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|
mod lerp;
mod poly;
use lerp::Lerp;
use poly::Poly;
use std::ffi::{CStr, CString};
use sdl2::event::Event;
use sdl2::keyboard::Keycode;
use gl::types::*;
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 {
println!("Compilation error: {}", source.to_str().unwrap());
}
shader
}
}
fn compile_bezier_shader(a: Poly, b: Poly) -> GLuint {
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 pa[{sa}] = float[{sa}]({pa});
float pb[{sb}] = float[{sb}]({pb});
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 = 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));
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);
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();
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);
}
shader_program
}
fn main() {
let a = Lerp::new(vec![200.0, 500.0, 500.0]).to_poly();
let b = Lerp::new(vec![200.0, 500.0, 200.0]).to_poly();
let sdl_context = sdl2::init().unwrap();
let video_subsystem = sdl_context.video().unwrap();
let gl_attr = video_subsystem.gl_attr();
gl_attr.set_context_profile(sdl2::video::GLProfile::Core);
gl_attr.set_context_version(4, 1);
let window_w: u32 = 1920;
let window_h: u32 = 1080;
let window = video_subsystem
.window("bezier", window_w, window_h)
.position_centered()
.opengl()
.build()
.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);
unsafe {
gl::Viewport(0, 0, window_w as i32, window_h as i32);
}
let vertices: [f32; 18] = [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 mut vbo: GLuint = 0;
let mut vao: GLuint = 0;
unsafe {
gl::GenVertexArrays(1, &mut vao);
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::EnableVertexAttribArray(0);
}
let shader_program = compile_bezier_shader(a, b);
let mut event_pump = sdl_context.event_pump().unwrap();
'running: loop {
for event in event_pump.poll_iter() {
match event {
Event::Quit { .. }
| Event::KeyDown {
keycode: Some(Keycode::Escape),
..
} => break 'running,
_ => {}
}
}
unsafe {
gl::Clear(gl::COLOR_BUFFER_BIT);
gl::UseProgram(shader_program);
gl::DrawArrays(gl::TRIANGLES, 0, 6);
}
window.gl_swap_window();
}
}
|
