Fix region edge normal on small regions and normalize tangent and bin…

…ormal

src/shaders/main.glsl

@@ -180,16 +180,16 @@ vec3 get_normal(vec2 uv, out vec3 tangent, out vec3 binormal) {
  float u, v, height;
  vec3 normal;
  // Use vertex normals within radius of vertex_normals_distance, and along region borders.
- if (v_region_border_mask > 0.5 || v_vertex_xz_dist < vertex_normals_distance) {
+ if ((v_region_border_mask > 0.5 || v_vertex_xz_dist < vertex_normals_distance) && v_region.z >= 0) {
  normal = normalize(v_normal);
  } else {
  height = get_height(uv);
  u = height - get_height(uv + vec2(_region_texel_size, 0));
  v = height - get_height(uv + vec2(0, _region_texel_size));
  normal = normalize(vec3(u, _vertex_spacing, v));
  }
- tangent = cross(normal, vec3(0, 0, 1));
- binormal = cross(normal, tangent);
+ tangent = normalize(cross(normal, vec3(0, 0, 1)));
+ binormal = normalize(cross(normal, tangent));
  return normal;
 }