Question

note: glGetString(GL_VERSION) returned: 2.1.0 – Build 8.15.10.2361

I have installed GLEW to System32, and VCDir/lib and VCDir/include directories. So the linker should not have any issues finding the necessary bits of GLEW. The trouble I am having though is that the following code:

void foo()
{
    Uint32 vboId;

    glGenBuffers(1, &vboId);
}

Gives me the following error:

unresolved external symbol __imp____glewGenBuffers

This error was the entire reason I decided to install GLEW. See: unresolved external symbol _glGenBuffers error

In addition to this error, there are a few warnings that are a bit concerning:

Warning 1   warning C4028: formal parameter 3 different from declaration    c:\sdl-1.2.14\include\sdl_opengl.h  4855    1   Prototek
Warning 2   warning C4028: formal parameter 3 different from declaration    c:\sdl-1.2.14\include\sdl_opengl.h  4857    1   Prototek
Warning 3   warning C4028: formal parameter 2 different from declaration    c:\sdl-1.2.14\include\sdl_opengl.h  4859    1   Prototek
Warning 4   warning C4028: formal parameter 2 different from declaration    c:\sdl-1.2.14\include\sdl_opengl.h  4861    1   Prototek
Warning 5   warning C4028: formal parameter 3 different from declaration    c:\sdl-1.2.14\include\sdl_opengl.h  4868    1   Prototek
Warning 6   warning C4028: formal parameter 3 different from declaration    c:\sdl-1.2.14\include\sdl_opengl.h  4869    1   Prototek

Also, is it a good idea to simply install SDL to my VC inc and lib and System32 directories as I have done for GLEW?

My #include’s at the top of my file look like this:

#include <stdio.h>
#include <glew.h>
#include "sdl.h"
#include "sdl_opengl.h"
#include <gl/GLU.h>
#include <gl/GL.h>

But in case it is needed, here is the entire body of code:

#include <stdio.h>
#include <glew.h>
#include "sdl.h"
#include "sdl_opengl.h"
#include <gl/GLU.h>
#include <gl/GL.h>

Uint32 loadTexture(char* fileName)
{
    Uint32 id;
    SDL_Surface *img = NULL;

    //load into memory using SDL
    img = SDL_LoadBMP(fileName);
    //generate an id for this texture
    glGenTextures(1, &id);
    //use this texture
    glBindTexture(GL_TEXTURE_2D, id);
    //load the texture into video memory via OpenGL
    glTexImage2D(
        GL_TEXTURE_2D,
        0,
        GL_RGB,
        img->w,
        img->h,
        0,
        GL_BGR,
        GL_UNSIGNED_BYTE,
        img->pixels
        );

    //set mip map settings
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

    SDL_FreeSurface(img);

    return id;
}

Uint32 tex;

void init()
{
    glClearColor(0.0, 0.0, 0.0, 1.0);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    glOrtho(0.0, 1.0, 1.0, 0.0, -1.0, 1.0);
    glMatrixMode(GL_MODELVIEW);
    glEnable(GL_TEXTURE_2D);

    tex = loadTexture("fireball.bmp");
}
void foo()
{
    Uint32 vboId;

    glGenBuffers(1, &vboId);
}
void display()
{
    glClear(GL_COLOR_BUFFER_BIT);
    glLoadIdentity();

    glBindTexture(GL_TEXTURE_2D, tex);

    glBegin(GL_QUADS);
    glTexCoord2f(0.5, 0.5);
    glVertex3f(0.25, 0.25, 0.0);


    glTexCoord2f(1.0, 0.5);
    glVertex3f(0.5, 0.25, 0.0);


    glTexCoord2f(1.0, 1.0);
    glVertex3f(0.5, 0.5, 0.0);


    glTexCoord2f(0.5, 1.0);
    glVertex3f(0.25, 0.5, 0.0);
    glEnd();
}

int main()
{
    Uint32 isRunning = 1;
    SDL_Surface *screen = NULL;
    SDL_Event event;
    Uint32 start;
    Uint32 FPS = 30;

    SDL_Init(SDL_INIT_EVERYTHING);

    screen = SDL_SetVideoMode(640, 480, 32, SDL_OPENGL);

    init();

    while(isRunning)
    {
        start = SDL_GetTicks();

        while(SDL_PollEvent(&event))
        {
            switch(event.type)
            {
                case SDL_QUIT: isRunning = 0; break;
            }
        }

        display();

        SDL_GL_SwapBuffers();

        if(1000 / FPS > SDL_GetTicks() - start)
        {
            SDL_Delay(1000 / FPS - (SDL_GetTicks() - start));
        }
    }

    SDL_Quit();

    return(0);
}

Answer 1

I noticed you didn’t include a call to glewInit(), if you are planning to use glew make sure you call it before using any of the openGL function pointers it provides.