From 54dee43590a909df4995cd341fb2d3f645db4345 Mon Sep 17 00:00:00 2001
From: Chris Forbes <chrisf@ijw.co.nz>
Date: Mon, 4 Jul 2011 21:13:22 +1200
Subject: [PATCH] test for required extensions in Cg renderer too

---
 OpenRA.Renderer.Cg/GraphicsDevice.cs | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/OpenRA.Renderer.Cg/GraphicsDevice.cs b/OpenRA.Renderer.Cg/GraphicsDevice.cs
index e6962992f0..0755c59a58 100755
--- a/OpenRA.Renderer.Cg/GraphicsDevice.cs
+++ b/OpenRA.Renderer.Cg/GraphicsDevice.cs
@@ -11,6 +11,7 @@
 using System;
 using System.Drawing;
 using System.IO;
+using System.Linq;
 using OpenRA.FileFormats.Graphics;
 using Tao.Cg;
 using Tao.OpenGl;
@@ -119,6 +120,23 @@ namespace OpenRA.Renderer.Cg
 
 			CheckGlError();
 
+			// Test for required extensions
+			var required = new string[]
+			{
+				"GL_ARB_vertex_program",
+				"GL_ARB_fragment_program",
+				"GL_ARB_vertex_buffer_object",
+			};
+
+			var extensions = Gl.glGetString(Gl.GL_EXTENSIONS);
+			var missingExtensions = required.Where( r => !extensions.Contains(r) ).ToArray();
+
+			if (missingExtensions.Any())
+			{
+				WriteGraphicsLog("Unsupported GPU: Missing extensions: {0}".F(string.Join(",", missingExtensions)));
+				throw new InvalidProgramException("Unsupported GPU. See graphics.log for details.");
+			}
+
 			windowSize = size;
 
 			cgContext = Tao.Cg.Cg.cgCreateContext();