precision highp float;

varying vec2 vUv;
uniform sampler2D uVelocity;
uniform sampler2D uSource;
uniform vec2 texelSize;
uniform float dt;
uniform float uDissipation;

void main() {
    vec2 coord = vUv - dt * texture2D(uVelocity, vUv).xy * texelSize;

    gl_FragColor = uDissipation * texture2D(uSource, coord);

    gl_FragColor.a = 1.0;
}