--- src/engine/lightmap.cpp	(revision 6520)
+++ src/engine/lightmap.cpp	(working copy)
@@ -90,6 +90,42 @@
     skylightcolor = bvec((skylight>>16)&0xFF, (skylight>>8)&0xFF, skylight&0xFF);
 });
 
+static void sphericalCoordinate(float x, float y, vec *out) {
+    out->x = cos(x) * cos(y);
+    out->y = sin(x) * cos(y);
+    out->z = sin(y);
+}
+
+static float signum(float f) {
+    if(f == 0) return 0;
+    if(f < 0) return -1;
+    return 1;
+}
+
+vector<vec>skyrays;
+void setskylightrays();
+FVARFR(skylightspread, 1, 37, 180, setskylightrays());
+VARFR(skylightrays, 10, 17, 10000, setskylightrays());
+void setskylightrays() {
+    skyrays.reserve(skylightrays);
+    skyrays.setsize(skylightrays);
+
+    // https://scholar.rose-hulman.edu/cgi/viewcontent.cgi?article=1387&context=rhumj
+    float cutoff = (1 - cosf(skylightspread * M_PI / 180.0)) / 2;
+    float n = skylightrays / cutoff;
+    float x = 0.12 + 1.2 * n;
+    float step = 2.0 / n;
+    float s = 1.0;
+
+    for(int i = 0; i < skylightrays; i++, s -= step) {
+        sphericalCoordinate(
+            s * x,
+            M_PI / 2 * signum(s) * (1 - sqrt(1 - fabs(s))),
+            &skyrays[i]
+        );
+    }
+}
+
 extern void setupsunlight();
 bvec sunlightcolor(0, 0, 0);
 HVARFR(sunlight, 0, 0, 0xFFFFFF,
@@ -626,44 +662,20 @@
 
 static void calcskylight(lightmapworker *w, const vec &o, const vec &normal, float tolerance, uchar *skylight, int flags = RAY_ALPHAPOLY, extentity *t = NULL)
 {
-    static const vec rays[17] =
-    {
-        vec(cosf(21*RAD)*cosf(50*RAD), sinf(21*RAD)*cosf(50*RAD), sinf(50*RAD)),
-        vec(cosf(111*RAD)*cosf(50*RAD), sinf(111*RAD)*cosf(50*RAD), sinf(50*RAD)),
-        vec(cosf(201*RAD)*cosf(50*RAD), sinf(201*RAD)*cosf(50*RAD), sinf(50*RAD)),
-        vec(cosf(291*RAD)*cosf(50*RAD), sinf(291*RAD)*cosf(50*RAD), sinf(50*RAD)),
-
-        vec(cosf(66*RAD)*cosf(70*RAD), sinf(66*RAD)*cosf(70*RAD), sinf(70*RAD)),
-        vec(cosf(156*RAD)*cosf(70*RAD), sinf(156*RAD)*cosf(70*RAD), sinf(70*RAD)),
-        vec(cosf(246*RAD)*cosf(70*RAD), sinf(246*RAD)*cosf(70*RAD), sinf(70*RAD)),
-        vec(cosf(336*RAD)*cosf(70*RAD), sinf(336*RAD)*cosf(70*RAD), sinf(70*RAD)),
-       
-        vec(0, 0, 1),
-
-        vec(cosf(43*RAD)*cosf(60*RAD), sinf(43*RAD)*cosf(60*RAD), sinf(60*RAD)),
-        vec(cosf(133*RAD)*cosf(60*RAD), sinf(133*RAD)*cosf(60*RAD), sinf(60*RAD)),
-        vec(cosf(223*RAD)*cosf(60*RAD), sinf(223*RAD)*cosf(60*RAD), sinf(60*RAD)),
-        vec(cosf(313*RAD)*cosf(60*RAD), sinf(313*RAD)*cosf(60*RAD), sinf(60*RAD)),
-
-        vec(cosf(88*RAD)*cosf(80*RAD), sinf(88*RAD)*cosf(80*RAD), sinf(80*RAD)),
-        vec(cosf(178*RAD)*cosf(80*RAD), sinf(178*RAD)*cosf(80*RAD), sinf(80*RAD)),
-        vec(cosf(268*RAD)*cosf(80*RAD), sinf(268*RAD)*cosf(80*RAD), sinf(80*RAD)),
-        vec(cosf(358*RAD)*cosf(80*RAD), sinf(358*RAD)*cosf(80*RAD), sinf(80*RAD)),
-
-    };
     flags |= RAY_SHADOW;
     if(skytexturelight) flags |= RAY_SKIPSKY | (useskytexture ? RAY_SKYTEX : 0);
     int hit = 0;
-    if(w) loopi(17) 
+
+    if(w) loopv(skyrays)
     {
-        if(normal.dot(rays[i])>=0 && shadowray(w->shadowraycache, vec(rays[i]).mul(tolerance).add(o), rays[i], 1e16f, flags, t)>1e15f) hit++;
+        if(normal.dot(skyrays[i])>=0 && shadowray(w->shadowraycache, vec(skyrays[i]).mul(tolerance).add(o), skyrays[i], 1e16f, flags, t)>1e15f) hit++;
     }
-    else loopi(17) 
+    else loopv(skyrays)
     {
-        if(normal.dot(rays[i])>=0 && shadowray(vec(rays[i]).mul(tolerance).add(o), rays[i], 1e16f, flags, t)>1e15f) hit++;
+        if(normal.dot(skyrays[i])>=0 && shadowray(vec(skyrays[i]).mul(tolerance).add(o), skyrays[i], 1e16f, flags, t)>1e15f) hit++;
     }
 
-    loopk(3) skylight[k] = uchar(ambientcolor[k] + (max(skylightcolor[k], ambientcolor[k]) - ambientcolor[k])*hit/17.0f);
+    loopk(3) skylight[k] = uchar(ambientcolor[k] + (max(skylightcolor[k], ambientcolor[k]) - ambientcolor[k])*hit/(float)skyrays.length());
 }
 
 static inline bool hasskylight()
@@ -2135,6 +2147,7 @@
     if(numthreads > 1) preloadusedmapmodels(false, true);
     resetlightmaps(false);
     clearsurfaces(worldroot);
+    setskylightrays();
     taskprogress = progress = 0;
     progresstexticks = 0;
     progresslightmap = -1;
Index: engine/lightmap.cpp
===================================================================
--- engine/lightmap.cpp	(revision 6520)
+++ engine/lightmap.cpp	(working copy)
@@ -90,6 +90,42 @@
     skylightcolor = bvec((skylight>>16)&0xFF, (skylight>>8)&0xFF, skylight&0xFF);
 });
 
+static void sphericalCoordinate(float x, float y, vec *out) {
+    out->x = cos(x) * cos(y);
+    out->y = sin(x) * cos(y);
+    out->z = sin(y);
+}
+
+static float signum(float f) {
+    if(f == 0) return 0;
+    if(f < 0) return -1;
+    return 1;
+}
+
+vector<vec>skyrays;
+void setskylightrays();
+FVARFR(skylightspread, 1, 37, 180, setskylightrays());
+VARFR(skylightrays, 10, 17, 10000, setskylightrays());
+void setskylightrays() {
+    skyrays.reserve(skylightrays);
+    skyrays.setsize(skylightrays);
+
+    // https://scholar.rose-hulman.edu/cgi/viewcontent.cgi?article=1387&context=rhumj
+    float cutoff = (1 - cosf(skylightspread * RAD)) / 2;
+    float n = skylightrays / cutoff;
+    float x = 0.12 + 1.2 * n;
+    float step = 2.0 / n;
+    float s = 1.0;
+
+    for(int i = 0; i < skylightrays; i++, s -= step) {
+        sphericalCoordinate(
+            s * x,
+            PI / 2 * signum(s) * (1 - sqrt(1 - fabs(s))),
+            &skyrays[i]
+        );
+    }
+}
+
 extern void setupsunlight();
 bvec sunlightcolor(0, 0, 0);
 HVARFR(sunlight, 0, 0, 0xFFFFFF,
@@ -626,44 +662,20 @@
 
 static void calcskylight(lightmapworker *w, const vec &o, const vec &normal, float tolerance, uchar *skylight, int flags = RAY_ALPHAPOLY, extentity *t = NULL)
 {
-    static const vec rays[17] =
-    {
-        vec(cosf(21*RAD)*cosf(50*RAD), sinf(21*RAD)*cosf(50*RAD), sinf(50*RAD)),
-        vec(cosf(111*RAD)*cosf(50*RAD), sinf(111*RAD)*cosf(50*RAD), sinf(50*RAD)),
-        vec(cosf(201*RAD)*cosf(50*RAD), sinf(201*RAD)*cosf(50*RAD), sinf(50*RAD)),
-        vec(cosf(291*RAD)*cosf(50*RAD), sinf(291*RAD)*cosf(50*RAD), sinf(50*RAD)),
-
-        vec(cosf(66*RAD)*cosf(70*RAD), sinf(66*RAD)*cosf(70*RAD), sinf(70*RAD)),
-        vec(cosf(156*RAD)*cosf(70*RAD), sinf(156*RAD)*cosf(70*RAD), sinf(70*RAD)),
-        vec(cosf(246*RAD)*cosf(70*RAD), sinf(246*RAD)*cosf(70*RAD), sinf(70*RAD)),
-        vec(cosf(336*RAD)*cosf(70*RAD), sinf(336*RAD)*cosf(70*RAD), sinf(70*RAD)),
-       
-        vec(0, 0, 1),
-
-        vec(cosf(43*RAD)*cosf(60*RAD), sinf(43*RAD)*cosf(60*RAD), sinf(60*RAD)),
-        vec(cosf(133*RAD)*cosf(60*RAD), sinf(133*RAD)*cosf(60*RAD), sinf(60*RAD)),
-        vec(cosf(223*RAD)*cosf(60*RAD), sinf(223*RAD)*cosf(60*RAD), sinf(60*RAD)),
-        vec(cosf(313*RAD)*cosf(60*RAD), sinf(313*RAD)*cosf(60*RAD), sinf(60*RAD)),
-
-        vec(cosf(88*RAD)*cosf(80*RAD), sinf(88*RAD)*cosf(80*RAD), sinf(80*RAD)),
-        vec(cosf(178*RAD)*cosf(80*RAD), sinf(178*RAD)*cosf(80*RAD), sinf(80*RAD)),
-        vec(cosf(268*RAD)*cosf(80*RAD), sinf(268*RAD)*cosf(80*RAD), sinf(80*RAD)),
-        vec(cosf(358*RAD)*cosf(80*RAD), sinf(358*RAD)*cosf(80*RAD), sinf(80*RAD)),
-
-    };
     flags |= RAY_SHADOW;
     if(skytexturelight) flags |= RAY_SKIPSKY | (useskytexture ? RAY_SKYTEX : 0);
     int hit = 0;
-    if(w) loopi(17) 
+
+    if(w) loopv(skyrays)
     {
-        if(normal.dot(rays[i])>=0 && shadowray(w->shadowraycache, vec(rays[i]).mul(tolerance).add(o), rays[i], 1e16f, flags, t)>1e15f) hit++;
+        if(normal.dot(skyrays[i])>=0 && shadowray(w->shadowraycache, vec(skyrays[i]).mul(tolerance).add(o), skyrays[i], 1e16f, flags, t)>1e15f) hit++;
     }
-    else loopi(17) 
+    else loopv(skyrays)
     {
-        if(normal.dot(rays[i])>=0 && shadowray(vec(rays[i]).mul(tolerance).add(o), rays[i], 1e16f, flags, t)>1e15f) hit++;
+        if(normal.dot(skyrays[i])>=0 && shadowray(vec(skyrays[i]).mul(tolerance).add(o), skyrays[i], 1e16f, flags, t)>1e15f) hit++;
     }
 
-    loopk(3) skylight[k] = uchar(ambientcolor[k] + (max(skylightcolor[k], ambientcolor[k]) - ambientcolor[k])*hit/17.0f);
+    loopk(3) skylight[k] = uchar(ambientcolor[k] + (max(skylightcolor[k], ambientcolor[k]) - ambientcolor[k])*hit/(float)skyrays.length());
 }
 
 static inline bool hasskylight()
@@ -2135,6 +2147,7 @@
     if(numthreads > 1) preloadusedmapmodels(false, true);
     resetlightmaps(false);
     clearsurfaces(worldroot);
+    setskylightrays();
     taskprogress = progress = 0;
     progresstexticks = 0;
     progresslightmap = -1;