From 7b2524be8efae04a80691743b06018a6b0fdbe3e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Juan=20Manuel=20Tom=C3=A1s?= <jtomas1815@gmail.com>
Date: Sun, 17 Jan 2021 16:14:08 -0300
Subject: Pass external data to the fragment shader

---
 src/main.rs | 60 ++++++++++++++++++++++++++++++++----------------------------
 src/poly.rs | 27 ++++++++++++---------------
 2 files changed, 44 insertions(+), 43 deletions(-)

(limited to 'src')

diff --git a/src/main.rs b/src/main.rs
index 5768622..becb510 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -3,17 +3,12 @@ mod number;
 mod poly;
 
 use lerp::Lerp;
-use number::Number;
 
-use std::thread;
-use std::time::Duration;
 use std::os::raw::c_void;
 use std::ffi::{CString, CStr};
 
 use sdl2::event::Event;
 use sdl2::keyboard::Keycode;
-use sdl2::pixels::Color;
-use sdl2::rect::Rect;
 
 use gl::types::*;
 
@@ -32,11 +27,8 @@ fn shader_from_source(source: &CStr, shader_type: GLenum) -> GLuint {
 }
 
 fn main() {
-    let a = Lerp::new(vec![200.0, 200.0, 200.0]);
-    let b = Lerp::new(vec![100.0, 550.0, 1000.0]);
-    let pa = lerp::lp(a);
-    let pb = lerp::lp(b);
-    let p = poly::gcd(&pa, &pb);
+    let a = lerp::lp(Lerp::new(vec![100.0, 200.0, 800.0]));
+    let b = lerp::lp(Lerp::new(vec![100.0, 550.0, 500.0]));
 
     let sdl_context = sdl2::init().unwrap();
     let video_subsystem = sdl_context.video().unwrap();
@@ -84,42 +76,54 @@ fn main() {
     }
     ".to_vec();
 
-    let fragment_shader_source = b"
+    let fragment_shader_source = String::from(format!("
 #version 410 core
 out vec4 FragColor;
 
-float p1[3] = float[3](200, 400, 1300);
-float p2[3] = float[3](100, 900, -970);
+float pa[{sa}] = float[{sa}]({pa});
+float pb[{sb}] = float[{sb}]({pb});
 float threshold = 0.1;
 
-float eval(float[3] v, float t) {
-  return v[2] * t * t + v[1] * t + v[0];
-}
-
-float inside(vec2 pos) {
+float eval_a(float[{sa}] v, float t) {{
+    float result = 0.0;
+    for (int i = 0; i < {sa}; i++) {{
+      result += v[i] * pow(t, i);
+    }}
+    return result;
+}}
+
+float eval_b(float[{sb}] v, float t) {{
+    float result = 0.0;
+    for (int i = 0; i < {sb}; i++) {{
+      result += v[i] * pow(t, i);
+    }}
+    return result;
+}}
+
+float inside(vec2 pos) {{
   float res = 100;
   float thr = 32;
   float closest = 10000;
   float t = 0.0;
-  while (t < 1.0) {
+  while (t < 1.0) {{
     float step = t + 1.0 / res;
-    vec2 a = vec2(eval(p1, t), eval(p2, t));
-    vec2 b = vec2(eval(p1, step), eval(p2, step));
+    vec2 a = vec2(eval_a(pa, t), eval_b(pb, t));
+    vec2 b = vec2(eval_a(pa, step), eval_b(pb, step));
     vec2 n = vec2(-(b - a).y, (b - a).x);
     float d = dot(a - pos, n) / length(n);
-    if (d < closest) {
+    if (d < closest) {{
       closest = d;
-    }
+    }}
     t = step;
-  }
+  }}
   return 1 - pow(closest / thr, 2);
-}
+}}
 
-void main() {
+void main() {{
   float r = inside(gl_FragCoord.xy);
     FragColor = vec4(r * 0.8, r * 0.2, r, 1.0);
-}
-    ".to_vec();
+}}
+    ", sa = a.degree() + 1, sb = b.degree() + 1, pa = &a, pb = &b)).into_bytes();
 
     let mut vbo: GLuint = 0;
     let mut vao: GLuint = 0;
diff --git a/src/poly.rs b/src/poly.rs
index 7d964a4..9c70048 100644
--- a/src/poly.rs
+++ b/src/poly.rs
@@ -3,6 +3,7 @@ mod iter;
 use crate::number::Number;
 use iter::Iter;
 use std::ops::{Add, Div, Mul, Sub};
+use std::fmt;
 
 #[derive(PartialEq, Debug, Clone)]
 pub struct Poly {
@@ -29,7 +30,7 @@ impl Poly {
         }
     }
 
-    fn degree(&self) -> usize {
+    pub fn degree(&self) -> usize {
         self.degree
     }
 
@@ -109,21 +110,17 @@ impl Div for &Poly {
     }
 }
 
-pub fn gcd(a: &Poly, b: &Poly) -> Poly {
-    let (_, c) = a / b;
-    if c.is_zero() {
-        b.clone()
-    } else {
-        gcd(b, &c)
-    }
-}
-
-pub fn derivative(p: &Poly) -> Poly {
-    let mut v = vec![0.0; p.degree()];
-    for i in 0..v.len() {
-        v[i] = p.data[i + 1] * (i + 1) as Number;
+impl fmt::Display for &Poly {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let mut s = String::new();
+        for i in 0..self.data.len() {
+            s.push_str(&self.data[i].clone().to_string());
+            if i < self.data.len() - 1 {
+                s.push_str(", ");
+            }
+        }
+        write!(f, "{}", s)
     }
-    Poly::new(v)
 }
 
 #[cfg(test)]
-- 
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