Add -visdist param from bjptools (#300)

* Add support for -visdist param from bjp tools

* add mention to man

Co-authored-by: Shpuld Shpuldson <shp@cock.li>

include/vis/vis.hh

@@ -124,6 +124,7 @@ extern qboolean ambientsky;
 extern qboolean ambientwater;
 extern qboolean ambientslime;
 extern qboolean ambientlava;
+extern int visdist;
 
 extern byte *uncompressed;
 extern int leafbytes;

man/vis.1

@@ -51,6 +51,8 @@ Disable ambient sound generation for textures with names beginning
 with '*LAVA'.
 .IP "\fB-noambient\fP"
 Disable all ambient sound generation.
+.IP "\fB-visdist n\fP"
+Allow culling of areas further than n units.
 
 .SH AUTHOR
 Kevin Shanahan (aka Tyrann) - http://disenchant.net

vis/flow.cc

@@ -417,6 +417,28 @@ SimpleFlood(portal_t *srcportal, int leafnum, byte *portalsee)
     }
 }
 
+/*
+  ============================================================================
+  Used for visdist to get the distance from a winding to a portal
+  ============================================================================
+*/
+
+float
+distFromWinding(winding_t *w, portal_t *p)
+{
+    float dist, mindist;
+    mindist = 1e20;
+
+    for (int i = 0; i < w->numpoints; ++i) {
+        dist = fabs(DotProduct(w->points[i], p->plane.normal) - p->plane.dist);
+
+        if (dist < mindist)
+            mindist = dist;
+    }
+    return mindist;
+}
+
+
 /*
   ==============
   BasePortalVis
@@ -479,6 +501,11 @@ BasePortalThread(void *dummy)
             if (j == w->numpoints)
                 continue;       // no points on back
 
+            if (visdist > 0) {
+                if (distFromWinding(tp->winding, p) > visdist || distFromWinding(p->winding, tp) > visdist)
+                    continue;
+            }
+
             portalsee[i] = 1;
         }
 

vis/vis.cc

@@ -47,6 +47,7 @@ qboolean ambientsky = true;
 qboolean ambientwater = true;
 qboolean ambientslime = true;
 qboolean ambientlava = true;
+int visdist = 0;
 
 #if 0
 void
@@ -1269,6 +1270,10 @@ main(int argc, char **argv)
             ambientwater = false;
             ambientslime = false;
             ambientlava = false;
+        } else if (!strcmp(argv[i], "-visdist")) {
+            visdist = atoi(argv[i+1]);
+            i++;
+            logprint("visdist = %i\n", visdist);
         } else if (argv[i][0] == '-')
             Error("Unknown option \"%s\"", argv[i]);
         else