render colored triangle, but something is weird with coordinates

src/main.rs

@@ -15,6 +15,8 @@ use point::*;
 mod model;
 use model::*;
 
+const BLACK: TGAColor = TGAColor { bgra: [0u8; 4] };
+
 const WHITE: TGAColor = TGAColor {
     bgra: [255, 255, 255, 255],
 };
@@ -36,44 +38,17 @@ const YELLOW: TGAColor = TGAColor {
 };
 
 fn main() {
-    let w = 800;
-    let h = 800;
+    let w = 640;
+    let h = 640;
     let mut fb = TGAImage::new(w, h, TGAFormat::RGB);
 
-    render_head(&mut fb);
-}
+    let a = Point2i::new(170, 40).with_color(BLUE);
+    let b = Point2i::new(550, 390).with_color(GREEN);
+    let c = Point2i::new(230, 590).with_color(RED);
 
-fn _render_diablo(fb: &mut TGAImage) {
-    let model = Model::from_obj("diablo3_pose.obj");
-    model.render_wireframe(fb);
-    fb.write_file("diablo.tga", true, true).unwrap();
-}
-
-fn render_head(fb: &mut TGAImage) {
-    let model = Model::from_obj("head.obj");
-    model.render_triangles(fb);
-    fb.write_file("head.tga", true, true).unwrap();
-}
-fn _baseline(framebuffer: &mut TGAImage) {
-    let ax = 7;
-    let ay = 3;
-    let bx = 12;
-    let by = 37;
-    let cx = 62;
-    let cy = 53;
-
-    framebuffer.set(ax, ay, WHITE);
-    framebuffer.set(bx, by, WHITE);
-    framebuffer.set(cx, cy, WHITE);
-
-    let a = Point2i::newu(ax, ay);
-    let b = Point2i::newu(bx, by);
-    let c = Point2i::newu(cx, cy);
-
-    line(a, b, BLUE, framebuffer);
-    line(c, b, GREEN, framebuffer);
-    line(c, a, YELLOW, framebuffer);
-    line(a, c, RED, framebuffer);
+    let t = Triangle2i::new(a, b, c);
+    t.render_filled(BLACK, &mut fb);
+    fb.write_file("triangle.tga", true, true).unwrap();
 }
 
 fn line(mut a: Point2i, mut b: Point2i, color: TGAColor, mut fb: &mut TGAImage) {
@@ -140,15 +115,23 @@ impl Triangle2i {
         (bb.ymin()..=bb.ymax()).into_par_iter().for_each(|y| {
             (bb.xmin()..bb.xmax()).into_par_iter().for_each(|x| {
                 let p = Point2i::new(x, y);
-                let a = Triangle2i::new(p, self.a, self.b).signed_area() * it;
-                let b = Triangle2i::new(p, self.b, self.c).signed_area() * it;
-                let c = Triangle2i::new(p, self.c, self.a).signed_area() * it;
+                let alpha = Triangle2i::new(p, self.a, self.b).signed_area() * it;
+                let beta = Triangle2i::new(p, self.b, self.c).signed_area() * it;
+                let gamma = Triangle2i::new(p, self.c, self.a).signed_area() * it;
 
-                if a.is_sign_positive()
-                    && b.is_sign_positive()
-                    && c.is_sign_positive()
+                if alpha.is_sign_positive()
+                    && beta.is_sign_positive()
+                    && gamma.is_sign_positive()
                     && let Ok(mut fb) = fb.lock()
                 {
+                    let color = if let Some(ca) = self.a.color
+                        && let Some(cb) = self.b.color
+                        && let Some(cc) = self.c.color
+                    {
+                        ca * alpha + cb * beta + cc * gamma + color
+                    } else {
+                        color
+                    };
                     fb.set(x as u32, y as u32, color);
                 }
             });

src/point.rs

@@ -6,25 +6,25 @@ use crate::tga::TGAColor;
 pub struct Point2i {
     pub x: i32,
     pub y: i32,
-    pub c: Option<TGAColor>,
+    pub color: Option<TGAColor>,
 }
 
 impl Point2i {
     pub fn new(x: i32, y: i32) -> Self {
-        Self { x, y, c: None }
+        Self { x, y, color: None }
     }
 
     pub fn newu(x: u32, y: u32) -> Self {
         Self {
             x: x as i32,
             y: y as i32,
-            c: None,
+            color: None,
         }
     }
 
     pub fn with_color(self, color: TGAColor) -> Self {
         Self {
-            c: Some(color),
+            color: Some(color),
             ..self
         }
     }
@@ -37,7 +37,7 @@ impl Add for Point2i {
         Self {
             x: self.x + rhs.x,
             y: self.y + rhs.y,
-            c: None,
+            color: None,
         }
     }
 }
@@ -49,7 +49,7 @@ impl Sub for Point2i {
         Self {
             x: self.x - rhs.x,
             y: self.y - rhs.y,
-            c: None,
+            color: None,
         }
     }
 }
@@ -61,7 +61,7 @@ impl Mul for Point2i {
         Self {
             x: self.x * rhs.x,
             y: self.y * rhs.y,
-            c: None,
+            color: None,
         }
     }
 }
@@ -143,7 +143,7 @@ impl From<Point3f> for Point2i {
         Self {
             x: p.x().round_ties_even() as i32,
             y: p.y().round_ties_even() as i32,
-            c: None,
+            color: None,
         }
     }
 }

src/tga.rs

@@ -1,7 +1,7 @@
 use std::{
     fs::File,
     io::{Read, Write},
-    ops::{Deref, DerefMut},
+    ops::{Add, Deref, DerefMut, Mul},
 };
 
 const HEADER_SIZE: usize = 18;
@@ -73,6 +73,34 @@ impl From<ColorBuf> for TGAColor {
     }
 }
 
+impl Add for TGAColor {
+    type Output = Self;
+
+    fn add(self, rhs: Self) -> Self::Output {
+        Self {
+            bgra: [
+                self[0].saturating_add(rhs[0]),
+                self[1].saturating_add(rhs[1]),
+                self[2].saturating_add(rhs[2]),
+                self[3].saturating_add(rhs[3]),
+            ],
+        }
+    }
+}
+
+impl Mul<f32> for TGAColor {
+    type Output = Self;
+
+    fn mul(self, rhs: f32) -> Self::Output {
+        let b = (self.b() as f32 * rhs).round_ties_even() as u8;
+        let g = (self.g() as f32 * rhs).round_ties_even() as u8;
+        let r = (self.r() as f32 * rhs).round_ties_even() as u8;
+        let a = (self.a() as f32 * rhs).round_ties_even() as u8;
+
+        Self { bgra: [b, g, r, a] }
+    }
+}
+
 impl TGAColor {
     pub fn new() -> Self {
         Self {
@@ -80,20 +108,20 @@ impl TGAColor {
         }
     }
 
-    pub fn b(&mut self) -> &mut u8 {
-        &mut self[0]
+    pub fn b(&self) -> u8 {
+        self[0]
     }
 
-    pub fn g(&mut self) -> &mut u8 {
-        &mut self[1]
+    pub fn g(&self) -> u8 {
+        self[1]
     }
 
-    pub fn r(&mut self) -> &mut u8 {
-        &mut self[2]
+    pub fn r(&self) -> u8 {
+        self[2]
     }
 
-    pub fn a(&mut self) -> &mut u8 {
-        &mut self[3]
+    pub fn a(&self) -> u8 {
+        self[3]
     }
 }