private boolean drawWallpaperWithOpenGL(SurfaceHolder sh, int w, int h, int left, int top) {
            if (!initGL(sh)) return false;

            final float right = left + mBackgroundWidth;
            final float bottom = top + mBackgroundHeight;

            final Rect frame = sh.getSurfaceFrame();

            final Matrix4f ortho = new Matrix4f();
            ortho.loadOrtho(0.0f, frame.width(), frame.height(), 0.0f, -1.0f, 1.0f);

            final FloatBuffer triangleVertices = createMesh(left, top, right, bottom);

            final int texture = loadTexture(mBackground);
            final int program = buildProgram(sSimpleVS, sSimpleFS);

            final int attribPosition = glGetAttribLocation(program, "position");
            final int attribTexCoords = glGetAttribLocation(program, "texCoords");
            final int uniformTexture = glGetUniformLocation(program, "texture");
            final int uniformProjection = glGetUniformLocation(program, "projection");

            checkGlError();

            glViewport(0, 0, frame.width(), frame.height());
            glBindTexture(GL_TEXTURE_2D, texture);

            glUseProgram(program);
            glEnableVertexAttribArray(attribPosition);

           glEnableVertexAttribArray(attribTexCoords);
            glUniform1i(uniformTexture, 0);
            glUniformMatrix4fv(uniformProjection, 1, false, ortho.getArray(), 0);

            checkGlError();

            if (w < 0 || h < 0) {
                glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
                glClear(GL_COLOR_BUFFER_BIT);
            }

            // drawQuad
            triangleVertices.position(TRIANGLE_VERTICES_DATA_POS_OFFSET);
            glVertexAttribPointer(attribPosition, 3, GL_FLOAT, false,
                    TRIANGLE_VERTICES_DATA_STRIDE_BYTES, triangleVertices);

            triangleVertices.position(TRIANGLE_VERTICES_DATA_UV_OFFSET);
            glVertexAttribPointer(attribTexCoords, 3, GL_FLOAT, false,
                    TRIANGLE_VERTICES_DATA_STRIDE_BYTES, triangleVertices);

            glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);

            if (!mEgl.eglSwapBuffers(mEglDisplay, mEglSurface)) {
                throw new RuntimeException("Cannot swap buffers");
            }
            checkEglError();

            finishGL();

            return true;
        }