line rendering - selection box!!

OpenRa.Game/Graphics/LineRenderer.cs

@@ -0,0 +1,66 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using Ijw.DirectX;
+using System.Runtime.InteropServices;
+using System.Drawing;
+
+namespace OpenRa.Game.Graphics
+{
+    class LineRenderer
+    {
+        Renderer renderer;
+        FvfVertexBuffer<Vertex> vertexBuffer;
+        IndexBuffer indexBuffer;            /* kindof a waste of space, but the GPU likes indexing, oh well */
+
+        const int linesPerBatch = 1024;
+
+        Vertex[] vertices = new Vertex[2 * linesPerBatch];
+        ushort[] indices = new ushort[2 * linesPerBatch];
+        int lines = 0;
+        int nv = 0, ni = 0;
+
+        public LineRenderer(Renderer renderer)
+        {
+            this.renderer = renderer;
+            vertexBuffer = new FvfVertexBuffer<Vertex>(renderer.Device, vertices.Length, Vertex.Format);
+            indexBuffer = new IndexBuffer(renderer.Device, indices.Length);
+        }
+
+        public void Flush()
+        {
+            if (lines > 0)
+            {
+                renderer.LineShader.Render(() =>
+                {
+                    vertexBuffer.SetData(vertices);
+                    indexBuffer.SetData(indices);
+                    renderer.DrawBatch(vertexBuffer, indexBuffer,
+                        nv, ni / 2, null, PrimitiveType.LineList);
+                });
+
+                nv = 0; ni = 0;
+                lines = 0;
+            }
+        }
+
+        public void DrawLine(float2 start, float2 end, Color startColor, Color endColor)
+        {
+            indices[ni++] = (ushort)nv;
+            
+            vertices[nv++] = new Vertex(start,
+                new float2(startColor.R / 255.0f, startColor.G / 255.0f),
+                new float2(startColor.B / 255.0f, startColor.A / 255.0f));
+
+            indices[ni++] = (ushort)nv;
+
+            vertices[nv++] = new Vertex(end,
+                new float2(endColor.R / 255.0f, endColor.G / 255.0f),
+                new float2(endColor.B / 255.0f, endColor.A / 255.0f));
+
+            if (++lines >= linesPerBatch)
+                Flush();
+        }
+    }
+}