feat!: add raylib rendering

1 files changed, 67 insertions, 0 deletions

diff --git a/physics/src/ppm.rs b/physics/src/ppm.rs
new file mode 100644
index 0000000..be26127
--- /dev/null
+++ b/physics/src/ppm.rs
@@ -0,0 +1,67 @@
+use std::{fs::File, io::Write, path::PathBuf};
+
+use nalgebra::Point2;
+use crate::algebra::{Scalar, N};
+use crate::renderer::Camera;
+use crate::particle_system::Particle;
+
+pub struct PPM<const WIDTH: usize, const HEIGHT: usize> {
+    pub prefix: PathBuf,
+
+    buffer: [[bool; WIDTH]; HEIGHT],
+    // pixels_per_unit: usize,
+}
+
+impl<const WIDTH: usize, const HEIGHT: usize> PPM<WIDTH, HEIGHT> {
+    pub fn new(prefix: PathBuf) -> Self {
+        Self {
+            prefix,
+            buffer: [[false; WIDTH]; HEIGHT],
+        }
+    }
+
+    pub fn clear_buffer(&mut self) {
+        self.buffer = [[false; WIDTH]; HEIGHT]
+    }
+
+    pub fn draw_circle(&mut self, center: Point2<Scalar>, radius: Scalar) {
+        let screen_center = Point2::new((WIDTH / 2) as Scalar, (HEIGHT / 2) as Scalar);
+
+        for pixel_row in 0..HEIGHT {
+            for pixel_col in 0..WIDTH {
+                let point = Point2::new(pixel_col as Scalar, pixel_row as Scalar);
+
+                if (point - center - screen_center.coords).norm() <= radius {
+                    self.buffer[HEIGHT - pixel_row - 1][pixel_col] = true
+                }
+            }
+        }
+    }
+
+    pub fn render_particles(&mut self, particles: &Vec<Particle>, camera: &Camera) {
+        for p in particles {
+            let point = camera.world_to_screen_space(p.position);
+            self.draw_circle(point, p.mass.powf(1.0 / N as Scalar));
+        }
+    }
+
+    pub fn save_frame(&self, time: Scalar) {
+        let file_name = format!("frame-{:08.3}", time);
+        let path = self.prefix.join(file_name);
+        let mut file = File::create(path).unwrap();
+
+        let mut s = format!("P3\n{} {}\n255\n", WIDTH, HEIGHT);
+        let white = "255 255 255 ";
+        let black = "0 0 0 ";
+
+        for row in self.buffer {
+            for pixel in row {
+                let color = if pixel { black } else { white };
+                s += color
+            }
+            s += "\n";
+        }
+
+        file.write(s.as_bytes()).unwrap();
+    }
+}