fixed colors/comments of PGM

09-smoke-basin/code.scm

@@ -105,7 +105,7 @@
     low-points))
 
 ; write a PGM file for given heightmap and low points
-; max altitude (9) is white
+; basin limits are grey
 ; basins are red-ish (brighter the higher the point)
 ; low points are bright green
 ;
@@ -148,20 +148,18 @@
 	  (when (< y (- height 1))
 	    (y-loop (+ y 1))))
 
-	; show basins as redish areas
-	; show low points as full green pixels
 	(for-each
 	  (lambda (lp)
-	    ; red channel to max on pixels of basins
+	    ; show basins as redish areas
 	    (visit-basin heightmap lp
 			 (lambda (x y)
 			   (let [(ofs (offset x y))]
 			     (vector-set! data ofs 255))))
-	    ; green channel to max on pixels of low point
+	    ; show low points as bright green
 	    (let [(ofs (offset (low-point-x lp) (low-point-y lp)))]
-	      (vector-set! data ofs 255)
+	      (vector-set! data ofs 0)
 	      (vector-set! data (+ 1 ofs) 255)
-	      (vector-set! data (+ 2 ofs) 255)))
+	      (vector-set! data (+ 2 ofs) 0)))
 	  low-points)
 
 	; write pixels to file