vec3 I_0 = texture(image0_tex, image_pos + I_0_check_offset).rgb;
vec3 I_1 = texture(image1_tex, image_pos + I_1_check_offset).rgb;
vec3 diff = abs(I_1 - I_0);
vec3 I_0 = texture(image0_tex, image_pos + I_0_check_offset).rgb;
vec3 I_1 = texture(image1_tex, image_pos + I_1_check_offset).rgb;
vec3 diff = abs(I_1 - I_0);