Some phones don't draw models if indicesComponentType=5125-GL_UNSIGNED_INT. But they draw fine if indicesComponentType=5123-GL_UNSIGNED_SHORT. I think it may be related to the support on the phone OpenGLES3+. Or are there other reasons? about gltf-tutorials

[javagl]

That's almost certainly the (only) reason.

GLES 2.0: https://registry.khronos.org/OpenGL-Refpages/es2.0/xhtml/glDrawElements.xml

type: Specifies the type of the values in indices. Must be GL_UNSIGNED_BYTE or GL_UNSIGNED_SHORT.

GLES 3.0: https://registry.khronos.org/OpenGL-Refpages/es3.0/html/glDrawElements.xhtml

type: Specifies the type of the values in indices. Must be one of GL_UNSIGNED_BYTE, GL_UNSIGNED_SHORT, or GL_UNSIGNED_INT.

(There are extensions for supporting GL_UNSIGNED_INT in 2.0, but I don't know how widely these are supported)

[lexaknyazev]

• For OpenGL ES 2.0, check for the GL_OES_element_index_uint extension string presence.
• For WebGL 1.0, enable the OES_element_index_uint extension.

[3dportable]

thank