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feat: add many_cubes ECS demo with 400 entities

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Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
This commit is contained in:
tolelom
2026-03-24 20:09:44 +09:00
parent 59753b2264
commit 19e37f7f96
3 changed files with 386 additions and 0 deletions
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1
Cargo.toml
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@@ -7,6 +7,7 @@ members = [
"crates/voltex_ecs", "crates/voltex_ecs",
"examples/triangle", "examples/triangle",
"examples/model_viewer", "examples/model_viewer",
"examples/many_cubes",
] ]
[workspace.dependencies] [workspace.dependencies]

16
examples/many_cubes/Cargo.toml Normal file
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@@ -0,0 +1,16 @@
[package]
name = "many_cubes"
version = "0.1.0"
edition = "2021"
[dependencies]
voltex_math.workspace = true
voltex_platform.workspace = true
voltex_renderer.workspace = true
voltex_ecs.workspace = true
wgpu.workspace = true
winit.workspace = true
bytemuck.workspace = true
pollster.workspace = true
env_logger.workspace = true
log.workspace = true

369
examples/many_cubes/src/main.rs Normal file
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@@ -0,0 +1,369 @@
use winit::{
application::ApplicationHandler,
event::WindowEvent,
event_loop::{ActiveEventLoop, EventLoop},
keyboard::{KeyCode, PhysicalKey},
window::WindowId,
};
use voltex_math::{Vec3, Mat4};
use voltex_platform::{VoltexWindow, WindowConfig, InputState, GameTimer};
use voltex_renderer::{
GpuContext, Camera, FpsController, CameraUniform, LightUniform, Mesh, GpuTexture, pipeline, obj,
};
use voltex_ecs::{World, Transform};
use wgpu::util::DeviceExt;
/// App-level component: index into the mesh list.
struct MeshHandle(#[allow(dead_code)] u32);
struct ManyCubesApp {
state: Option<AppState>,
}
struct AppState {
window: VoltexWindow,
gpu: GpuContext,
pipeline: wgpu::RenderPipeline,
mesh: Mesh,
camera: Camera,
fps_controller: FpsController,
camera_uniform: CameraUniform,
light_uniform: LightUniform,
camera_buffer: wgpu::Buffer,
light_buffer: wgpu::Buffer,
camera_light_bind_group: wgpu::BindGroup,
_texture: GpuTexture,
input: InputState,
timer: GameTimer,
world: World,
time: f32,
}
fn camera_light_bind_group_layout(device: &wgpu::Device) -> wgpu::BindGroupLayout {
device.create_bind_group_layout(&wgpu::BindGroupLayoutDescriptor {
label: Some("Camera+Light Bind Group Layout"),
entries: &[
wgpu::BindGroupLayoutEntry {
binding: 0,
visibility: wgpu::ShaderStages::VERTEX | wgpu::ShaderStages::FRAGMENT,
ty: wgpu::BindingType::Buffer {
ty: wgpu::BufferBindingType::Uniform,
has_dynamic_offset: false,
min_binding_size: None,
},
count: None,
},
wgpu::BindGroupLayoutEntry {
binding: 1,
visibility: wgpu::ShaderStages::FRAGMENT,
ty: wgpu::BindingType::Buffer {
ty: wgpu::BufferBindingType::Uniform,
has_dynamic_offset: false,
min_binding_size: None,
},
count: None,
},
],
})
}
impl ApplicationHandler for ManyCubesApp {
fn resumed(&mut self, event_loop: &ActiveEventLoop) {
let config = WindowConfig {
title: "Voltex - Many Cubes (ECS)".to_string(),
width: 1280,
height: 720,
..Default::default()
};
let window = VoltexWindow::new(event_loop, &config);
let gpu = GpuContext::new(window.handle.clone());
// Parse OBJ
let obj_src = include_str!("../../../assets/cube.obj");
let obj_data = obj::parse_obj(obj_src);
let mesh = Mesh::new(&gpu.device, &obj_data.vertices, &obj_data.indices);
// Camera at (0, 15, 25) looking down at the grid
let aspect = gpu.config.width as f32 / gpu.config.height as f32;
let mut camera = Camera::new(Vec3::new(0.0, 15.0, 25.0), aspect);
camera.pitch = -0.5;
let fps_controller = FpsController::new();
// Uniforms
let camera_uniform = CameraUniform::new();
let light_uniform = LightUniform::new();
let camera_buffer = gpu.device.create_buffer_init(&wgpu::util::BufferInitDescriptor {
label: Some("Camera Uniform Buffer"),
contents: bytemuck::cast_slice(&[camera_uniform]),
usage: wgpu::BufferUsages::UNIFORM | wgpu::BufferUsages::COPY_DST,
});
let light_buffer = gpu.device.create_buffer_init(&wgpu::util::BufferInitDescriptor {
label: Some("Light Uniform Buffer"),
contents: bytemuck::cast_slice(&[light_uniform]),
usage: wgpu::BufferUsages::UNIFORM | wgpu::BufferUsages::COPY_DST,
});
// Bind group layouts
let cl_layout = camera_light_bind_group_layout(&gpu.device);
let tex_layout = GpuTexture::bind_group_layout(&gpu.device);
// Bind groups
let camera_light_bind_group = gpu.device.create_bind_group(&wgpu::BindGroupDescriptor {
label: Some("Camera+Light Bind Group"),
layout: &cl_layout,
entries: &[
wgpu::BindGroupEntry {
binding: 0,
resource: camera_buffer.as_entire_binding(),
},
wgpu::BindGroupEntry {
binding: 1,
resource: light_buffer.as_entire_binding(),
},
],
});
// Default white texture
let texture = GpuTexture::white_1x1(&gpu.device, &gpu.queue, &tex_layout);
// Pipeline
let render_pipeline = pipeline::create_mesh_pipeline(
&gpu.device,
gpu.surface_format,
&cl_layout,
&tex_layout,
);
// ECS: spawn 400 entities in a 20x20 grid
let mut world = World::new();
let spacing = 1.5_f32;
let offset = (20.0 - 1.0) * spacing * 0.5;
for row in 0..20 {
for col in 0..20 {
let x = col as f32 * spacing - offset;
let z = row as f32 * spacing - offset;
let entity = world.spawn();
world.add(entity, Transform::from_position(Vec3::new(x, 0.0, z)));
world.add(entity, MeshHandle(0));
}
}
self.state = Some(AppState {
window,
gpu,
pipeline: render_pipeline,
mesh,
camera,
fps_controller,
camera_uniform,
light_uniform,
camera_buffer,
light_buffer,
camera_light_bind_group,
_texture: texture,
input: InputState::new(),
timer: GameTimer::new(60),
world,
time: 0.0,
});
}
fn window_event(
&mut self,
event_loop: &ActiveEventLoop,
_window_id: WindowId,
event: WindowEvent,
) {
let state = match &mut self.state {
Some(s) => s,
None => return,
};
match event {
WindowEvent::CloseRequested => event_loop.exit(),
WindowEvent::KeyboardInput {
event: winit::event::KeyEvent {
physical_key: PhysicalKey::Code(key_code),
state: key_state,
..
},
..
} => {
let pressed = key_state == winit::event::ElementState::Pressed;
state.input.process_key(key_code, pressed);
if key_code == KeyCode::Escape && pressed {
event_loop.exit();
}
}
WindowEvent::Resized(size) => {
state.gpu.resize(size.width, size.height);
if size.width > 0 && size.height > 0 {
state.camera.aspect = size.width as f32 / size.height as f32;
}
}
WindowEvent::CursorMoved { position, .. } => {
state.input.process_mouse_move(position.x, position.y);
}
WindowEvent::MouseInput { state: btn_state, button, .. } => {
let pressed = btn_state == winit::event::ElementState::Pressed;
state.input.process_mouse_button(button, pressed);
}
WindowEvent::MouseWheel { delta, .. } => {
let y = match delta {
winit::event::MouseScrollDelta::LineDelta(_, y) => y,
winit::event::MouseScrollDelta::PixelDelta(pos) => pos.y as f32,
};
state.input.process_scroll(y);
}
WindowEvent::RedrawRequested => {
// 1. Tick timer
state.timer.tick();
let dt = state.timer.frame_dt();
// 2. Read input state BEFORE begin_frame clears it
if state.input.is_mouse_button_pressed(winit::event::MouseButton::Right) {
let (dx, dy) = state.input.mouse_delta();
state.fps_controller.process_mouse(&mut state.camera, dx, dy);
}
let mut forward = 0.0f32;
let mut right = 0.0f32;
let mut up = 0.0f32;
if state.input.is_key_pressed(KeyCode::KeyW) { forward += 1.0; }
if state.input.is_key_pressed(KeyCode::KeyS) { forward -= 1.0; }
if state.input.is_key_pressed(KeyCode::KeyD) { right += 1.0; }
if state.input.is_key_pressed(KeyCode::KeyA) { right -= 1.0; }
if state.input.is_key_pressed(KeyCode::Space) { up += 1.0; }
if state.input.is_key_pressed(KeyCode::ShiftLeft) { up -= 1.0; }
state.fps_controller.process_movement(&mut state.camera, forward, right, up, dt);
// 3. Clear per-frame input state for next frame
state.input.begin_frame();
// 4. Accumulate time for rotation
state.time += dt;
// Update view_proj and light (shared across all entities)
let view_proj = state.camera.view_projection();
state.camera_uniform.view_proj = view_proj.cols;
state.camera_uniform.camera_pos = [
state.camera.position.x,
state.camera.position.y,
state.camera.position.z,
];
state.gpu.queue.write_buffer(
&state.light_buffer,
0,
bytemuck::cast_slice(&[state.light_uniform]),
);
// 5. Render
let output = match state.gpu.surface.get_current_texture() {
Ok(t) => t,
Err(wgpu::SurfaceError::Lost) => {
let (w, h) = state.window.inner_size();
state.gpu.resize(w, h);
return;
}
Err(wgpu::SurfaceError::OutOfMemory) => {
event_loop.exit();
return;
}
Err(_) => return,
};
let view = output.texture.create_view(&wgpu::TextureViewDescriptor::default());
let mut encoder = state.gpu.device.create_command_encoder(
&wgpu::CommandEncoderDescriptor { label: Some("Render Encoder") },
);
{
let mut render_pass = encoder.begin_render_pass(&wgpu::RenderPassDescriptor {
label: Some("Render Pass"),
color_attachments: &[Some(wgpu::RenderPassColorAttachment {
view: &view,
resolve_target: None,
depth_slice: None,
ops: wgpu::Operations {
load: wgpu::LoadOp::Clear(wgpu::Color {
r: 0.1,
g: 0.1,
b: 0.15,
a: 1.0,
}),
store: wgpu::StoreOp::Store,
},
})],
depth_stencil_attachment: Some(wgpu::RenderPassDepthStencilAttachment {
view: &state.gpu.depth_view,
depth_ops: Some(wgpu::Operations {
load: wgpu::LoadOp::Clear(1.0),
store: wgpu::StoreOp::Store,
}),
stencil_ops: None,
}),
occlusion_query_set: None,
timestamp_writes: None,
multiview_mask: None,
});
// Set pipeline and bind groups ONCE
render_pass.set_pipeline(&state.pipeline);
render_pass.set_bind_group(0, &state.camera_light_bind_group, &[]);
render_pass.set_bind_group(1, &state._texture.bind_group, &[]);
render_pass.set_vertex_buffer(0, state.mesh.vertex_buffer.slice(..));
render_pass.set_index_buffer(
state.mesh.index_buffer.slice(..),
wgpu::IndexFormat::Uint32,
);
// Per-entity draw: query ECS for all (Transform, MeshHandle) pairs
let entities = state.world.query2::<Transform, MeshHandle>();
for (_entity, transform, _mesh_handle) in &entities {
// Compute model matrix with time-based Y rotation
let model = transform.matrix()
* Mat4::rotation_y(state.time * 0.5);
state.camera_uniform.model = model.cols;
// Write updated uniform to GPU buffer
state.gpu.queue.write_buffer(
&state.camera_buffer,
0,
bytemuck::cast_slice(&[state.camera_uniform]),
);
render_pass.draw_indexed(0..state.mesh.num_indices, 0, 0..1);
}
}
state.gpu.queue.submit(std::iter::once(encoder.finish()));
output.present();
}
_ => {}
}
}
fn about_to_wait(&mut self, _event_loop: &ActiveEventLoop) {
if let Some(state) = &self.state {
state.window.request_redraw();
}
}
}
fn main() {
env_logger::init();
let event_loop = EventLoop::new().unwrap();
let mut app = ManyCubesApp { state: None };
event_loop.run_app(&mut app).unwrap();
}