problem with OpenGL drawing in qt

[alex111]

Hello, I try to draw two triangles, but only the first comes out, what's the problem?

  GLfloat vertices[] = {
                         0.0f, 0.0f,
                        +1.0f, +1.0f,
                       -1.0f, +1.0f,

                       0.0f, 0.0f,
                        -1.0f, -1.0f
                        +1.0f, -1.0f,
};
        GLuint myBufferID;
       glGenBuffers(1, &myBufferID);
       glBindBuffer(GL_ARRAY_BUFFER, myBufferID);
       glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
       glEnableVertexAttribArray(0);
       glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 0, 0);
       glDrawArrays(GL_TRIANGLES,0,6);