From 444181ff1a47ff87d1b8db8e0300eb17698b2b21 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Juan=20Manuel=20Tom=C3=A1s?= <jtomas1815@gmail.com>
Date: Sun, 17 Jan 2021 15:39:20 -0300
Subject: Render hardcoded bezier curve

---
 src/main.rs | 48 +++++++++++++++++++++++++++++++++++++-----------
 1 file changed, 37 insertions(+), 11 deletions(-)

(limited to 'src')

diff --git a/src/main.rs b/src/main.rs
index aa149e3..5768622 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -23,9 +23,7 @@ fn shader_from_source(source: &CStr, shader_type: GLenum) -> GLuint {
         gl::ShaderSource(shader, 1, &source.as_ptr(), std::ptr::null());
         gl::CompileShader(shader);
         let mut success: gl::types::GLint = 1;
-        unsafe {
-                gl::GetShaderiv(shader, gl::COMPILE_STATUS, &mut success);
-        }
+        gl::GetShaderiv(shader, gl::COMPILE_STATUS, &mut success);
         if success == 0 {
             println!("Compilation error: {}", source.to_str().unwrap());
         }
@@ -34,8 +32,8 @@ fn shader_from_source(source: &CStr, shader_type: GLenum) -> GLuint {
 }
 
 fn main() {
-    let a = Lerp::new(vec![2.0, -2.0, 2.0]);
-    let b = Lerp::new(vec![-1.0, 1.0, 2.0]);
+    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);
@@ -48,8 +46,8 @@ fn main() {
     gl_attr.set_context_profile(sdl2::video::GLProfile::Core);
     gl_attr.set_context_version(4, 1);
 
-    let window_w: u32 = 800;
-    let window_h: u32 = 600;
+    let window_w: u32 = 1920;
+    let window_h: u32 = 1080;
 
     let window = video_subsystem
         .window("bezier", window_w, window_h)
@@ -87,12 +85,40 @@ fn main() {
     ".to_vec();
 
     let fragment_shader_source = b"
-    #version 410 core
-    out vec4 FragColor;
+#version 410 core
+out vec4 FragColor;
 
-    void main() {
-        FragColor = vec4(0.4, 0.8, 0.2, 1.0);
+float p1[3] = float[3](200, 400, 1300);
+float p2[3] = float[3](100, 900, -970);
+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 res = 100;
+  float thr = 32;
+  float closest = 10000;
+  float t = 0.0;
+  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 n = vec2(-(b - a).y, (b - a).x);
+    float d = dot(a - pos, n) / length(n);
+    if (d < closest) {
+      closest = d;
     }
+    t = step;
+  }
+  return 1 - pow(closest / thr, 2);
+}
+
+void main() {
+  float r = inside(gl_FragCoord.xy);
+    FragColor = vec4(r * 0.8, r * 0.2, r, 1.0);
+}
     ".to_vec();
 
     let mut vbo: GLuint = 0;
-- 
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