Use bicubic interpolation for terrain.

assets/voxygen/shaders/include/lod.glsl

@@ -7,6 +7,50 @@ vec2 pos_to_uv(vec2 pos) {
 	return vec2(uv_pos.x, 1.0 - uv_pos.y);
 }
 
+// textureBicubic from https://stackoverflow.com/a/42179924
+vec4 cubic(float v) {
+    vec4 n = vec4(1.0, 2.0, 3.0, 4.0) - v;
+    vec4 s = n * n * n;
+    float x = s.x;
+    float y = s.y - 4.0 * s.x;
+    float z = s.z - 4.0 * s.y + 6.0 * s.x;
+    float w = 6.0 - x - y - z;
+    return vec4(x, y, z, w) * (1.0/6.0);
+}
+
+vec4 textureBicubic(sampler2D sampler, vec2 texCoords) {
+   vec2 texSize = textureSize(sampler, 0);
+   vec2 invTexSize = 1.0 / texSize;
+
+   texCoords = texCoords * texSize - 0.5;
+
+
+    vec2 fxy = fract(texCoords);
+    texCoords -= fxy;
+
+    vec4 xcubic = cubic(fxy.x);
+    vec4 ycubic = cubic(fxy.y);
+
+    vec4 c = texCoords.xxyy + vec2 (-0.5, +1.5).xyxy;
+
+    vec4 s = vec4(xcubic.xz + xcubic.yw, ycubic.xz + ycubic.yw);
+    vec4 offset = c + vec4 (xcubic.yw, ycubic.yw) / s;
+
+    offset *= invTexSize.xxyy;
+
+    vec4 sample0 = texture(sampler, offset.xz);
+    vec4 sample1 = texture(sampler, offset.yz);
+    vec4 sample2 = texture(sampler, offset.xw);
+    vec4 sample3 = texture(sampler, offset.yw);
+
+    float sx = s.x / (s.x + s.y);
+    float sy = s.z / (s.z + s.w);
+
+    return mix(
+       mix(sample3, sample2, sx), mix(sample1, sample0, sx)
+    , sy);
+}
+
 float alt_at(vec2 pos) {
 	return texture(t_map, pos_to_uv(pos)).a * (1300.0) + 140.0;
 		//+ (texture(t_noise, pos * 0.002).x - 0.5) * 64.0;
@@ -52,6 +96,6 @@ vec3 lod_pos(vec2 v_pos, vec2 focus_pos) {
 
 vec3 lod_col(vec2 pos) {
 	//return vec3(0, 0.5, 0);
-	return texture(t_map, pos_to_uv(pos)).rgb;
+	return textureBicubic(t_map, pos_to_uv(pos)).rgb;
 		//+ (texture(t_noise, pos * 0.04 + texture(t_noise, pos * 0.005).xy * 2.0 + texture(t_noise, pos * 0.06).xy * 0.6).x - 0.5) * 0.1;
 }

assets/voxygen/shaders/lod-terrain-frag.glsl

@@ -2,7 +2,6 @@
 
 #include <globals.glsl>
 #include <sky.glsl>
-#include <srgb.glsl>
 #include <lod.glsl>
 
 in vec3 f_pos;
@@ -19,7 +18,7 @@ void main() {
 
 	vec3 light, diffuse_light, ambient_light;
 	get_sun_diffuse(f_norm, time_of_day.x, light, diffuse_light, ambient_light, 1.0);
-	vec3 surf_color = illuminate(srgb_to_linear(f_col), light, diffuse_light, ambient_light);
+	vec3 surf_color = illuminate(f_col, light, diffuse_light, ambient_light);
 
 	float fog_level = fog(f_pos.xyz, focus_pos.xyz, medium.x);
 
@@ -27,7 +26,7 @@ void main() {
 	vec3 fog_color = get_sky_color(normalize(f_pos - cam_pos.xyz), time_of_day.x, cam_pos.xyz, f_pos, 1.0, true, clouds);
 	vec3 color = mix(mix(surf_color, fog_color, fog_level), clouds.rgb, clouds.a);
 
-	float mist_factor = max(1 - (f_pos.z + (texture(t_noise, f_pos.xy * 0.0005 + time_of_day.x * 0.001).x - 0.5) * 128.0) / 400.0, 0.0);
+	float mist_factor = max(1 - (f_pos.z + (texture(t_noise, f_pos.xy * 0.0005 + time_of_day.x * 0.0003).x - 0.5) * 128.0) / 400.0, 0.0);
 	//float mist_factor = f_norm.z * 2.0;
 	color = mix(color, vec3(1.0) * diffuse_light, clamp(mist_factor * 0.00005 * distance(f_pos.xy, focus_pos.xy), 0, 0.3));
 

voxygen/src/hud/settings_window.rs

@@ -1612,7 +1612,8 @@ impl<'a> Widget for SettingsWindow<'a> {
                 .set(state.ids.lod_detail_text, ui);
 
             if let Some(new_val) = ImageSlider::discrete(
-                ((self.global_state.settings.graphics.lod_detail as f32 / 100.0).log(5.0) * 10.0).round() as i32,
+                ((self.global_state.settings.graphics.lod_detail as f32 / 100.0).log(5.0) * 10.0)
+                    .round() as i32,
                 0,
                 20,
                 self.imgs.slider_indicator,
@@ -1625,7 +1626,9 @@ impl<'a> Widget for SettingsWindow<'a> {
             .pad_track((5.0, 5.0))
             .set(state.ids.lod_detail_slider, ui)
             {
-                events.push(Event::AdjustLodDetail((5.0f32.powf(new_val as f32 / 10.0) * 100.0) as u32));
+                events.push(Event::AdjustLodDetail(
+                    (5.0f32.powf(new_val as f32 / 10.0) * 100.0) as u32,
+                ));
             }
 
             Text::new(&format!(