Using two textures in OpenGL

Question

I am writing a program in which I have to use two different textures. I can get one file read in and used as a texture but have so far been unable to get two textures to work. Here is my code to set up the one texture that I have:

        FILE *fd;
        int k, nm;
        char c;
        int i, i;
        char b[256];
        float s;
        int red, green, blue;

        fd = fopen("AI_Lab.ppm", "r");

        // check first line for P3
        fscanf(fd, "%[^\n]", b);
        if (b[0] != 'P' || b[1] != '3') {
                 printf("%s is not a PPM file\n", b);
                 system("pause");
                 exit(0);
                 }
        // skip comments
        fscanf(fd, "%c%c", &c, &c);
        while (c == '#') {
              fscanf(fd, "%[^\n]", b);
              fscanf(fd, "%c%c", &c, &c);
        }

        // put back first character of first non-comment line
        ungetc(c, fd);
        // read file info
        fscanf(fd, "%d %d %d", &o, &m, &k);

        nm = o * m; // overall size

        image = malloc(3*sizeof(GLuint)*nm);

        s = 255./k;

        for (i=0; i<nm; i++) {
            fscanf(fd, "%d %d %d", &red, &green, &blue);
            image[3*nm - 3*i - 3] = red;
            image[3*nm - 3*i - 2] = green;
            image[3*nm - 3*i - 1] = blue;
        }

        glPixelTransferf(GL_RED_SCALE, s);
        glPixelTransferf(GL_GREEN_SCALE, s);
        glPixelTransferf(GL_BLUE_SCALE, s);
        glPixelStorei(GL_UNPACK_SWAP_BYTES, GL_TRUE);
        glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
        glEnable(GL_TEXTURE_2D);
        glTexImage2D(GL_TEXTURE_2D, 0, 3, o1, m1, 0, GL_RGB, GL_UNSIGNED_INT, image);
        glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
        glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
        glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
        glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);

        glEnable (GL_DEPTH_TEST);
        glClearColor(0.0, 0.0, 0.0, 1.0);

I have tried all I can think of and cannot get things to work correctly.

Answer 1

Your texture specification looks to be alright, but you'll need to brush up on the basics of OpenGL. The red-book is a good place to start.

http://www.glprogramming.com/red/chapter09.html

Head on down to the section on Texture Objects.

Before calling glTexImage2d, you will want to generate and bind a new texture object. Each one of your textures should have its own object!

When rendering, you simply bind the texture that you want to render prior to drawing any primitives.