Framebuffer Class Reference

Inheritance diagram for Framebuffer:

Public Member Functions
int	init ()
	a deriver pour creer les objets openGL. More...
int	quit ()
	a deriver pour detruire les objets openGL. More...
int	update (const float time, const float delta)
	a deriver et redefinir pour animer les objets en fonction du temps. More...
int	render ()
	a deriver pour afficher les objets. More...
Public Member Functions inherited from App
	App (const int width, const int height, const int major=3, const int minor=3)
	constructeur, dimensions de la fenetre et version d'openGL. More...
int	run ()
	execution de l'application. More...
float	global_time ()
	renvoie le temps ecoule depuis le lancement de l'application, en millisecondes. More...
float	delta_time ()
	renvoie le temps ecoule depuis la derniere frame, en millisecondes. More...

Protected Attributes
Transform	m_model
Orbiter	m_camera
Orbiter	m_framebuffer_camera
GLuint	m_vao
GLuint	m_buffer
GLuint	m_texture_program
int	m_vertex_count
GLuint	m_color_texture
GLuint	m_color_buffer
GLuint	m_depth_buffer
GLuint	m_framebuffer
int	m_framebuffer_width
int	m_framebuffer_height
Protected Attributes inherited from App
Window	m_window
Context	m_context
unsigned int	m_time
unsigned int	m_delta

Detailed Description

Definition at line 18 of file tuto_framebuffer.cpp.

Member Function Documentation

int Framebuffer::init ( )

inlinevirtual

a deriver pour creer les objets openGL.

Implements App.

Definition at line 24 of file tuto_framebuffer.cpp.

    {
        m_framebuffer_width= 512;
        m_framebuffer_height= 512;
        
        // etape 1 : creer une texture couleur...
        glGenTextures(1, &m_color_buffer);
        glBindTexture(GL_TEXTURE_2D, m_color_buffer);
        
        glTexImage2D(GL_TEXTURE_2D, 0,
            GL_RGBA, m_framebuffer_width, m_framebuffer_height, 0,
            GL_RGBA, GL_UNSIGNED_BYTE, nullptr);

        // ... et tous ses mipmaps
        glGenerateMipmap(GL_TEXTURE_2D);
        
        // etape 1 : creer aussi une texture depth, sinon pas de zbuffer...
        glGenTextures(1, &m_depth_buffer);
        glBindTexture(GL_TEXTURE_2D, m_depth_buffer);
        
        glTexImage2D(GL_TEXTURE_2D, 0,
            GL_DEPTH_COMPONENT, m_framebuffer_width, m_framebuffer_height, 0,
            GL_DEPTH_COMPONENT, GL_UNSIGNED_INT, nullptr);
        
        // un seul mipmap pour le zbuffer
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAX_LEVEL, 0);
        
        // etape 2 : creer et configurer un framebuffer object
        glGenFramebuffers(1, &m_framebuffer);
        glBindFramebuffer(GL_DRAW_FRAMEBUFFER, m_framebuffer);
        glFramebufferTexture(GL_DRAW_FRAMEBUFFER,  /* attachment */ GL_COLOR_ATTACHMENT0, /* texture */ m_color_buffer, /* mipmap level */ 0);
        glFramebufferTexture(GL_DRAW_FRAMEBUFFER,  /* attachment */ GL_DEPTH_ATTACHMENT, /* texture */ m_depth_buffer, /* mipmap level */ 0);

        GLenum buffers[]= { GL_COLOR_ATTACHMENT0 };
        glDrawBuffers(1, buffers);
        
        // nettoyage
        glBindFramebuffer(GL_DRAW_FRAMEBUFFER, 0);
        
        // charge un mesh
        Mesh mesh= read_mesh("data/cube.obj");
        if(mesh == Mesh::error()) return -1;
        
        Point pmin, pmax;
        mesh.bounds(pmin, pmax);
        m_camera.lookat(pmin, pmax);
        m_framebuffer_camera.lookat(pmin, pmax);
        
        m_vertex_count= mesh.vertex_count();

        m_color_texture= read_texture(0, "data/debug2x2red.png");
        
        // cree les buffers et le vao
        glGenVertexArrays(1, &m_vao);
        glBindVertexArray(m_vao);
        
        // buffer : positions + texcoords + normals
        glGenBuffers(1, &m_buffer);
        glBindBuffer(GL_ARRAY_BUFFER, m_buffer);
        
        size_t size= mesh.vertex_buffer_size() + mesh.texcoord_buffer_size() + mesh.normal_buffer_size();
        glBufferData(GL_ARRAY_BUFFER, size, nullptr, GL_STATIC_DRAW);
        
        // transfere les positions des sommets
        size_t offset= 0;
        size= mesh.vertex_buffer_size();
        glBufferSubData(GL_ARRAY_BUFFER, offset, size, mesh.vertex_buffer());
        // configure l'attribut 0, vec3 position
        glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, /* stride */ 0, (const GLvoid *) offset);
        glEnableVertexAttribArray(0);

        // transfere les texcoords des sommets
        offset= offset + size;
        size= mesh.texcoord_buffer_size();
        glBufferSubData(GL_ARRAY_BUFFER, offset, size, mesh.texcoord_buffer());
        // configure l'attribut 1, vec2 texcoord
        glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, /* stride */ 0, (const GLvoid *) offset);
        glEnableVertexAttribArray(1);

        // transfere les normales des sommets
        offset= offset + size;
        size= mesh.normal_buffer_size();
        glBufferSubData(GL_ARRAY_BUFFER, offset, size, mesh.normal_buffer());
        // configure l'attribut 2, vec3 normal
        glVertexAttribPointer(2, 3, GL_FLOAT, GL_FALSE, /* stride */ 0, (const GLvoid *) offset);
        glEnableVertexAttribArray(2);
        
        //
        mesh.release();
        glBindVertexArray(0);
        glBindBuffer(GL_ARRAY_BUFFER, 0);

        // shaders
        m_texture_program= read_program("tutos/texcoords.glsl");
        program_print_errors(m_texture_program);
        
        // etat openGL par defaut
        glClearColor(0.2f, 0.2f, 0.2f, 1.f);        // couleur par defaut de la fenetre
        
        glClearDepthf(1.f);                          // profondeur par defaut
        glDepthFunc(GL_LESS);                       // ztest, conserver l'intersection la plus proche de la camera
        glEnable(GL_DEPTH_TEST);                    // activer le ztest

        return 0;   // ras, pas d'erreur
    }

int Framebuffer::quit ( )

inlinevirtual

a deriver pour detruire les objets openGL.

Implements App.

Definition at line 131 of file tuto_framebuffer.cpp.

    {
        glDeleteTextures(1, &m_color_buffer);
        glDeleteTextures(1, &m_depth_buffer);
        glDeleteFramebuffers(1, &m_framebuffer);

        release_program(m_texture_program);
        glDeleteTextures(1, &m_color_texture);
        glDeleteVertexArrays(1, &m_vao);
        glDeleteBuffers(1, &m_buffer);
        return 0;
    }

int Framebuffer::update ( const float  time, const float  delta  )

inlinevirtual

a deriver et redefinir pour animer les objets en fonction du temps.

Reimplemented from App.

Definition at line 144 of file tuto_framebuffer.cpp.

    {
        m_model= RotationY(time / 20);
        return 0;
    }

int Framebuffer::render ( )

inlinevirtual

a deriver pour afficher les objets.

Implements App.

Definition at line 151 of file tuto_framebuffer.cpp.

    {
        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

        // deplace la camera
        int mx, my;
        unsigned int mb= SDL_GetRelativeMouseState(&mx, &my);
        if(mb & SDL_BUTTON(1))              // le bouton gauche est enfonce
            m_camera.rotation(mx, my);
        else if(mb & SDL_BUTTON(3))         // le bouton droit est enfonce
            m_camera.move(mx);
        else if(mb & SDL_BUTTON(2))         // le bouton du milieu est enfonce
            m_camera.translation((float) mx / (float) window_width(), (float) my / (float) window_height());

        
        /* passe 1 : dessiner dans le framebuffer
         */
        {
            glBindFramebuffer(GL_DRAW_FRAMEBUFFER, m_framebuffer);
            glViewport(0, 0, m_framebuffer_width, m_framebuffer_height);
            glClearColor(1, 1, 0, 1);
            glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
            
            // draw "classique"
            glBindVertexArray(m_vao);
            glUseProgram(m_texture_program);
            
            Transform m= m_model;
            Transform v= m_framebuffer_camera.view();
            Transform p= m_framebuffer_camera.projection(m_framebuffer_width, m_framebuffer_height, 45);
            Transform mvp= p * v * m;
            Transform mv= v * m;
            
            program_uniform(m_texture_program, "mvpMatrix", mvp);
            program_uniform(m_texture_program, "mvMatrix", mv);
            program_uniform(m_texture_program, "normalMatrix", mv.normal());
            program_use_texture(m_texture_program, "color_texture", 0, m_color_texture, 0);
            
            glDrawArrays(GL_TRIANGLES, 0, m_vertex_count);
        }
        
        if(key_state(' '))
        {
            /* montrer le resultat de la passe 1
                copie le framebuffer sur la fenetre
             */
            
            glBindFramebuffer(GL_READ_FRAMEBUFFER, m_framebuffer);
            glBindFramebuffer(GL_DRAW_FRAMEBUFFER, 0);
            glViewport(0, 0, window_width(), window_height());
            glClearColor(0, 0, 0, 1);
            glClear(GL_COLOR_BUFFER_BIT);
            
            glBlitFramebuffer(0, 0, m_framebuffer_width, m_framebuffer_height,
                0, 0, m_framebuffer_width, m_framebuffer_height,
                GL_COLOR_BUFFER_BIT, GL_LINEAR);
        }
        else
        {
            /* passe 2 : utiliser la texture du framebuffer 
            */
            
            glBindFramebuffer(GL_DRAW_FRAMEBUFFER, 0);
            glViewport(0, 0, window_width(), window_height());
            glClearColor(0.2f, 0.2f, 0.2f, 1.f);        // couleur par defaut de la fenetre
            glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
            
            // draw "classique"
            glBindVertexArray(m_vao);
            glUseProgram(m_texture_program);
            
            Transform m= m_model;
            Transform v= m_camera.view();
            Transform p= m_camera.projection(window_width(), window_height(), 45);
            Transform mvp= p * v * m;
            Transform mv= v * m;
            
            program_uniform(m_texture_program, "mvpMatrix", mvp);
            program_uniform(m_texture_program, "mvMatrix", mv);
            program_uniform(m_texture_program, "normalMatrix", mv.normal());
            
            // utilise la texture attachee au framebuffer
            program_uniform(m_texture_program, "color_texture", 0);
            
            glBindTexture(GL_TEXTURE_2D, m_color_buffer);
            // recalcule les mipmaps de la texture... ils sont necessaires pour afficher le cube texture, 
            // pourquoi ? un draw dans un framebuffer ne modifie que le mipmap 0, pas les autres, donc il faut les recalculer...
            glGenerateMipmap(GL_TEXTURE_2D);
            
            glDrawArrays(GL_TRIANGLES, 0, m_vertex_count);
        }
        
        return 1;
    }

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The documentation for this class was generated from the following file:

• tutos/tuto_framebuffer.cpp