openglscreenshothelper.cpp

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/*
 * The ManaPlus Client
 * Copyright (C) 2004-2009 The Mana World Development Team
 * Copyright (C) 2009-2010 The Mana Developers
 * Copyright (C) 2011-2019 The ManaPlus Developers
 *
 * This file is part of The ManaPlus Client.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */

#ifdef USE_OPENGL

#include "resources/openglscreenshothelper.h"

#include "configuration.h"
#include "graphicsmanager.h"

#include "render/graphics.h"
#include "render/opengl/mgl.h"
#ifdef __native_client__
#include "render/opengl/naclglfunctions.h"
#endif // __native_client__

#include "debug.h"

OpenGLScreenshotHelper::OpenGLScreenshotHelper() :
 ScreenshotHelper(),
 mFbo()
{
}

OpenGLScreenshotHelper::~OpenGLScreenshotHelper()
{
}

void OpenGLScreenshotHelper::prepare()
{
 if (config.getBoolValue("usefbo"))
 graphicsManager.createFBO(mainGraphics->mWidth,
 mainGraphics->mHeight,
 &mFbo);
}

SDL_Surface *OpenGLScreenshotHelper::getScreenshot()
{
 const int h = mainGraphics->mHeight;
 const int w = mainGraphics->mWidth - (mainGraphics->mWidth % 4);
 GLint pack = 1;

 SDL_Surface *const screenshot = MSDL_CreateRGBSurface(
 SDL_SWSURFACE, w, h, 24,
 0xff0000, 0x00ff00, 0x0000ff, 0x000000);

 if (screenshot == nullptr)
 return nullptr;

 if (SDL_MUSTLOCK(screenshot))
 SDL_LockSurface(screenshot);

 const size_t lineSize = 3 * w;
 GLubyte *const buf = new GLubyte[lineSize];

 // Grap the pixel buffer and write it to the SDL surface
 mglGetIntegerv(GL_PACK_ALIGNMENT, &pack);
 mglPixelStorei(GL_PACK_ALIGNMENT, 1);
 mglReadPixels(0, 0, w, h, GL_RGB, GL_UNSIGNED_BYTE, screenshot->pixels);

 // Flip the screenshot, as OpenGL has 0,0 in bottom left
 const int h2 = h / 2;
 for (int i = 0; i < h2; i++)
 {
 GLubyte *const top = static_cast<GLubyte*>(
 screenshot->pixels) + lineSize * i;
 GLubyte *const bot = static_cast<GLubyte*>(
 screenshot->pixels) + lineSize * (h - 1 - i);

 memcpy(buf, top, lineSize);
 memcpy(top, bot, lineSize);
 memcpy(bot, buf, lineSize);
 }

 delete [] buf;

 if (config.getBoolValue("usefbo"))
 graphicsManager.deleteFBO(&mFbo);

 mglPixelStorei(GL_PACK_ALIGNMENT, pack);

 if (SDL_MUSTLOCK(screenshot))
 SDL_UnlockSurface(screenshot);

 return screenshot;
}

#endif // USE_OPENGL