OPENGL/SDL: Add screenshot support.

3 files changed, 93 insertions, 1 deletions

diff --git a/backends/graphics/opengl/opengl-graphics.cpp b/backends/graphics/opengl/opengl-graphics.cpp
index e3c56dccca..00e8dc358e 100644
--- a/backends/graphics/opengl/opengl-graphics.cpp
+++ b/backends/graphics/opengl/opengl-graphics.cpp
@@ -29,6 +29,7 @@
 #include "common/textconsole.h"
 #include "common/translation.h"
 #include "common/algorithm.h"
+#include "common/file.h"
 #ifdef USE_OSD
 #include "common/tokenizer.h"
 #include "common/rect.h"
@@ -849,6 +850,11 @@ void OpenGLGraphicsManager::notifyContextChange(const Graphics::PixelFormat &def
 
 	GLCALL(glEnable(GL_TEXTURE_2D));
 
+	// 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
+	// code and that requires the same alignment too.
+	GLCALL(glPixelStorei(GL_PACK_ALIGNMENT, 4));
+
 	// Query information needed by textures.
 	Texture::queryTextureInformation();
 
@@ -1082,4 +1088,61 @@ const Graphics::Font *OpenGLGraphicsManager::getFontOSD() {
 }
 #endif
 
+void OpenGLGraphicsManager::saveScreenshot(const Common::String &filename) const {
+	const uint width  = _outputScreenWidth;
+	const uint height = _outputScreenHeight;
+
+	// A line of a BMP image must have a size divisible by 4.
+	// We calculate the padding bytes needed here.
+	// Since we use a 3 byte per pixel mode, we can use width % 4 here, since
+	// it is equal to 4 - (width * 3) % 4. (4 - (width * Bpp) % 4, is the
+	// usual way of computing the padding bytes required).
+	const uint linePaddingSize = width % 4;
+	const uint lineSize        = width * 3 + linePaddingSize;
+
+	// Allocate memory for screenshot
+	uint8 *pixels = new uint8[lineSize * height];
+
+	// Get pixel data from OpenGL buffer
+	GLCALL(glReadPixels(0, 0, width, height, GL_RGB, GL_UNSIGNED_BYTE, pixels));
+
+	// BMP stores as BGR. Since we can't assume that GL_BGR is supported we
+	// will swap the components from the RGB we read to BGR on our own.
+	for (uint y = height; y-- > 0;) {
+		uint8 *line = pixels + y * lineSize;
+
+		for (uint x = width; x > 0; --x, line += 3) {
+			SWAP(line[0], line[2]);
+		}
+	}
+
+	// Open file
+	Common::DumpFile out;
+	out.open(filename);
+
+	// Write BMP header
+	out.writeByte('B');
+	out.writeByte('M');
+	out.writeUint32LE(height * lineSize + 54);
+	out.writeUint32LE(0);
+	out.writeUint32LE(54);
+	out.writeUint32LE(40);
+	out.writeUint32LE(width);
+	out.writeUint32LE(height);
+	out.writeUint16LE(1);
+	out.writeUint16LE(24);
+	out.writeUint32LE(0);
+	out.writeUint32LE(0);
+	out.writeUint32LE(0);
+	out.writeUint32LE(0);
+	out.writeUint32LE(0);
+	out.writeUint32LE(0);
+
+	// Write pixel data to BMP
+	out.write(pixels, lineSize * height);
+
+	// Free allocated memory
+	delete[] pixels;
+}
+
 } // End of namespace OpenGL
diff --git a/backends/graphics/opengl/opengl-graphics.h b/backends/graphics/opengl/opengl-graphics.h
index 67ad5aa067..ebfe38fb60 100644
--- a/backends/graphics/opengl/opengl-graphics.h
+++ b/backends/graphics/opengl/opengl-graphics.h
@@ -247,6 +247,14 @@ protected:
 	 */
 	virtual bool loadVideoMode(uint requestedWidth, uint requestedHeight, const Graphics::PixelFormat &format) = 0;
 
+	/**
+	 * Save a screenshot of the full display as BMP to the given file. This
+	 * uses Common::DumpFile for writing the screenshot.
+	 *
+	 * @param filename The output filename.
+	 */
+	void saveScreenshot(const Common::String &filename) const;
+
 private:
 	//
 	// OpenGL utilities
diff --git a/backends/graphics/openglsdl/openglsdl-graphics.cpp b/backends/graphics/openglsdl/openglsdl-graphics.cpp
index a1a3e8590a..925237b75e 100644
--- a/backends/graphics/openglsdl/openglsdl-graphics.cpp
+++ b/backends/graphics/openglsdl/openglsdl-graphics.cpp
@@ -355,6 +355,26 @@ bool OpenGLSdlGraphicsManager::notifyEvent(const Common::Event &event) {
 #endif
 				return true;
 			}
+
+			if (event.kbd.keycode == Common::KEYCODE_s) {
+				// Alt-s creates a screenshot
+				Common::String filename;
+
+				for (int n = 0;; n++) {
+					SDL_RWops *file;
+
+					filename = Common::String::format("scummvm%05d.bmp", n);
+					file = SDL_RWFromFile(filename.c_str(), "r");
+					if (!file)
+						break;
+					SDL_RWclose(file);
+				}
+
+				saveScreenshot(filename.c_str());
+				debug("Saved screenshot '%s'", filename.c_str());
+
+				return true;
+			}
 		} else if (event.kbd.hasFlags(Common::KBD_CTRL | Common::KBD_ALT)) {
 			if (   event.kbd.keycode == Common::KEYCODE_PLUS || event.kbd.keycode == Common::KEYCODE_MINUS
 			    || event.kbd.keycode == Common::KEYCODE_KP_PLUS || event.kbd.keycode == Common::KEYCODE_KP_MINUS) {
@@ -502,7 +522,8 @@ bool OpenGLSdlGraphicsManager::notifyEvent(const Common::Event &event) {
 bool OpenGLSdlGraphicsManager::isHotkey(const Common::Event &event) {
 	if (event.kbd.hasFlags(Common::KBD_ALT)) {
 		return    event.kbd.keycode == Common::KEYCODE_RETURN
-		       || event.kbd.keycode == (Common::KeyCode)SDLK_KP_ENTER;
+		       || event.kbd.keycode == (Common::KeyCode)SDLK_KP_ENTER
+		       || event.kbd.keycode == Common::KEYCODE_s;
 	} else if (event.kbd.hasFlags(Common::KBD_CTRL | Common::KBD_ALT)) {
 		return    event.kbd.keycode == Common::KEYCODE_PLUS || event.kbd.keycode == Common::KEYCODE_MINUS
 		       || event.kbd.keycode == Common::KEYCODE_KP_PLUS || event.kbd.keycode == Common::KEYCODE_KP_MINUS