From 5a450b5eaa3dcc937223e083c8733b519c344279 Mon Sep 17 00:00:00 2001
From: Rachael Alexanderson <eruanna@drdteam.org>
Date: Wed, 3 May 2017 15:56:33 -0400
Subject: [PATCH] - fixed: +FLIPSPRITE works in mirrors in OpenGL now.

---
 src/gl/scene/gl_sprite.cpp | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/src/gl/scene/gl_sprite.cpp b/src/gl/scene/gl_sprite.cpp
index 1cd2070b8..629f8acb9 100644
--- a/src/gl/scene/gl_sprite.cpp
+++ b/src/gl/scene/gl_sprite.cpp
@@ -814,7 +814,12 @@ void GLSprite::Process(AActor* thing, sector_t * sector, int thruportal)
 		if (thing->renderflags & RF_YFLIP) std::swap(vt, vb);
 
 		gltexture->GetSpriteRect(&r);
-		if ((mirror ^ !!(thing->renderflags & RF_XFLIP)) || (thing->flags7 & MF7_SPRITEFLIP))
+
+		// [SP] SpriteFlip
+		if (thing->flags7 & MF7_SPRITEFLIP)
+			thing->renderflags ^= RF_XFLIP;
+
+		if (mirror ^ !!(thing->renderflags & RF_XFLIP))
 		{
 			r.left = -r.width - r.left;	// mirror the sprite's x-offset
 			ul = gltexture->GetSpriteUL();
@@ -826,6 +831,9 @@ void GLSprite::Process(AActor* thing, sector_t * sector, int thruportal)
 			ur = gltexture->GetSpriteUL();
 		}
 
+		if (thing->flags7 & MF7_SPRITEFLIP) // [SP] Flip back
+			thing->renderflags ^= RF_XFLIP;
+
 		r.Scale(sprscale.X, sprscale.Y);
 
 		float rightfac = -r.left;