tweak when lines fade

crates/viewer/re_renderer/shader/world_grid.wgsl

@@ -109,7 +109,7 @@ fn main_fs(in: VertexOutput) -> @location(0) vec4f {
     //
     // Tried smoothstep here, but didn't feel right even with lots of range tweaking.
     let line_density = 1.0 / max(width_in_grid_units.x, width_in_grid_units.y);
-    let grid_closeness_fade = linearstep(1.0, 10.0, line_density);
+    let grid_closeness_fade = linearstep(4.0, 20.0, line_density);
     intensity_regular *= grid_closeness_fade;
 
     // Every tenth line is a more intense, we call those "cardinal" lines.
@@ -119,7 +119,7 @@ fn main_fs(in: VertexOutput) -> @location(0) vec4f {
     let distance_to_grid_line_cardinal = calc_distance_to_grid_line(in.scaled_world_plane_position * (1.0 / CARDINAL_LINE_FACTOR));
     var cardinal_line_intensity = linearstep2(width_in_grid_units + line_anti_alias, width_in_grid_units - line_anti_alias,
                                               distance_to_grid_line_cardinal * CARDINAL_LINE_FACTOR);
-    let cardinal_grid_closeness_fade = linearstep(2.0, 10.0, line_density * CARDINAL_LINE_FACTOR); // Fade cardinal lines a little bit earlier (because it looks nicer)
+    let cardinal_grid_closeness_fade = linearstep(4.0, 20.0, line_density * CARDINAL_LINE_FACTOR);
     cardinal_line_intensity *= cardinal_grid_closeness_fade;
 
     // Combine all lines.