From aa39a6ce4b2285d1308eb4607bdd53d317304661 Mon Sep 17 00:00:00 2001
From: Thierry Crozat
Date: Thu, 13 Oct 2016 00:19:15 +0100
Subject: SURFACESDL: Improve toggling filtering on/off

We don't need to recreate the window when turning filtering on or off.
Only the texture needs to be recreated.
---
 .../graphics/surfacesdl/surfacesdl-graphics.cpp    | 26 +++++++++++++++++++++-
 backends/graphics/surfacesdl/surfacesdl-graphics.h |  4 ++++
 2 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/backends/graphics/surfacesdl/surfacesdl-graphics.cpp b/backends/graphics/surfacesdl/surfacesdl-graphics.cpp
index 2b62cc2c6e..90d079d151 100644
--- a/backends/graphics/surfacesdl/surfacesdl-graphics.cpp
+++ b/backends/graphics/surfacesdl/surfacesdl-graphics.cpp
@@ -313,6 +313,9 @@ void SurfaceSdlGraphicsManager::beginGFXTransaction() {
 	_transactionDetails.needUpdatescreen = false;
 
 	_transactionDetails.normal1xScaler = false;
+#if SDL_VERSION_ATLEAST(2, 0, 0)
+	_transactionDetails.needTextureUpdate = false;
+#endif
 #ifdef USE_RGB_COLOR
 	_transactionDetails.formatChanged = false;
 #endif
@@ -420,6 +423,12 @@ OSystem::TransactionError SurfaceSdlGraphicsManager::endGFXTransaction() {
 			if (_transactionDetails.needUpdatescreen)
 				internUpdateScreen();
 		}
+#if SDL_VERSION_ATLEAST(2, 0, 0)
+	} else if (_transactionDetails.needTextureUpdate) {
+		setGraphicsModeIntern();
+		recreateScreenTexture();
+		internUpdateScreen();
+#endif
 	} else if (_transactionDetails.needUpdatescreen) {
 		setGraphicsModeIntern();
 		internUpdateScreen();
@@ -1301,7 +1310,7 @@ void SurfaceSdlGraphicsManager::setFilteringMode(bool enable) {
 
 	if (_transactionMode == kTransactionActive) {
 		_videoMode.filtering = enable;
-		_transactionDetails.needHotswap = true;
+		_transactionDetails.needTextureUpdate = true;
 	}
 }
 #endif
@@ -2355,6 +2364,7 @@ bool SurfaceSdlGraphicsManager::handleScalerHotkeys(Common::KeyCode key) {
 			displayMessageOnOSD(_("Filtering disabled"));
 		}
 #endif
+		_forceFull = true;
 		internUpdateScreen();
 		return true;
 	}
@@ -2580,6 +2590,20 @@ void SurfaceSdlGraphicsManager::setWindowResolution(int width, int height) {
 	_forceFull = true;
 }
 
+void SurfaceSdlGraphicsManager::recreateScreenTexture() {
+	if (!_renderer)
+		return;
+
+	SDL_SetHint(SDL_HINT_RENDER_SCALE_QUALITY, _videoMode.filtering ? "linear" : "nearest");
+	
+	SDL_Texture *oldTexture = _screenTexture;
+	_screenTexture = SDL_CreateTexture(_renderer, SDL_PIXELFORMAT_RGB565, SDL_TEXTUREACCESS_STREAMING, _videoMode.hardwareWidth, _videoMode.hardwareHeight);
+	if (_screenTexture)
+		SDL_DestroyTexture(oldTexture);
+	else
+		_screenTexture = oldTexture;
+}
+
 SDL_Surface *SurfaceSdlGraphicsManager::SDL_SetVideoMode(int width, int height, int bpp, Uint32 flags) {
 	deinitializeRenderer();
 
diff --git a/backends/graphics/surfacesdl/surfacesdl-graphics.h b/backends/graphics/surfacesdl/surfacesdl-graphics.h
index bc2edc964c..975cbfe27b 100644
--- a/backends/graphics/surfacesdl/surfacesdl-graphics.h
+++ b/backends/graphics/surfacesdl/surfacesdl-graphics.h
@@ -198,6 +198,7 @@ protected:
 	int _windowWidth, _windowHeight;
 	void deinitializeRenderer();
 	void setWindowResolution(int width, int height);
+	void recreateScreenTexture();
 
 	SDL_Surface *SDL_SetVideoMode(int width, int height, int bpp, Uint32 flags);
 	void SDL_UpdateRects(SDL_Surface *screen, int numrects, SDL_Rect *rects);
@@ -237,6 +238,9 @@ protected:
 		bool needHotswap;
 		bool needUpdatescreen;
 		bool normal1xScaler;
+#if SDL_VERSION_ATLEAST(2, 0, 0)
+		bool needTextureUpdate;
+#endif
 #ifdef USE_RGB_COLOR
 		bool formatChanged;
 #endif
-- 
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