From eefd0c17b6722da6ed0b1d5dcf8e866ce6aef38c Mon Sep 17 00:00:00 2001
From: Thomas Harte <thomas.harte@gmail.com>
Date: Fri, 1 Jul 2016 16:27:45 -0400
Subject: [PATCH] Actually, I guess that to fulfil the contract I can't
 silently decide not to draw if I'm being told I definitely need to draw.

---
 Outputs/CRT/Internals/CRTOpenGL.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Outputs/CRT/Internals/CRTOpenGL.cpp b/Outputs/CRT/Internals/CRTOpenGL.cpp
index 497eb0167..21e606fd9 100644
--- a/Outputs/CRT/Internals/CRTOpenGL.cpp
+++ b/Outputs/CRT/Internals/CRTOpenGL.cpp
@@ -193,7 +193,7 @@ void OpenGLOutputBuilder::draw_frame(unsigned int output_width, unsigned int out
 	if(_fence != nullptr)
 	{
 		// if the GPU is still busy, don't wait; we'll catch it next time
-		if(glClientWaitSync(_fence, GL_SYNC_FLUSH_COMMANDS_BIT, 0) == GL_TIMEOUT_EXPIRED)
+		if(glClientWaitSync(_fence, GL_SYNC_FLUSH_COMMANDS_BIT, only_if_dirty ? 0 : GL_TIMEOUT_IGNORED) == GL_TIMEOUT_EXPIRED)
 		{
 			_draw_mutex->unlock();
 			return;