diff --git a/libkwineffects/kwingltexture.cpp b/libkwineffects/kwingltexture.cpp
--- a/libkwineffects/kwingltexture.cpp
+++ b/libkwineffects/kwingltexture.cpp
@@ -113,6 +113,7 @@
             { GL_RGB8,     GL_BGR,  GL_UNSIGNED_SHORT_5_6_5_REV    }, // QImage::Format_RGB16
             { 0,           0,       0                              }, // QImage::Format_ARGB8565_Premultiplied
             { 0,           0,       0                              }, // QImage::Format_RGB666
+            { 0,           0,       0                              }, // QImage::Format_ARGB6666_Premultiplied
             { GL_RGB5,     GL_BGRA, GL_UNSIGNED_SHORT_1_5_5_5_REV  }, // QImage::Format_RGB555
             { 0,           0,       0                              }, // QImage::Format_ARGB8555_Premultiplied
             { GL_RGB8,     GL_RGB,  GL_UNSIGNED_BYTE               }, // QImage::Format_RGB888