ComputeBuffer Struct Reference

Inheritance diagram for ComputeBuffer:

Public Member Functions
int	init ()
	a deriver pour creer les objets openGL. renvoie -1 pour indiquer une erreur, 0 sinon.
int	quit ()
	a deriver pour detruire les objets openGL. renvoie -1 pour indiquer une erreur, 0 sinon.
int	render ()
	a deriver pour afficher les objets. renvoie 1 pour continuer, 0 pour fermer l'application.
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.
virtual int	update (const float time, const float delta)
	a deriver et redefinir pour animer les objets en fonction du temps.
int	run ()
	execution de l'application.

Public Attributes
std::vector< int >	m_data
GLuint	m_gpu_buffer1
GLuint	m_gpu_buffer2
GLuint	m_read_buffer
GLuint	m_program

Additional Inherited Members
Protected Member Functions inherited from App
virtual int	prerender ()
virtual int	postrender ()
void	vsync_off ()
Protected Attributes inherited from App
Window	m_window
Context	m_context
bool	sync

Detailed Description

Definition at line 9 of file tuto_compute_buffer.cpp.

Constructor & Destructor Documentation

ComputeBuffer()

ComputeBuffer::ComputeBuffer ( )

inline

Definition at line 11 of file tuto_compute_buffer.cpp.

: App(1280, 768, 4,3) {}

Member Function Documentation

init()

int ComputeBuffer::init ( )

inlinevirtual

a deriver pour creer les objets openGL. renvoie -1 pour indiquer une erreur, 0 sinon.

Implements App.

Definition at line 13 of file tuto_compute_buffer.cpp.

    {
        m_program= read_program("gkit2_tutos/M2/compute_buffer.glsl");
        program_print_errors(m_program);
        
        // initialise un tableau de valeurs
        m_data= std::vector<int>(1024);
        
        // cree les buffers pour les parametres du shader
        glGenBuffers(1, &m_gpu_buffer1);
        glBindBufferBase(GL_SHADER_STORAGE_BUFFER, 0, m_gpu_buffer1);
        glBufferData(GL_SHADER_STORAGE_BUFFER, sizeof(int) * m_data.size(), m_data.data(), GL_STATIC_COPY);
        
        // buffer resultat, meme taille, mais pas de donnees...
        glGenBuffers(1, &m_gpu_buffer2);
        glBindBufferBase(GL_SHADER_STORAGE_BUFFER, 1, m_gpu_buffer2);
        glBufferData(GL_SHADER_STORAGE_BUFFER, sizeof(int) * m_data.size(), nullptr, GL_STATIC_COPY);
        
        return 0;
    }

quit()

int ComputeBuffer::quit ( )

inlinevirtual

a deriver pour detruire les objets openGL. renvoie -1 pour indiquer une erreur, 0 sinon.

Implements App.

Definition at line 34 of file tuto_compute_buffer.cpp.

    {
        release_program(m_program);
        glDeleteBuffers(1, &m_gpu_buffer1);
        glDeleteBuffers(1, &m_gpu_buffer2);
        
        return 0;
    }

render()

int ComputeBuffer::render ( )

inlinevirtual

a deriver pour afficher les objets. renvoie 1 pour continuer, 0 pour fermer l'application.

Implements App.

Definition at line 43 of file tuto_compute_buffer.cpp.

    {
        glBindBufferBase(GL_SHADER_STORAGE_BUFFER, 0, m_gpu_buffer1);
        glBindBufferBase(GL_SHADER_STORAGE_BUFFER, 1, m_gpu_buffer2);
        
        // execute les shaders
        glUseProgram(m_program);
        
        // recupere le nombre de threads declare par le shader
        int threads[3]= {};
        glGetProgramiv(m_program, GL_COMPUTE_WORK_GROUP_SIZE, threads);
        
        int n= m_data.size() / threads[0];
        // nombre de groupes de threads, arrondi...
        if(m_data.size() % threads[0])
            n++;
        // oui on peut calculer ca de maniere plus directe... 
        // ou utiliser directement 256, comme dans le shader...
        
        // go !
        glDispatchCompute(n, 1, 1);
        
        // attendre que les resultats soient disponibles
        glMemoryBarrier(GL_BUFFER_UPDATE_BARRIER_BIT);
        
        // relire le resultat
        std::vector<int> tmp(1024);
        glBindBuffer(GL_SHADER_STORAGE_BUFFER, m_gpu_buffer2);
        glGetBufferSubData(GL_SHADER_STORAGE_BUFFER, 0, sizeof(int) * tmp.size(), tmp.data());
        
        for(unsigned i= 0; i < tmp.size(); i++)
            printf("%d ", tmp[i]);
        printf("\n");
        
        return 0;
    }

Member Data Documentation

m_data

std::vector<int> ComputeBuffer::m_data

Definition at line 80 of file tuto_compute_buffer.cpp.

m_gpu_buffer1

GLuint ComputeBuffer::m_gpu_buffer1

Definition at line 81 of file tuto_compute_buffer.cpp.

m_gpu_buffer2

GLuint ComputeBuffer::m_gpu_buffer2

Definition at line 82 of file tuto_compute_buffer.cpp.

m_read_buffer

GLuint ComputeBuffer::m_read_buffer

Definition at line 83 of file tuto_compute_buffer.cpp.

m_program

GLuint ComputeBuffer::m_program

Definition at line 84 of file tuto_compute_buffer.cpp.

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

• gkit2_tutos/M2/tuto_compute_buffer.cpp