OPENGL: Commenting.

svn-id: r51338

3 files changed, 52 insertions, 17 deletions

diff --git a/backends/graphics/opengl/gltexture.cpp b/backends/graphics/opengl/gltexture.cpp
index 679538585f..708788eeae 100644
--- a/backends/graphics/opengl/gltexture.cpp
+++ b/backends/graphics/opengl/gltexture.cpp
@@ -97,6 +97,9 @@ GLTexture::~GLTexture() {
 }
 
 void GLTexture::refresh() {
+	// Delete previous texture
+	glDeleteTextures(1, &_textureName); CHECK_GL_ERROR();
+
 	// Generate the texture ID
 	glGenTextures(1, &_textureName); CHECK_GL_ERROR();
 	_refresh = true;
diff --git a/backends/graphics/opengl/opengl-graphics.cpp b/backends/graphics/opengl/opengl-graphics.cpp
index 58ca7f09ce..a115878e53 100644
--- a/backends/graphics/opengl/opengl-graphics.cpp
+++ b/backends/graphics/opengl/opengl-graphics.cpp
@@ -355,6 +355,7 @@ void OpenGLGraphicsManager::copyRectToScreen(const byte *buf, int pitch, int x,
 		dst += _screenData.pitch;
 	}
 
+	// Extend dirty area if not full screen redraw is flagged
 	if (!_screenNeedsRedraw) {
 		const Common::Rect dirtyRect(x, y, x + w, y + h);
 		_screenDirtyRect.extend(dirtyRect);
@@ -514,6 +515,7 @@ void OpenGLGraphicsManager::copyRectToOverlay(const OverlayColor *buf, int pitch
 		}
 	}
 
+	// Extend dirty area if not full screen redraw is flagged
 	if (!_overlayNeedsRedraw) {
 		const Common::Rect dirtyRect(x, y, x + w, y + h);
 		_overlayDirtyRect.extend(dirtyRect);
@@ -797,21 +799,27 @@ void OpenGLGraphicsManager::refreshCursor() {
 }
 
 void OpenGLGraphicsManager::refreshCursorScale() {
+	// Get the window minimum scale factor. The cursor will mantain its original aspect
+	// ratio, and we do not want it to get too big if only one dimension is resized
 	float scaleFactor = MIN((float)_videoMode.hardwareWidth / _videoMode.screenWidth,
 		(float)_videoMode.hardwareHeight / _videoMode.screenHeight);
 
 	if (_cursorTargetScale >= scaleFactor && _videoMode.scaleFactor >= scaleFactor) {
+		// If the cursor target scale and the video mode scale factor are bigger than
+		// the current window scale, do not scale the cursor for the overlay
 		_cursorState.rW = _cursorState.w;
 		_cursorState.rH = _cursorState.h;
 		_cursorState.rHotX = _cursorState.hotX;
 		_cursorState.rHotY = _cursorState.hotY;
 	} else {
+		// Otherwise, scale the cursor for the overlay
 		_cursorState.rW = _cursorState.w * scaleFactor;
 		_cursorState.rH = _cursorState.h * scaleFactor;
 		_cursorState.rHotX = _cursorState.hotX * scaleFactor;
 		_cursorState.rHotY = _cursorState.hotY * scaleFactor;
 	}
 
+	// Always scale the cursor for the game
 	_cursorState.vW = _cursorState.w * scaleFactor;
 	_cursorState.vH = _cursorState.h * scaleFactor;
 	_cursorState.vHotX = _cursorState.hotX * scaleFactor;
@@ -846,36 +854,36 @@ void OpenGLGraphicsManager::getGLPixelFormat(Graphics::PixelFormat pixelFormat,
 		glFormat = GL_RGB;
 		gltype = GL_UNSIGNED_BYTE;
 	} else {
-		error("Pixel format not supported");
+		error("OpenGLGraphicsManager: Pixel format not supported");
 	}
 }
 
 void OpenGLGraphicsManager::internUpdateScreen() {
-	// Clear the screen
+	// Clear the screen buffer
 	glClear(GL_COLOR_BUFFER_BIT); CHECK_GL_ERROR();
 
-	// Draw the game screen
 	if (_screenNeedsRedraw || !_screenDirtyRect.isEmpty())
 		// Refresh texture if dirty
 		refreshGameScreen();
 
+	// Draw the game screen
 	_gameTexture->drawTexture(0, 0, _videoMode.hardwareWidth, _videoMode.hardwareHeight);
 
-	// Draw the overlay
 	if (_overlayVisible) {
-		// Refresh texture if dirty
 		if (_overlayNeedsRedraw || !_overlayDirtyRect.isEmpty())
+			// Refresh texture if dirty
 			refreshOverlay();
 
+		// Draw the overlay
 		_overlayTexture->drawTexture(0, 0, _videoMode.hardwareWidth, _videoMode.hardwareHeight);
 	}
 
-	// Draw the cursor
 	if (_cursorVisible) {
-		// Refresh texture if dirty
 		if (_cursorNeedsRedraw)
+			// Refresh texture if dirty
 			refreshCursor();
 
+		// Draw the cursor
 		if (_overlayVisible)
 			_cursorTexture->drawTexture(_cursorState.x - _cursorState.rHotX,
 				_cursorState.y - _cursorState.rHotY, _cursorState.rW, _cursorState.rH);
@@ -886,7 +894,7 @@ void OpenGLGraphicsManager::internUpdateScreen() {
 
 #ifdef USE_OSD
 	if (_osdAlpha > 0) {
-		// Updated alpha value
+		// Update alpha value
 		const int diff = g_system->getMillis() - _osdFadeStartTime;
 		if (diff > 0) {
 			if (diff >= kOSDFadeOutDuration) {
@@ -898,13 +906,13 @@ void OpenGLGraphicsManager::internUpdateScreen() {
 			}
 		}
 		// Set the osd transparency
-		glColor4f(1.0f, 1.0f, 1.0f, _osdAlpha / 100.0f);
+		glColor4f(1.0f, 1.0f, 1.0f, _osdAlpha / 100.0f); CHECK_GL_ERROR();
 
 		// Draw the osd texture
 		_osdTexture->drawTexture(0, 0, _videoMode.hardwareWidth, _videoMode.hardwareHeight);
 
 		// Reset color
-		glColor4f(1.0f, 1.0f, 1.0f, 1.0f);
+		glColor4f(1.0f, 1.0f, 1.0f, 1.0f); CHECK_GL_ERROR();
 	}
 #endif
 }
@@ -980,11 +988,14 @@ void OpenGLGraphicsManager::loadTextures() {
 	_cursorTexture->setFilter(filter);
 
 	if (_transactionDetails.newContext || _transactionDetails.filterChanged) {
+		// If the context was destroyed or it is needed to change the texture filter
+		// we need to recreate the textures
 		_gameTexture->refresh();
 		_overlayTexture->refresh();
 		_cursorTexture->refresh();
 	}
 
+	// Allocate texture memory and finish refreshing
 	_gameTexture->allocBuffer(_videoMode.screenWidth, _videoMode.screenHeight);
 	_overlayTexture->allocBuffer(_videoMode.overlayWidth, _videoMode.overlayHeight);
 	_cursorTexture->allocBuffer(_cursorState.w, _cursorState.h);
@@ -1113,10 +1124,11 @@ bool OpenGLGraphicsManager::saveScreenshot(const char *filename) {
 	uint8 *pixels = new uint8[width * height * 3];
 
 	// Get pixel data from opengl buffer
-	if (_formatBGR)
-		glReadPixels(0, 0, width, height, GL_BGR, GL_UNSIGNED_BYTE, pixels);
-	else
-		glReadPixels(0, 0, width, height, GL_RGB, GL_UNSIGNED_BYTE, pixels);
+	if (_formatBGR) {
+		glReadPixels(0, 0, width, height, GL_BGR, GL_UNSIGNED_BYTE, pixels); CHECK_GL_ERROR();
+	} else {
+		glReadPixels(0, 0, width, height, GL_RGB, GL_UNSIGNED_BYTE, pixels); CHECK_GL_ERROR();
+	}
 
 	// Open file
 	Common::DumpFile out;
diff --git a/backends/graphics/openglsdl/openglsdl-graphics.cpp b/backends/graphics/openglsdl/openglsdl-graphics.cpp
index 880a38dbc2..ea01727238 100644
--- a/backends/graphics/openglsdl/openglsdl-graphics.cpp
+++ b/backends/graphics/openglsdl/openglsdl-graphics.cpp
@@ -118,7 +118,7 @@ Common::List<Graphics::PixelFormat> OpenGLSdlGraphicsManager::getSupportedFormat
 		if (RGBList[i] != format)
 			list.push_back(RGBList[i]);
 	}
-	//list.push_back(Graphics::PixelFormat::createFormatCLUT8());
+	list.push_back(Graphics::PixelFormat::createFormatCLUT8());
 	return list;
 }
 
@@ -148,6 +148,8 @@ void OpenGLSdlGraphicsManager::warpMouse(int x, int y) {
 bool OpenGLSdlGraphicsManager::loadGFXMode() {
 	_videoMode.overlayWidth = _videoMode.screenWidth * _videoMode.scaleFactor;
 	_videoMode.overlayHeight = _videoMode.screenHeight * _videoMode.scaleFactor;
+
+	// If the screen was resized, do not change its size
 	if (!_screenResized) {
 		_videoMode.hardwareWidth = _videoMode.overlayWidth;
 		_videoMode.hardwareHeight = _videoMode.overlayHeight;
@@ -161,10 +163,13 @@ bool OpenGLSdlGraphicsManager::loadGFXMode() {
 	SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE, 16);
 	SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
 
+	// Find the best mode for fullscreen
 	if (_videoMode.fullscreen) {
 		SDL_Rect const* const*availableModes = SDL_ListModes(NULL, SDL_FULLSCREEN | SDL_OPENGL);
 		const SDL_Rect *bestMode = NULL;
 		uint bestMetric = (uint)-1;
+
+		// Iterate over all available fullscreen modes
 		while (const SDL_Rect *mode = *availableModes++) {
 			if (mode->w < _videoMode.hardwareWidth)
 				continue;
@@ -180,18 +185,24 @@ bool OpenGLSdlGraphicsManager::loadGFXMode() {
 		}
 
 		if (bestMode) {
+			// If there is a suiting mode, use it
 			_videoMode.hardwareWidth = bestMode->w;
 			_videoMode.hardwareHeight = bestMode->h;
 		} else {
+			// If the last mode was in fullscreen, cancel GFX load
 			if (_oldVideoMode.fullscreen)
 				return false;
+
 			_videoMode.fullscreen = false;
 		}
 	}
 
+	// If changing to any fullscreen mode or from fullscreen,
+	// the OpenGL context is destroyed
 	if (_oldVideoMode.fullscreen || _videoMode.fullscreen)
 		_transactionDetails.newContext = true;
 
+	// Create our window
 	_hwscreen = SDL_SetVideoMode(_videoMode.hardwareWidth, _videoMode.hardwareHeight, 32,
 		_videoMode.fullscreen ? (SDL_FULLSCREEN | SDL_OPENGL) : (SDL_OPENGL | SDL_RESIZABLE)
 	);
@@ -202,13 +213,15 @@ bool OpenGLSdlGraphicsManager::loadGFXMode() {
 		if (!_oldVideoMode.setup) {
 			warning("SDL_SetVideoMode says we can't switch to that mode (%s)", SDL_GetError());
 			g_system->quit();
-		} else {
+		} else
+			// Cancel GFX load, and go back to last mode
 			return false;
-		}
 	}
 
+	// Check if the screen is BGR format
 	_formatBGR = _hwscreen->format->Rshift != 0;
 
+	// Call and return parent implementation of this method
 	return OpenGLGraphicsManager::loadGFXMode();
 }
 
@@ -220,8 +233,10 @@ void OpenGLSdlGraphicsManager::unloadGFXMode() {
 }
 
 void OpenGLSdlGraphicsManager::internUpdateScreen() {
+	// Call to parent implementation of this method
 	OpenGLGraphicsManager::internUpdateScreen();
 
+	// Swap OpenGL buffers
 	SDL_GL_SwapBuffers(); 
 }
 
@@ -377,10 +392,15 @@ bool OpenGLSdlGraphicsManager::notifyEvent(const Common::Event &event) {
 	// HACK: Handle special SDL event
 	case OSystem_SDL::kSdlEventResize:
 		beginGFXTransaction();
+			// Set the new screen size. It is saved on the mouse event as part of HACK,
+			// there is no common resize event
 			_videoMode.hardwareWidth = event.mouse.x;
 			_videoMode.hardwareHeight = event.mouse.y;
 			_screenResized = true;
 			_transactionDetails.sizeChanged = true;
+			// The OpenGL context is not always destroyed during resizing,
+			// however it is better to waste some time recreating it than
+			// getting a blank screen
 			_transactionDetails.newContext = true;
 		endGFXTransaction();
 		return true;