112 lines
3.3 KiB
Plaintext
112 lines
3.3 KiB
Plaintext
use glow::*;
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use glutin::event::*;
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use glutin::event_loop::{ControlFlow, EventLoop};
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use std::os::raw::c_uint;
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const VERTEX: &str = "#version 410
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const vec2 verts[3] = vec2[3](
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vec2(0.5f, 1.0f),
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vec2(0.0f, 0.0f),
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vec2(1.0f, 0.0f)
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);
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out vec2 vert;
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void main() {
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vert = verts[gl_VertexID];
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gl_Position = vec4(vert - 0.5, 0.0, 1.0);
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}";
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const FRAGMENT: &str = "#version 410
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precision mediump float;
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in vec2 vert;
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out vec4 color;
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void main() {
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color = vec4(vert, 0.5, 1.0);
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}";
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unsafe fn create_program(gl: &Context, vert: &str, frag: &str) -> c_uint {
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let program = gl.create_program().expect("Cannot create program");
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let shader_sources = [(glow::VERTEX_SHADER, vert), (glow::FRAGMENT_SHADER, frag)];
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let mut shaders = Vec::new();
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for (shader_type, shader_source) in shader_sources.iter() {
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let shader = gl
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.create_shader(*shader_type)
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.expect("Cannot create shader");
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gl.shader_source(shader, shader_source);
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gl.compile_shader(shader);
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if !gl.get_shader_compile_status(shader) {
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panic!(gl.get_shader_info_log(shader));
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}
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gl.attach_shader(program, shader);
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shaders.push(shader);
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}
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gl.link_program(program);
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if !gl.get_program_link_status(program) {
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panic!(gl.get_program_info_log(program));
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}
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for shader in shaders {
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gl.detach_shader(program, shader);
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gl.delete_shader(shader);
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}
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program
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}
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fn main() {
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let (gl, event_loop, window) = unsafe {
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let el = EventLoop::new();
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let wb = glutin::window::WindowBuilder::new()
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.with_title("Hello triangle!")
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.with_inner_size(glutin::dpi::LogicalSize::new(1024.0, 768.0));
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let windowed_context = glutin::ContextBuilder::new()
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.with_vsync(true)
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.build_windowed(wb, &el)
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.unwrap();
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let windowed_context = windowed_context.make_current().unwrap();
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let context = glow::Context::from_loader_function(|s| {
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windowed_context.get_proc_address(s) as *const _
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});
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(context, el, windowed_context)
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};
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let (program, vab) = unsafe {
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let vertex_array = gl
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.create_vertex_array()
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.expect("Cannot create vertex array");
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gl.bind_vertex_array(Some(vertex_array));
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let program = create_program(&gl, VERTEX, FRAGMENT);
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gl.use_program(Some(program));
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(program, vertex_array)
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};
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event_loop.run(move |ev, _, flow| match ev {
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Event::WindowEvent {
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event: WindowEvent::CloseRequested, ..
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} => {
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unsafe {
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gl.delete_program(program);
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gl.delete_vertex_array(vab);
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}
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*flow = ControlFlow::Exit;
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}
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Event::WindowEvent {
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event: WindowEvent::Resized(size), ..
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} => {
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unsafe {
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gl.viewport(0, 0, size.width as i32, size.height as i32);
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}
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window.resize(size);
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}
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Event::RedrawRequested(_) => unsafe {
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gl.clear_color(0.1, 0.2, 0.3, 1.0);
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gl.clear(glow::COLOR_BUFFER_BIT);
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gl.draw_arrays(glow::TRIANGLES, 0, 3);
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window.swap_buffers().unwrap();
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},
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_ => {}
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});
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}
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