game.loop: fps word to divide a value into 1,000,000

extra/game/loop/loop-docs.factor

@@ -2,6 +2,10 @@
 USING: help.markup help.syntax kernel math ui.gadgets.worlds ;
 IN: game.loop
 
+HELP: fps
+{ $values { "fps" real } { "micros" integer } }
+{ $description "Converts a frames per second value into an interval length in microseconds." } ;
+
 HELP: <game-loop>
 { $values
     { "tick-interval-micros" integer } { "delegate" "a " { $link "game.loop-delegates" } }

extra/game/loop/loop.factor

@@ -39,6 +39,9 @@ TUPLE: game-loop-error game-loop error ;
 : game-loop-error ( game-loop error -- )
     [ drop stop-loop ] [ \ game-loop-error boa ?ui-error ] 2bi ;
 
+: fps ( fps -- micros )
+    1,000,000 swap /i ; inline
+
 <PRIVATE
 
 : redraw ( loop -- )

extra/gpu/demos/bunny/bunny.factor

@@ -307,5 +307,5 @@ GAME: bunny-game {
         } }
         { grab-input? t }
         { pref-dim { 1024 768 } }
-        { tick-interval-micros $[ 1,000,000 60 /i ] }
+        { tick-interval-micros $[ 60 fps ] }
     } ;

extra/gpu/demos/raytrace/raytrace.factor

@@ -103,5 +103,5 @@ GAME: raytrace-game {
         } }
         { grab-input? t }
         { pref-dim { 1024 768 } }
-        { tick-interval-micros $[ 1,000,000 60 /i ] }
+        { tick-interval-micros $[ 60 fps ] }
     } ;

extra/terrain/terrain.factor

@@ -297,5 +297,5 @@ GAME: terrain-game {
         } }
         { grab-input? t }
         { pref-dim { 1024 768 } }
-        { tick-interval-micros $[ 1,000,000 60 /i ] }
+        { tick-interval-micros $[ 60 fps ] }
     } ;