ios opengles sample texture error （use stb_image）while android is ok

[zhangbaochong]

https://stackoverflow.com/questions/71566579/ios-opengles-sample-texture-error-use-stb-image-while-android-is-ok

I use stb_image load texture, such as

`stbi_set_flip_vertically_on_load(true);
GLuint textureID;
glGenTextures(1, &textureID);
int width, height, nrComponents;
unsigned char *data = stbi_load(path, &width, &height, &nrComponents, 0);

GLenum format;
if (nrComponents == 1) {
format = GL_RED;
} else if (nrComponents == 3) {
format = GL_RGB;
} else {
format = GL_RGBA;
}

glTexImage2D(GL_TEXTURE_2D, 0, format, width, height, 0, format, GL_UNSIGNED_BYTE, data);
glGenerateMipmap(GL_TEXTURE_2D);
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_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);`

The same code in android is ok, while in ios the rendering result get some problem:

if set stbi_set_flip_vertically_on_load(false):

the correct result with android:

[nothings]

the last image does not look like it's the same image as the first two. are you sure it is?

[nothings]

no idea

[zhangbaochong]

its ok if I sample texture to a square, so it may be not an issues with stb_image. thanks

[mmozeiko]

I don't know on which GL version iOS is, but in OpenGL ES 2.0 non-power-of-two textures support only GL_CLAMP_TO_EDGE wrap mode and GL_NEAREST or GL_LINEAR filter modes. Other combinations are not supported unless special extensions are present.

[zhangbaochong]

Its OpenGLES 3.0 and my texutre also is power-of-two texture.

[nothings]

The texture inside model.zip is 1280x1280, which is not a power-of-two.

[zhangbaochong]

The issue is that GLKView not set depth buffer, just add one line code : view.drawableDepthFormat = GLKViewDrawableDepthFormat24;