Better snow cover

assets/voxygen/shaders/fluid-frag/shiny.glsl

@@ -192,7 +192,7 @@ void main() {
     reflect_color *= f_light;
 
     // Prevent the sky affecting light when underground
-    float not_underground = clamp((f_pos.z - f_alt) / 128.0 + 1.0, 0.0, 1.0);
+    float not_underground = clamp((f_pos.z - f_alt) / 32.0 + 1.0, 0.0, 1.0);
     reflect_color *= not_underground;
     // /*const */vec3 water_color = srgb_to_linear(vec3(0.2, 0.5, 1.0));
     // /*const */vec3 water_color = srgb_to_linear(vec3(0.8, 0.9, 1.0));

assets/voxygen/shaders/lod-object-vert.glsl

@@ -51,7 +51,7 @@ void main() {
     f_norm = v_norm;
     f_col = vec4(vec3(inst_col) * (1.0 / 255.0) * v_col * (hash(inst_pos.xyxy) * 0.35 + 0.65), 1.0);
 
-    if ((inst_flags & FLAG_SNOW_COVERED) > 0u) {
+    if ((inst_flags & FLAG_SNOW_COVERED) > 0u && f_norm.z > 0.0) {
         snow_cover = 1.0;
     } else {
         snow_cover = 0.0;

world/src/column/mod.rs

@@ -87,6 +87,7 @@ impl<'a> Sampler<'a> for ColumnGen<'a> {
         let rockiness = sim.get_interpolated(wpos, |chunk| chunk.rockiness)?;
         let tree_density = sim.get_interpolated(wpos, |chunk| chunk.tree_density)?;
         let spawn_rate = sim.get_interpolated(wpos, |chunk| chunk.spawn_rate)?;
+        let flux = sim.get_interpolated(wpos, |chunk| chunk.flux)?;
         let near_water =
             sim.get_interpolated(
                 wpos,
@@ -1108,10 +1109,15 @@ impl<'a> Sampler<'a> for ColumnGen<'a> {
             })
             .max(-humidity.sub(CONFIG.desert_hum))
             .mul(4.0)
-            .add(((marble - 0.5) / 0.5) * 0.5)
-            .add(((marble_mid - 0.5) / 0.5) * 0.25)
-            .add(((marble_small - 0.5) / 0.5) * 0.175);
-        let (alt, ground, sub_surface_color) = if snow_factor <= 0.0 && alt > water_level {
+            .max(-0.25)
+            // 'Simulate' avalanches moving snow from areas with high gradients to areas with high flux
+            .add((gradient.unwrap_or(0.0) - 0.5).max(0.0) * 0.1)
+            // .add(-flux * 0.003 * gradient.unwrap_or(0.0))
+            .add(((marble - 0.5) / 0.5) * 0.25)
+            .add(((marble_mid - 0.5) / 0.5) * 0.125)
+            .add(((marble_small - 0.5) / 0.5) * 0.0625);
+        let snow_cover = snow_factor <= 0.0;
+        let (alt, ground, sub_surface_color) = if snow_cover && alt > water_level {
             // Allow snow cover.
             (
                 alt + 1.0 - snow_factor.max(0.0),
@@ -1121,7 +1127,6 @@ impl<'a> Sampler<'a> for ColumnGen<'a> {
         } else {
             (alt, ground, sub_surface_color)
         };
-        let snow_cover = snow_factor <= 0.0;
 
         // Make river banks not have grass
         let ground = water_dist

world/src/lib.rs

@@ -554,15 +554,27 @@ impl World {
                         .reduce_and()
                 })
                 .filter(|(_, site)| matches!(&site.kind, SiteKind::GiantTree(_)))
-                .map(|(_, site)| lod::Object {
-                    kind: lod::ObjectKind::GiantTree,
-                    pos: {
-                        let wpos2d = site.get_origin();
-                        (wpos2d - min_wpos)
-                            .map(|e| e as i16)
-                            .with_z(self.sim().get_alt_approx(wpos2d).unwrap_or(0.0) as i16)
-                    },
-                    flags: lod::Flags::empty(),
+                .filter_map(|(_, site)| {
+                    let wpos2d = site.get_origin();
+                    let col = ColumnGen::new(self.sim()).get((
+                        wpos2d,
+                        index,
+                        self.sim().calendar.as_ref(),
+                    ))?;
+                    Some(lod::Object {
+                        kind: lod::ObjectKind::GiantTree,
+                        pos: {
+                            (wpos2d - min_wpos)
+                                .map(|e| e as i16)
+                                .with_z(self.sim().get_alt_approx(wpos2d).unwrap_or(0.0) as i16)
+                        },
+                        flags: lod::Flags::empty()
+                            | if col.snow_cover {
+                                lod::Flags::SNOW_COVERED
+                            } else {
+                                lod::Flags::empty()
+                            },
+                    })
                 }),
         );
 

world/src/sim/mod.rs

@@ -2348,6 +2348,10 @@ impl SimChunk {
         const MIN_TREE_HUM: f32 = 0.15;
         // Tree density increases exponentially with humidity...
         let tree_density = (tree_density * (humidity - MIN_TREE_HUM).max(0.0).mul(1.0 + MIN_TREE_HUM) / temp.max(0.75))
+            // Places that are *too* wet (like marshes) also get fewer trees because the ground isn't stable enough for
+            // them.
+            //.mul((1.0 - flux * 0.05/*(humidity - 0.9).max(0.0) / 0.1*/).max(0.0))
+            .mul(0.25 + flux * 0.05)
             // ...but is ultimately limited by available sunlight (and our tree generation system)
             .min(1.0);