Buffer the rendering for better framerates; create a more useful example

src/render.rs

@@ -1,6 +1,7 @@
 use ansi_term::Color::RGB;
 use crate::consts;
 use crate::SimState;
+use std::fmt::Write as _;
 
 pub struct NumericTermRenderer;
 
@@ -34,17 +35,19 @@ fn norm_color(v: f32) -> u8 {
 
 impl ColorTermRenderer {
     pub fn render(&self, state: &SimState) {
+        let mut buf = String::new();
         let square = "█";
         for y in 0..state.height() {
             for x in 0..state.width() {
                 let cell = state.get(x, y);
-                let r = norm_color(cell.bz() * consts::C);
+                //let r = norm_color(cell.bz() * consts::C);
+                let r = 0;
                 let g = norm_color(cell.ex());
                 let b = norm_color(cell.ey());
-                print!("{}", RGB(r, g, b).paint(square));
+                write!(&mut buf, "{}", RGB(r, g, b).paint(square));
             }
-            print!("\n");
+            write!(&mut buf, "\n");
         }
-        print!("\n");
+        println!("{}", buf);
     }
 }