glFramebufferTexture2D(GL_FRAMEBUFFER, GL_STENCIL_ATTACHMENT, GL_TEXTURE_2D, stencil_buffer_1, 0);
glStencilFunc(GL_ALWAYS, 1, 0xFF);
glStencilMask(0xFF);
draw_object_1();
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_STENCIL_ATTACHMENT, GL_TEXTURE_2D, stencil_buffer_2, 0);
glStencilFunc(GL_ALWAYS, 1, 0xFF);
glStencilMask(0xFF);
draw_object_2();
glStencilMask(0x00);
...
draw_other_stuff();
...
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_STENCIL_ATTACHMENT, GL_TEXTURE_2D, stencil_buffer_1, 0);
glStencilFunc(GL_NOTEQUAL, 1, 0xFF);
draw_object_1_outline();
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_STENCIL_ATTACHMENT, GL_TEXTURE_2D, stencil_buffer_2, 0);
glStencilFunc(GL_NOTEQUAL, 1, 0xFF);
draw_object_1_outline();