simple_ppm writer.

rtiow/src/bin/simple_ppm.rs

@@ -0,0 +1,18 @@
+fn main() -> Result<(), std::io::Error> {
+    let nx = 200;
+    let ny = 100;
+    println!("P3\n{} {}\n255", nx, ny);
+    for j in (0..ny).rev() {
+        for i in 0..nx {
+            let r = i as f32 / nx as f32;
+            let g = j as f32 / ny as f32;
+            let b = 0.2;
+
+            let ir = (255.99 * r) as u8;
+            let ig = (255.99 * g) as u8;
+            let ib = (255.99 * b) as u8;
+            println!("{} {} {}", ir, ig, ib);
+        }
+    }
+    Ok(())
+}

rtiow/src/lib.rs

@@ -0,0 +1,7 @@
+#[cfg(test)]
+mod tests {
+    #[test]
+    fn it_works() {
+        assert_eq!(2 + 2, 4);
+    }
+}