bind_sampler(sor_program, uniform_equation_red_tex, 2, equation_red_tex, nearest_sampler);
bind_sampler(sor_program, uniform_equation_black_tex, 3, equation_black_tex, nearest_sampler);
bind_sampler(sor_program, uniform_equation_red_tex, 2, equation_red_tex, nearest_sampler);
bind_sampler(sor_program, uniform_equation_black_tex, 3, equation_black_tex, nearest_sampler);