I like the way this renders, but the implementation is an absolute disaster...

src/camera.rs

@@ -5,7 +5,8 @@ use cgmath::{Decomposed, InnerSpace, Matrix4, Point3, Rad, Vector3};
 use winit_24::dpi::{LogicalPosition, PhysicalPosition};
 use winit_24::event::{ElementState, MouseScrollDelta, VirtualKeyCode};
 use crate::render::OPENGL_TO_WGPU_MATRIX;
-
+use imgui::Condition;
+use imgui::*;
 
 #[derive(Clone, Copy, Debug, PartialEq)]
 pub struct Camera {
@@ -150,6 +151,7 @@ impl CameraController {
     }
 
     pub fn update_camera(&mut self, camera: &mut Camera, dt: f32) {
+
         // Move forward/backward and left/right
         let view_vector = Vector3::new(
             (1.0 * camera.pitch.0.sin() * camera.yaw.0.sin()),

src/components.rs

@@ -8,11 +8,13 @@ use rapier3d::geometry::ColliderHandle;
 use wgpu::{BindGroup, Buffer, TextureView};
 
 use crate::runtime::state::{TomlPositionDescription, TomlRotationDescription};
+use imgui::Ui;
 
 // a component is any type that is 'static, sized, send and sync
 
-pub struct ImguiWindow<'a> {
-    pub window: imgui::Window<'a>,
+pub struct ImguiWindow<'a, T> {
+    pub window: fn() -> imgui::Window<'a>,
+    pub func: fn(&Ui, &T),
 }
 
 #[derive(Clone, Copy, Debug, PartialEq)]
@@ -30,6 +32,21 @@ pub struct Position {
     pub rot: cgmath::Euler<Deg<f32>>,
 }
 
+impl Default for Position {
+    fn default() -> Self {
+        Position {
+            x: 0.0,
+            y: 0.0,
+            z: 0.0,
+            rot: Euler {
+                x: Deg(0.0),
+                y: Deg(0.0),
+                z: Deg(0.0),
+            },
+        }
+    }
+}
+
 impl From<TomlPositionDescription> for Position {
     fn from(pos: TomlPositionDescription) -> Self {
         let euler = match pos.rot {

src/main.rs

@@ -1,16 +1,17 @@
+extern crate env_logger;
 extern crate imgui;
 extern crate imgui_wgpu;
 #[macro_use]
 extern crate lazy_static;
-extern crate tobj;
-extern crate winit_24;
-extern crate env_logger;
-extern crate toml;
 #[macro_use]
 extern crate serde_derive;
+extern crate tobj;
+extern crate toml;
+extern crate winit_24;
 
-
+use std::collections::HashMap;
 use std::f32::consts::PI;
+use std::fs;
 use std::sync::{Arc, Mutex};
 #[cfg(not(target_arch = "wasm32"))]
 use std::time::{Duration, Instant};
@@ -20,6 +21,7 @@ use cgmath::{
 };
 use futures::executor::block_on;
 use futures::task::LocalSpawn;
+use futures::FutureExt;
 use gilrs::Event as GilEvent;
 use gilrs::{Gamepad, Gilrs};
 use imgui::FontSource;
@@ -28,6 +30,7 @@ use imgui::*;
 use imgui_wgpu::{Renderer as ImguiRenderer, RendererConfig as ImguiRendererConfig};
 use legion::systems::{SyncResources, UnsafeResources};
 use legion::*;
+use log::LevelFilter;
 use rapier3d::counters::Timer;
 use rapier3d::dynamics::{
     IntegrationParameters, JointSet, RigidBody, RigidBodyBuilder, RigidBodyHandle, RigidBodySet,
@@ -40,6 +43,8 @@ use rapier3d::pipeline::PhysicsPipeline;
 use wgpu::{BindGroup, Buffer, TextureView};
 use wgpu_subscriber;
 use winit_24::event::DeviceEvent::MouseMotion;
+use winit_24::event::{ElementState, VirtualKeyCode};
+use winit_24::event_loop::EventLoopProxy;
 use winit_24::platform::unix::x11::ffi::Time;
 use winit_24::window::Window;
 use winit_24::{
@@ -54,13 +59,8 @@ use crate::imgui_supp::extended_winit_imgui_support;
 use crate::imgui_supp::imgui_support::{ImguiContext, ImguiPlatform};
 use crate::owned_event::{OwnedEvent, OwnedEventExtension};
 use crate::physics::state::PhysicsState;
-use std::fs;
-use winit_24::event::{VirtualKeyCode, ElementState};
-use std::collections::HashMap;
-use futures::FutureExt;
-use log::LevelFilter;
+use crate::render::system::ImguiPerformanceProfilerLine;
 use crate::runtime::state::RuntimeState;
-use winit_24::event_loop::EventLoopProxy;
 
 mod camera;
 mod components;
@@ -112,15 +112,18 @@ Todo:
 
 //log::info!("");
 
-// ImGUI works on more or less a global state. which is MegaLame
+// ImGUI works on more or less an unsafe global state. which is MegaLame
 static mut CURRENT_UI: Option<imgui::Ui<'static>> = None;
 pub unsafe fn current_ui<'a>() -> Option<&'a imgui::Ui<'a>> {
     CURRENT_UI.as_ref()
 }
 
-fn main() {
 
-    let logger = env_logger::builder().filter(Some("minimal_viable_game_engine"), LevelFilter::Info).init();
+
+fn main() {
+    let logger = env_logger::builder()
+        .filter(Some("minimal_viable_game_engine"), LevelFilter::Info)
+        .init();
 
     let mut world = World::default();
 
@@ -134,6 +137,7 @@ fn main() {
         .build();
 
     let mut render_schedule = Schedule::builder()
+        .add_system(render::system::render_imgui_system())
         .add_system(render::system::render_test_system())
         .build();
 
@@ -156,6 +160,8 @@ fn main() {
 
     let mut resources = Resources::default();
 
+
+
     // Load up all the resources
     {
         let mut imgui_context = imgui::Context::create();
@@ -242,21 +248,26 @@ fn main() {
             //      conditionally, and run the fps locked renderer
             event::Event::MainEventsCleared => {
                 event_schedule.execute(&mut world, &mut resources);
-                imgui_prepare_schedule.execute(&mut world, &mut resources);
                 resources
                     .get_mut::<Vec<OwnedEvent<OwnedEventExtension>>>()
                     .unwrap()
                     .clear();
 
+                imgui_prepare_schedule.execute(&mut world, &mut resources);
+
                 let (step_size, elapsed_time) = {
-                    // deltatime since last frame
-                    let loop_state = resources.get::<LoopState>().unwrap();
+                    let mut loop_state = resources.get_mut::<LoopState>().unwrap();
                     (
                         loop_state.step_size,
                         loop_state.start_time.elapsed().as_secs_f32(),
                     )
                 };
                 delta_time = elapsed_time - current_time;
+
+                {
+                    let mut loop_state = resources.get_mut::<LoopState>().unwrap();
+                    loop_state.delta_time = Duration::from_secs_f32(delta_time);
+                }
                 current_time = elapsed_time;
                 if delta_time > 0.02 {
                     delta_time = 0.02;
@@ -265,10 +276,10 @@ fn main() {
 
                 while accumulator_time - step_size >= step_size {
                     accumulator_time -= step_size;
+
                     // ==== DELTA TIME LOCKED ====
                     update_schedule.execute(&mut world, &mut resources);
                 }
-
                 // ==== FPS LOCKED ====
                 render_schedule.execute(&mut world, &mut resources);
             }
@@ -289,6 +300,7 @@ fn main() {
                 event: winit_24::event::DeviceEvent::Key(keyboard_input),
                 ..
             } => {
+                if keyboard_input.virtual_keycode.is_some() {
                     match keyboard_input.virtual_keycode.unwrap() {
                         VirtualKeyCode::Escape => {
                             if keyboard_input.state == ElementState::Pressed {
@@ -297,7 +309,8 @@ fn main() {
                                 //d
                             }
                         }
-                    _ => ()
+                        _ => (),
+                    }
                 }
             }
             event::Event::WindowEvent {
@@ -320,7 +333,6 @@ fn main() {
 }
 
 pub fn setup_gamepad(event_loop: &EventLoop<OwnedEventExtension>) {
-
     let event_loop_proxy = event_loop.create_proxy();
 
     std::thread::spawn(move || {
@@ -362,4 +374,3 @@ pub fn setup_gamepad(event_loop: &EventLoop<OwnedEventExtension>) {
         }
     });
 }
-

src/physics/system.rs

@@ -10,8 +10,9 @@ use rapier3d::geometry::{BroadPhase, ColliderSet, NarrowPhase};
 use rapier3d::pipeline::{PhysicsPipeline, ChannelEventCollector};
 
 use crate::camera::{Camera, CameraController};
-use crate::components::{Collider, LoopState, Mesh, Physics, Position};
-use imgui::FontSource;
+use crate::components::{Collider, LoopState, Mesh, Physics, Position, ImguiWindow};
+use imgui::{FontSource, Condition};
+use imgui::*;
 use crate::physics::state::PhysicsState;
 
 
@@ -73,10 +74,12 @@ pub fn run_physics(
     }
 }
 
+
 #[system]
 #[write_component(Camera)]
 #[write_component(CameraController)]
 pub fn update_camera(world: &mut SubWorld, #[resource] loop_state: &mut LoopState) {
+
     let mut query = <(&mut Camera, &mut CameraController)>::query();
     for (mut camera, controller) in query.iter_mut(world) {
         controller.update_camera(&mut camera, loop_state.step_size)

src/render/system.rs

@@ -24,13 +24,15 @@ use winit_24::platform::unix::x11::ffi::Time;
 use winit_24::window::Window;
 
 use crate::camera::{Camera, CameraController};
-use crate::components::{Mesh, Position, RangeCopy};
+use crate::components::{Mesh, Position, RangeCopy, LoopState, ImguiWindow};
 use crate::current_ui;
 use crate::geometry::{load_obj, Vertex};
 use crate::imgui_supp::imgui_support::{ImguiContext, ImguiPlatform};
 use crate::light::{DirectionalLight, LightRaw};
 use crate::render::state::{RenderState};
 use crate::render::{push_debug_group_checked, insert_debug_marker_checked, pop_debug_group_checked, EntityUniforms};
+use std::iter::Chain;
+use std::slice::Iter;
 
 
 #[system]
@@ -53,19 +55,92 @@ pub fn imgui_prepare(
     unsafe { crate::CURRENT_UI = Some(std::mem::transmute(imgui_context.frame())) }
 }
 
+/// Go through each "global" window-data component and render it's data
+#[system]
+#[write_component(ImguiWindow<ImguiPerformanceProfilerLine>)]
+#[write_component(ImguiPerformanceProfilerLine)]
+pub fn render_imgui(world: &mut SubWorld, #[resource] loop_state: &mut LoopState) {
+
+    let ui = unsafe { crate::current_ui().unwrap() };
+
+    let mut query = <(&ImguiPerformanceProfilerLine, &mut ImguiWindow<ImguiPerformanceProfilerLine>)>::query();
+    for (state, mut window) in query.iter_mut(world) {
+        let new_window = (window.window)();
+        new_window.build(&ui, || { (window.func)(ui, state) });
+
+    }
+}
+
+
+// This would be the shared state for all imgui performance window things
+pub struct ImguiPerformanceProfilerLine {
+    pub label: String,
+    list_of_fps: [f32; 400],
+    index: usize,
+    scale_min: f32,
+    pub scale_max: f32,
+}
+
+impl ImguiPerformanceProfilerLine {
+    fn add_sample(&mut self, sample: f32) {
+
+        self.list_of_fps[self.index] = sample;
+
+        if self.index >= 399 {
+            self.scale_max = self.list_of_fps.iter().cloned().fold(0./0., f32::max);
+            self.index = 0;
+        } else {
+            self.index += 1;
+        }
+
+        if self.scale_max < sample {
+            self.scale_max = sample;
+        }
+    }
+
+    pub fn iter_data_from_head(&self) -> Chain<Iter<f32>, Iter<f32>> {
+        let (left, right) = self.list_of_fps.split_at(self.index);
+        right.iter().chain(left.iter())
+    }
+
+    pub fn current_average_label(&self) -> (f32, String) {
+        let (left, right) = self.list_of_fps.split_at(self.index);
+        ((left.iter().rev().chain(right.iter().rev()).take(50).sum::<f32>() / 50.0), "FPS".to_string())
+    }
+
+    pub fn new(label: String) -> ImguiPerformanceProfilerLine {
+        ImguiPerformanceProfilerLine {
+            label,
+            list_of_fps: [0.0; 400],
+            index: 0,
+            scale_min: 0.0,
+            scale_max: 0.0
+        }
+    }
+}
+
 #[system]
 #[write_component(Camera)]
 #[write_component(Position)]
+#[write_component(ImguiPerformanceProfilerLine)]
 #[write_component(Point3<f32>)]
 #[write_component(Mesh)]
 #[write_component(DirectionalLight)]
 pub fn render_test(
     world: &mut SubWorld,
+    #[resource] loop_state: &mut LoopState,
     #[resource] renderer: &mut RenderState,
     #[resource] winit_window: &mut Window,
     #[resource] imgui_context: &mut Arc<Mutex<ImguiContext>>,
     #[resource] imgui_platform: &mut Arc<Mutex<ImguiPlatform>>,
 ) {
+
+    let mut query = <(&mut ImguiPerformanceProfilerLine)>::query();
+    for (mut profiler) in query.iter_mut(world) {
+        let delta_time = loop_state.delta_time.as_secs_f32();
+        profiler.add_sample(delta_time);
+    }
+
     let mut encoder = renderer
         .device
         .create_command_encoder(&wgpu::CommandEncoderDescriptor { label: None });
@@ -221,16 +296,8 @@ pub fn render_test(
         let mut imgui_context = &mut imgui_context.lock().unwrap().context;
         let mut imgui_platform = &mut imgui_platform.lock().unwrap().platform;
 
-        //imgui_state.context.io_mut().update_delta_time(Duration::new(0,160));
         let ui = unsafe { crate::current_ui().unwrap() };
 
-        let window = imgui::Window::new(im_str!("Hello too"));
-        window
-            .size([400.0, 100.0], Condition::FirstUseEver)
-            .position([50.0, 50.0], Condition::FirstUseEver)
-            .build(&ui, || {
-                ui.text(im_str!("Frametime: {:?}", 10.0));
-            });
 
         // ui.show_demo_window(&mut true);
         imgui_platform.prepare_render(&ui, &winit_window);

src/runtime/system.rs

@@ -3,7 +3,8 @@ use std::path::PathBuf;
 use std::time::Instant;
 
 use cgmath::{Deg, Euler, Point3, Quaternion, Rad};
-use imgui::FontSource;
+use imgui::*;
+use imgui::{Condition, FontSource, Ui};
 use legion::systems::CommandBuffer;
 use legion::world::SubWorld;
 use legion::IntoQuery;
@@ -17,16 +18,76 @@ use rapier3d::na::{Isometry3, Vector, Vector3};
 use rapier3d::pipeline::{ChannelEventCollector, PhysicsPipeline};
 
 use crate::camera::{Camera, CameraController};
-use crate::components::{Collider, LoopState, Mesh, Physics, Position};
+use crate::components::{Collider, ImguiWindow, LoopState, Mesh, Physics, Position};
 use crate::geometry::RawMesh;
 use crate::physics::state::PhysicsState;
 use crate::render::state::RenderState;
+use crate::render::system::ImguiPerformanceProfilerLine;
 use crate::runtime::state::RuntimeState;
 
+pub fn quad_color(color: [f32; 4]) -> [[f32; 4]; 4] {
+    [color, color, color, color]
+}
+
 #[system]
 #[write_component(Mesh)]
-pub fn runtime_load(world: &mut SubWorld, #[resource] runtime_state: &mut RuntimeState) {
+pub fn runtime_load(
+    cmd: &mut CommandBuffer,
+    world: &mut SubWorld,
+    #[resource] runtime_state: &mut RuntimeState,
+) {
     runtime_state.preload_meshes(PathBuf::from("./resources"));
+
+    let entity: Entity = cmd.push((
+        ImguiWindow {
+            // a window that does everything for the performance profiler
+            window: || {
+                imgui::Window::new(im_str!("Performance Profiler"))
+                    .size([400.0, 500.0], Condition::FirstUseEver)
+                    .position([50.0, 50.0], Condition::FirstUseEver)
+            },
+            func: |ui: &Ui, a: &ImguiPerformanceProfilerLine| {
+                ui.text(im_str!("Performance Graph"));
+
+                let draw_list = ui.get_window_draw_list();
+                let top_left = ui.cursor_screen_pos();
+                let region_size = ui.content_region_avail();
+
+                // Fill rect
+                let qcolor = quad_color([0.5, 0.5, 1.0, 0.1]);
+                draw_list.add_rect_filled_multicolor(
+                    top_left,
+                    [top_left[0] + (region_size[0] - region_size[0]/5.0), top_left[1] + region_size[1]],
+                    qcolor[0],
+                    qcolor[1],
+                    qcolor[2],
+                    qcolor[3],
+                );
+
+                let x_scale = (region_size[0] - region_size[0]/5.0) / 400.0;
+                let y_scale = region_size[1] / a.scale_max;
+                a.iter_data_from_head()
+                    .fold((0, 0.0f32), |accum, &fps_val| {
+                        let x1 = accum.0 as f32 * x_scale + top_left[0];
+                        let y1 = top_left[1] + region_size[1] - accum.1 * y_scale;
+                        let x2 = (accum.0 as f32 + 1.0) * x_scale + top_left[0];
+                        let y2 = top_left[1] + region_size[1] - fps_val * y_scale;
+                        let p1 = [x1, y1];
+                        let p2 = [x2, y2];
+                        draw_list
+                            .add_line(p1, p2, [1.0, 1.0, 0.0])
+                            .thickness(1.0)
+                            .build();
+                        (accum.0 + 1, fps_val)
+                    });
+
+                let text_x = (region_size[0] - region_size[0]/5.0 + 75.0);
+                let text_y = top_left[1] + region_size[1] - a.current_average_label().0 * y_scale;
+                draw_list.add_text([text_x, text_y], [1.0,1.0,0.0,1.0], format!("{} {:.0}",a.current_average_label().1, 1.0/a.current_average_label().0));
+            },
+        },
+        ImguiPerformanceProfilerLine::new("RenderFFS".to_string()),
+    ));
 }
 
 #[system]