Load jpg image as texture - freeimage, opengl

Question

I tried to load jpg image with FreeImage Library. I used this code, but the result was only white window. I think to use this image like background and after that to load object file.

It`s the code, that i used:

#include <windows.h>
#include <GL/glut.h>
#include <iostream>
#include <FreeImage.h>

FIBITMAP  *loadImage(const char *filename)
{
    FIBITMAP *dib1 = NULL;
    FREE_IMAGE_FORMAT fif = FreeImage_GetFIFFromFilename(filename);

    dib1 = FreeImage_Load(fif, filename, JPEG_DEFAULT);
    if (!dib1)
    {
       std::cerr << "Erreur ouverture d\'image" << std::endl;
       exit (0);

    } 
    std::cerr << "Success" << std::endl;
    return dib1;
}

GLuint loadTexture (FIBITMAP  * dib1)
{
    GLuint tex_id = 0;
    int x, y;
    int height, width;

    RGBQUAD rgbquad;
    FREE_IMAGE_TYPE type;
    BITMAPINFOHEADER *header;

    type = FreeImage_GetImageType(dib1);
    height = FreeImage_GetHeight(dib1);
    width = FreeImage_GetWidth(dib1);

    header = FreeImage_GetInfoHeader(dib1);
    int scanLineWidh = ((3*width)%4 == 0) ? 3*width : ((3*width)/4)*4+4;
    unsigned char * texels= (GLubyte*)calloc(height*scanLineWidh, sizeof(GLubyte));
    for (x=0 ; x<width ; x++)
        for (y=0 ; y<height; y++)
        {  
          FreeImage_GetPixelColor(dib1,x,y,&rgbquad);

          texels[(y*scanLineWidh+3*x)]=((GLubyte*)&rgbquad)[2];
          texels[(y*scanLineWidh+3*x)+1]=((GLubyte*)&rgbquad)[1];
          texels[(y*scanLineWidh+3*x)+2]=((GLubyte*)&rgbquad)[0];
         }

        glGenTextures (1, &tex_id);
        glBindTexture (GL_TEXTURE_2D, tex_id);

        glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
        glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);


        glTexImage2D (GL_TEXTURE_2D, 0, GL_RGB,
            width, height, 0, GL_RGB,
            GL_UNSIGNED_BYTE, texels);

      free(texels);
      return tex_id;
}
void display(void)
{  
    glClearColor (0.0,0.0,0.0,1.0); 
    glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    glLoadIdentity();
    glutSwapBuffers(); //swap the buffers

}


int main(int argc, char **argv) {

 FIBITMAP  *dib1 = loadImage("planina.jpg");

    glutInit(&argc,argv);
    glutInitDisplayMode(GLUT_DOUBLE|GLUT_RGB|GLUT_DEPTH);
    glutInitWindowSize(800,450);
    glutInitWindowPosition(20,20);
    glutCreateWindow("Loader");
    //glutReshapeFunc(reshape);
    //glutDisplayFunc(display);
    loadTexture(dib1);
    FreeImage_Unload(dib1);
    glutMainLoop();
    return 0;
}

What I am doing wrong?

Answer 1

This is your display function:

void display(void)
{  
    glClearColor (0.0,0.0,0.0,1.0); 
    glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    glLoadIdentity();
    glutSwapBuffers(); //swap the buffers

}

And what's immediately apparent is, that the only thing it does is

1. setting a clear color
2. clear the window
3. load an identity matrix
4. displays the result

What's lacking is any kind of actually drawing something. You have to draw some triangles or quads with the texture applied for the texture to actually show up somehow.