Texture is black when manually building mipmap

Question

I am trying to manually build a mipmap from a series of images. For the sake of brevity, let's assume the file containing the images I want (from 256x256 to 32x32) have paths file_1...4.

What I do to load the texture is:

GLuint textureID;
glGenTextures(1,&textureID);
glBindTexture(GL_TEXTURE_2D, textureID);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
glTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MAX_LEVEL, 4);

for i from 1 to 4
    unsigned char* image =  stbi_load_from_file(file_i, &width, &height, &comp, 3);
    glTexImage2D(GL_TEXTURE_2D, (i-1), GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, image);
    stbi_free_image(image);

When I go and try to use this created texture in a render all I got is a black result. Using singularly each texture works properly, so I excluded they're malformed. What can it be?

Answer 1

The only apparent error in your code is that you seem to specifying 4 mip-levels, from level 0 to level 3, however, you set GL_TEXTURE_MAX_LEVEL to 4. The max level is the zero-based index of the last mip-level, so in this case, it should be 3:

glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAX_LEVEL, 3);