precision mediump float;

attribute vec4 xyuv;
uniform float uLevel;
uniform float uOffset;
varying vec2 vUv0;
varying vec2 vUv1;
varying vec2 vUv2;

void main() {
    vec2 levelOffset = vec2(0, (uLevel - 3.0) * .3);
    
    vUv0 = xyuv.zw + vec2(uOffset * .31, 0) + levelOffset;
    vUv1 = xyuv.zw + vec2(uOffset * .19, 0) + levelOffset;
    vUv2 = xyuv.zw + vec2(uOffset * .11, 0) + levelOffset;
    gl_Position = vec4(xyuv.xy, 0, 1);
}