OpenGL Red Book 8th - First Example gives black box (Ubuntu)

Question

After getting the first example program compiled from the 8th edition OpenGL Programming Guide after many alterations suggested by many sites, I am the proud owner of a black box - a vast improvement from the hours before, but it's embarrassing to admit that I've watch most of this with a debugger and unless something basic is wrong with the program, I have no clue where to look. Other OpenGL examples have run, but I'm trying to get the first example in the new book to run.

My box:

john@zerofluid:~/Downloads$ glxinfo | grep OpenGL
OpenGL vendor string: NVIDIA Corporation
OpenGL renderer string: GeForce GT 610/PCIe/SSE2
OpenGL version string: 4.3.0 NVIDIA 313.30
OpenGL shading language version string: 4.30 NVIDIA via Cg compiler
OpenGL extensions:

Linux zerofluid 3.8.0-26-generic #38-Ubuntu SMP Mon Jun 17 21:43:33 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux (latest 13.04 Ubuntu)

I have a problem - it's way too much code to post here, but it is the first example of the book - as small as it gets and I have no idea of where the problem really is. It would be cool if someone actually wants to help - I'd feed it back to the author of the book. Yes, the LoadShader was found elsewhere and might be the problem, but it was supposed to be a solution. It's kind of hard to have any faith in the book when I can't get the first example to compile.

It can be found here: https://github.com/kestess/opengl8thfirstexample.git

genpfault genpfault · Accepted Answer · 2013-07-11T14:44:32

it's way too much code to post here

Not really.

Try this:

#include <GL/glew.h>
#include <GL/freeglut.h>
#include <vector>
#include <iostream>

struct Program
{
    static GLuint Load( const char* vert, const char* geom, const char* frag )
    {
        GLuint prog = glCreateProgram();
        if( vert ) AttachShader( prog, GL_VERTEX_SHADER, vert );
        if( geom ) AttachShader( prog, GL_GEOMETRY_SHADER, geom );
        if( frag ) AttachShader( prog, GL_FRAGMENT_SHADER, frag );
        glLinkProgram( prog );
        CheckStatus( prog );
        return prog;
    }

private:
    static void CheckStatus( GLuint obj )
    {
        GLint status = GL_FALSE, len = 10;
        if( glIsShader(obj) )   glGetShaderiv( obj, GL_COMPILE_STATUS, &status );
        if( glIsProgram(obj) )  glGetProgramiv( obj, GL_LINK_STATUS, &status );
        if( status == GL_TRUE ) return;
        if( glIsShader(obj) )   glGetShaderiv( obj, GL_INFO_LOG_LENGTH, &len );
        if( glIsProgram(obj) )  glGetProgramiv( obj, GL_INFO_LOG_LENGTH, &len );
        std::vector< char > log( len, 'X' );
        if( glIsShader(obj) )   glGetShaderInfoLog( obj, len, NULL, &log[0] );
        if( glIsProgram(obj) )  glGetProgramInfoLog( obj, len, NULL, &log[0] );
        std::cerr << &log[0] << std::endl;
        exit( -1 );
    }

    static void AttachShader( GLuint program, GLenum type, const char* src )
    {
        GLuint shader = glCreateShader( type );
        glShaderSource( shader, 1, &src, NULL );
        glCompileShader( shader );
        CheckStatus( shader );
        glAttachShader( program, shader );
        glDeleteShader( shader );
    }
};
#define GLSL(version, shader) "#version " #version "\n" #shader


const char* vert = GLSL
( 
    400 core,
    layout( location = 0 ) in vec4 vPosition;
    void main()
    {
        gl_Position = vPosition;
    }
);

const char* frag = GLSL
( 
    400 core,
    out vec4 fColor;
    void main()
    {
        fColor = vec4( 0.0, 0.0, 1.0, 1.0 );
    }
);

enum VAO_IDs { Triangles, NumVAOs };
enum Buffer_IDs { ArrayBuffer, NumBuffers };
enum Attrib_IDs { vPosition = 0 };

GLuint VAOs[NumVAOs];
GLuint Buffers[NumBuffers];

const GLuint  NumVertices = 6;

void init(void)
{
    glGenVertexArrays(NumVAOs, VAOs);
    glBindVertexArray(VAOs[Triangles]);

    GLfloat  vertices[NumVertices][2] = {
        { -0.90, -0.90 },  // Triangle 1
        {  0.85, -0.90 },
        { -0.90,  0.85 },
        {  0.90, -0.85 },  // Triangle 2
        {  0.90,  0.90 },
        { -0.85,  0.90 }
    };

    glGenBuffers(NumBuffers, Buffers);
    glBindBuffer(GL_ARRAY_BUFFER, Buffers[ArrayBuffer]);
    glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);

    GLuint program = Program::Load( vert, NULL, frag );
    glUseProgram(program);

    glVertexAttribPointer(vPosition, 2, GL_FLOAT, GL_FALSE, 0, (void*)(0) );
    glEnableVertexAttribArray(vPosition);
}

void display(void)
{
    glClear(GL_COLOR_BUFFER_BIT);

    glBindVertexArray(VAOs[Triangles]);
    glDrawArrays(GL_TRIANGLES, 0, NumVertices);

    glutSwapBuffers();
}

int main(int argc, char** argv)
{
     glutInit(&argc, argv);
     glutInitDisplayMode( GLUT_RGBA | GLUT_DOUBLE );
     glutInitWindowSize(512, 512);
     glutInitContextVersion(4, 0);
     glutInitContextProfile(GLUT_CORE_PROFILE);
     glutCreateWindow(argv[0]);

     glewExperimental = GL_TRUE;
     if( GLEW_OK != glewInit() )
         exit(EXIT_FAILURE);

     init();

     glutDisplayFunc(display);
     glutMainLoop();
}

No reason to request a 4.3 context if you're using #version 400 core.

OpenGL Red Book 8th - First Example gives black box (Ubuntu)

1 Answers