Gradiant shading of polygons

Dear forum members, i'm developing an application which able to solve FE problmes for 2D and 3D structural models. For the post processing of the same i would like to show it deformation contours with gradiant distinct.I've gone through the code of User_cylinder module, but i could not able to absorb it( for a triangle each vertex i want to apply different colors) . Pls kindly help me in this reg.


Creating library Debug/FECAD.lib and object Debug/FECAD.exp
Dear friends, however i could able move on user_cylinder module, but i',m getting the following error, pls kindly help me in this regard.

LINK : warning LNK4098: defaultlib "MSVCRTD" conflicts with use of other libs; use /NODEFAULTLIB:library
FECADDoc.obj : error LNK2001: unresolved external symbol "private: class Quantity_Color __thiscall CFECADDoc::Color(class gp_Pnt &,double,double,int)" (?Color@CFECADDoc@@AAE?AVQuantity_Color@@AAVgp_Pnt@@NNH@Z)
Debug/FECAD.exe : fatal error LNK1120: 1 unresolved externals
Error executing link.exe.