renders with depth buffer

src/main.rs

@@ -12,6 +12,8 @@ mod model;
 mod triangle;
 use triangle::*;
 
+use crate::model::Model;
+
 const BLACK: TGAColor = TGAColor { bgra: [0u8; 4] };
 
 const WHITE: TGAColor = TGAColor {
@@ -35,18 +37,13 @@ const YELLOW: TGAColor = TGAColor {
 };
 
 fn main() {
-    let w = 640;
-    let h = 640;
+    let w = 800;
+    let h = 800;
     let mut fb = TGAImage::new(w, h, TGAFormat::RGB);
+    let model = Model::from_obj("diablo3_pose.obj");
+    model.render_triangles(&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);
-
-    let t = Triangle2i::new(a, b, c);
-    t.render_lines(20, BLACK, &mut fb);
-
-    fb.write_file("triangle.tga", true).unwrap();
+    //fb.write_file("triangle.tga", true).unwrap();
 }
 
 fn line(mut a: Point2i, mut b: Point2i, color: TGAColor, mut fb: &mut TGAImage) {

src/model.rs

@@ -4,8 +4,9 @@ use rand::Rng;
 
 use crate::{
     RED, Triangle2i, line,
-    point::{Point2i, Point3f},
+    point::{Point2i, Point3f, Point3i},
     tga::TGAImage,
+    triangle::Triangle3i,
 };
 
 #[derive(Default, Debug, Clone, Copy, PartialEq, PartialOrd)]
@@ -98,12 +99,18 @@ impl Model {
         let width = framebuffer.width;
         let height = framebuffer.height;
 
+        let mut db = TGAImage::new(
+            framebuffer.width,
+            framebuffer.height,
+            crate::tga::TGAFormat::Grayscale,
+        );
+
         let mut rng = rand::rng();
         for face in self.faces.iter() {
-            let a = world2view(self.verts[face[0]], width, height);
-            let b = world2view(self.verts[face[1]], width, height);
-            let c = world2view(self.verts[face[2]], width, height);
-            let triangle = Triangle2i::new(a, b, c);
+            let a = world2iso(self.verts[face[0]], width, height);
+            let b = world2iso(self.verts[face[1]], width, height);
+            let c = world2iso(self.verts[face[2]], width, height);
+            let triangle = Triangle3i::new(a, b, c);
             let color = [
                 rng.random_range(0..=255u8),
                 rng.random_range(0..=255u8),
@@ -111,8 +118,9 @@ impl Model {
                 255,
             ]
             .into();
-            triangle.render_filled(color, framebuffer);
+            triangle.render_filled(color, framebuffer, &mut db);
         }
+        //db.write_file("zbuffer.tga", true);
     }
 }
 
@@ -122,3 +130,11 @@ fn world2view(point: Point3f, width: u32, height: u32) -> Point2i {
     let y = (point.y() * height as f32).round_ties_even() as i32;
     Point2i::new(x, y)
 }
+
+fn world2iso(point: Point3f, width: u32, height: u32) -> Point3i {
+    let point = (point + 1.0) * 0.5;
+    let x = (point.x() * width as f32).round_ties_even() as i32;
+    let y = (point.y() * height as f32).round_ties_even() as i32;
+    let z = (point.z() * 255.0).round_ties_even() as i32;
+    Point3i::new(x, y, z)
+}

src/point.rs

@@ -184,3 +184,112 @@ impl From<Point3f> for Point2i {
         }
     }
 }
+
+#[derive(Debug, Default, Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]
+pub struct Point3i {
+    pub x: i32,
+    pub y: i32,
+    pub z: i32,
+    pub color: Option<TGAColor>,
+}
+
+impl Point3i {
+    pub fn new(x: i32, y: i32, z: i32) -> Self {
+        Self {
+            x,
+            y,
+            z,
+            color: None,
+        }
+    }
+
+    pub fn with_color(self, color: TGAColor) -> Self {
+        Self {
+            color: Some(color),
+            ..self
+        }
+    }
+}
+
+impl From<Point3f> for Point3i {
+    fn from(p: Point3f) -> Self {
+        Self {
+            x: p.x().round_ties_even() as i32,
+            y: p.y().round_ties_even() as i32,
+            z: p.z().round_ties_even() as i32,
+            color: None,
+        }
+    }
+}
+
+impl Add for Point3i {
+    type Output = Self;
+
+    fn add(self, rhs: Self) -> Self::Output {
+        Self {
+            x: self.x + rhs.x,
+            y: self.y + rhs.y,
+            z: self.z + rhs.z,
+            color: if self.color.is_none() {
+                rhs.color
+            } else {
+                self.color
+                    .map(|c| if let Some(oc) = rhs.color { c + oc } else { c })
+            },
+        }
+    }
+}
+
+impl Sub for Point3i {
+    type Output = Self;
+
+    fn sub(self, rhs: Self) -> Self::Output {
+        Self {
+            x: self.x - rhs.x,
+            y: self.y - rhs.y,
+            z: self.z - rhs.z,
+            color: if self.color.is_none() {
+                rhs.color
+            } else {
+                self.color
+                    .map(|c| if let Some(oc) = rhs.color { c - oc } else { c })
+            },
+        }
+    }
+}
+
+impl Mul for Point3i {
+    type Output = Self;
+
+    fn mul(self, rhs: Self) -> Self::Output {
+        Self {
+            x: self.x * rhs.x,
+            y: self.y * rhs.y,
+            z: self.z * rhs.z,
+            color: None,
+        }
+    }
+}
+
+impl Mul<f32> for Point3i {
+    type Output = Self;
+
+    fn mul(self, rhs: f32) -> Self::Output {
+        Self {
+            x: (self.x as f32 * rhs).round_ties_even() as i32,
+            y: (self.y as f32 * rhs).round_ties_even() as i32,
+            z: (self.z as f32 * rhs).round_ties_even() as i32,
+            color: self.color,
+        }
+    }
+}
+
+impl From<Point3i> for Point2i {
+    fn from(p: Point3i) -> Self {
+        Self {
+            x: p.x,
+            y: p.y,
+            color: p.color,
+        }
+    }
+}

src/tga.rs

@@ -73,6 +73,12 @@ impl From<ColorBuf> for TGAColor {
     }
 }
 
+impl From<u8> for TGAColor {
+    fn from(value: u8) -> Self {
+        [value; 4].into()
+    }
+}
+
 impl Add for TGAColor {
     type Output = Self;
 
@@ -145,7 +151,7 @@ pub struct TGAImage {
     pub format: TGAFormat,
     pub width: u32,
     pub height: u32,
-    data: Vec<u8>,
+    pub data: Vec<u8>,
 }
 
 pub type IoResult = std::result::Result<(), TGAError>;

src/triangle.rs

@@ -4,7 +4,7 @@ use rayon::iter::{IntoParallelIterator, ParallelIterator};
 
 use crate::{
     AABB, BLACK,
-    point::Point2i,
+    point::{Point2i, Point3i},
     tga::{TGAColor, TGAImage},
 };
 
@@ -38,7 +38,7 @@ impl Triangle2i {
         }
     }
 
-    pub fn render_filled(&self, color: TGAColor, fb: &mut TGAImage) {
+    pub fn render_filled(&self, color: TGAColor, fb: &mut TGAImage, depth_buffer: &mut TGAImage) {
         let fb = Arc::new(Mutex::new(fb));
         let bb = self.bb();
         let total_area = self.signed_area();
@@ -139,3 +139,96 @@ impl Triangle2i {
         Point2i { x, y, color }
     }
 }
+
+pub struct Triangle3i {
+    a: Point3i,
+    b: Point3i,
+    c: Point3i,
+}
+
+struct Wrapper<T>(T);
+unsafe impl<T> Send for Wrapper<T> {}
+
+impl Triangle3i {
+    pub fn new(a: Point3i, b: Point3i, c: Point3i) -> Self {
+        Self { a, b, c }
+    }
+
+    pub fn signed_area(&self) -> f32 {
+        0.5 * ((self.b.y - self.a.y) * (self.a.x + self.b.x)
+            + (self.c.y - self.b.y) * (self.c.x + self.b.x)
+            + (self.a.y - self.c.y) * (self.a.x + self.c.x)) as f32
+    }
+
+    pub fn bb(&self) -> AABB {
+        let xmax = self.a.x.max(self.b.x.max(self.c.x));
+        let xmin = self.a.x.min(self.b.x.min(self.c.x));
+
+        let ymax = self.a.y.max(self.b.y.max(self.c.y));
+        let ymin = self.a.y.min(self.b.y.min(self.c.y));
+        AABB {
+            lower_left: Point2i::new(xmin, ymin),
+            upper_right: Point2i::new(xmax, ymax),
+        }
+    }
+
+    pub fn render_filled(&self, color: TGAColor, fb: &mut TGAImage, depth_buffer: &mut TGAImage) {
+        let fb = Arc::new(Mutex::new(fb));
+        let zb = Arc::new(Mutex::new(depth_buffer));
+        let bb = self.bb();
+        let total_area = self.signed_area();
+        if total_area < 1.0 {
+            return;
+        }
+        let it = 1.0 / total_area;
+        (bb.xmin()..=bb.xmax()).into_par_iter().for_each(|x| {
+            (bb.ymin()..=bb.ymax()).into_par_iter().for_each(|y| {
+                let p = Point2i::new(x, y);
+                let alpha = Triangle2i::new(p, self.b.into(), self.c.into()).signed_area() * it;
+                let beta = Triangle2i::new(p, self.c.into(), self.a.into()).signed_area() * it;
+                let gamma = Triangle2i::new(p, self.a.into(), self.b.into()).signed_area() * it;
+
+                if alpha.is_sign_positive() && beta.is_sign_positive() && gamma.is_sign_positive() {
+                    let color = if let Some(ca) = self.a.color
+                        && let Some(cb) = self.b.color
+                        && let Some(cc) = self.c.color
+                    {
+                        color + (ca * alpha) + (cb * beta) + (cc * gamma)
+                    } else {
+                        color
+                    };
+                    let z = (alpha * self.a.z as f32
+                        + beta * self.b.z as f32
+                        + gamma * self.c.z as f32)
+                        .round_ties_even() as u8;
+                    if let Ok(mut zb) = zb.lock() {
+                        let oz = zb.get(x as u32, y as u32).unwrap_or_default().b();
+                        if oz <= z {
+                            if let Ok(mut fb) = fb.lock() {
+                                zb.set(x as u32, y as u32, z.into());
+                                fb.set(x as u32, y as u32, color);
+                            }
+                        }
+                    }
+                };
+            });
+        });
+    }
+
+    pub fn centroid(&self) -> Point3i {
+        let x = self.a.x / 3 + self.b.x / 3 + self.c.x / 3;
+        let y = self.a.y / 3 + self.b.y / 3 + self.c.y / 3;
+        let z = self.a.z / 3 + self.b.z / 3 + self.c.z / 3;
+        let has_color = self.a.color.is_some() || self.b.color.is_some() || self.c.color.is_some();
+        let denom = 1.0 / 3.0;
+        let color = if has_color {
+            let c = self.a.color.unwrap_or(BLACK) * denom
+                + self.b.color.unwrap_or(BLACK) * denom
+                + self.c.color.unwrap_or(BLACK) * denom;
+            Some(c)
+        } else {
+            None
+        };
+        Point3i { x, y, z, color }
+    }
+}