SURFACESDL: Add support for filtering feature when using SDL2

This implements the request from ticket #9573: SDL1/2: Different
rendering/filtering?

2 files changed, 48 insertions, 0 deletions

diff --git a/backends/graphics/surfacesdl/surfacesdl-graphics.cpp b/backends/graphics/surfacesdl/surfacesdl-graphics.cpp
index 46e243c945..cc1d8dbafa 100644
--- a/backends/graphics/surfacesdl/surfacesdl-graphics.cpp
+++ b/backends/graphics/surfacesdl/surfacesdl-graphics.cpp
@@ -190,6 +190,10 @@ SurfaceSdlGraphicsManager::SurfaceSdlGraphicsManager(SdlEventSource *sdlEventSou
 #else
 	_videoMode.fullscreen = true;
 #endif
+
+#if SDL_VERSION_ATLEAST(2, 0, 0)
+	_videoMode.filtering = ConfMan.getBool("filtering");
+#endif
 }
 
 SurfaceSdlGraphicsManager::~SurfaceSdlGraphicsManager() {
@@ -227,6 +231,9 @@ bool SurfaceSdlGraphicsManager::hasFeature(OSystem::Feature f) {
 	return
 		(f == OSystem::kFeatureFullscreenMode) ||
 		(f == OSystem::kFeatureAspectRatioCorrection) ||
+#if SDL_VERSION_ATLEAST(2, 0, 0)
+		(f == OSystem::kFeatureFilteringMode) ||
+#endif
 		(f == OSystem::kFeatureCursorPalette) ||
 		(f == OSystem::kFeatureIconifyWindow);
 }
@@ -239,6 +246,11 @@ void SurfaceSdlGraphicsManager::setFeatureState(OSystem::Feature f, bool enable)
 	case OSystem::kFeatureAspectRatioCorrection:
 		setAspectRatioCorrection(enable);
 		break;
+#if SDL_VERSION_ATLEAST(2, 0, 0)
+	case OSystem::kFeatureFilteringMode:
+		setFilteringMode(enable);
+		break;
+#endif
 	case OSystem::kFeatureCursorPalette:
 		_cursorPaletteDisabled = !enable;
 		blitCursor();
@@ -263,6 +275,10 @@ bool SurfaceSdlGraphicsManager::getFeatureState(OSystem::Feature f) {
 		return _videoMode.fullscreen;
 	case OSystem::kFeatureAspectRatioCorrection:
 		return _videoMode.aspectRatioCorrection;
+#if SDL_VERSION_ATLEAST(2, 0, 0)
+	case OSystem::kFeatureFilteringMode:
+		return _videoMode.filtering;
+#endif
 	case OSystem::kFeatureCursorPalette:
 		return !_cursorPaletteDisabled;
 	default:
@@ -323,6 +339,12 @@ OSystem::TransactionError SurfaceSdlGraphicsManager::endGFXTransaction() {
 
 			_videoMode.mode = _oldVideoMode.mode;
 			_videoMode.scaleFactor = _oldVideoMode.scaleFactor;
+#if SDL_VERSION_ATLEAST(2, 0, 0)
+		} else if (_videoMode.filtering != _oldVideoMode.filtering) {
+			errors |= OSystem::kTransactionFilteringFailed;
+			
+			_videoMode.filtering = _oldVideoMode.filtering;
+#endif
 #ifdef USE_RGB_COLOR
 		} else if (_videoMode.format != _oldVideoMode.format) {
 			errors |= OSystem::kTransactionFormatNotSupported;
@@ -342,6 +364,9 @@ OSystem::TransactionError SurfaceSdlGraphicsManager::endGFXTransaction() {
 		if (_videoMode.fullscreen == _oldVideoMode.fullscreen &&
 			_videoMode.aspectRatioCorrection == _oldVideoMode.aspectRatioCorrection &&
 			_videoMode.mode == _oldVideoMode.mode &&
+#if SDL_VERSION_ATLEAST(2, 0, 0)
+			_videoMode.filtering == _oldVideoMode.filtering &&
+#endif
 			_videoMode.screenWidth == _oldVideoMode.screenWidth &&
 			_videoMode.screenHeight == _oldVideoMode.screenHeight) {
 
@@ -1267,6 +1292,20 @@ void SurfaceSdlGraphicsManager::setAspectRatioCorrection(bool enable) {
 	}
 }
 
+#if SDL_VERSION_ATLEAST(2, 0, 0)
+void SurfaceSdlGraphicsManager::setFilteringMode(bool enable) {
+	Common::StackLock lock(_graphicsMutex);
+
+	if (_oldVideoMode.setup && _oldVideoMode.filtering == enable)
+		return;
+
+	if (_transactionMode == kTransactionActive) {
+		_videoMode.filtering = enable;
+		_transactionDetails.needHotswap = true;
+	}
+}
+#endif
+
 void SurfaceSdlGraphicsManager::copyRectToScreen(const void *buf, int pitch, int x, int y, int w, int h) {
 	assert(_transactionMode == kTransactionNone);
 	assert(buf);
@@ -2542,6 +2581,8 @@ SDL_Surface *SurfaceSdlGraphicsManager::SDL_SetVideoMode(int width, int height,
 
 	SDL_GetWindowSize(_window->getSDLWindow(), &_windowWidth, &_windowHeight);
 	setWindowResolution(_windowWidth, _windowHeight);
+	
+	SDL_SetHint(SDL_HINT_RENDER_SCALE_QUALITY, _videoMode.filtering ? "linear" : "nearest");
 
 	_screenTexture = SDL_CreateTexture(_renderer, SDL_PIXELFORMAT_RGB565, SDL_TEXTUREACCESS_STREAMING, width, height);
 	if (!_screenTexture) {
diff --git a/backends/graphics/surfacesdl/surfacesdl-graphics.h b/backends/graphics/surfacesdl/surfacesdl-graphics.h
index 82f4a33d8e..bc2edc964c 100644
--- a/backends/graphics/surfacesdl/surfacesdl-graphics.h
+++ b/backends/graphics/surfacesdl/surfacesdl-graphics.h
@@ -250,6 +250,10 @@ protected:
 		bool aspectRatioCorrection;
 		AspectRatio desiredAspectRatio;
 
+#if SDL_VERSION_ATLEAST(2, 0, 0)
+		bool filtering;
+#endif
+
 		int mode;
 		int scaleFactor;
 
@@ -383,6 +387,9 @@ protected:
 
 	virtual void setFullscreenMode(bool enable);
 	virtual void setAspectRatioCorrection(bool enable);
+#if SDL_VERSION_ATLEAST(2, 0, 0)
+	virtual void setFilteringMode(bool enable);
+#endif
 
 	virtual int effectiveScreenHeight() const;