Branchless 3D DDA cursor

dda-cursor.h

#include <glm/glm.hpp>
using namespace glm;

struct DDACursor {
  vec3 mask;
  vec3 mapPos;
  vec3 rayStep;
  vec3 rayDir;
  vec3 rayPos;
  vec3 sideDist;
  vec3 deltaDist;
  DDACursor(){}
  DDACursor(vec3 pos, vec3 rayDir) {
    rayPos = pos;
    rayDir = rayDir;
    mapPos = glm::floor(pos);
    deltaDist = glm::abs(vec3(glm::length(rayDir)) / rayDir);
    rayStep = glm::sign(rayDir);
    vec3 p = (mapPos - pos);
    sideDist = (
      rayStep * p + (rayStep * 0.5f) + 0.5f
    ) * deltaDist;
    compute_mask();
  }

  void compute_mask() {
    mask = glm::step(sideDist, vec3(sideDist.y, sideDist.z, sideDist.x)) *
            glm::step(sideDist, vec3(sideDist.z, sideDist.x, sideDist.y));
  }

  void step() {
    compute_mask();
    sideDist += mask * deltaDist;
    mapPos += mask * rayStep;
    rayPos += mask * rayStep;
  }
};

Nice snippet! Guessing this is sourced by: https://www.shadertoy.com/view/4dX3zl?fbclid=IwAR2nfmGTTCNqLIm23aUXtXJvPEwZ4SOQufoGSnBwlmDocOaCmf9cOhQNA_U
?

correct!