GLDL : OpenGL Debug Library

Author(s) : Adrian 'Revk' Dubouchet <[email protected]>

GLDL is an OpenGL Core Profile loading library that adds a debug layer in between.
It works as GLEW or gl3w would work, as a statically linked library (or by directly adding the GLDL source files in your project). It's a temporary remplacement of one of those, and should be used for Debug only.
Like gl3w do it, GLDL will download the gl3.h header from the Khronos OpenGL website and generates the code needed for function loading and debug, with a script.

This is my work project of my Analyse et Comprehension de Programmes class at the Universite de Montreal for this session.

This library works on Linux and Windows.

Features

• GL Core Profile functions exposition.
• Interactive debug with breakpoints.
• Trace logging (one init trace until the first glClear, and 5 custom traces).
• Buffer (VBO) displaying.
• Shader source displaying.
• Texture visualization (in a separate window).
• GL states displaying.

Installation & Usage

Just execute the gldl.py python(2.7) script to download and generate the GLDL library code.
Once done, add the gldl.c and gldl.h files to your project, or compile them as a static or dynamic library.

When calling gldlInit(), the GLDL interactive debug session will begin. Typing the command help or h will fill you with some pointers on how to use this debug tool. If you used the GNU debugger(GDB) before, you shouldn't be too disoriented.

If you need it, you could very well use GDB and GLDL together. Just launch your client program (using GLDL) with GDB, and experience the best possible debugging experience !

API

int gldlInit()

GLDL library initialization function. This must be called after an OpenGL context has been created. The function returns 1 if the library is correctly initialized, or 0 otherwise.

int gldlIsSupported( int major, int minor )

Check if the given major.minor OpenGL version is available. Returns 1 if it is, or 0 otherwise.

void gldlBreak()

This will cause a break into interactive debug session, wherever you put it.

void gldlBeginTrace( int traceNumber )

Activate logging of every GL function call after that. This will be stored in a file called traceX.log, with X being the traceNumber. traceNumber is a value between 1 and 5. This means you can have a maximum of 5 different custom logs.

void gldlEndTrace( int traceNumber )

Stop logging for the given trace number.

Example Code

#include <GL/glfw.h>
#include <GL/gldl.h>
#include <stdio.h>


int main() {
    
    if( !glfwInit() ) {
    	printf("GLFW Init error!\n");
        return -1;
    }

    glfwOpenWindow( 800, 600,
                    8, 8, 8, 8,
                    24, 8, GLFW_WINDOW);


    if( !gldlInit() ) {
        printf( "Error initializing gldl!\n" );
        return 1;
    }
    
    if( !gldlIsSupported( 3, 3 ) ) {
        printf( "GL 3.3 not supported.\n" );
        return 1;
    }
    
    
    gldlBeginTrace( 1 );
    
    printf( "OpenGL v%s.\n", glGetString( GL_VERSION ) );
    printf( "GLSL v%s\n", glGetString( GL_SHADING_LANGUAGE_VERSION ) );
    
    glClearColor( 1.f, 1.f, 1.f, 1.f );
    
    gldlEndTrace( 1 );
    
    while( glfwGetWindowParam( GLFW_OPENED ) ) {
        glClear( GL_COLOR_BUFFER_BIT );
        
        gldlBreak();
        
        // ...
        
        glfwSwapBuffers();
    }
    
    return 0;
}