tuto5GL.cpp File Reference

#include <stdio.h>
#include "window.h"
#include "vec.h"
#include "mat.h"
#include "program.h"
#include "uniforms.h"
#include "mesh.h"
#include "wavefront.h"
#include "orbiter.h"
#include "image_io.h"

Go to the source code of this file.

Functions
int	init ()
int	quit ()
int	draw ()
int	main (int argc, char **argv)

Variables
GLuint	program
GLuint	texture
GLuint	vao
GLuint	vertex_buffer
GLuint	texcoord_buffer
int	vertex_count
Orbiter	camera

Function Documentation

init()

int init

(

)

Definition at line 32 of file tuto5GL.cpp.

{
    // etape 1 : shaders
    program= read_program("gkit2_tutos/tuto5GL.glsl");
    program_print_errors(program);
 
    // etape 2 : charger un mesh, (avec des texcoords), vao + vertex buffer
    Mesh mesh= read_mesh("data/cube.obj");
    if(mesh.vertex_count() == 0)
        return -1;      // gros probleme, pas de sommets...
 
    vertex_count= mesh.vertex_count();
 
    Point pmin, pmax;
    mesh.bounds(pmin, pmax);
    camera.lookat(pmin, pmax);
 
    // vertex format : position + texcoord,
    // cf tuto4GL_normals.cpp
    glGenVertexArrays(1, &vao);
    glBindVertexArray(vao);
 
    // vertex buffer
    glGenBuffers(1, &vertex_buffer);
    glBindBuffer(GL_ARRAY_BUFFER, vertex_buffer);
    glBufferData(GL_ARRAY_BUFFER, mesh.vertex_buffer_size(), mesh.vertex_buffer(), GL_STATIC_DRAW);
 
    // configurer l'attribut position, cf declaration dans le vertex shader : in vec3 position;
    GLint position= glGetAttribLocation(program, "position");
    if(position < 0)
        return -1;
    glVertexAttribPointer(position, 3, GL_FLOAT, GL_FALSE, 0, 0);
    glEnableVertexAttribArray(position);
 
    // texcoord buffer
    glGenBuffers(1, &texcoord_buffer);
    glBindBuffer(GL_ARRAY_BUFFER, texcoord_buffer);
    glBufferData(GL_ARRAY_BUFFER, mesh.texcoord_buffer_size(), mesh.texcoord_buffer(), GL_STATIC_DRAW);
 
    // configurer l'attribut texcoord, cf declaration dans le vertex shader : in vec2 texcoord;
    GLint texcoord= glGetAttribLocation(program, "texcoord");
    if(texcoord < 0)
        return -1;
    glVertexAttribPointer(texcoord, 2, GL_FLOAT, GL_FALSE, 0, 0);
    glEnableVertexAttribArray(texcoord);
 
    // nettoyage
    mesh.release();
    glBindVertexArray(0);
    glBindBuffer(GL_ARRAY_BUFFER, 0);
 
    // etape 3 : texture
    ImageData image= read_image_data("data/debug2x2red.png");
 
    GLenum data_format;
    GLenum data_type= GL_UNSIGNED_BYTE;
    if(image.channels == 3)
        data_format= GL_RGB;
    else // par defaut
        data_format= GL_RGBA;
 
    glGenTextures(1, &texture);
    glBindTexture(GL_TEXTURE_2D, texture);
 
    glTexImage2D(GL_TEXTURE_2D, 0,
        GL_RGBA, image.width, image.height, 0,
        data_format, data_type, image.data());
 
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAX_LEVEL, 0);
 
    // nettoyage
    glBindTexture(GL_TEXTURE_2D, 0);
    glUseProgram(0);
 
    // etat par defaut
    glClearColor(0.2f, 0.2f, 0.2f, 1);
    glClearDepthf(1);
 
    glDepthFunc(GL_LESS);
    glEnable(GL_DEPTH_TEST);
 
    glFrontFace(GL_CCW);
    glCullFace(GL_BACK);
    glEnable(GL_CULL_FACE);
    return 0;
}

quit()

int quit

(

)

Definition at line 119 of file tuto5GL.cpp.

{
    release_program(program);
    glDeleteVertexArrays(1, &vao);
    glDeleteBuffers(1, &vertex_buffer);
    glDeleteBuffers(1, &texcoord_buffer);
    glDeleteTextures(1, &texture);
    return 0;
}

draw()

int draw

(

void

)

Definition at line 129 of file tuto5GL.cpp.

{
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
 
#if 1
    // recupere les mouvements de la souris, utilise directement SDL2
    int mx, my;
    unsigned int mb= SDL_GetRelativeMouseState(&mx, &my);
 
    // deplace la camera
    if(mb & SDL_BUTTON(1))              // le bouton gauche est enfonce
        // tourne autour de l'objet
        camera.rotation(mx, my);
 
    else if(mb & SDL_BUTTON(3))         // le bouton droit est enfonce
        // approche / eloigne l'objet
        camera.move(mx);
 
    else if(mb & SDL_BUTTON(2))         // le bouton du milieu est enfonce
        // deplace le point de rotation
        camera.translation((float) mx / (float) window_width(), (float) my / (float) window_height());
#endif
 
    /*  config pipeline :
        vertex array object
        program
        uniforms
        texture
     */
 
    glBindVertexArray(vao);
    glUseProgram(program);
 
    // recupere le point de vue et la projection de la camera
    Transform model= Identity();
    Transform view= camera.view();
    Transform projection= camera.projection(window_width(), window_height(), 45);
 
    // compose les matrices pour passer du repere local de l'objet au repere projectif
    Transform mvp= projection * view * model;
    program_uniform(program, "mvpMatrix", mvp);
 
    // texture
    glBindTexture(GL_TEXTURE_2D, texture);
 
    // sampler2D declare par le fragment shader
    GLint location= glGetUniformLocation(program, "texture0");
    glUniform1i(location, 0);
    // ou program_uniform(program, "texture0", 0);
 
    glDrawArrays(GL_TRIANGLES, 0, vertex_count);
 
    // nettoyage
    glBindTexture(GL_TEXTURE_2D, 0);
    glUseProgram(0);
    glBindVertexArray(0);
 
    return 1;
}

main()

int main	(	int	argc,
		char **	argv )

Definition at line 190 of file tuto5GL.cpp.

{
    // etape 1 : creer la fenetre
    Window window= create_window(1024, 640);
    if(window == NULL)
        return 1;       // erreur lors de la creation de la fenetre ou de l'init de sdl2
 
    // etape 2 : creer un contexte opengl pour pouvoir dessiner
    Context context= create_context(window);
    if(context == NULL)
        return 1;       // erreur lors de la creation du contexte opengl
 
    // etape 3 : creation des objets
    if(init() < 0)
    {
        printf("[error] init failed.\n");
        return 1;
    }
 
    // etape 4 : affichage de l'application, tant que la fenetre n'est pas fermee. ou que draw() ne renvoie pas 0
    run(window, draw);
 
    // etape 5 : nettoyage
    quit();
    release_context(context);
    release_window(window);
    return 0;
}

Variable Documentation

program

GLuint program

Definition at line 20 of file tuto5GL.cpp.

texture

GLuint texture

Definition at line 22 of file tuto5GL.cpp.

vao

GLuint vao

Definition at line 24 of file tuto5GL.cpp.

vertex_buffer

GLuint vertex_buffer

Definition at line 25 of file tuto5GL.cpp.

texcoord_buffer

GLuint texcoord_buffer

Definition at line 26 of file tuto5GL.cpp.

vertex_count

int vertex_count

Definition at line 27 of file tuto5GL.cpp.

camera

Orbiter camera

Definition at line 29 of file tuto5GL.cpp.