in [0] to go with
+   * #COM_SetAlphaMultiplyOperation and the Value output. */
+
+  /* Algorithm from book "Video Demystified", does not include the spill reduction part. */
+  /* Find theta, the angle that the color space should be rotated based on key. */
+
+  /* rescale to -1.0..1.0 */
+  // inImage[0] = (inImage[0] * 2.0f) - 1.0f;  // UNUSED
+  inImage[1] = (inImage[1] * 2.0f) - 1.0f;
+  inImage[2] = (inImage[2] * 2.0f) - 1.0f;
+
+  // inKey[0] = (inKey[0] * 2.0f) - 1.0f;  // UNUSED
+  inKey[1] = (inKey[1] * 2.0f) - 1.0f;
+  inKey[2] = (inKey[2] * 2.0f) - 1.0f;
+
+  theta = atan2(inKey[2], inKey[1]);
+
+  /*rotate the cb and cr into x/z space */
+  x_angle = inImage[1] * cosf(theta) + inImage[2] * sinf(theta);
+  z_angle = inImage[2] * cosf(theta) - inImage[1] * sinf(theta);
+
+  /*if within the acceptance angle */
+  /* if kfg is <0 then the pixel is outside of the key color */
+  kfg = x_angle - (fabsf(z_angle) / tanf(acceptance / 2.0f));
+
+  if (kfg > 0.0f) { /* found a pixel that is within key color */
+    alpha = 1.0f - (kfg / gain);
+
+    beta = atan2(z_angle, x_angle);
+
+    /* if beta is within the cutoff angle */
+    if (fabsf(beta) < (cutoff / 2.0f)) {
+      alpha = 0.0f;
+    }
+
+    /* don't make something that was more transparent less transparent */
+    if (alpha < inImage[3]) {
+      output[0] = alpha;
+    }
+    else {
+      output[0] = inImage[3];
+    }
+  }
+  else {                    /*pixel is outside key color */
+    output[0] = inImage[3]; /* make pixel just as transparent as it was before */
+  }
+}