CFBORender.cpp

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/* +------------------------------------------------------------------------+
   |                     Mobile Robot Programming Toolkit (MRPT)            |
   |                          http://www.mrpt.org/                          |
   |                                                                        |
   | Copyright (c) 2005-2017, Individual contributors, see AUTHORS file     |
   | See: http://www.mrpt.org/Authors - All rights reserved.                |
   | Released under BSD License. See details in http://www.mrpt.org/License |
   +------------------------------------------------------------------------+ */

#include "opengl-precomp.h"  // Precompiled header

#include <mrpt/opengl/CFBORender.h>
#include "opengl_internals.h"

using namespace std;
using namespace mrpt;
using namespace mrpt::utils;
using namespace mrpt::opengl;

/*---------------------------------------------------------------
                                                Constructor
---------------------------------------------------------------*/
CFBORender::CFBORender(
        unsigned int width, unsigned int height, const bool skip_glut_window)
        : m_width(width),
          m_height(height),
          m_win_used(!skip_glut_window),
          m_default_bk_color(.6f, .6f, .6f, 1)
{
#if MRPT_HAS_OPENCV && MRPT_HAS_OPENGL_GLUT

        MRPT_START

        if (m_win_used)
        {
                // check a previous initialization of the GLUT
                if (!glutGet(GLUT_INIT_STATE))
                {
                        // create the context (a little trick)
                        int argc = 1;
                        char* argv[1] = {nullptr};
                        glutInit(&argc, argv);
                }

                // create a hidden window
                m_win = glutCreateWindow("CFBORender");
                glutHideWindow();
        }

        // call after creating the hidden window
        if (!isExtensionSupported("GL_EXT_framebuffer_object"))
                THROW_EXCEPTION("Framebuffer Object extension unsupported");

// In win32 we have to load the pointers to the functions:
#ifdef MRPT_OS_WINDOWS
        glGenFramebuffersEXT =
                (PFNGLGENFRAMEBUFFERSEXTPROC)wglGetProcAddress("glGenFramebuffersEXT");
        glDeleteFramebuffersEXT = (PFNGLDELETEFRAMEBUFFERSEXTPROC)wglGetProcAddress(
                "glDeleteFramebuffersEXT");
        glBindFramebufferEXT =
                (PFNGLBINDFRAMEBUFFEREXTPROC)wglGetProcAddress("glBindFramebufferEXT");
        glFramebufferTexture2DEXT =
                (PFNGLFRAMEBUFFERTEXTURE2DEXTPROC)wglGetProcAddress(
                        "glFramebufferTexture2DEXT");

        ASSERT_(glGenFramebuffersEXT != nullptr)
        ASSERT_(glDeleteFramebuffersEXT != nullptr)
        ASSERT_(glBindFramebufferEXT != nullptr)
        ASSERT_(glFramebufferTexture2DEXT != nullptr)
#endif

        // gen the frambuffer object (FBO), similar manner as a texture
        glGenFramebuffersEXT(1, &m_fbo);

        // bind the framebuffer, fbo, so operations will now occur on it
        glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, m_fbo);

        // change viewport size (in pixels)
        glViewport(0, 0, m_width, m_height);

        // make a texture
        glGenTextures(1, &m_tex);

        // initialize texture that will store the framebuffer image
        const GLenum texTarget =
#if defined(GL_TEXTURE_RECTANGLE_NV)
                GL_TEXTURE_RECTANGLE_NV;
#elif defined(GL_TEXTURE_RECTANGLE_ARB)
                GL_TEXTURE_RECTANGLE_ARB;
#else
                GL_TEXTURE_RECTANGLE_EXT;
#endif

        glBindTexture(texTarget, m_tex);
        glTexImage2D(
                texTarget, 0, GL_RGB, m_width, m_height, 0, GL_RGB, GL_UNSIGNED_BYTE,
                nullptr);

        // bind this texture to the current framebuffer obj. as color_attachement_0
        glFramebufferTexture2DEXT(
                GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT, texTarget, m_tex, 0);

        //'unbind' the frambuffer object, so subsequent drawing ops are not drawn
        // into the FBO.
        // '0' means "windowing system provided framebuffer
        glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);

        MRPT_END

//#else
//      THROW_EXCEPTION("MRPT compiled without OpenCV and/or OpenGL support!!")
#endif
}

/*---------------------------------------------------------------
                                                Destructor:
 ---------------------------------------------------------------*/
CFBORender::~CFBORender()
{
#if MRPT_HAS_OPENGL_GLUT
        // delete the current texture, the framebuffer object and the GLUT window
        glDeleteTextures(1, &m_tex);
        glDeleteFramebuffersEXT(1, &m_fbo);
        if (m_win_used) glutDestroyWindow(m_win);
#endif
}

/*---------------------------------------------------------------
                                        Set the scene camera
 ---------------------------------------------------------------*/
void CFBORender::setCamera(const COpenGLScene& scene, const CCamera& camera)
{
        MRPT_START

        scene.getViewport("main")->getCamera() = camera;

        MRPT_END
}

/*---------------------------------------------------------------
                                        Get the scene camera
 ---------------------------------------------------------------*/
CCamera& CFBORender::getCamera(const COpenGLScene& scene)
{
        MRPT_START

        return scene.getViewport("main")->getCamera();

        MRPT_END
}

/*---------------------------------------------------------------
                Render the scene and get the rendered rgb image. This
                function resizes the image buffer if it is necessary
 ---------------------------------------------------------------*/
void CFBORender::getFrame(const COpenGLScene& scene, CImage& buffer)
{
#if MRPT_HAS_OPENCV && MRPT_HAS_OPENGL_GLUT

        MRPT_START

        // resize the buffer if it is necessary
        if (buffer.getWidth() != static_cast<size_t>(m_width) ||
                buffer.getHeight() != static_cast<size_t>(m_height) ||
                buffer.getChannelCount() != 3 || buffer.isOriginTopLeft() != false)
        {
                buffer.resize(m_width, m_height, 3, false);
        }

        // Go on.
        getFrame2(scene, buffer);
        ;

        MRPT_END
#else
        MRPT_UNUSED_PARAM(scene);
        MRPT_UNUSED_PARAM(buffer);
#endif
}

/*---------------------------------------------------------------
                Render the scene and get the rendered rgb image. This
                function does not resize the image buffer.
 ---------------------------------------------------------------*/
void CFBORender::getFrame2(const COpenGLScene& scene, CImage& buffer)
{
#if MRPT_HAS_OPENGL_GLUT

        MRPT_START

        // check the buffer size
        ASSERT_EQUAL_(buffer.getWidth(), static_cast<size_t>(m_width))
        ASSERT_EQUAL_(buffer.getHeight(), static_cast<size_t>(m_height))
        ASSERT_EQUAL_(buffer.getChannelCount(), 3)
        ASSERT_EQUAL_(buffer.isOriginTopLeft(), false)

        // bind the framebuffer, fbo, so operations will now occur on it
        glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, m_fbo);

        glClearColor(
                m_default_bk_color.R, m_default_bk_color.G, m_default_bk_color.B,
                m_default_bk_color.A);

        // Render opengl objects:
        // ---------------------------
        scene.render();

        // If any, draw the 2D text messages:
        // ----------------------------------
        render_text_messages(m_width, m_height);

        // TODO NOTE: This should fail if the image has padding bytes. See
        // glPixelStore() etc.
        glReadPixels(
                0, 0, m_width, m_height, GL_BGR_EXT, GL_UNSIGNED_BYTE, buffer(0, 0));

        //'unbind' the frambuffer object, so subsequent drawing ops are not drawn
        // into the FBO.
        // '0' means "windowing system provided framebuffer
        glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);

        MRPT_END
#else
        MRPT_UNUSED_PARAM(scene);
        MRPT_UNUSED_PARAM(buffer);
#endif
}

/*---------------------------------------------------------------
                                        Resize the image size
 ---------------------------------------------------------------*/
void CFBORender::resize(unsigned int width, unsigned int height)
{
#if MRPT_HAS_OPENCV && MRPT_HAS_OPENGL_GLUT

        MRPT_START

        // update members
        m_width = width;
        m_height = height;

        // bind the framebuffer, fbo, so operations will now occur on it
        glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, m_fbo);

        // change viewport size (in pixels)
        glViewport(0, 0, m_width, m_height);

        // change texture size
        const GLenum texTarget =
#if defined(GL_TEXTURE_RECTANGLE_NV)
                GL_TEXTURE_RECTANGLE_NV;
#elif defined(GL_TEXTURE_RECTANGLE_ARB)
                GL_TEXTURE_RECTANGLE_ARB;
#else
                GL_TEXTURE_RECTANGLE_EXT;
#endif

        glBindTexture(texTarget, m_tex);
        glTexImage2D(
                texTarget, 0, GL_RGB, m_width, m_height, 0, GL_RGB, GL_UNSIGNED_BYTE,
                nullptr);

        //'unbind' the frambuffer object, so subsequent drawing ops are not drawn
        // into the FBO.
        // '0' means "windowing system provided framebuffer
        glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);

        MRPT_END

//#else
//      THROW_EXCEPTION("MRPT compiled without OpenCV and/or OpenGL support!!")
#else
        MRPT_UNUSED_PARAM(width);
        MRPT_UNUSED_PARAM(height);
#endif
}

/*---------------------------------------------------------------
                Provide information on Framebuffer object extension
 ---------------------------------------------------------------*/
int CFBORender::isExtensionSupported(const char* extension)
{
#if MRPT_HAS_OPENGL_GLUT

        MRPT_START

        const GLubyte* extensions = nullptr;
        const GLubyte* start;
        GLubyte *where, *terminator;

        /* Extension names should not have spaces. */
        where = (GLubyte*)strchr(extension, ' ');
        if (where || *extension == '\0') return 0;
        extensions = glGetString(GL_EXTENSIONS);

        /* It takes a bit of care to be fool-proof about parsing the
        OpenGL extensions string. Don't be fooled by sub-strings,
        etc. */
        start = extensions;
        for (;;)
        {
                where = (GLubyte*)strstr((const char*)start, extension);
                if (!where) break;
                terminator = where + strlen(extension);
                if (where == start || *(where - 1) == ' ')
                        if (*terminator == ' ' || *terminator == '\0') return 1;
                start = terminator;
        }

        MRPT_END

//#else
//      THROW_EXCEPTION("MRPT compiled without OpenGL support!!")
#else
        MRPT_UNUSED_PARAM(extension);
#endif

        return 0;
}