From 9724f0d0fe318615e4ed79b1600dd4557a2378eb Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Juan=20Manuel=20Tom=C3=A1s?= <jtomas1815@gmail.com>
Date: Thu, 7 Jan 2021 20:14:15 -0300
Subject: Visualize polynomials using sdl

---
 Cargo.lock  | 56 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 Cargo.toml  |  1 +
 src/main.rs | 64 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++---
 3 files changed, 118 insertions(+), 3 deletions(-)

diff --git a/Cargo.lock b/Cargo.lock
index b1c5475..6e75461 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1,5 +1,61 @@
 # This file is automatically @generated by Cargo.
 # It is not intended for manual editing.
+[[package]]
+name = "bitflags"
+version = "1.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cf1de2fe8c75bc145a2f577add951f8134889b4795d47466a54a5c846d691693"
+
+[[package]]
+name = "cfg-if"
+version = "0.1.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "4785bdd1c96b2a846b2bd7cc02e86b6b3dbf14e7e53446c4f54c92a361040822"
+
+[[package]]
+name = "lazy_static"
+version = "1.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e2abad23fbc42b3700f2f279844dc832adb2b2eb069b2df918f455c4e18cc646"
+
+[[package]]
+name = "libc"
+version = "0.2.81"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1482821306169ec4d07f6aca392a4681f66c75c9918aa49641a2595db64053cb"
+
 [[package]]
 name = "poly"
 version = "0.1.0"
+dependencies = [
+ "sdl2",
+]
+
+[[package]]
+name = "sdl2"
+version = "0.34.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fcbb85f4211627a7291c83434d6bbfa723e28dcaa53c7606087e3c61929e4b9c"
+dependencies = [
+ "bitflags",
+ "lazy_static",
+ "libc",
+ "sdl2-sys",
+]
+
+[[package]]
+name = "sdl2-sys"
+version = "0.34.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "28d81feded049b9c14eceb4a4f6d596a98cebbd59abdba949c5552a015466d33"
+dependencies = [
+ "cfg-if",
+ "libc",
+ "version-compare",
+]
+
+[[package]]
+name = "version-compare"
+version = "0.0.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d63556a25bae6ea31b52e640d7c41d1ab27faba4ccb600013837a3d0b3994ca1"
diff --git a/Cargo.toml b/Cargo.toml
index ab64b5d..cad75f6 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -7,3 +7,4 @@ edition = "2018"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
+sdl2 = "0.34.3"
diff --git a/src/main.rs b/src/main.rs
index 1e4f704..13f13da 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,5 +1,63 @@
+use poly::Poly;
+use poly::Number;
+use poly::Lerp;
+
+use sdl2::pixels::Color;
+use sdl2::event::Event;
+use sdl2::keyboard::Keycode;
+use sdl2::rect::Rect;
+
+use std::thread;
+use std::time::Duration;
+
+fn eval_poly(p: &Poly, t: Number) -> Number {
+    let mut r = 0.0;
+    for i in 0..p.len() {
+        r += p[i] * t.powi(i as i32);
+    }
+    r
+}
+
 fn main() {
-    let a = poly::Lerp::new(vec![1.0, 5.0, 8.0, 3.0, 10.0]);
-    println!("{:?}", a);
-    println!("{:?}", poly::lp(a));
+    let a = Lerp::new(vec![100.0, 200.0, 300.0, 500.0]);
+    let b = Lerp::new(vec![400.0, 140.0, 500.0, 300.0]);
+    let pa = poly::lp(a);
+    let pb = poly::lp(b);
+
+    let sdl_context = sdl2::init().unwrap();
+    let video_subsystem = sdl_context.video().unwrap();
+
+    let window = video_subsystem.window("rust-sdl2 demo", 800, 600)
+        .position_centered()
+        .build()
+        .unwrap();
+
+    let mut canvas = window.into_canvas().build().unwrap();
+
+    let mut event_pump = sdl_context.event_pump().unwrap();
+    'running: loop {
+        canvas.set_draw_color(Color::RGB(20, 20, 20));
+        canvas.clear();
+        for event in event_pump.poll_iter() {
+            match event {
+                Event::Quit {..} |
+                    Event::KeyDown { keycode: Some(Keycode::Escape), .. } => {
+                        break 'running
+                    },
+                _ => {}
+            }
+        }
+
+        for t in 0..800 {
+            let x = eval_poly(&pa, t as Number / 800.0);
+            let y = eval_poly(&pb, t as Number / 800.0);
+            canvas.set_draw_color(Color::RGB(180, 20, 20));
+            canvas.fill_rect(Rect::new(t, x as i32, 5, 5)).unwrap();
+            canvas.set_draw_color(Color::RGB(20, 180, 20));
+            canvas.fill_rect(Rect::new(t, y as i32, 5, 5)).unwrap();
+        }
+
+        canvas.present();
+        thread::sleep(Duration::new(0, 1_000_000_000u32 / 60));
+    }
 }
-- 
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