float-y line function

Cargo.lock

@@ -2,6 +2,24 @@
 # It is not intended for manual editing.
 version = 4
 
+[[package]]
+name = "cfg-if"
+version = "1.0.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2fd1289c04a9ea8cb22300a459a72a385d7c73d3259e2ed7dcb2af674838cfa9"
+
+[[package]]
+name = "getrandom"
+version = "0.3.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "26145e563e54f2cadc477553f1ec5ee650b00862f0a58bcd12cbdc5f0ea2d2f4"
+dependencies = [
+ "cfg-if",
+ "libc",
+ "r-efi",
+ "wasi",
+]
+
 [[package]]
 name = "justerror"
 version = "1.1.0"
@@ -13,6 +31,21 @@ dependencies = [
  "syn 1.0.109",
 ]
 
+[[package]]
+name = "libc"
+version = "0.2.175"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6a82ae493e598baaea5209805c49bbf2ea7de956d50d7da0da1164f9c6d28543"
+
+[[package]]
+name = "ppv-lite86"
+version = "0.2.21"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "85eae3c4ed2f50dcfe72643da4befc30deadb458a9b590d720cde2f2b1e97da9"
+dependencies = [
+ "zerocopy",
+]
+
 [[package]]
 name = "proc-macro2"
 version = "1.0.101"
@@ -31,6 +64,41 @@ dependencies = [
  "proc-macro2",
 ]
 
+[[package]]
+name = "r-efi"
+version = "5.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "69cdb34c158ceb288df11e18b4bd39de994f6657d83847bdffdbd7f346754b0f"
+
+[[package]]
+name = "rand"
+version = "0.9.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6db2770f06117d490610c7488547d543617b21bfa07796d7a12f6f1bd53850d1"
+dependencies = [
+ "rand_chacha",
+ "rand_core",
+]
+
+[[package]]
+name = "rand_chacha"
+version = "0.9.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d3022b5f1df60f26e1ffddd6c66e8aa15de382ae63b3a0c1bfc0e4d3e3f325cb"
+dependencies = [
+ "ppv-lite86",
+ "rand_core",
+]
+
+[[package]]
+name = "rand_core"
+version = "0.9.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "99d9a13982dcf210057a8a78572b2217b667c3beacbf3a0d8b454f6f82837d38"
+dependencies = [
+ "getrandom",
+]
+
 [[package]]
 name = "syn"
 version = "1.0.109"
@@ -78,6 +146,7 @@ name = "tinyrender"
 version = "0.1.0"
 dependencies = [
  "justerror",
+ "rand",
  "thiserror",
 ]
 
@@ -86,3 +155,38 @@ name = "unicode-ident"
 version = "1.0.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "5a5f39404a5da50712a4c1eecf25e90dd62b613502b7e925fd4e4d19b5c96512"
+
+[[package]]
+name = "wasi"
+version = "0.14.3+wasi-0.2.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6a51ae83037bdd272a9e28ce236db8c07016dd0d50c27038b3f407533c030c95"
+dependencies = [
+ "wit-bindgen",
+]
+
+[[package]]
+name = "wit-bindgen"
+version = "0.45.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5c573471f125075647d03df72e026074b7203790d41351cd6edc96f46bcccd36"
+
+[[package]]
+name = "zerocopy"
+version = "0.8.26"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1039dd0d3c310cf05de012d8a39ff557cb0d23087fd44cad61df08fc31907a2f"
+dependencies = [
+ "zerocopy-derive",
+]
+
+[[package]]
+name = "zerocopy-derive"
+version = "0.8.26"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9ecf5b4cc5364572d7f4c329661bcc82724222973f2cab6f050a4e5c22f75181"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn 2.0.106",
+]

Cargo.toml

@@ -5,4 +5,5 @@ edition = "2024"
 
 [dependencies]
 justerror = "1.1.0"
+rand = "0.9.2"
 thiserror = "2.0.16"

src/main.rs

@@ -2,6 +2,7 @@
 extern crate justerror;
 
 mod tga;
+use rand::Rng;
 use tga::*;
 
 mod point;
@@ -32,6 +33,15 @@ fn main() {
     let h = 64;
     let mut framebuffer = TGAImage::new(w, h, TGAFormat::RGB);
 
+    //bench(&mut framebuffer);
+    baseline(&mut framebuffer);
+
+    framebuffer
+        .write_file("framebuffer.tga", true, true)
+        .unwrap();
+}
+
+fn baseline(framebuffer: &mut TGAImage) {
     let ax = 7;
     let ay = 3;
     let bx = 12;
@@ -47,23 +57,52 @@ fn main() {
     let b = Point::new(bx, by);
     let c = Point::new(cx, cy);
 
-    line(a, b, &mut framebuffer, BLUE);
-    line(c, b, &mut framebuffer, GREEN);
-    line(c, a, &mut framebuffer, YELLOW);
-    line(a, c, &mut framebuffer, RED);
-
-    framebuffer
-        .write_file("framebuffer.tga", true, true)
-        .unwrap();
+    line(a, b, framebuffer, BLUE);
+    line(c, b, framebuffer, GREEN);
+    line(c, a, framebuffer, YELLOW);
+    line(a, c, framebuffer, RED);
 }
 
-fn line(a: Point, b: Point, fb: &mut TGAImage, color: TGAColor) {
-    let mut t = 0.0;
-    let step = 0.02;
-    while t < 1.0 {
-        let x = (a.x as f32 + (b.x - a.x) as f32 * t).round_ties_even() as u32;
-        let y = (a.y as f32 + (b.y - a.y) as f32 * t).round_ties_even() as u32;
-        fb.set(x, y, color);
-        t += step;
+fn bench(fb: &mut TGAImage) {
+    let mut rng = rand::rng();
+
+    for _ in 0..1 << 24 {
+        let ax = rng.random_range(0..fb.width);
+        let ay = rng.random_range(0..fb.height);
+        let a = Point::new(ax, ay);
+
+        let bx = rng.random_range(0..fb.width);
+        let by = rng.random_range(0..fb.height);
+        let b = Point::new(bx, by);
+
+        line(
+            a,
+            b,
+            fb,
+            [rng.random(), rng.random(), rng.random(), rng.random()].into(),
+        );
+    }
+}
+
+fn line(mut a: Point, mut b: Point, fb: &mut TGAImage, color: TGAColor) {
+    let is_steep = (a.x - b.x).abs() < (a.y - b.y).abs();
+    if is_steep {
+        std::mem::swap(&mut a.x, &mut a.y);
+        std::mem::swap(&mut b.x, &mut b.y);
+    }
+    if a.x > b.x {
+        std::mem::swap(&mut a.x, &mut b.x);
+        std::mem::swap(&mut a.y, &mut b.y);
+    }
+
+    let mut y = a.y as f32;
+    let step = (b.y - a.y) as f32 / (b.x - a.x) as f32;
+    for x in (a.x)..b.x {
+        if is_steep {
+            fb.set(y as u32, x as u32, color);
+        } else {
+            fb.set(x as u32, y as u32, color);
+        }
+        y += step;
     }
 }

src/point.rs

@@ -31,8 +31,8 @@ impl Sub for Point {
 
     fn sub(self, rhs: Self) -> Self::Output {
         Self {
-            x: self.x.saturating_sub(rhs.x),
-            y: self.y.saturating_sub(rhs.y),
+            x: self.x - rhs.x,
+            y: self.y - rhs.y,
         }
     }
 }