 vec4 voxel(vec3 pos) {
     return texture3dFrom2dNearest(tVolumeData, pos, uGridDim, uGridTexDim.xy);
 }
-
-#pragma glslify: decodeFloatRGB = require(../utils/decode-float-rgb.glsl)
 
 void main(void) {
     // get 1D index

uniform vec2 uScale;

varying vec2 vCoordinate;

// cube corners
const vec3 c0 = vec3(0., 0., 0.);


    float t = (uIsoValue - v0) / (v0 - v1);
    // t = -0.5;
    gl_FragData[0].xyz = (uGridTransform * vec4(b0 + t * (b0 - b1), 1.0)).xyz;
    gl_FragData[0].w = decodeFloatRGB(d0.rgb); // group id

    // normals from gradients
    vec3 n0 = -normalize(vec3(
