void StateEnum ( PipelineState ps, Flags flags )
{
switch ( flags ) {
case Flags.OPAQUE : ps.BlendState = BlendState.Opaque ; break;
case Flags.ALPHA_BLEND : ps.BlendState = BlendState.AlphaBlend ; break;
case Flags.ALPHA_BLEND_PREMUL : ps.BlendState = BlendState.AlphaBlendPremul ; break;
case Flags.ADDITIVE : ps.BlendState = BlendState.Additive ; break;
case Flags.SCREEN : ps.BlendState = BlendState.Screen ; break;
case Flags.MULTIPLY : ps.BlendState = BlendState.Multiply ; break;
case Flags.NEG_MULTIPLY : ps.BlendState = BlendState.NegMultiply ; break;
case Flags.ALPHA_ONLY : ps.BlendState = BlendState.AlphaMaskWrite ; break;
}
ps.RasterizerState = RasterizerState.CullNone;
ps.DepthStencilState = DepthStencilState.None;
ps.Primitive = Primitive.TriangleList;
ps.VertexInputElements = VertexInputElement.FromStructure( typeof(SpriteVertex) );
}