Fix artifacts when curve crosses itself

2 files changed, 43 insertions, 25 deletions

diff --git a/src/main.rs b/src/main.rs
index becb510..242a1ef 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -4,8 +4,7 @@ mod poly;
 
 use lerp::Lerp;
 
-use std::os::raw::c_void;
-use std::ffi::{CString, CStr};
+use std::ffi::{CStr, CString};
 
 use sdl2::event::Event;
 use sdl2::keyboard::Keycode;
@@ -27,8 +26,8 @@ fn shader_from_source(source: &CStr, shader_type: GLenum) -> GLuint {
 }
 
 fn main() {
-    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 a = lerp::lp(Lerp::new(vec![100.0, 200.0, 800.0, 400.0, 800.0, 100.0]));
+    let b = lerp::lp(Lerp::new(vec![100.0, 550.0, 500.0, 300.0, 200.0, 800.0]));
 
     let sdl_context = sdl2::init().unwrap();
     let video_subsystem = sdl_context.video().unwrap();
@@ -48,7 +47,7 @@ fn main() {
         .build()
         .unwrap();
 
-    let gl_context = window.gl_create_context().unwrap();
+    let _gl_context = window.gl_create_context().unwrap();
 
     gl::load_with(|s| video_subsystem.gl_get_proc_address(s) as *const std::os::raw::c_void);
 
@@ -57,14 +56,8 @@ fn main() {
     }
 
     let vertices: [f32; 18] = [
-        // first triangle
-        1.0, 1.0, 0.0,
-        1.0, -1.0, 0.0,
-        -1.0, 1.0, 0.0,
-        // // second triangle
-        1.0, -1.0, 0.0,
-        -1.0, -1.0, 0.0,
-        -1.0, 1.0, 0.0
+        1.0, 1.0, 0.0, 1.0, -1.0, 0.0, -1.0, 1.0, 0.0,
+        1.0, -1.0, 0.0, -1.0, -1.0, 0.0, -1.0, 1.0, 0.0,
     ];
 
     let vertex_shader_source = b"
@@ -74,15 +67,16 @@ fn main() {
     void main() {
         gl_Position = vec4(aPos.xyz, 1.0);
     }
-    ".to_vec();
+    "
+    .to_vec();
 
-    let fragment_shader_source = String::from(format!("
+    let fragment_shader_source = String::from(format!(
+        "
 #version 410 core
 out vec4 FragColor;
 
 float pa[{sa}] = float[{sa}]({pa});
 float pb[{sb}] = float[{sb}]({pb});
-float threshold = 0.1;
 
 float eval_a(float[{sa}] v, float t) {{
     float result = 0.0;
@@ -103,14 +97,14 @@ float eval_b(float[{sb}] v, float t) {{
 float inside(vec2 pos) {{
   float res = 100;
   float thr = 32;
-  float closest = 10000;
+  float closest = 1000000;
   float t = 0.0;
   while (t < 1.0) {{
     float step = t + 1.0 / res;
     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);
+    float c = pow(length(a - b), 2);
+    float d = distance(pos, a + clamp(dot(pos - a, b - a) / c, 0, 1) * (b - a));
     if (d < closest) {{
       closest = d;
     }}
@@ -123,7 +117,13 @@ void main() {{
   float r = inside(gl_FragCoord.xy);
     FragColor = vec4(r * 0.8, r * 0.2, r, 1.0);
 }}
-    ", sa = a.degree() + 1, sb = b.degree() + 1, pa = &a, pb = &b)).into_bytes();
+    ",
+        sa = a.degree() + 1,
+        sb = b.degree() + 1,
+        pa = &a,
+        pb = &b
+    ))
+    .into_bytes();
 
     let mut vbo: GLuint = 0;
     let mut vao: GLuint = 0;
@@ -132,15 +132,33 @@ void main() {{
         gl::BindVertexArray(vao);
         gl::GenBuffers(1, &mut vbo);
         gl::BindBuffer(gl::ARRAY_BUFFER, vbo);
-        gl::BufferData(gl::ARRAY_BUFFER, (vertices.len() * std::mem::size_of::<f32>()) as GLsizeiptr, vertices.as_ptr() as *const GLvoid, gl::STATIC_DRAW);
-        gl::VertexAttribPointer(0, 3, gl::FLOAT, gl::FALSE, (3 * std::mem::size_of::<f32>()) as GLint, std::ptr::null());
+        gl::BufferData(
+            gl::ARRAY_BUFFER,
+            (vertices.len() * std::mem::size_of::<f32>()) as GLsizeiptr,
+            vertices.as_ptr() as *const GLvoid,
+            gl::STATIC_DRAW,
+        );
+        gl::VertexAttribPointer(
+            0,
+            3,
+            gl::FLOAT,
+            gl::FALSE,
+            (3 * std::mem::size_of::<f32>()) as GLint,
+            std::ptr::null(),
+        );
         gl::EnableVertexAttribArray(0);
     }
 
     let mut shader_program: GLuint = 0;
     unsafe {
-        let vertex_shader = shader_from_source(&CString::from_vec_unchecked(vertex_shader_source), gl::VERTEX_SHADER);
-        let fragment_shader = shader_from_source(&CString::from_vec_unchecked(fragment_shader_source), gl::FRAGMENT_SHADER);
+        let vertex_shader = shader_from_source(
+            &CString::from_vec_unchecked(vertex_shader_source),
+            gl::VERTEX_SHADER,
+        );
+        let fragment_shader = shader_from_source(
+            &CString::from_vec_unchecked(fragment_shader_source),
+            gl::FRAGMENT_SHADER,
+        );
         shader_program = gl::CreateProgram();
         gl::AttachShader(shader_program, vertex_shader);
         gl::AttachShader(shader_program, fragment_shader);
diff --git a/src/poly.rs b/src/poly.rs
index 9c70048..34df7a0 100644
--- a/src/poly.rs
+++ b/src/poly.rs
@@ -2,8 +2,8 @@ mod iter;
 
 use crate::number::Number;
 use iter::Iter;
-use std::ops::{Add, Div, Mul, Sub};
 use std::fmt;
+use std::ops::{Add, Div, Mul, Sub};
 
 #[derive(PartialEq, Debug, Clone)]
 pub struct Poly {