Draw lines

Additionally convert Point2D to use f64

src/main.rs

@@ -18,7 +18,7 @@ use consts::*;
 
 use core::f64; use std::{num::NonZeroU32, u32};
 
-use softbuffer::{Context, Rect, Surface};
+use softbuffer::{Buffer, Context, Rect, Surface};
 use winit::{self, event_loop::EventLoop, window::Window};
 
 fn main() {
@@ -45,20 +45,25 @@ fn main() {
         )
         .expect("Couldn't resize surface");
 
-    let mut t: u128 = 0;
+    let mut t: u128 = 1;
 
-    let scene = vec![Object {
+    let mut scene = vec![Object {
         vertices: vec![
-            Point3D(0.0, f64::MAX / 2.0, 0.0),
+            // Point3D(0.0, f64::MAX / 2.0, 1.0),
-            Point3D(f64::MAX / 2.0, -f64::MAX / 2.0, 0.0),
+            // Point3D(f64::MAX / 2.0, -f64::MAX / 2.0, 1.0),
-            Point3D(-f64::MAX / 2.0, -f64::MAX / 2.0, 0.0),
+            // Point3D(-f64::MAX / 2.0, -f64::MAX / 2.0, 1.0),
             // Point3D(0.0, 0.0, f64::MAX / 2.0),
+            // Point3D(0.0, 0.0, 0.0),
+            Point3D(f64::MAX / 2.0, f64::MAX / 2.0, 0.0)
+        ],
+        edges: vec![
+            (Point3D(0.0, 0.0, 0.0), Point3D(f64::MAX / 2.0, f64::MAX / 2.0, 0.0))
         ],
-        edges: vec![],
     }];
 
     loop {
         let mut sbuffer = surface.buffer_mut().expect("Couldn't create buffer");
+        // set_scene(t, &mut scene);
         render(t, &scene, &mut *sbuffer);
         t += 1;
 

src/points.rs

@@ -1,7 +1,7 @@
 use crate::consts::*;
 
 #[derive(Debug)]
-pub struct Point2D(pub u32, pub u32);
+pub struct Point2D(pub f64, pub f64);
 impl Point2D {
     pub fn to_canvas_coordinates(&self) -> Point3D {
         todo!();
@@ -10,9 +10,10 @@ impl Point2D {
     pub fn distance(self, p2: &Point2D) -> f64 {
         let p1 = self;
         // Pythagorean formula
+        // TODO: use hypot function
         f64::sqrt(
-            (u32::pow(p2.0.max(p1.0) - p1.0.min(p2.0), 2)
+            (f64::powf(p2.0.max(p1.0) - p1.0.min(p2.0), 2.0)
-                + u32::pow(p2.1.max(p1.1) - p1.1.min(p2.1), 2)) as f64,
+                + f64::powf(p2.1.max(p1.1) - p1.1.min(p2.1), 2.0)) as f64,
         )
     }
 }
@@ -23,6 +24,7 @@ impl Point3D {
     pub fn to_screen_coordinates(&self) -> Point2D {
         let Point3D(x, y, z) = *self;
 
+        if self.2 == 0.0 {
             // Normalize to the interval [0, 1]
             let x = (x / f64::MAX + 1.0) / 2.0;
             let y = (-y / f64::MAX + 1.0) / 2.0;
@@ -30,18 +32,24 @@ impl Point3D {
 
             assert!(x <= 1.0 && y <= 1.0 && z <= 1.0);
 
-        if self.2 == 0.0 {
             Point2D(
-                (x * (SCREEN_WIDTH - 1) as f64) as u32, // Scale to the interval [0, SCREEN_WIDTH)
+                x * (SCREEN_WIDTH - 1) as f64, // Scale to the interval [0, SCREEN_WIDTH)
-                (y * (SCREEN_HEIGHT - 1) as f64) as u32, // Scale to the interval [0, SCREEN_HEIGHT)
+                y * (SCREEN_HEIGHT - 1) as f64, // Scale to the interval [0, SCREEN_HEIGHT)
             )
         } else {
             let x = x / z;
             let y = y / z;
 
+            // Normalize to the interval [0, 1]
+            let x = (x / f64::MAX + 1.0) / 2.0;
+            let y = (-y / f64::MAX + 1.0) / 2.0;
+            let z = (z / f64::MAX + 1.0) / 2.0;
+
+            assert!(x <= 1.0 && y <= 1.0 && z <= 1.0);
+
             Point2D(
-                (x * (SCREEN_WIDTH - 1) as f64) as u32,
+                x * (SCREEN_WIDTH - 1) as f64,
-                (y * (SCREEN_HEIGHT - 1) as f64) as u32,
+                y * (SCREEN_HEIGHT - 1) as f64,
             )
         }
     }
@@ -50,7 +58,7 @@ impl Point3D {
         let p1 = self;
         // Pythagorean formula
         f64::sqrt(
-            f64::powf(p2.0 - p1.0, 2.0) + f64::powf(p2.1 - p1.1, 2.0) + f64::powf(p2.2 - p1.2, 2.0),
+            f64::powf(p2.0 - p1.0, 2.0) + f64::powf(p2.1 - p1.1, 2.0) + f64::powf(p2.2 - p1.2, 2.0) // Fix to use max and min
         )
     }
 }

src/render.rs

@@ -1,7 +1,6 @@
 use crate::consts::*;
 use crate::scene::Scene;
 
-
 type Pixel = u32;
 type Subpixels = (u8, u8, u8);
 
@@ -14,27 +13,54 @@ fn to_rgb((red, green, blue): Subpixels) -> Pixel {
     pixel
 }
 
+const fn index_buffer(buf: &mut [u32], x: f64, y: f64) -> &mut u32 {
+    let x = x.round_ties_even(); // Banker's round
+    let y = y.round_ties_even();
+
+    &mut buf[(x as usize) + (y as usize) * STRIDE as usize]
+}
+
 pub fn render(t: u128, scene: &Scene, buf: &mut [u32]) {
     for pix in buf.iter_mut() {
         *pix = to_rgb((0, 0, 0));
     }
+
     for obj in scene {
         for vertex in &obj.vertices {
             let vertex = vertex.to_screen_coordinates();
             let x = vertex.0;
             let y = vertex.1;
 
-            for i in [
+            for i in -10..10 {
-                -10, -9, -8, -7, -6, -5, -4, -3, -2, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10,
+                for j in -10..10 {
-            ] {
+                    let x = x + i as f64;
-                for j in [
+                    let y = y + j as f64;
-                    -10, -9, -8, -7, -6, -5, -4, -3, -2, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10,
+                    *index_buffer(buf, x, y) = to_rgb((255, 255, 255));
-                ] {
-                    let x = x as i32 + i;
-                    let y = y as i32 + j;
-                    buf[(x + y * STRIDE as i32) as usize] = to_rgb(((t % 256).try_into().unwrap(), 0, 0));
                 }
             }
         }
+
+        for edge in &obj.edges { // Draw lines
+            dbg!(&edge.0, &edge.1);
+            let start = edge.0.to_screen_coordinates();
+            let end = edge.1.to_screen_coordinates();
+
+            dbg!(&start, &end);
+            if (end.0 - start.0).abs() == 0.0 { // Vertical line case - m is undefined
+                for y in (start.0.min(end.0) as u32)..(end.0.max(start.0) + 1.0) as u32 {
+                    *index_buffer(buf, end.0, y as f64) = to_rgb((255, 255, 255));
+                }
+                continue
+            }
+
+            let m = (end.1 - start.1) / (end.0 - start.0); // m = rise/run
+            let c = start.1 as f64 - m * start.0 as f64; // c = y - mx
+
+            for x in 0..SCREEN_WIDTH {
+                let x = x as f64;
+                let y = m * x + c; // y = mx + c
+                *index_buffer(buf, x, y) = to_rgb((255, 255, 255));
+            }
+        }
     }
 }

src/scene.rs

@@ -1,3 +1,4 @@
+use core::f64;
 use crate::points::Point3D;
 
 #[derive(Debug)]
@@ -12,6 +13,6 @@ pub type Scene = Vec<Object>;
 
 pub fn set_scene(t: u128, scene: &mut Scene) {
     for obj in scene {
-        obj.vertices.push(Point3D(t as f64, t as f64, t as f64));
+        obj.vertices[0] = Point3D(f64::MAX / 2.0, f64::MAX / 2.0, 1.0_f64.max(t as f64 / 100.0));
     }
 }