Android NDK C++ openGL ES 2 context gives bad display

Question

I am trying to implement a openGL ES 2.0 game using NDK in C++ . My test device was ASUS Zenphone 5 I am pretty sure it supports openGL ES 2.0 as it can run games based on openGL ES 2 from play store very smoothly and also the helloGl2 sample in androind NDK.

When I called glCreateShader log cat gave an error "called unimplemented api" by googling a bit I found out it was because the app was using openGL ES 1 context by default.

So I modified the EGL context creation code from:

context = eglCreateContext(display, config, NULL, NULL);

to

EGLint contextAttrs[] = {
        EGL_CONTEXT_CLIENT_VERSION,2,EGL_NONE
};

context = eglCreateContext(display, config, NULL, contextAttrs);

Now this gave a different error

 E/libEGL(12670): validate_display:257 error 3008 (EGL_BAD_DISPLAY)

However when I tested it on a galaxy s3 (GT-I9100) there was no BAD DISPLAY ERROR , but the app crashed on calling glCreateShader with fatal signal SIGSEV

What is going on here?

Answer 1

If you are creating an ES 2 context, you also need to include EGL_RENDERABLE_TYPE, EGL_OPENGL_ES2_BIT in the attributes for the EGL config, it's not enough to add EGL_CONTEXT_CLIENT_VERSION, 2 to the context attributes.

Also, make sure you are linking to libGLESv2.so ( -lGLESv2 in LOCAL_LDLIBS ), and make sure you aren't linking in libGLESv1_CM.so by accident. (Using them both in the same process requires a bit of extra trickery.)