Shader Pass support

[ogniK5377]

What can't you do?
Currently, there's no easy way to handle shader passes. The way to deal with multiple shader passes is to manually render the object twice with a RenderEntity and calling drawing the same object multiple time using different materials.

How would you like it to work?

ShaderPassCount(2);

#if (S_SHADER_PASS == 0)
// Do shader pass 1
#elif (S_SHADER_PASS == 1)
// Do shader pass 2
#endif

What have you tried?
Currently, the only other way to deal with this is to force an object to render right after the other manually. One method of this is to use the DoRender override for RenderEntities.

public override void DoRender( SceneObject obj )
{
     _vertexBuffer.Draw( _materialPass1 );
     _vertexBuffer.Draw( _materialPass2 );
}

Additional context
Define an extra pass should just render the object multiple times in successive order and rendering on the correct pass