X-Git-Url: https://harrygodden.com/git/?a=blobdiff_plain;f=shaders%2Flight_clearskies.glsl;h=0af3be0774ff0899ff6de75e026a85180c49b815;hb=c0e4a67ba2f001179df6e2cde97370a946669c22;hp=5b97f97cfc332e1d63ece04d303702691237977c;hpb=0ca7f5ca2560908de1a03db112df67e52b476107;p=carveJwlIkooP6JGAAIwe30JlM.git

diff --git a/shaders/light_clearskies.glsl b/shaders/light_clearskies.glsl
index 5b97f97..0af3be0 100644
--- a/shaders/light_clearskies.glsl
+++ b/shaders/light_clearskies.glsl
@@ -6,7 +6,7 @@
 //const vec3  SUN_COLOUR      = vec3( 1.10, 0.89, 0.35 );
 
 const float SUN_ANGLE       = 0.0001;
-const float PI              = 3.14159265;
+const float PI              = 3.14159265358979323846264;
 
 //struct world_info
 //{
@@ -18,6 +18,37 @@ const float PI              = 3.14159265;
 //   vec3 sun_dir;
 //};
 
+vec3 rand33(vec3 p3)
+{
+	p3 = fract(p3 * vec3(.1031, .1030, .0973));
+   p3 += dot(p3, p3.yxz+33.33);
+   return fract((p3.xxy + p3.yxx)*p3.zyx);
+}
+
+float stars( vec3 rd, float rr, float size ){
+   vec3 co = rd * rr;
+
+   float a = atan(co.y, length(co.xz)) + 4.0 * PI;
+
+   float spaces = 1.0 / rr;
+   size = (rr * 0.0015) * fwidth(a) * 1000.0 * size;
+   a -= mod(a, spaces) - spaces * 0.5;
+
+   float count = floor(sqrt(pow(rr, 2.0) * (1.0 - pow(sin(a), 2.0))) * 3.0);
+   
+   float plane = atan(co.z, co.x) + 4.0 * PI;
+   plane = plane - mod(plane, PI / count);
+
+   vec2 delta = rand33(vec3(plane, a, 0.0)).xy;
+
+   float level = sin(a + spaces * (delta.y - 0.5) * (1.0 - size)) * rr;
+   float ydist = sqrt(rr * rr - level * level);
+   float angle = plane + (PI * (delta.x * (1.0-size) + size * 0.5) / count);
+   vec3 center = vec3(cos(angle) * ydist, level, sin(angle) * ydist);
+   float star = smoothstep(size, 0.0, distance(center, co));
+   return star;
+}
+
 float luminance( vec3 v )
 {
    return dot( v, vec3(0.2126, 0.7152, 0.0722) );
@@ -52,8 +83,19 @@ vec3 clearskies_sky( vec3 ray_dir )
          
    vec3 sun_colour  = mix( vec3(1.0), g_sunset_colour.rgb, g_sunset_phase*0.5 );
         sun_colour *= sun_shape;
+
+   
+   float star = 0.0;
+   float star_blend = 10.0*max(0.0,(1.0-g_day_phase*2.0));
+
+   if( star_blend > 0.001 ){
+      for( float j = 1.0; j <= 4.1; j += 1.0 ){
+         float m = mix(0.6, 0.9, smoothstep(1.0, 2.0, j));
+         star += stars( ray_dir, 1.94 * pow( 1.64, j ), m ) * (1.0/pow(4.0, j));
+      }
+   }
    
-   vec3 composite   = sky_colour + sun_colour;
+   vec3 composite   = sky_colour + sun_colour + star*star_blend;
    return composite;
 }