public void Draw(Skeleton skeleton)
        {
            float[]     vertices = this.vertices;
            List <Slot> drawOrder = skeleton.DrawOrder;
            float       skeletonR = skeleton.R, skeletonG = skeleton.G, skeletonB = skeleton.B, skeletonA = skeleton.A;

            for (int i = 0, n = drawOrder.Count; i < n; i++)
            {
                Slot       slot       = drawOrder[i];
                Attachment attachment = slot.Attachment;
                if (attachment is RegionAttachment)
                {
                    RegionAttachment regionAttachment = (RegionAttachment)attachment;
                    BlendState       blend            = slot.Data.AdditiveBlending ? BlendState.Additive : defaultBlendState;
                    if (device.BlendState != blend)
                    {
                        End();
                        device.BlendState = blend;
                    }

                    MeshItem item = batcher.NextItem(4, 6);
                    item.triangles = quadTriangles;
                    VertexPositionColorTexture[] itemVertices = item.vertices;

                    AtlasRegion region = (AtlasRegion)regionAttachment.RendererObject;
                    item.texture = (Texture2D)region.page.rendererObject;

                    Color color;
                    float a = skeletonA * slot.A * regionAttachment.A;
                    if (premultipliedAlpha)
                    {
                        color = new Color(
                            skeletonR * slot.R * regionAttachment.R * a,
                            skeletonG * slot.G * regionAttachment.G * a,
                            skeletonB * slot.B * regionAttachment.B * a, a);
                    }
                    else
                    {
                        color = new Color(
                            skeletonR * slot.R * regionAttachment.R,
                            skeletonG * slot.G * regionAttachment.G,
                            skeletonB * slot.B * regionAttachment.B, a);
                    }
                    itemVertices[TL].Color = color;
                    itemVertices[BL].Color = color;
                    itemVertices[BR].Color = color;
                    itemVertices[TR].Color = color;

                    regionAttachment.ComputeWorldVertices(slot.Bone, vertices);
                    itemVertices[TL].Position.X = vertices[RegionAttachment.X1];
                    itemVertices[TL].Position.Y = vertices[RegionAttachment.Y1];
                    itemVertices[TL].Position.Z = 0;
                    itemVertices[BL].Position.X = vertices[RegionAttachment.X2];
                    itemVertices[BL].Position.Y = vertices[RegionAttachment.Y2];
                    itemVertices[BL].Position.Z = 0;
                    itemVertices[BR].Position.X = vertices[RegionAttachment.X3];
                    itemVertices[BR].Position.Y = vertices[RegionAttachment.Y3];
                    itemVertices[BR].Position.Z = 0;
                    itemVertices[TR].Position.X = vertices[RegionAttachment.X4];
                    itemVertices[TR].Position.Y = vertices[RegionAttachment.Y4];
                    itemVertices[TR].Position.Z = 0;

                    float[] uvs = regionAttachment.UVs;
                    itemVertices[TL].TextureCoordinate.X = uvs[RegionAttachment.X1];
                    itemVertices[TL].TextureCoordinate.Y = uvs[RegionAttachment.Y1];
                    itemVertices[BL].TextureCoordinate.X = uvs[RegionAttachment.X2];
                    itemVertices[BL].TextureCoordinate.Y = uvs[RegionAttachment.Y2];
                    itemVertices[BR].TextureCoordinate.X = uvs[RegionAttachment.X3];
                    itemVertices[BR].TextureCoordinate.Y = uvs[RegionAttachment.Y3];
                    itemVertices[TR].TextureCoordinate.X = uvs[RegionAttachment.X4];
                    itemVertices[TR].TextureCoordinate.Y = uvs[RegionAttachment.Y4];
                }
                else if (attachment is MeshAttachment)
                {
                    MeshAttachment mesh        = (MeshAttachment)attachment;
                    int            vertexCount = mesh.Vertices.Length;
                    if (vertices.Length < vertexCount)
                    {
                        vertices = new float[vertexCount];
                    }
                    mesh.ComputeWorldVertices(slot, vertices);

                    int[]    triangles = mesh.Triangles;
                    MeshItem item      = batcher.NextItem(vertexCount, triangles.Length);
                    item.triangles = triangles;

                    AtlasRegion region = (AtlasRegion)mesh.RendererObject;
                    item.texture = (Texture2D)region.page.rendererObject;

                    Color color;
                    float a = skeletonA * slot.A * mesh.A;
                    if (premultipliedAlpha)
                    {
                        color = new Color(
                            skeletonR * slot.R * mesh.R * a,
                            skeletonG * slot.G * mesh.G * a,
                            skeletonB * slot.B * mesh.B * a, a);
                    }
                    else
                    {
                        color = new Color(
                            skeletonR * slot.R * mesh.R,
                            skeletonG * slot.G * mesh.G,
                            skeletonB * slot.B * mesh.B, a);
                    }

                    float[] uvs = mesh.UVs;
                    VertexPositionColorTexture[] itemVertices = item.vertices;
                    for (int ii = 0, v = 0; v < vertexCount; ii++, v += 2)
                    {
                        itemVertices[ii].Color               = color;
                        itemVertices[ii].Position.X          = vertices[v];
                        itemVertices[ii].Position.Y          = vertices[v + 1];
                        itemVertices[ii].Position.Z          = 0;
                        itemVertices[ii].TextureCoordinate.X = uvs[v];
                        itemVertices[ii].TextureCoordinate.Y = uvs[v + 1];
                    }
                }
                else if (attachment is SkinnedMeshAttachment)
                {
                    SkinnedMeshAttachment mesh = (SkinnedMeshAttachment)attachment;
                    int vertexCount            = mesh.UVs.Length;
                    if (vertices.Length < vertexCount)
                    {
                        vertices = new float[vertexCount];
                    }
                    mesh.ComputeWorldVertices(slot, vertices);

                    int[]    triangles = mesh.Triangles;
                    MeshItem item      = batcher.NextItem(vertexCount, triangles.Length);
                    item.triangles = triangles;

                    AtlasRegion region = (AtlasRegion)mesh.RendererObject;
                    item.texture = (Texture2D)region.page.rendererObject;

                    Color color;
                    float a = skeletonA * slot.A * mesh.A;
                    if (premultipliedAlpha)
                    {
                        color = new Color(
                            skeletonR * slot.R * mesh.R * a,
                            skeletonG * slot.G * mesh.G * a,
                            skeletonB * slot.B * mesh.B * a, a);
                    }
                    else
                    {
                        color = new Color(
                            skeletonR * slot.R * mesh.R,
                            skeletonG * slot.G * mesh.G,
                            skeletonB * slot.B * mesh.B, a);
                    }

                    float[] uvs = mesh.UVs;
                    VertexPositionColorTexture[] itemVertices = item.vertices;
                    for (int ii = 0, v = 0; v < vertexCount; ii++, v += 2)
                    {
                        itemVertices[ii].Color               = color;
                        itemVertices[ii].Position.X          = vertices[v];
                        itemVertices[ii].Position.Y          = vertices[v + 1];
                        itemVertices[ii].Position.Z          = 0;
                        itemVertices[ii].TextureCoordinate.X = uvs[v];
                        itemVertices[ii].TextureCoordinate.Y = uvs[v + 1];
                    }
                }
            }
        }
        public void Draw(Skeleton skeleton)
        {
            var   drawOrder = skeleton.DrawOrder;
            var   drawOrderItems = skeleton.DrawOrder.Items;
            float skeletonR = skeleton.R, skeletonG = skeleton.G, skeletonB = skeleton.B, skeletonA = skeleton.A;
            Color color = new Color();

            if (VertexEffect != null)
            {
                VertexEffect.Begin(skeleton);
            }

            for (int i = 0, n = drawOrder.Count; i < n; i++)
            {
                Slot       slot       = drawOrderItems[i];
                Attachment attachment = slot.Attachment;

                float     attachmentColorR, attachmentColorG, attachmentColorB, attachmentColorA;
                Texture2D texture       = null;
                int       verticesCount = 0;
                float[]   vertices      = this.vertices;
                int       indicesCount  = 0;
                int[]     indices       = null;
                float[]   uvs           = null;

                if (attachment is RegionAttachment)
                {
                    RegionAttachment regionAttachment = (RegionAttachment)attachment;
                    attachmentColorR = regionAttachment.R; attachmentColorG = regionAttachment.G; attachmentColorB = regionAttachment.B; attachmentColorA = regionAttachment.A;
                    AtlasRegion region = (AtlasRegion)regionAttachment.RendererObject;
                    texture       = (Texture2D)region.page.rendererObject;
                    verticesCount = 4;
                    regionAttachment.ComputeWorldVertices(slot.Bone, vertices, 0, 2);
                    indicesCount = 6;
                    indices      = quadTriangles;
                    uvs          = regionAttachment.UVs;
                }
                else if (attachment is MeshAttachment)
                {
                    MeshAttachment mesh = (MeshAttachment)attachment;
                    attachmentColorR = mesh.R; attachmentColorG = mesh.G; attachmentColorB = mesh.B; attachmentColorA = mesh.A;
                    AtlasRegion region = (AtlasRegion)mesh.RendererObject;
                    texture = (Texture2D)region.page.rendererObject;
                    int vertexCount = mesh.WorldVerticesLength;
                    if (vertices.Length < vertexCount)
                    {
                        vertices = new float[vertexCount];
                    }
                    verticesCount = vertexCount >> 1;
                    mesh.ComputeWorldVertices(slot, vertices);
                    indicesCount = mesh.Triangles.Length;
                    indices      = mesh.Triangles;
                    uvs          = mesh.UVs;
                }
                else if (attachment is ClippingAttachment)
                {
                    ClippingAttachment clip = (ClippingAttachment)attachment;
                    clipper.ClipStart(slot, clip);
                    continue;
                }
                else
                {
                    continue;
                }

                // set blend state
                BlendState blend = slot.Data.BlendMode == BlendMode.Additive ? BlendState.Additive : defaultBlendState;
                if (device.BlendState != blend)
                {
                    //End();
                    //device.BlendState = blend;
                }

                // calculate color
                float a = skeletonA * slot.A * attachmentColorA;
                if (premultipliedAlpha)
                {
                    color = new Color(
                        skeletonR * slot.R * attachmentColorR * a,
                        skeletonG * slot.G * attachmentColorG * a,
                        skeletonB * slot.B * attachmentColorB * a, a);
                }
                else
                {
                    color = new Color(
                        skeletonR * slot.R * attachmentColorR,
                        skeletonG * slot.G * attachmentColorG,
                        skeletonB * slot.B * attachmentColorB, a);
                }

                Color darkColor = new Color();
                if (slot.HasSecondColor)
                {
                    if (premultipliedAlpha)
                    {
                        darkColor = new Color(slot.R2 * a, slot.G2 * a, slot.B2 * a);
                    }
                    else
                    {
                        darkColor = new Color(slot.R2 * a, slot.G2 * a, slot.B2 * a);
                    }
                }
                darkColor.A = premultipliedAlpha ? (byte)255 : (byte)0;

                // clip
                if (clipper.IsClipping)
                {
                    clipper.ClipTriangles(vertices, verticesCount << 1, indices, indicesCount, uvs);
                    vertices      = clipper.ClippedVertices.Items;
                    verticesCount = clipper.ClippedVertices.Count >> 1;
                    indices       = clipper.ClippedTriangles.Items;
                    indicesCount  = clipper.ClippedTriangles.Count;
                    uvs           = clipper.ClippedUVs.Items;
                }

                if (verticesCount == 0 || indicesCount == 0)
                {
                    continue;
                }

                // submit to batch
                MeshItem item = batcher.NextItem(verticesCount, indicesCount);
                item.texture = texture;
                for (int ii = 0, nn = indicesCount; ii < nn; ii++)
                {
                    item.triangles[ii] = indices[ii];
                }
                VertexPositionColorTextureColor[] itemVertices = item.vertices;
                for (int ii = 0, v = 0, nn = verticesCount << 1; v < nn; ii++, v += 2)
                {
                    itemVertices[ii].Color               = color;
                    itemVertices[ii].Color2              = darkColor;
                    itemVertices[ii].Position.X          = vertices[v];
                    itemVertices[ii].Position.Y          = vertices[v + 1];
                    itemVertices[ii].Position.Z          = 0;
                    itemVertices[ii].TextureCoordinate.X = uvs[v];
                    itemVertices[ii].TextureCoordinate.Y = uvs[v + 1];
                    if (VertexEffect != null)
                    {
                        VertexEffect.Transform(ref itemVertices[ii]);
                    }
                }

                clipper.ClipEnd(slot);
            }
            clipper.ClipEnd();
            if (VertexEffect != null)
            {
                VertexEffect.End();
            }
        }