protected void PrepareVerticesLight(ref VertexC1P3T2A4[] vertices, IDrawDevice device, ColorRgba mainClr, Rect uvRect, DrawTechnique tech)
        {
            bool perPixel = tech is LightingTechnique;

            Vector3 pos       = this.GameObj.Transform.Pos;
            Vector3 posTemp   = pos;
            float   scaleTemp = 1.0f;

            device.PreprocessCoords(ref posTemp, ref scaleTemp);

            Vector2 xDot, yDot;
            float   rotation = this.GameObj.Transform.Angle;

            MathF.GetTransformDotVec(rotation, out xDot, out yDot);

            Rect    rectTemp = this.rect.Transformed(this.GameObj.Transform.Scale, this.GameObj.Transform.Scale);
            Vector2 edge1    = rectTemp.TopLeft;
            Vector2 edge2    = rectTemp.BottomLeft;
            Vector2 edge3    = rectTemp.BottomRight;
            Vector2 edge4    = rectTemp.TopRight;

            MathF.TransformDotVec(ref edge1, ref xDot, ref yDot);
            MathF.TransformDotVec(ref edge2, ref xDot, ref yDot);
            MathF.TransformDotVec(ref edge3, ref xDot, ref yDot);
            MathF.TransformDotVec(ref edge4, ref xDot, ref yDot);

            // Using Per-Vertex Lighting? Calculate vertex light values
            Vector4[] vertexLight = null;
            if (!perPixel)
            {
                vertexLight = new Vector4[4];
                Light.GetLightAtWorldPos(pos + new Vector3(edge1), out vertexLight[0], this.vertexTranslucency);
                Light.GetLightAtWorldPos(pos + new Vector3(edge2), out vertexLight[1], this.vertexTranslucency);
                Light.GetLightAtWorldPos(pos + new Vector3(edge3), out vertexLight[2], this.vertexTranslucency);
                Light.GetLightAtWorldPos(pos + new Vector3(edge4), out vertexLight[3], this.vertexTranslucency);
            }

            Vector2.Multiply(ref edge1, scaleTemp, out edge1);
            Vector2.Multiply(ref edge2, scaleTemp, out edge2);
            Vector2.Multiply(ref edge3, scaleTemp, out edge3);
            Vector2.Multiply(ref edge4, scaleTemp, out edge4);

            // Using Per-Pixel Lighting? Pass objRotation Matrix via vertex attribute.
            Vector4 objRotMat = Vector4.Zero;

            if (perPixel)
            {
                objRotMat = new Vector4((float)Math.Cos(-rotation), -(float)Math.Sin(-rotation), (float)Math.Sin(-rotation), (float)Math.Cos(-rotation));
            }

            if (vertices == null || vertices.Length != 4)
            {
                vertices = new VertexC1P3T2A4[4];
            }

            // Directly pass World Position with each vertex, see note in Light.cs
            vertices[0].Pos.X      = posTemp.X + edge1.X;
            vertices[0].Pos.Y      = posTemp.Y + edge1.Y;
            vertices[0].Pos.Z      = posTemp.Z + this.VertexZOffset;
            vertices[0].TexCoord.X = uvRect.X;
            vertices[0].TexCoord.Y = uvRect.Y;
            vertices[0].Color      = mainClr;
            vertices[0].Attrib     = perPixel ? objRotMat : vertexLight[0];

            vertices[1].Pos.X      = posTemp.X + edge2.X;
            vertices[1].Pos.Y      = posTemp.Y + edge2.Y;
            vertices[1].Pos.Z      = posTemp.Z + this.VertexZOffset;
            vertices[1].TexCoord.X = uvRect.X;
            vertices[1].TexCoord.Y = uvRect.BottomY;
            vertices[1].Color      = mainClr;
            vertices[1].Attrib     = perPixel ? objRotMat : vertexLight[1];

            vertices[2].Pos.X      = posTemp.X + edge3.X;
            vertices[2].Pos.Y      = posTemp.Y + edge3.Y;
            vertices[2].Pos.Z      = posTemp.Z + this.VertexZOffset;
            vertices[2].TexCoord.X = uvRect.RightX;
            vertices[2].TexCoord.Y = uvRect.BottomY;
            vertices[2].Color      = mainClr;
            vertices[2].Attrib     = perPixel ? objRotMat : vertexLight[2];

            vertices[3].Pos.X      = posTemp.X + edge4.X;
            vertices[3].Pos.Y      = posTemp.Y + edge4.Y;
            vertices[3].Pos.Z      = posTemp.Z + this.VertexZOffset;
            vertices[3].TexCoord.X = uvRect.RightX;
            vertices[3].TexCoord.Y = uvRect.Y;
            vertices[3].Color      = mainClr;
            vertices[3].Attrib     = perPixel ? objRotMat : vertexLight[3];

            if (this.pixelGrid)
            {
                vertices[0].Pos.X = MathF.Round(vertices[0].Pos.X);
                vertices[1].Pos.X = MathF.Round(vertices[1].Pos.X);
                vertices[2].Pos.X = MathF.Round(vertices[2].Pos.X);
                vertices[3].Pos.X = MathF.Round(vertices[3].Pos.X);

                if (MathF.RoundToInt(device.TargetSize.X) != (MathF.RoundToInt(device.TargetSize.X) / 2) * 2)
                {
                    vertices[0].Pos.X += 0.5f;
                    vertices[1].Pos.X += 0.5f;
                    vertices[2].Pos.X += 0.5f;
                    vertices[3].Pos.X += 0.5f;
                }

                vertices[0].Pos.Y = MathF.Round(vertices[0].Pos.Y);
                vertices[1].Pos.Y = MathF.Round(vertices[1].Pos.Y);
                vertices[2].Pos.Y = MathF.Round(vertices[2].Pos.Y);
                vertices[3].Pos.Y = MathF.Round(vertices[3].Pos.Y);

                if (MathF.RoundToInt(device.TargetSize.Y) != (MathF.RoundToInt(device.TargetSize.Y) / 2) * 2)
                {
                    vertices[0].Pos.Y += 0.5f;
                    vertices[1].Pos.Y += 0.5f;
                    vertices[2].Pos.Y += 0.5f;
                    vertices[3].Pos.Y += 0.5f;
                }
            }
        }