- float surface = texelFetch(surface_in, coord, 0).x;
- float depth = surface-texelFetch(bottom_in, coord, 0).x;
- float surface_left = texelFetch(surface_in, coord-ivec2(1, 0), 0).x;
- float surface_right = texelFetch(surface_in, coord+ivec2(1, 0), 0).x;
- float depth_right = surface_right-texelFetch(bottom_in, coord+ivec2(1, 0), 0).x;
- float surface_down = texelFetch(surface_in, coord-ivec2(0, 1), 0).x;
- float surface_up = texelFetch(surface_in, coord+ivec2(0, 1), 0).x;
- float depth_up = surface_up-texelFetch(bottom_in, coord+ivec2(0, 1), 0).x;
- vec2 velocity = texelFetch(velocity_in, coord, 0).xy;
+ vec4 data = get_data(coord);
+ vec2 sd_right = get_depth(coord+ivec2(1, 0));
+ vec2 sd_up = get_depth(coord+ivec2(0, 1));