
    uniform sampler2D u_velocity_texture;

    uniform sampler2D u_text_texture;

    void main () {
        float L = texture2D(u_pressure_texture, vL).x;
        float R = texture2D(u_pressure_texture, vR).x;
        float T = texture2D(u_pressure_texture, vT).x;
        float B = texture2D(u_pressure_texture, vB).x;
        vec2 velocity = texture2D(u_velocity_texture, vUv).xy;
        velocity.xy -= vec2(R - L, T - B);
        gl_FragColor = vec4(velocity, 0., 1.);
    }
</script>

<scr