archclip: special-case version of arch

doc/reference.adoc

@@ -647,6 +647,13 @@ width, i.e. if width = 128, then subdivision = 64 gives you sectors of 2 units w
 Arch adds to xoff automatically to reduce funny texturing. On the y axis it is best
 if you precede arch by unpegged.
 
+
+    archclip(height,width,depth,subdivision,floor,lightlevel,clip)
+
+This is a special-case version of arch which has an additional parameter, clip, to
+cut short generating the arch. This can be used to create structures such as gothic
+arches.
+
     mergesectors
 
 turns sector merge mode on. In this mode WadC will check for existing sectors

doc/release_notes.adoc

@@ -20,6 +20,9 @@ Thank you Kayvan, for introducing me to Doom, amongst many other things.
 
 === Language features
 
+ * New (experimental) built-in `archclip`: behaves the same as `arch`,
+   but stops generating the arch after N units, where N is the seventh
+   parameter supplied
  * Two new built-ins: `getx` and `gety` return the cursor's current X/Y
    position.
 

src/main/java/org/redmars/wadc/Builtin.java

@@ -18,6 +18,7 @@ class Builtin {
   Exp eval(Exp a, Exp b, Exp c, Exp d) { return null; }
   Exp eval(Exp a, Exp b, Exp c, Exp d, Exp e) { return null; }
   Exp eval(Exp a, Exp b, Exp c, Exp d, Exp e, Exp f) { return null; }
+  Exp eval(Exp a, Exp b, Exp c, Exp d, Exp e, Exp f, Exp g) { return null; }
   Exp eval(Exp a, Exp b, Exp c, Exp d, Exp e, Exp f, Exp g, Exp h) { return null; }
 };
 

src/main/java/org/redmars/wadc/WadRun.java

@@ -177,6 +177,38 @@ void addBuiltins() {
       return n;
     }});
 
+    builtin("archclip", 7, new Builtin() { Exp eval(Exp a, Exp b, Exp c, Exp d, Exp e, Exp f, Exp g) {
+      int height = a.ival();
+      int width = b.ival();
+      int depth = c.ival();
+      int steps = d.ival();
+      int step = width/steps;
+      floor = e.ival();
+      lightlevel = f.ival();
+
+      int maxLength = g.ival(); // maximum length we will generate, to make shortened arches
+      int curLength = 0;
+
+      for(int i = 0; i<steps && curLength < maxLength; i++) {
+        step = width/steps;
+        if( (maxLength - curLength) < step) {
+          step = maxLength - curLength;
+        }
+        curLength += step;
+
+        int xtra = (int)(Math.sin(Math.acos(2*i/(double)steps-1.0))*width/2);
+        step(step,0);
+        step(0,depth);
+        step(-step,0);
+        step(0,-depth);
+        step(step,0);
+        makesector(true,-1,floor,floor+height+xtra,lightlevel);
+        xoff += step;
+      }
+      return n;
+    }});
+
+
     builtin("arch", 6, new Builtin() { Exp eval(Exp a, Exp b, Exp c, Exp d, Exp e, Exp f) {
       int height = a.ival();
       int width = b.ival();
@@ -1336,6 +1368,13 @@ Exp call(Id caller) {
                            ((Exp)v.elementAt(3)).eval(this),
                            ((Exp)v.elementAt(4)).eval(this),
                            ((Exp)v.elementAt(5)).eval(this)); break;
+        case 7: r = b.eval(((Exp)v.elementAt(0)).eval(this),
+                           ((Exp)v.elementAt(1)).eval(this),
+                           ((Exp)v.elementAt(2)).eval(this),
+                           ((Exp)v.elementAt(3)).eval(this),
+                           ((Exp)v.elementAt(4)).eval(this),
+                           ((Exp)v.elementAt(5)).eval(this),
+                           ((Exp)v.elementAt(6)).eval(this)); break;
         case 8: r = b.eval(((Exp)v.elementAt(0)).eval(this),
                            ((Exp)v.elementAt(1)).eval(this),
                            ((Exp)v.elementAt(2)).eval(this),