using System.Runtime.InteropServices;
using UnitTestSharp;
using Blacklight.GPUBridge;

namespace Blacklight.SharpDX9.UnitTesting
{
    public class SharpDX9VertexLayoutTests : TestFixture
    {
        public class ElementsTests : TestFixture
        {
            // A wrong offset here means the shader silently reads the wrong bytes, so pin every element to the
            // CustomVertexDefinition field it describes.
            public void MatchTheStructFieldsTheyDescribe()
            {
                int OffsetOf(string field) => Marshal.OffsetOf(typeof(VertexDefinition), field).ToInt32();
                var elements = SharpDX9VertexLayout.Elements;

                CheckEqual(OffsetOf(nameof(VertexDefinition.TranslationAndVertexPosition)), (int)elements[0].Offset);
                CheckEqual(OffsetOf(nameof(VertexDefinition.ScaleAndOrientation)), (int)elements[1].Offset);
                CheckEqual(OffsetOf(nameof(VertexDefinition.BorderStyle)), (int)elements[2].Offset);
                CheckEqual(OffsetOf(nameof(VertexDefinition.UserData_1)), (int)elements[3].Offset);
                CheckEqual(OffsetOf(nameof(VertexDefinition.ClipWindowLS)), (int)elements[4].Offset);
                CheckEqual(OffsetOf(nameof(VertexDefinition.SpriteDestinationRect)), (int)elements[5].Offset);
                CheckEqual(OffsetOf(nameof(VertexDefinition.InsideColor)), (int)elements[6].Offset);
                CheckEqual(OffsetOf(nameof(VertexDefinition.BorderColor)), (int)elements[7].Offset);
                CheckEqual(OffsetOf(nameof(VertexDefinition.BorderTextureSlot)), (int)elements[8].Offset);
            }
        }
    }
}