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|
mod poly;
use poly::Poly;
use std::ffi::{CStr, CString};
use gl::types::*;
pub struct Bezier {
pub degree: usize,
pub vx: Vec<f32>,
pub vy: Vec<f32>,
pub px: Poly,
pub py: Poly,
pub dpx: Poly,
pub dpy: Poly,
}
impl Bezier {
pub fn new() -> Bezier {
Bezier {
vx: Vec::<f32>::new(),
vy: Vec::<f32>::new(),
px: Poly::new(vec![]),
py: Poly::new(vec![]),
dpy: Poly::new(vec![]),
dpx: Poly::new(vec![]),
degree: 0,
}
}
pub fn push(&mut self, x: i32, y: i32) {
self.vx.push(x as f32);
self.vy.push(y as f32);
self.px = to_poly(&self.vx);
self.py = to_poly(&self.vy);
self.dpx = self.px.deriv();
self.dpy = self.py.deriv();
self.degree += 1;
}
pub fn remove(&mut self, index: usize) {
self.vx.remove(index);
self.vy.remove(index);
self.px = to_poly(&self.vx);
self.py = to_poly(&self.vy);
self.dpx = self.px.deriv();
self.dpy = self.py.deriv();
self.degree -= 1;
}
pub fn show_x(&self) -> String {
let mut s = String::new();
for i in 0..self.degree {
s.push_str(&self.vx[i].to_string());
if i < self.degree - 1 {
s.push_str(", ");
}
}
s
}
pub fn show_y(&self) -> String {
let mut s = String::new();
for i in 0..self.degree {
s.push_str(&self.vy[i].to_string());
if i < self.degree - 1 {
s.push_str(", ");
}
}
s
}
pub fn draw(&self) {
let vertex_shader_source = b"
#version 410 core
layout (location = 0) in vec3 aPos;
void main() {
gl_Position = vec4(aPos.xyz, 1.0);
}
"
.to_vec();
let fragment_shader_source = format!(
"
#version 410 core
out vec4 FragColor;
float vx[{s}] = float[{s}]({vx});
float vy[{s}] = float[{s}]({vy});
float px[{sx}] = float[{sx}]({px});
float py[{sy}] = float[{sy}]({py});
float dpx[{dsx}] = float[{dsx}]({dpx});
float dpy[{dsy}] = float[{dsy}]({dpy});
float thr = 32;
float step_size = 10;
float inf = 1000000;
float eval_px(float t) {{
float result = 0.0;
for (int i = 0; i < {sx}; i++) {{
result += px[i] * pow(t, i);
}}
return result;
}}
float eval_py(float t) {{
float result = 0.0;
for (int i = 0; i < {sy}; i++) {{
result += py[i] * pow(t, i);
}}
return result;
}}
float eval_dpx(float t) {{
float result = 0.0;
for (int i = 0; i < {dsx}; i++) {{
result += dpx[i] * pow(t, i);
}}
return result;
}}
float eval_dpy(float t) {{
float result = 0.0;
for (int i = 0; i < {dsy}; i++) {{
result += dpy[i] * pow(t, i);
}}
return result;
}}
float control(vec2 pos) {{
float closest = inf;
for (int i = 0; i < {s}; i++) {{
float d = distance(pos, vec2(vx[i], vy[i]));
if (d < closest) {{
closest = d;
}}
}}
return 1 - closest / thr;
}}
float inside(vec2 pos) {{
float closest = inf;
float t = 0.0;
while (t < 1.0) {{
float dstep = step_size / length(vec2(eval_dpx(t), eval_dpy(t)));
float step = min(t + dstep, 1.0);
vec2 a = vec2(eval_px(t), eval_py(t));
vec2 b = vec2(eval_px(step), eval_py(step));
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;
}}
t = step;
}}
return 1 - closest / thr;
}}
void main() {{
float r = inside(gl_FragCoord.xy);
float c = control(gl_FragCoord.xy);
FragColor = vec4(r, c, 0.0, 1.0);
}}
",
s = self.degree,
vx = self.show_x(),
vy = self.show_y(),
px = &self.px,
py = &self.py,
sx = self.px.degree() + 1,
sy = self.py.degree() + 1,
dpx = &self.dpx,
dpy = &self.dpy,
dsx = self.dpx.degree() + 1,
dsy = self.dpy.degree() + 1,
)
.into_bytes();
let shader_program: GLuint;
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,
);
shader_program = gl::CreateProgram();
gl::AttachShader(shader_program, vertex_shader);
gl::AttachShader(shader_program, fragment_shader);
gl::LinkProgram(shader_program);
gl::DeleteShader(vertex_shader);
gl::DeleteShader(fragment_shader);
gl::UseProgram(shader_program);
}
}
}
fn to_poly(v: &Vec<f32>) -> Poly {
match v.len() {
0 => Poly::new(vec![0.0]),
1 => Poly::new(vec![v[0]]),
2 => Poly::new(vec![v[0], v[1] - v[0]]),
_ => {
let mut pv = Vec::new();
for i in 0..v.len() - 1 {
pv.push(Poly::new(vec![v[i], v[i + 1] - v[i]]));
}
while pv.len() > 1 {
let mut npv = Vec::new();
for i in 0..pv.len() - 1 {
let c = &pv[i + 1] - &pv[i];
npv.push(&pv[i] + &c.shift());
}
pv = npv;
}
pv[0].clone()
}
}
}
fn shader_from_source(source: &CStr, shader_type: GLenum) -> GLuint {
unsafe {
let shader: GLuint = gl::CreateShader(shader_type);
gl::ShaderSource(shader, 1, &source.as_ptr(), std::ptr::null());
gl::CompileShader(shader);
let mut success: gl::types::GLint = 1;
gl::GetShaderiv(shader, gl::COMPILE_STATUS, &mut success);
if success == 0 {
let mut length: GLint = 0;
gl::GetShaderiv(shader, gl::INFO_LOG_LENGTH, &mut length);
let mut buffer: Vec<u8> = Vec::with_capacity(length as usize + 1);
buffer.extend([b' '].iter().cycle().take(length as usize));
let error: CString = CString::from_vec_unchecked(buffer);
gl::GetShaderInfoLog(shader, length, std::ptr::null_mut(), error.as_ptr() as *mut GLchar);
println!("Compilation error: {}", error.to_str().unwrap());
}
shader
}
}
|
