Texture on a sphere

[wisher]

Hi, I have a problem applying a texture to a sphere.
In the setup phase I do this:

	earth = gluNewQuadric();
 
	gluQuadricTexture( earth, GL_TRUE);
 
	earthTexture = LoadBitmap("data/EarthTexture.bmp");

And when I draw the I use this code

	    glEnable ( GL_TEXTURE_2D );
	    glBindTexture ( GL_TEXTURE_2D, earthTexture);
	    gluSphere( earth, 0.9, 36, 72);
	  glDisable ( GL_TEXTURE_2D );

But something goes wrong and I obtain this http://yfrog.com/14screenshot20091119at105j

What am I doing wrong?

If I try to move the sphere the result is getting even worst.

[wisher]

If I try to draw only the texture on a square it works, but if I try to draw the texture on the square after I call the gluSphere also the image on the square is screwed :-(

[marshats]

The image mapped on the sphere appears like it is rotated 90. Can you rotate your image 90 degrees in some image editor and try again. Is LoadBitmap() a custom function or winOS library function?

Do you have some code affecting the texture Matrix ie do you call the following somewhere in your code?

glMatrixMode(GL_TEXTURE);

[wisher]

Thanks for your answer. I never use the matrix mode GL_TEXTURE explicitly, is there any GL command that makes that matrix change?

The code for the load bitmap was found on internet and it is this:

int LoadBitmap(char *filename)
{
    FILE * file;
    char temp;
    long i;
 
    BITMAPINFOHEADER infoheader;
 
    GLuint num_texture;
 
    if( (file = fopen(filename, "rb"))==NULL) return (-1); // Open the file for reading
 
    fseek(file, 18, SEEK_CUR);  /* start reading width & height */
    fread(&infoheader.biWidth, sizeof(int), 1, file);
 
    fread(&infoheader.biHeight, sizeof(int), 1, file);
 
    fread(&infoheader.biPlanes, sizeof(short int), 1, file);
    if (infoheader.biPlanes != 1) {
	    printf("Planes from %s is not 1: %u\n", filename, infoheader.biPlanes);
	    return 0;
    }
 
    // read the bpp
    fread(&infoheader.biBitCount, sizeof(unsigned short int), 1, file);
    if (infoheader.biBitCount != 24) {
      printf("Bpp from %s is not 24: %d\n", filename, infoheader.biBitCount);
      return 0;
    }
 
    fseek(file, 24, SEEK_CUR);
 
    // read the data
    if(infoheader.biWidth<0){
	infoheader.biWidth = -infoheader.biWidth;
    }
    if(infoheader.biHeight<0){
	infoheader.biHeight = -infoheader.biHeight;
    }
    infoheader.data = (char *) malloc(infoheader.biWidth * infoheader.biHeight * 3);
    if (infoheader.data == NULL) {
	    printf("Error allocating memory for color-corrected image data\n");
	    return 0;
    }
 
    if ((i = fread(infoheader.data, infoheader.biWidth * infoheader.biHeight * 3, 1, file)) != 1) {
	    printf("Error reading image data from %s.\n", filename);
	    return 0;
    }
 
    for (i=0; i<(infoheader.biWidth * infoheader.biHeight * 3); i+=3) { // reverse all of the colors. (bgr -> rgb)
	    temp = infoheader.data[i];
	    infoheader.data[i] = infoheader.data[i+2];
	    infoheader.data[i+2] = temp;
    }
 
 
    fclose(file); // Closes the file stream
 
    glGenTextures(1, &amp;num_texture);
    glBindTexture(GL_TEXTURE_2D, num_texture); // Bind the ID texture specified by the 2nd parameter
 
    // The next commands sets the texture parameters
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT); // If the u,v coordinates overflow the range 0,1 the image is repeated
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); // The magnification function ("linear" produces better results)
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_NEAREST); //The minifying function
 
    glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
 
    // Finally we define the 2d texture
    glTexImage2D(GL_TEXTURE_2D, 0, 3, infoheader.biWidth, infoheader.biHeight, 0, GL_RGB, GL_UNSIGNED_BYTE, infoheader.data);
 
    // And create 2d mipmaps for the minifying function
    gluBuild2DMipmaps(GL_TEXTURE_2D, 3, infoheader.biWidth, infoheader.biHeight, GL_RGB, GL_UNSIGNED_BYTE, infoheader.data);
 
    free(infoheader.data); // Free the memory we used to load the texture
 
    return (num_texture); // Returns the current texture OpenGL ID
}

[wisher]

I tried to rotate the texture, but it doesn't help

[marshats]

Mhhm, the glMatrixMode(GL_TEXTURE) question was a remote possibility because you can affect texture coordinates with glTranslate/glRotate etc with it. So it is good to rule that out right away.

I am surprised rotating the image 90 degrees did nothing.

Some versions of openGL don't accept non-power of two sizes ie what are the actual values of infoheader.biWidth and infoheader.biHeight? If they are not 64, 128,256 ... 2^integer then try scaling your image file to the nearest power of 2 before loadBMP called.