Update sky

- Add simple cloudy fog effect (#17)
- Mirror sky gradient

src/materials/RenderChunk/vertex.sc

@@ -132,6 +132,12 @@ void main() {
     fogColor.rgb = mix(fogColor.rgb, vec3(0.8,0.2,0.12)*1.5, lit.x*(1.67-fogColor.a*1.67));
   }
 
+  #ifdef NL_CLOUDY_FOG
+    float fg = smoothstep(0.0, 1.0-NL_CLOUDY_FOG, relativeDist);
+    fg *= noise2D(4.0*viewDir.xz - 3.0*abs(viewDir.y) + 0.2*t);
+    fogColor.a += (1.0-fogColor.a)*fg;
+  #endif
+
   vec4 refl = vec4(0.0,0.0,0.0,0.0);
   vec4 pos;
 

src/newb/config.h

@@ -62,6 +62,7 @@
 #define NL_FOG_TYPE 2             // 0:no fog, 1:vanilla, 2:smoother vanilla
 #define NL_MIST_DENSITY 0.18      // 0.0 no mist ~ 1.0 misty
 #define NL_RAIN_MIST_OPACITY 0.12 // [toggle] 0.04 very subtle ~ 0.5 thick rain mist blow
+#define NL_CLOUDY_FOG 0.1         // [toggle] 0.0 subtle - 0.8 dense fog clouds
 
 /* Sky colors - zenith=top, horizon=bottom */
 #define NL_DAY_ZENITH_COL    vec3(0.15,0.45,1.0)
@@ -146,7 +147,7 @@
 /* Shooting star */
 #define NL_SHOOTING_STAR 1.0        // [toggle] 0.2 dim ~ 1.0 bright
 #define NL_SHOOTING_STAR_PERIOD 6.0 // 0.4 fast ~ 12.0 slow (12 secs)
-#define NL_SHOOTING_STAR_DELAY 64.0  // 0.0 no delay ~ 100.0 long time (100 secs)
+#define NL_SHOOTING_STAR_DELAY 64.0 // 0.0 no delay ~ 100.0 long time (100 secs)
 
 /* Chunk loading slide in animation */
 //#define NL_CHUNK_LOAD_ANIM 100.0 // [toggle] -600.0 fall from top ~ 600.0 rise from bottom

src/newb/functions/noise.h

@@ -32,4 +32,18 @@ float disp(vec3 pos, highp float t) {
   return mix(fastRand(pos.xz), fastRand(pos.xz+vec2_splat(1.0)), val);
 }
 
+float noise2D(vec2 u) {
+  vec2 u0 = floor(u);
+  vec2 v = u-u0;
+  v = 3.0*v*v - 2.0*v*v*v;
+
+  float c0 = rand(u0);
+  float c1 = rand(u0+vec2(1.0, 0.0));
+  float c2 = rand(u0+vec2(1.0, 1.0));
+  float c3 = rand(u0+vec2(0.0, 1.0));
+
+  float n = mix(mix(c0, c3, v.y),mix(c1, c2, v.y), v.x);
+  return n;
+}
+
 #endif

src/newb/functions/sky.h

@@ -61,18 +61,22 @@ vec3 getHorizonEdgeCol(vec3 horizonCol, float rainFactor, vec3 FOG_COLOR) {
 
 // 1D sky with three color gradient
 vec3 renderOverworldSky(vec3 horizonEdgeCol, vec3 horizonColor, vec3 zenithColor, vec3 viewDir) {
-  float h = max(viewDir.y, 0.0);
-  h = 1.0-h*h;
+  float h = 1.0-viewDir.y*viewDir.y;
   float hsq = h*h;
+  if (viewDir.y < 0.0) {
+    hsq *= hsq*hsq;
+    hsq *= hsq;
+  }
 
   // gradient 1  h^16
   // gradient 2  h^8 mix h^2
-  float gradient1 = hsq*hsq*hsq*hsq;
+  float gradient1 = hsq*hsq;
+  gradient1 *= gradient1;
   float gradient2 = 0.6*gradient1 + 0.4*hsq;
   gradient1 *= gradient1;
 
   vec3 sky = mix(horizonColor, horizonEdgeCol, gradient1);
-  sky = mix(zenithColor,horizonColor, gradient2);
+  sky = mix(zenithColor, horizonColor, gradient2);
 
   return sky;
 }