Make code a bit more idiomatic

Author: coder543

src/main.rs

@@ -39,60 +39,6 @@ fn load_database() -> Result<Vec<Star>, &'static str> {
     }
 }
 
-
-//translated from http://stackoverflow.com/a/22630970/389837
-fn bv2rgb(mut bv: f64) -> (f32, f32, f32) {
-    let r: f64;
-    let g: f64;
-    let b: f64;
-    let mut t: f64;
-    if bv < -0.4 {
-        bv = -0.4;
-    }
-    if bv > 2.0 {
-        bv = 2.0;
-    }
-    if (bv >= -0.40) && (bv < 0.00) {
-        t = (bv + 0.40) / (0.00 + 0.40);
-        r = 0.61 + (0.11 * t) + (0.1 * t * t);
-    } else if (bv >= 0.00) && (bv < 0.40) {
-        t = (bv - 0.00) / (0.40 - 0.00);
-        r = 0.83 + (0.17 * t);
-    } else if (bv >= 0.40) && (bv < 2.10) {
-        r = 1.00;
-    } else {
-        r = 1.0;
-    }
-    if (bv >= -0.40) && (bv < 0.00) {
-        t = (bv + 0.40) / (0.00 + 0.40);
-        g = 0.70 + (0.07 * t) + (0.1 * t * t);
-    } else if (bv >= 0.00) && (bv < 0.40) {
-        t = (bv - 0.00) / (0.40 - 0.00);
-        g = 0.87 + (0.11 * t);
-    } else if (bv >= 0.40) && (bv < 1.60) {
-        t = (bv - 0.40) / (1.60 - 0.40);
-        g = 0.98 - (0.16 * t);
-    } else if (bv >= 1.60) && (bv < 2.00) {
-        t = (bv - 1.60) / (2.00 - 1.60);
-        g = 0.82 - (0.5 * t * t);
-    } else {
-        g = 1.0;
-    }
-    if (bv >= -0.40) && (bv < 0.40) {
-        b = 1.00;
-    } else if (bv >= 0.40) && (bv < 1.50) {
-        t = (bv - 0.40) / (1.50 - 0.40);
-        b = 1.00 - (0.47 * t) + (0.1 * t * t);
-    } else if (bv >= 1.50) && (bv < 1.94) {
-        t = (bv - 1.50) / (1.94 - 1.50);
-        b = 0.63 - (0.6 * t * t);
-    } else {
-        b = 1.0;
-    }
-    
-    (r as f32, g as f32, b as f32)
-}
-
 fn main() {
     let maxdist: f64;
     let stars: Vec<Star> = load_database().unwrap();
@@ -133,16 +79,10 @@ fn main() {
         if star.id == 0 {
             sph.set_color(1.0, 1.0, 0.7);
         } else {
-            if let Some(bv) = star.color_index {
-                let (r, g, b) = bv2rgb(bv);
-                sph.set_color(r, g, b);
-            } else {
-                //use a green color to denote that the color isn't known, since green stars don't exist
-                //sph.set_color(0.0, 1.0, 0.0);
-
-                //use a white color to look more natural, but still slightly unnatural.
-                sph.set_color(1.0, 1.0, 1.0);
-            }
+            let (r, g, b) = star.bv2rgb_opt().or(Some((1.0, 1.0, 1.0))).unwrap();
+            let mag = star.magnitude as f32;
+            let lum = 2.512f32.powf(-mag);
+            sph.set_color(r * lum, g * lum, b * lum);
         }
         sph.append_translation(&Vector3::new(star.x as f32, star.y as f32, star.z as f32));
         println!("{:.3} lightyears\n{:?}\n\n", star.distance * 3.26156, star);

src/sim_data.rs

@@ -45,3 +45,64 @@ pub struct Star {
     pub var_min: Option<f64>, // approximate minimum magnitude for variable star
     pub var_max: Option<f64>, // approximate maximum magnitude for variable star
 }
+
+
+impl Star {
+    // translated from http://stackoverflow.com/a/22630970/389837
+    pub fn bv2rgb_opt(&self) -> Option<(f32, f32, f32)> {
+        self.color_index.map(|_| self.bv2rgb())
+    }
+
+    pub fn bv2rgb(&self) -> (f32, f32, f32) {
+        let mut bv = self.color_index.unwrap();
+        let r: f64;
+        let g: f64;
+        let b: f64;
+        let mut t: f64;
+        if bv < -0.4 {
+            bv = -0.4;
+        }
+        if bv > 2.0 {
+            bv = 2.0;
+        }
+        if (bv >= -0.40) && (bv < 0.00) {
+            t = (bv + 0.40) / (0.00 + 0.40);
+            r = 0.61 + (0.11 * t) + (0.1 * t * t);
+        } else if (bv >= 0.00) && (bv < 0.40) {
+            t = (bv - 0.00) / (0.40 - 0.00);
+            r = 0.83 + (0.17 * t);
+        } else if (bv >= 0.40) && (bv < 2.10) {
+            r = 1.00;
+        } else {
+            r = 1.0;
+        }
+        if (bv >= -0.40) && (bv < 0.00) {
+            t = (bv + 0.40) / (0.00 + 0.40);
+            g = 0.70 + (0.07 * t) + (0.1 * t * t);
+        } else if (bv >= 0.00) && (bv < 0.40) {
+            t = (bv - 0.00) / (0.40 - 0.00);
+            g = 0.87 + (0.11 * t);
+        } else if (bv >= 0.40) && (bv < 1.60) {
+            t = (bv - 0.40) / (1.60 - 0.40);
+            g = 0.98 - (0.16 * t);
+        } else if (bv >= 1.60) && (bv < 2.00) {
+            t = (bv - 1.60) / (2.00 - 1.60);
+            g = 0.82 - (0.5 * t * t);
+        } else {
+            g = 1.0;
+        }
+        if (bv >= -0.40) && (bv < 0.40) {
+            b = 1.00;
+        } else if (bv >= 0.40) && (bv < 1.50) {
+            t = (bv - 0.40) / (1.50 - 0.40);
+            b = 1.00 - (0.47 * t) + (0.1 * t * t);
+        } else if (bv >= 1.50) && (bv < 1.94) {
+            t = (bv - 1.50) / (1.94 - 1.50);
+            b = 0.63 - (0.6 * t * t);
+        } else {
+            b = 1.0;
+        }
+
+        (r as f32, g as f32, b as f32)
+    }
+}