White textures with OpenGL and DevIL on some Windows systems

I'm having some problems trying to load images with DevIL and creating textures in OpenGL. When a friend of mine tested my program on his Windows, all the rects, whom were supposed to contain textures, were white, without any image (texture). The problem seems to occur only on Window XP, Windows Vista and Windows 7, but not in every Windows PC: my Windows XP runs the program without problems.

Maybe there're some missing DLLs or files (improbable), or something that don't let the image to be loaded or used as a texture. By the other hand, the program runs fine on *UNIX systems.

This is the code I'm using to load an image and generate a texture:

void Image::load(const char* filename)
{
    ILuint ilimg;

    ilGenImages(1, &ilimg);
  开发者_如何学编程  ilBindImage(ilimg);

    if (!ilLoadImage(filename))
        throw ImageLoadError;

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

    bpp = ilGetInteger(IL_IMAGE_BPP);
    width = ilGetInteger(IL_IMAGE_WIDTH);
    height = ilGetInteger(IL_IMAGE_HEIGHT);
    format = ilGetInteger(IL_IMAGE_FORMAT);

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

    glTexImage2D(GL_TEXTURE_2D, 0, bpp, width, height, 0, format,
        GL_UNSIGNED_BYTE, ilGetData());

    ilDeleteImages(1, &ilimg);
}

This is the code that draws a rect with the texture applied:

void Rect::show()
{
    glPushAttrib(GL_CURRENT_BIT);

    glEnable(GL_TEXTURE_2D);
    glColor4f(1.0, 1.0, 1.0, opacity);
    glBindTexture(GL_TEXTURE_2D, texture->get_image());

    glBegin(GL_POLYGON);
        glTexCoord2i(0, 0); glVertex2f(x, y);
        glTexCoord2i(1, 0); glVertex2f(x+width, y);
        glTexCoord2i(1, 1); glVertex2f(x+width, y+height);
        glTexCoord2i(0, 1); glVertex2f(x, y+height);
    glEnd();

    glDisable(GL_TEXTURE_2D);

    glPopAttrib();
}

If you need some other code that I don't mentioned, ask me and i'll post it.

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glTexImage2D(target, level, internal format, width, height, border, format, type, data);

The internal format parameter of glTexImage is not bits per pixel. Actually its numerical value is not related to the format at all. OpenGL defines only specific values to be valid, among them also four with numeric relation, but just as a mnemonic: 1 (shorthand for GL_LUMINANCE), 2 (GL_LUMINANCE_ALPHA), 3 (GL_RGB), 4 (GL_RGBA). There are also a number of other format tokens, but their numeric value is arbitrarily choosen.

Also the bpp for the image data is used to find the format and type parameters. You'll need to implement a LUT or switch-case structure for that.

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The issue you are experiencing sounds like an implementation version issue. Probably a "correct" but less "nice" implementation isn't letting you get away with something subtly incorrect. Or on the other hand the implementation may have a subtle bug and isn't accepting your valid code.

I might try swapping

glColor4f(1.0, 1.0, 1.0, opacity);
glBindTexture(GL_TEXTURE_2D, texture->get_image());

to

glBindTexture(GL_TEXTURE_2D, texture->get_image());
glColor4f(1.0, 1.0, 1.0, opacity);

and declaring vertex before texcoord like.

glVertex2f(x, y);
glTexCoord2i(0, 0);

Short of that if you do not already have "The Red Book" consult http://glprogramming.com/red/chapter09.html