BACKENDS: OPENGL: Allow the backend to specify the render target

For now only backbuffer is used.

backends/graphics/android/android-graphics.cpp

@@ -96,11 +96,13 @@ void AndroidGraphicsManager::initSurface() {
 	if (JNI::egl_bits_per_pixel == 16) {
 		// We default to RGB565 and RGBA5551 which is closest to what we setup in Java side
 		notifyContextCreate(OpenGL::kContextGLES2,
+				new OpenGL::Backbuffer(),
 				Graphics::PixelFormat(2, 5, 6, 5, 0, 11, 5, 0, 0),
 				Graphics::PixelFormat(2, 5, 5, 5, 1, 11, 6, 1, 0));
 	} else {
 		// If not 16, this must be 24 or 32 bpp so make use of them
 		notifyContextCreate(OpenGL::kContextGLES2,
+				new OpenGL::Backbuffer(),
 #ifdef SCUMM_BIG_ENDIAN
 				Graphics::PixelFormat(3, 8, 8, 8, 0, 16, 8, 0, 0),
 				Graphics::PixelFormat(4, 8, 8, 8, 8, 24, 16, 8, 0)
@@ -234,7 +236,7 @@ void AndroidGraphicsManager::refreshScreen() {
 }
 
 void AndroidGraphicsManager::touchControlDraw(int16 x, int16 y, int16 w, int16 h, const Common::Rect &clip) {
-	_backBuffer.enableBlend(OpenGL::Framebuffer::kBlendModeTraditionalTransparency);
+	_targetBuffer->enableBlend(OpenGL::Framebuffer::kBlendModeTraditionalTransparency);
 	OpenGL::Pipeline *pipeline = getPipeline();
 	pipeline->activate();
 	pipeline->drawTexture(_touchcontrols->getGLTexture(),

backends/graphics/opengl/opengl-graphics.cpp

@@ -71,7 +71,7 @@ namespace OpenGL {
 OpenGLGraphicsManager::OpenGLGraphicsManager()
 	: _currentState(), _oldState(), _transactionMode(kTransactionNone), _screenChangeID(1 << (sizeof(int) * 8 - 2)),
 	  _pipeline(nullptr), _stretchMode(STRETCH_FIT),
-	  _defaultFormat(), _defaultFormatAlpha(),
+	  _defaultFormat(), _defaultFormatAlpha(), _targetBuffer(nullptr),
 	  _gameScreen(nullptr), _overlay(nullptr),
 	  _cursor(nullptr), _cursorMask(nullptr),
 	  _cursorHotspotX(0), _cursorHotspotY(0),
@@ -105,6 +105,7 @@ OpenGLGraphicsManager::~OpenGLGraphicsManager() {
 	ShaderManager::destroy();
 #endif
 	delete _pipeline;
+	delete _targetBuffer;
 }
 
 bool OpenGLGraphicsManager::hasFeature(OSystem::Feature f) const {
@@ -609,16 +610,16 @@ void OpenGLGraphicsManager::renderCursor() {
 	the inversion and opacity mask at once.  We use 1-srcAlpha instead of srcAlpha so zero-fill is transparent.
 	*/
 	if (_cursorMask) {
-		_backBuffer.enableBlend(Framebuffer::kBlendModeMaskAlphaAndInvertByColor);
+		_targetBuffer->enableBlend(Framebuffer::kBlendModeMaskAlphaAndInvertByColor);
 
 		_pipeline->drawTexture(_cursorMask->getGLTexture(),
 							   _cursorX - _cursorHotspotXScaled + _shakeOffsetScaled.x,
 							   _cursorY - _cursorHotspotYScaled + _shakeOffsetScaled.y,
 							   _cursorWidthScaled, _cursorHeightScaled);
 
-		_backBuffer.enableBlend(Framebuffer::kBlendModeAdditive);
+		_targetBuffer->enableBlend(Framebuffer::kBlendModeAdditive);
 	} else
-		_backBuffer.enableBlend(Framebuffer::kBlendModePremultipliedTransparency);
+		_targetBuffer->enableBlend(Framebuffer::kBlendModePremultipliedTransparency);
 
 	_pipeline->drawTexture(_cursor->getGLTexture(),
 						   _cursorX - _cursorHotspotXScaled + _shakeOffsetScaled.x,
@@ -687,14 +688,14 @@ void OpenGLGraphicsManager::updateScreen() {
 		// The scissor test is enabled to:
 		// - Clip the cursor to the game screen
 		// - Clip the game screen when the shake offset is non-zero
-		_backBuffer.enableScissorTest(true);
+		_targetBuffer->enableScissorTest(true);
 	}
 
 	// Don't draw cursor if it's not visible or there is none
 	bool drawCursor = _cursorVisible && _cursor;
 
 	// Alpha blending is disabled when drawing the screen
-	_backBuffer.enableBlend(Framebuffer::kBlendModeDisabled);
+	_targetBuffer->enableBlend(Framebuffer::kBlendModeDisabled);
 
 	// First step: Draw the (virtual) game screen.
 	_pipeline->drawTexture(_gameScreen->getGLTexture(), _gameDrawRect.left, _gameDrawRect.top, _gameDrawRect.width(), _gameDrawRect.height());
@@ -710,7 +711,7 @@ void OpenGLGraphicsManager::updateScreen() {
 			drawCursor = false;
 
 			// Everything we need to clip has been clipped
-			_backBuffer.enableScissorTest(false);
+			_targetBuffer->enableScissorTest(false);
 		}
 
 		// Overlay must not be scaled and its cursor won't be either
@@ -722,7 +723,7 @@ void OpenGLGraphicsManager::updateScreen() {
 	if (_overlayVisible) {
 		int dstX = (_windowWidth - _overlayDrawRect.width()) / 2;
 		int dstY = (_windowHeight - _overlayDrawRect.height()) / 2;
-		_backBuffer.enableBlend(Framebuffer::kBlendModeTraditionalTransparency);
+		_targetBuffer->enableBlend(Framebuffer::kBlendModeTraditionalTransparency);
 		_pipeline->drawTexture(_overlay->getGLTexture(), dstX, dstY, _overlayDrawRect.width(), _overlayDrawRect.height());
 	}
 
@@ -731,13 +732,13 @@ void OpenGLGraphicsManager::updateScreen() {
 		renderCursor();
 
 	if (!_overlayVisible) {
-		_backBuffer.enableScissorTest(false);
+		_targetBuffer->enableScissorTest(false);
 	}
 
 #ifdef USE_OSD
 	// Fourth step: Draw the OSD.
 	if (_osdMessageSurface || _osdIconSurface) {
-		_backBuffer.enableBlend(Framebuffer::kBlendModeTraditionalTransparency);
+		_targetBuffer->enableBlend(Framebuffer::kBlendModeTraditionalTransparency);
 	}
 
 	if (_osdMessageSurface) {
@@ -1261,7 +1262,7 @@ void OpenGLGraphicsManager::grabPalette(byte *colors, uint start, uint num) cons
 
 void OpenGLGraphicsManager::handleResizeImpl(const int width, const int height) {
 	// Setup backbuffer size.
-	_backBuffer.setSize(width, height);
+	_targetBuffer->setSize(width, height);
 
 	uint overlayWidth = width;
 	uint overlayHeight = height;
@@ -1312,8 +1313,13 @@ void OpenGLGraphicsManager::handleResizeImpl(const int width, const int height)
 }
 
 void OpenGLGraphicsManager::notifyContextCreate(ContextType type,
+	Framebuffer *target,
 	const Graphics::PixelFormat &defaultFormat,
 	const Graphics::PixelFormat &defaultFormatAlpha) {
+	// Set up the target: backbuffer usually
+	delete _targetBuffer;
+	_targetBuffer = target;
+
 	// Initialize pipeline.
 	delete _pipeline;
 	_pipeline = nullptr;
@@ -1361,9 +1367,9 @@ void OpenGLGraphicsManager::notifyContextCreate(ContextType type,
 	// Setup backbuffer state.
 
 	// Default to opaque black as clear color.
-	_backBuffer.setClearColor(0.0f, 0.0f, 0.0f, 1.0f);
+	_targetBuffer->setClearColor(0.0f, 0.0f, 0.0f, 1.0f);
 
-	_pipeline->setFramebuffer(&_backBuffer);
+	_pipeline->setFramebuffer(_targetBuffer);
 
 	// We use a "pack" alignment (when reading from textures) to 4 here,
 	// since the only place where we really use it is the BMP screenshot
@@ -1450,6 +1456,10 @@ void OpenGLGraphicsManager::notifyContextDestroy() {
 	_libretroPipeline = nullptr;
 #endif
 
+	// Destroy the target
+	delete _targetBuffer;
+	_targetBuffer = nullptr;
+
 	// Rest our context description since the context is gone soon.
 	OpenGLContext.reset();
 }
@@ -1632,7 +1642,7 @@ void OpenGLGraphicsManager::recalculateDisplayAreas() {
 	// Setup drawing limitation for game graphics.
 	// This involves some trickery because OpenGL's viewport coordinate system
 	// is upside down compared to ours.
-	_backBuffer.setScissorBox(_gameDrawRect.left,
+	_targetBuffer->setScissorBox(_gameDrawRect.left,
 	                          _windowHeight - _gameDrawRect.height() - _gameDrawRect.top,
 	                          _gameDrawRect.width(),
 	                          _gameDrawRect.height());

backends/graphics/opengl/opengl-graphics.h

@@ -149,6 +149,7 @@ protected:
 	 */
 	void notifyContextCreate(
 			ContextType type,
+			Framebuffer *target,
 			const Graphics::PixelFormat &defaultFormat,
 			const Graphics::PixelFormat &defaultFormatAlpha);
 
@@ -339,9 +340,9 @@ protected:
 	Graphics::PixelFormat _defaultFormatAlpha;
 
 	/**
-	 * Render back buffer.
+	 * Render target.
 	 */
-	Backbuffer _backBuffer;
+	Framebuffer *_targetBuffer;
 
 	/**
 	 * The rendering surface for the virtual game screen.

backends/graphics/openglsdl/openglsdl-graphics.cpp

@@ -547,7 +547,7 @@ bool OpenGLSdlGraphicsManager::setupMode(uint width, uint height) {
 		warning("Unable to %s VSync: %s", _vsync ? "enable" : "disable", SDL_GetError());
 	}
 
-	notifyContextCreate(_glContextType, rgba8888, rgba8888);
+	notifyContextCreate(_glContextType, new OpenGL::Backbuffer(), rgba8888, rgba8888);
 	int actualWidth, actualHeight;
 	getWindowSizeFromSdl(&actualWidth, &actualHeight);
 
@@ -616,7 +616,7 @@ bool OpenGLSdlGraphicsManager::setupMode(uint width, uint height) {
 	_lastVideoModeLoad = SDL_GetTicks();
 
 	if (_hwScreen) {
-		notifyContextCreate(_glContextType, rgba8888, rgba8888);
+		notifyContextCreate(_glContextType, new OpenGL::Backbuffer(), rgba8888, rgba8888);
 		handleResize(_hwScreen->w, _hwScreen->h);
 	}