glCreateShader and glCreateProgram fail on android

Question

I'm having a very difficult problem creating a shader program on android. when I call glCreateShader or glCreateProgram each always returns 0.

I've covered all my bases with regards to troubleshooting:

• I checked to make sure I had an ogl context (I do, i tested this by clearing the frame buffer with various colors, which worked).

• I tried glGetError but it returned nothing (GL_NO_ERROR)

I'm not an opengl or android expert so I don't know of any thing else that could be causing this.

I've been running my app on a nexus 7 tablet and I use OpenGL ES 2.0, and I target the latest version of Android (version 17).

Lastly, I have my code to show as well:

Here is my boilerplate code that sets up the app:

public class Platform implements ILinkable<Activity> {
    class GameLoop extends GLSurfaceView implements GLSurfaceView.Renderer {
        class Graphics2D implements IGraphics2D {
            int width  = 0;
            int height = 0;

            public void setWidth (int width ) { this.width = width; }
            public void setHeight(int height) { this.height = height; }

            public int getWidth () { return width;  }
            public int getHeight() { return height; }
        }

        class Time implements ITime {
            float frametime = 0;
            float totaltime = 0;
            long  temptime = 0;
            boolean running = true;

            public void beginTimeCount() {
                temptime = System.nanoTime();
            }

            public void endTimeCount() {
                frametime  = (System.nanoTime() - temptime) / 1000000;
                totaltime += frametime;
            }

            public float getFrameTime() { return frametime; }
            public float getTotalTime() { return totaltime; }
        }

        Graphics2D graphics2d = new Graphics2D();
        Time       time       = new Time();
        boolean    running    = true;

        public GameLoop(Context context) {
            super(context);

            setEGLContextClientVersion(2);
            setRenderer(this);
            //setRenderMode(GLSurfaceView.RENDERMODE_WHEN_DIRTY);
        }

        public void onSurfaceCreated(GL10 unused, EGLConfig config) {
            GLES20.glClearColor(0.5f, 0.0f, 0.5f, 1.0f);
        }

        public void onDrawFrame(GL10 unused) {
            if (running) {
                time.beginTimeCount();

                for (IUpdateable u : Platform.this.root.update)
                    u.onUpdate(time);

                GLES20.glClear(GLES20.GL_COLOR_BUFFER_BIT);
                for (IDrawable2D d : Platform.this.root.draw2d) {
                    d.onDraw2D(graphics2d);
                }

                for (IDrawable3D d : Platform.this.root.draw3d)
                    d.onDraw3D();

                time.endTimeCount();
            }
        }

        public void onSurfaceChanged(GL10 unused, int width, int height) {
            GLES20.glViewport(0,0, width, height);
            graphics2d.setWidth(width);
            graphics2d.setHeight(height);
            for (IDrawable2D d : Platform.this.root.draw2d)
                d.onSize2D(graphics2d);
        }

        public void onPause() {
            super.onPause();
            running = false;
        }

        public void onResume() {
            super.onResume();
            running = true;
        }
    }

    private GameLoop gameloop;
    public Node root;

    public Platform() {
        this.root = new Node();
    }

    public void link(Activity activity) {
        this.gameloop = new GameLoop(activity);
        activity.requestWindowFeature(Window.FEATURE_NO_TITLE);
        activity.setContentView(this.gameloop);
    }

    public void unlink(Activity activity) {
        this.gameloop = null;
        activity.setContentView(null);
    }
}

and this is the main activity:

public class MainActivity extends Activity {

    private Game game;
    private Platform platform;

    public MainActivity() {
        platform = new Platform();
        game = new Game();
    }

    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        platform.link(this);
        game.link(platform.root);
        game.onStart();
    }

    public void onDestroy() {
        super.onDestroy();
        game.onStop();
        game.unlink(platform.root);
        platform.unlink(this);
    }
}

and this is the code that creates the shaders and program:

public static int loadShader(int shaderType, String source) throws FmtException {
    int[] gotVar = new int[]{ 0 };
    int shader = GLES20.glCreateShader(shaderType);

    if (shader == 0)
        throw new FmtException(FmtException.GLES,"could not create shader: %s",getError());

    GLES20.glShaderSource(shader, source);
    GLES20.glCompileShader(shader);

    GLES20.glGetShaderiv(shader, GLES20.GL_COMPILE_STATUS, gotVar, 0);
    if (gotVar[0] == 0) {
        GLES20.glGetShaderiv(shader, GLES20.GL_INFO_LOG_LENGTH, gotVar, 0);
        if (gotVar[0] != 0) {
            GLES20.glDeleteShader(shader);
            throw new FmtException(FmtException.GLES, "could not compile shader %d:\n%s\n",shaderType, GLES20.glGetShaderInfoLog(shader));
        }
    }

    return shader;
}

public static int createProgram(String pVertexSource, String pFragmentSource) throws FmtException {
    int[] gotVar = new int[]{ GLES20.GL_FALSE };
    int vertexShader = loadShader(GLES20.GL_VERTEX_SHADER, pVertexSource);
    int pixelShader = loadShader(GLES20.GL_FRAGMENT_SHADER, pFragmentSource);

    int program = GLES20.glCreateProgram();
    if (program == 0)
        throw new FmtException(FmtException.GLES, "could not create program: %s",getError());


    GLES20.glAttachShader(program, vertexShader);
    GLES20.glAttachShader(program, pixelShader);
    GLES20.glLinkProgram(program);

    GLES20.glGetProgramiv(program, GLES20.GL_LINK_STATUS, gotVar, 0);
    if (gotVar[0] != GLES20.GL_TRUE) {
        GLES20.glGetProgramiv(program, GLES20.GL_INFO_LOG_LENGTH, gotVar, 0);
        if (gotVar[0] != 0) {
            GLES20.glDeleteProgram(program);
            throw new FmtException(FmtException.GLES, "could not link program:\n%s\n", GLES20.glGetProgramInfoLog(program));
        }
    }

    return program;
}

any help or suggestions would be greatly appreciated.

Answer 1

For the ones who are looking for the answer, it is hidden in the comments. I am quoting @Reigertje from comments.

Shader calls should be within a GL thread that is onSurfaceChanged(), onSurfaceCreated() or onDrawFrame()