git-svn-id: svn://svn.ijw.co.nz/svn/OpenRa@1169 993157c7-ee19-0410-b2c4-bb4e9862e678

OpenRa.Game/Util.cs

@@ -0,0 +1,58 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+using OpenRa.FileFormats;
+using System.Drawing;
+
+namespace OpenRa.Game
+{
+	static class Util
+	{
+		public static float U(SheetRectangle<Sheet> s, float u)
+		{
+			float u0 = (float)(s.origin.X + 0.5f) / (float)s.sheet.bitmap.Width;
+			float u1 = (float)(s.origin.X + s.size.Width) / (float)s.sheet.bitmap.Width;
+
+			return (u > 0) ? u1 : u0;// (1 - u) * u0 + u * u1;
+		}
+
+		public static float V(SheetRectangle<Sheet> s, float v)
+		{
+			float v0 = (float)(s.origin.Y + 0.5f) / (float)s.sheet.bitmap.Height;
+			float v1 = (float)(s.origin.Y + s.size.Height) / (float)s.sheet.bitmap.Height;
+
+			return (v > 0) ? v1 : v0;// return (1 - v) * v0 + v * v1;
+		}
+
+		public static Vertex MakeVertex(PointF o, float u, float v, SheetRectangle<Sheet> r)
+		{
+			float x2 = o.X + r.size.Width;
+			float y2 = o.Y + r.size.Height;
+
+			return new Vertex(Lerp(o.X, x2, u), Lerp(o.Y, y2, v), 0, U(r, u), V(r, v));
+		}
+
+		static float Lerp(float a, float b, float t)
+		{
+			return (1 - t) * a + t * b;
+		}
+
+		public static void CreateQuad(List<Vertex> vertices, List<ushort> indices, PointF o, SheetRectangle<Sheet> r)
+		{
+			ushort offset = (ushort)vertices.Count;
+
+			vertices.Add(Util.MakeVertex(o, 0, 0, r));
+			vertices.Add(Util.MakeVertex(o, 1, 0, r));
+			vertices.Add(Util.MakeVertex(o, 0, 1, r));
+			vertices.Add(Util.MakeVertex(o, 1, 1, r));
+
+			indices.Add(offset);
+			indices.Add((ushort)(offset + 1));
+			indices.Add((ushort)(offset + 2));
+
+			indices.Add((ushort)(offset + 1));
+			indices.Add((ushort)(offset + 3));
+			indices.Add((ushort)(offset + 2));
+		}
+	}
+}