void main()

in showcases/wind/src/layers/wind-layer/wind-layer-vertex.js [59:125]
58 lines of code
9 McCabe index (conditional complexity)

void main(void) {
  // position in texture coords
  float x = (positions.x - bbox.x) / (bbox.y - bbox.x);
  float y = (positions.y - bbox.z) / (bbox.w - bbox.z);
  vec2 coord = vec2(x, 1. - y);
  vec4 texel1 = texture2D(dataFrom, coord);
  vec4 texel2 = texture2D(dataTo, coord);
  vec4 texel = mix(texel1, texel2, delta);

  // angle
  float angleFrom = texel1.x * PI4;
  float angleTo = texel2.x * PI4;
  if (angleFrom < 0.) {
    angleFrom += PI * 2.;
  }
  if (angleTo < 0.) {
    angleTo += PI * 2.;
  }
  if (angleFrom < angleTo) {
    if (abs(angleTo - angleFrom) > abs(angleTo - (angleFrom + PI * 2.))) {
      angleFrom += PI * 2.;
    }
  } else {
    if (abs(angleFrom - angleTo) > abs(angleFrom - (angleTo + PI * 2.))) {
      angleTo += PI * 2.;
    }
  }
  float angle = mix(angleFrom, angleTo, delta);
  mat2 rotation = mat2(cos(angle), sin(angle), -sin(angle), cos(angle));

  // wind speed in 0-1
  float wind = 0.05 + (texel.y - bounds1.x) / (bounds1.y - bounds1.x) * 0.95;
  // float wind = (texel.y - bounds1.x) / (bounds1.y - bounds1.x);
  float factor = wind * 4.;
  vec2 vertex = rotation * vertices.xy;
  vec2 normal = rotation * normals.xy;
  vec2 pos = project_position(positions.xy + vertex.xy * factor);

  // OLD
  // vec3 extrudedPosition = vec3(pos.xy, 1.0);

  // NEW
  float elevation = project_scale((vertices.z + texel.w) * ELEVATION_SCALE);
  vec3 extrudedPosition = vec3(pos.xy, elevation + 1.0);

  vec4 position_worldspace = vec4(extrudedPosition, 1.0);
  gl_Position = project_to_clipspace(position_worldspace);

  // temperature in 0-1
  float temp = (texel.z - bounds2.x) / (bounds2.y - bounds2.x);

  // OLD
  // temp = floor((log(temp + 1.) * 3.) * 3.) / 3.;
  // vColor = vec4(vec3(temp, temp, 0.8), 1);

  // NEW
  temp = floor(temp * 3.) / 3.;
  vColor = vec4((1. - vec3(3. * temp, 0.25, 0.4)), 1);

  vPosition = position_worldspace;
  vNormal = vec4(normal, normals.z, 1);
  vAltitude = getAltitude(positions.xy);
  // out of bounds
  if (texel.x == 0. && texel.y == 0. && texel.z == 0.) {
    vColor.a = 0.;
  }
}