1 files changed, 54 insertions, 0 deletions
diff --git a/source/blender/compositor/operations/COM_AlphaOverPremultiplyOperation.cc b/source/blender/compositor/operations/COM_AlphaOverPremultiplyOperation.cc
new file mode 100644
index 00000000000..4510c027d46
--- /dev/null
+++ b/source/blender/compositor/operations/COM_AlphaOverPremultiplyOperation.cc
@@ -0,0 +1,54 @@
+/*
+ * 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_AlphaOverPremultiplyOperation.h"
+
+AlphaOverPremultiplyOperation::AlphaOverPremultiplyOperation()
+{
+  /* pass */
+}
+
+void AlphaOverPremultiplyOperation::executePixelSampled(float output[4],
+                                                        float x,
+                                                        float y,
+                                                        PixelSampler sampler)
+{
+  float inputColor1[4];
+  float inputOverColor[4];
+  float value[4];
+
+  this->m_inputValueOperation->readSampled(value, x, y, sampler);
+  this->m_inputColor1Operation->readSampled(inputColor1, x, y, sampler);
+  this->m_inputColor2Operation->readSampled(inputOverColor, x, y, sampler);
+
+  /* Zero alpha values should still permit an add of RGB data */
+  if (inputOverColor[3] < 0.0f) {
+    copy_v4_v4(output, inputColor1);
+  }
+  else if (value[0] == 1.0f && inputOverColor[3] >= 1.0f) {
+    copy_v4_v4(output, inputOverColor);
+  }
+  else {
+    float mul = 1.0f - value[0] * inputOverColor[3];
+
+    output[0] = (mul * inputColor1[0]) + value[0] * inputOverColor[0];
+    output[1] = (mul * inputColor1[1]) + value[0] * inputOverColor[1];
+    output[2] = (mul * inputColor1[2]) + value[0] * inputOverColor[2];
+    output[3] = (mul * inputColor1[3]) + value[0] * inputOverColor[3];
+  }
+}