From b2b32aea5bafeeb3e036d1d347f63f5e7f46715e Mon Sep 17 00:00:00 2001
From: rdb <git@rdb.name>
Date: Sun, 31 Jan 2010 08:48:41 +0000
Subject: [PATCH] Fix longstanding bug with the FPU being forced into
 single-precision mode on Windows

---
 panda/src/windisplay/winDetectDx.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/panda/src/windisplay/winDetectDx.h b/panda/src/windisplay/winDetectDx.h
index 9745dca16e..37ca807f3d 100644
--- a/panda/src/windisplay/winDetectDx.h
+++ b/panda/src/windisplay/winDetectDx.h
@@ -538,6 +538,8 @@ static int get_display_information (DisplaySearchParameters &display_search_para
           else {
             behavior_flags = D3DCREATE_SOFTWARE_VERTEXPROCESSING;
           }
+          // This is important to prevent DirectX from forcing the FPU into single-precision mode.
+          behavior_flags |= D3DCREATE_FPU_PRESERVE;
 
           HRESULT result;