spinning_cube
A wireframe cube drawn with LINE_LIST topology and a hand-rolled 3D projection, which
keeps the example free of any matrix library.
cargo run --features examples --example spinning_cube
What it demonstrates
- Line primitives in a render pipeline
- Per-frame vertex uploads through a deposit transaction
Source
examples/spinning_cube.rs:
//! Spinning cube example - 3D wireframe cube.
//!
//! Demonstrates 3D projection via retained scheme with copy-to-present.
//!
//! Run with: cargo run --example spinning_cube
use goldy::{
Buffer, BufferFlags, BufferKind, Color, DepositTarget, DepositTransaction, Instance, Lease, LeaseRenderTarget,
MemoryExchange, NodeAccess, PrimitiveTopology, RenderPipeline, RenderPipelineDesc, RequestAdapterOptions,
RuntimeDescriptor, Scheme, ShaderModule, SurfaceConfig, SurfaceExchange, TargetLoad, Texture, TextureFormat,
Transaction, Vertex2D,
};
use std::ops::Shr;
use std::sync::Arc;
use std::time::Instant;
use winit::{
application::ApplicationHandler,
event::WindowEvent,
event_loop::{ActiveEventLoop, ControlFlow, EventLoop},
keyboard::{Key, NamedKey},
window::{Window, WindowId},
};
mod common;
use common::CaptureDump;
const CUBE_VERTICES: [[f32; 3]; 8] = [
[-1.0, -1.0, -1.0],
[1.0, -1.0, -1.0],
[1.0, 1.0, -1.0],
[-1.0, 1.0, -1.0],
[-1.0, -1.0, 1.0],
[1.0, -1.0, 1.0],
[1.0, 1.0, 1.0],
[-1.0, 1.0, 1.0],
];
const CUBE_EDGES: [[usize; 2]; 12] = [
[0, 1],
[1, 2],
[2, 3],
[3, 0],
[4, 5],
[5, 6],
[6, 7],
[7, 4],
[0, 4],
[1, 5],
[2, 6],
[3, 7],
];
fn rotate_y(p: [f32; 3], angle: f32) -> [f32; 3] {
let (s, c) = (angle.sin(), angle.cos());
[p[0] * c + p[2] * s, p[1], -p[0] * s + p[2] * c]
}
fn rotate_x(p: [f32; 3], angle: f32) -> [f32; 3] {
let (s, c) = (angle.sin(), angle.cos());
[p[0], p[1] * c - p[2] * s, p[1] * s + p[2] * c]
}
fn project(p: [f32; 3], fov: f32) -> [f32; 2] {
let z = p[2] + 4.0;
let scale = fov / z;
[p[0] * scale, p[1] * scale]
}
const MAX_LINE_VERTICES: usize = CUBE_EDGES.len() * 2;
struct App {
instance: Instance,
// Window + surface before ctx/device so Escape teardown destroys the swapchain
// while the CUDA context stream is still alive (avoids cudarc sticky error_state
// from stream Drop racing destroy_surface bind).
window: Option<Arc<Window>>,
surface: Option<SurfaceExchange>,
present: Option<Transaction>,
capture: Option<CaptureDump>,
readback: Option<Texture>,
scene_rt: Option<Lease<LeaseRenderTarget>>,
scheme: Option<Scheme>,
upload_scheme: Option<Scheme>,
vertex_deposit: Option<DepositTransaction>,
vertex_parcel: Option<Buffer>,
pipeline: Option<RenderPipeline>,
shader: Option<ShaderModule>,
ctx: Option<goldy::Context>,
device: Option<Arc<goldy::Runtime>>,
start_time: Instant,
frame_count: u32,
}
impl App {
fn new() -> anyhow::Result<Self> {
Ok(Self {
instance: Instance::new()?,
window: None,
surface: None,
present: None,
capture: None,
readback: None,
scene_rt: None,
scheme: None,
upload_scheme: None,
vertex_deposit: None,
vertex_parcel: None,
pipeline: None,
shader: None,
ctx: None,
device: None,
start_time: Instant::now(),
frame_count: 0,
})
}
fn create_pipeline(
device: &goldy::Runtime,
shader: &ShaderModule,
format: TextureFormat,
) -> anyhow::Result<RenderPipeline> {
common::render_pipeline(
device,
shader,
format,
RenderPipelineDesc {
vertex_layout: Vertex2D::layout(),
topology: PrimitiveTopology::LineList,
..Default::default()
},
)
}
fn record_pass(
scheme: &mut Scheme,
pipeline: &RenderPipeline,
vertex_parcel: &Buffer,
scene_rt: &Lease<LeaseRenderTarget>,
) {
let mut pass = scheme.render_pass(
"spinning_cube",
scene_rt,
TargetLoad::Clear(Color {
r: 0.02,
g: 0.02,
b: 0.05,
a: 1.0,
}),
);
pass.with_parcel(vertex_parcel, NodeAccess::Read);
pass.set_pipeline(pipeline);
pass.set_vertex_buffer(0, vertex_parcel);
pass.draw(0..MAX_LINE_VERTICES as u32, 0..1);
pass.finish();
}
fn bind_frame(
scheme: &mut Scheme,
scene_rt: &Lease<LeaseRenderTarget>,
surface: Option<&SurfaceExchange>,
readback: Option<&Texture>,
) -> anyhow::Result<Option<Transaction>> {
if let Some(surface) = surface {
let present = surface.bind_render_target(scheme, scene_rt)?;
Ok(Some(present))
} else {
let readback = readback.expect("capture readback");
scheme.copy_to_texture(scene_rt, readback)?;
Ok(None)
}
}
fn init_gpu(&mut self, window: Option<&Window>) -> anyhow::Result<()> {
let device = Arc::new(
self.instance
.request_adapter(&RequestAdapterOptions::default())?
.request_runtime(&RuntimeDescriptor::default())?,
);
let ctx = device.create_context()?;
let (surface, capture, readback, format, width, height) = if let Some(window) = window {
let surface = SurfaceExchange::new(&ctx, window, SurfaceConfig::default())?;
let format = surface.format();
let (width, height) = surface.size();
(Some(surface), None, None, format, width, height)
} else {
let capture = CaptureDump::from_env()?;
let (width, height) = capture.size();
let readback = common::capture_readback(&device, width, height)?;
(
None,
Some(capture),
Some(readback),
CaptureDump::format(),
width,
height,
)
};
let shader = ShaderModule::from_slang(&device, goldy::shader::builtins::VERTEX_COLOR_2D)?;
let pipeline = Self::create_pipeline(&device, &shader, format)?;
let vertex_parcel = device.acquire_buffer_sized::<Vertex2D>(
MAX_LINE_VERTICES as u64,
BufferKind::Scattered,
BufferFlags::empty(),
)?;
let mut scheme = Scheme::new(&ctx);
let scene_rt = ctx.lease_render_target(width.max(1), height.max(1), format, None)?;
Self::record_pass(&mut scheme, &pipeline, &vertex_parcel, &scene_rt);
let present = Self::bind_frame(&mut scheme, &scene_rt, surface.as_ref(), readback.as_ref())?;
self.ctx = Some(ctx);
let ctx = self.ctx.as_ref().unwrap();
self.device = Some(device);
self.shader = Some(shader);
self.pipeline = Some(pipeline);
self.vertex_parcel = Some(vertex_parcel);
let vertex_parcel = self.vertex_parcel.as_ref().unwrap();
let mut upload_scheme = Scheme::new(ctx);
let vertex_deposit = MemoryExchange::new(ctx).bind_deposit(
&mut upload_scheme,
DepositTarget::buffer(vertex_parcel, vertex_parcel.byte_size()),
)?;
self.upload_scheme = Some(upload_scheme);
self.vertex_deposit = Some(vertex_deposit);
self.surface = surface;
self.present = present;
self.capture = capture;
self.readback = readback;
self.scene_rt = Some(scene_rt);
self.scheme = Some(scheme);
Ok(())
}
fn render_frame(&mut self) -> anyhow::Result<()> {
self.frame_count += 1;
if let Some(window) = self.window.as_ref() {
let size = window.inner_size();
if size.width == 0 || size.height == 0 {
return Ok(());
}
}
let time = self
.capture
.as_ref()
.map(CaptureDump::time)
.unwrap_or_else(|| self.start_time.elapsed().as_secs_f32());
let transformed: Vec<[f32; 3]> = CUBE_VERTICES
.iter()
.map(|&v| rotate_x(rotate_y(v, time), time * 0.7))
.collect();
let mut vertices: Vec<Vertex2D> = Vec::new();
for edge in &CUBE_EDGES {
let p1 = project(transformed[edge[0]], 2.0);
let p2 = project(transformed[edge[1]], 2.0);
let z1 = transformed[edge[0]][2];
let z2 = transformed[edge[1]][2];
let avg_z = (z1 + z2) / 2.0;
let brightness = (avg_z + 1.5) / 3.0;
let color = Color {
r: 0.2 + brightness * 0.8,
g: 0.5 + brightness * 0.5,
b: 1.0,
a: 1.0,
};
vertices.push(Vertex2D::new(p1[0], p1[1], color));
vertices.push(Vertex2D::new(p2[0], p2[1], color));
}
let upload = self.upload_scheme.as_mut().unwrap();
(self.vertex_deposit.as_ref().unwrap() << vertices.as_slice())?;
upload.submit()?;
let scheme = self.scheme.as_mut().unwrap();
let mut submission = scheme.submit()?;
if let Some(present) = &self.present {
(&mut submission >> present).take()?;
} else {
let pixels = (&mut submission >> self.readback.as_ref().unwrap())
.take::<u8>()?
.to_vec();
self.capture.as_mut().unwrap().write_rgba(&pixels)?;
}
Ok(())
}
fn capture_done(&self) -> bool {
self.capture.as_ref().is_none_or(CaptureDump::finished)
}
fn handle_resize(&mut self, new_size: winit::dpi::PhysicalSize<u32>) {
if new_size.width == 0 || new_size.height == 0 {
return;
}
let Some(surface) = self.surface.as_mut() else {
return;
};
let _ = surface.resize(new_size.width, new_size.height);
let format = surface.format();
let (width, height) = surface.size();
if let (Some(ctx), Some(device), Some(shader), Some(vertex_parcel)) = (
self.ctx.as_ref(),
self.device.as_ref(),
self.shader.as_ref(),
self.vertex_parcel.as_ref(),
) {
if let Ok(pipeline) = Self::create_pipeline(device, shader, format) {
self.pipeline = Some(pipeline);
if let Some(pipeline) = self.pipeline.as_ref() {
let mut scheme = Scheme::new(ctx);
if let Ok(rt) = ctx.lease_render_target(width.max(1), height.max(1), format, None) {
Self::record_pass(&mut scheme, pipeline, vertex_parcel, &rt);
if let Ok(present) =
Self::bind_frame(&mut scheme, &rt, self.surface.as_ref(), self.readback.as_ref())
{
self.present = present;
self.scheme = Some(scheme);
self.scene_rt = Some(rt);
}
}
}
}
}
}
}
impl Drop for App {
fn drop(&mut self) {
let elapsed = self.start_time.elapsed().as_secs_f64();
let fps = if elapsed > 0.0 {
self.frame_count as f64 / elapsed
} else {
0.0
};
println!(
"GOLDY_PERF: frames={} elapsed={elapsed:.2}s avg_fps={fps:.1}",
self.frame_count
);
}
}
impl ApplicationHandler for App {
fn resumed(&mut self, event_loop: &ActiveEventLoop) {
if self.window.is_none() {
let window = Arc::new(
event_loop
.create_window(common::hidden_window(
"Goldy - Spinning Cube (Scheme + Present)",
800,
800,
))
.unwrap(),
);
self.window = Some(window.clone());
self.init_gpu(Some(window.as_ref())).unwrap();
if let Err(e) = self.render_frame() {
tracing::error!("First frame error: {e}");
}
common::reveal_window(&window);
window.request_redraw();
}
}
fn about_to_wait(&mut self, event_loop: &ActiveEventLoop) {
common::exit_if_timed_out(event_loop, self.start_time);
}
fn window_event(&mut self, event_loop: &ActiveEventLoop, _: WindowId, event: WindowEvent) {
match event {
WindowEvent::CloseRequested => event_loop.exit(),
WindowEvent::KeyboardInput { event, .. } if event.state.is_pressed() => {
if matches!(event.logical_key, Key::Named(NamedKey::Escape)) {
event_loop.exit();
}
}
WindowEvent::RedrawRequested => {
if let Err(e) = self.render_frame() {
tracing::error!("Render error: {}", e);
}
self.window.as_ref().unwrap().request_redraw();
}
WindowEvent::Resized(new_size) => {
self.handle_resize(new_size);
if let Some(window) = &self.window {
window.request_redraw();
}
}
_ => {}
}
}
}
fn main() -> anyhow::Result<()> {
tracing_subscriber::fmt()
.with_env_filter(
tracing_subscriber::EnvFilter::try_from_default_env()
.unwrap_or_else(|_| tracing_subscriber::EnvFilter::new("warn")),
)
.init();
if common::capture_requested() {
let mut app = App::new()?;
app.init_gpu(None)?;
while !app.capture_done() {
app.render_frame()?;
}
return Ok(());
}
println!("Goldy Spinning Cube Example (Scheme + Present) - Press Escape to exit");
let event_loop = EventLoop::new()?;
event_loop.set_control_flow(ControlFlow::Poll);
event_loop.run_app(&mut App::new()?)?;
Ok(())
}The example pulls in examples/common.rs — see Shared Helpers.
Shaders
shaders/vertex_color_2d.slang:
// Simple 2D vertex + fragment shader for colored vertices.
// Used by: triangle, particles, starfield, bouncing_lines, spinning_cube, instancing, waveform
struct VertexInput {
float2 position : POSITION;
float4 color : COLOR;
};
struct VertexOutput {
float4 position : SV_Position;
float4 color : COLOR;
};
[goldy_vertex]
VertexOutput vs_main(VertexInput input) {
VertexOutput output;
output.position = float4(input.position, 0.0, 1.0);
output.color = input.color;
return output;
}
[goldy_fragment]
float4 fs_main(VertexOutput input) : SV_Target {
return input.color;
}