add hd snapshot (GL3.3 required)

include/Utils/snapshotHD.h

+/*******************************************************************************
+* CGoGN: Combinatorial and Geometric modeling with Generic N-dimensional Maps  *
+* version 0.1                                                                  *
+* Copyright (C) 2009-2012, IGG Team, LSIIT, University of Strasbourg           *
+*                                                                              *
+* This library is free software; you can redistribute it and/or modify it      *
+* under the terms of the GNU Lesser General Public License as published by the *
+* Free Software Foundation; either version 2.1 of the License, or (at your     *
+* option) any later version.                                                   *
+*                                                                              *
+* This library 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 Lesser General Public License  *
+* for more details.                                                            *
+*                                                                              *
+* You should have received a copy of the GNU Lesser General Public License     *
+* along with this library; if not, write to the Free Software Foundation,      *
+* Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA.           *
+*                                                                              *
+* Web site: http://cgogn.unistra.fr/                                           *
+* Contact information: cgogn@unistra.fr                                        *
+*                                                                              *
+*******************************************************************************/
+
+#include <QImage>
+#include <GL/glew.h>
+
+namespace CGoGN
+{
+
+namespace Utils
+{
+
+/**
+ * HD snapshot class
+ * Use OGL FBO to do squared snapshot until 16k*16k
+ */
+class SnapshotHD
+{
+protected:
+	int imgSz;
+	GLuint color_tex;
+	GLuint fb;
+	GLuint depth_rb;
+	unsigned char* pixels;
+	GLint old_viewport[4];
+
+public:
+	/**
+	* constructor
+	* @param sz size of rendering (in a square sz*sz) must be < 16384
+	*/
+	inline SnapshotHD(int sz);
+	/**
+	 * @brief destructor
+	 */
+	inline ~SnapshotHD();
+	/**
+	 * @brief bind the fbo for snapshot (call before updateGL();)
+	 */
+	inline void bind();
+
+	/**
+	 * @brief unbind the fbo
+	 */
+	inline void unbind();
+
+	/**
+	 * @brief save the screen to file
+	 * @param name file name (use anything supported by Qt)
+	 */
+	inline void snapshot(const std::string& name);
+};	
+
+SnapshotHD::SnapshotHD(int sz):
+ imgSz(sz)
+{
+	glGenTextures(1, &color_tex);
+	glBindTexture(GL_TEXTURE_2D, color_tex);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+	glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB8, imgSz, imgSz, 0, GL_RGB, GL_UNSIGNED_BYTE, NULL);
+	glGenFramebuffersEXT(1, &fb);
+	glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, fb);
+	glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT, GL_TEXTURE_2D, color_tex, 0);
+	glGenRenderbuffersEXT(1, &depth_rb);
+	glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, depth_rb);
+	glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, GL_DEPTH_COMPONENT24, imgSz, imgSz);
+	glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_DEPTH_ATTACHMENT_EXT, GL_RENDERBUFFER_EXT, depth_rb);
+
+	pixels = new unsigned char[imgSz*imgSz*3];
+}
+
+
+SnapshotHD::~SnapshotHD()
+{
+	if (pixels != NULL)
+		delete pixels;
+	glDeleteTextures(1, &color_tex);
+	glDeleteRenderbuffersEXT(1, &depth_rb);
+	glDeleteFramebuffersEXT(1, &fb);
+}
+
+void SnapshotHD::snapshot(const std::string& name)
+{
+	for(int i=0; i<imgSz; ++i)
+		glReadPixels(0, imgSz-1-i, imgSz, 1, GL_RGB, GL_UNSIGNED_BYTE, pixels+i*imgSz*3);
+
+	QImage qim(pixels,imgSz,imgSz,QImage::Format_RGB888);
+	qim.save(QString(name.c_str()));
+}
+
+void SnapshotHD::bind()
+{
+	glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, fb);
+	glGetIntegerv( GL_VIEWPORT, old_viewport );
+
+	glViewport(0,0,imgSz,imgSz);
+}
+
+void SnapshotHD::unbind()
+{
+	glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);
+	glViewport(old_viewport[0],old_viewport[1],old_viewport[2],old_viewport[3]);
+}
+
+}
+}
+