float equation_texel_number_assuming_left = element_idx.x / 2.0f;
float equation_texel_number_assuming_right = (element_idx.x - 1.0f) / 2.0f;
equation_tc_assuming_left.x = (equation_texel_number_assuming_left + 0.5f) / textureSize(equation_red_tex, 0).x;
equation_tc_assuming_right.x = (equation_texel_number_assuming_right + 0.5f) / textureSize(equation_red_tex, 0).x;
equation_tc_assuming_left.y = tc.y;
equation_tc_assuming_right.y = tc.y;
float equation_texel_number_assuming_left = element_idx.x / 2.0f;
float equation_texel_number_assuming_right = (element_idx.x - 1.0f) / 2.0f;
equation_tc_assuming_left.x = (equation_texel_number_assuming_left + 0.5f) / textureSize(equation_red_tex, 0).x;
equation_tc_assuming_right.x = (equation_texel_number_assuming_right + 0.5f) / textureSize(equation_red_tex, 0).x;
equation_tc_assuming_left.y = tc.y;
equation_tc_assuming_right.y = tc.y;