Fix bug: used wrong parameter for alpha value of source pixel
Fix bug: used wrong parameter for alpha value of source pixel

jbush001/NyuziProcessor,hoangt/NyuziProcessor,FulcronZ/NyuziProcessor,jbush001/NyuziProcessor,jbush001/NyuziProcessor,jbush001/NyuziProcessor,jbush001/NyuziProcessor,jbush001/NyuziProcessor,hoangt/NyuziProcessor,FulcronZ/NyuziProcessor,hoangt/NyuziProcessor,hoangt/NyuziProcessor,FulcronZ/NyuziProcessor,FulcronZ/NyuziProcessor