Use new struct AnimationTimer instead of Instant to prevent random test failures. (#7685)

examples/features/src/ray_cube_compute/mod.rs

@@ -1,4 +1,4 @@
-use std::{borrow::Cow, future::Future, iter, mem, pin::Pin, task, time::Instant};
+use std::{borrow::Cow, future::Future, iter, mem, pin::Pin, task};
 
 use bytemuck::{Pod, Zeroable};
 use glam::{Affine3A, Mat4, Quat, Vec3};
@@ -6,6 +6,8 @@ use wgpu::util::DeviceExt;
 
 use wgpu::StoreOp;
 
+use crate::utils;
+
 // from cube
 #[repr(C)]
 #[derive(Clone, Copy, Pod, Zeroable)]
@@ -135,7 +137,7 @@ struct Example {
     compute_bind_group: wgpu::BindGroup,
     blit_pipeline: wgpu::RenderPipeline,
     blit_bind_group: wgpu::BindGroup,
-    start_inst: Instant,
+    animation_timer: utils::AnimationTimer,
 }
 
 impl crate::framework::Example for Example {
@@ -392,8 +394,6 @@ impl crate::framework::Example for Example {
 
         queue.submit(Some(encoder.finish()));
 
-        let start_inst = Instant::now();
-
         Example {
             rt_target,
             rt_view,
@@ -406,7 +406,7 @@ impl crate::framework::Example for Example {
             compute_bind_group,
             blit_pipeline,
             blit_bind_group,
-            start_inst,
+            animation_timer: utils::AnimationTimer::default(),
         }
     }
 
@@ -425,7 +425,7 @@ impl crate::framework::Example for Example {
     fn render(&mut self, view: &wgpu::TextureView, device: &wgpu::Device, queue: &wgpu::Queue) {
         device.push_error_scope(wgpu::ErrorFilter::Validation);
 
-        let anim_time = self.start_inst.elapsed().as_secs_f64() as f32;
+        let anim_time = self.animation_timer.time();
 
         self.tlas_package[0].as_mut().unwrap().transform =
             affine_to_rows(&Affine3A::from_rotation_translation(

examples/features/src/ray_cube_fragment/mod.rs

@@ -1,7 +1,8 @@
+use crate::utils;
 use bytemuck::{Pod, Zeroable};
 use glam::{Mat4, Quat, Vec3};
 use std::ops::IndexMut;
-use std::{borrow::Cow, future::Future, iter, mem, pin::Pin, task, time::Instant};
+use std::{borrow::Cow, future::Future, iter, mem, pin::Pin, task};
 use wgpu::util::DeviceExt;
 
 // from cube
@@ -101,7 +102,7 @@ struct Example {
     tlas_package: wgpu::TlasPackage,
     pipeline: wgpu::RenderPipeline,
     bind_group: wgpu::BindGroup,
-    start_inst: Instant,
+    animation_timer: utils::AnimationTimer,
 }
 
 impl crate::framework::Example for Example {
@@ -264,8 +265,6 @@ impl crate::framework::Example for Example {
 
         queue.submit(Some(encoder.finish()));
 
-        let start_inst = Instant::now();
-
         Example {
             uniforms,
             uniform_buf,
@@ -273,7 +272,7 @@ impl crate::framework::Example for Example {
             tlas_package,
             pipeline,
             bind_group,
-            start_inst,
+            animation_timer: utils::AnimationTimer::default(),
         }
     }
 
@@ -306,7 +305,7 @@ impl crate::framework::Example for Example {
 
             let side_count = 8;
 
-            let anim_time = self.start_inst.elapsed().as_secs_f64() as f32;
+            let anim_time = self.animation_timer.time();
 
             for x in 0..side_count {
                 for y in 0..side_count {

examples/features/src/ray_cube_normals/mod.rs

@@ -1,9 +1,10 @@
-use std::{borrow::Cow, future::Future, iter, mem, pin::Pin, task, time::Instant};
+use std::{borrow::Cow, future::Future, iter, mem, pin::Pin, task};
 
 use bytemuck::{Pod, Zeroable};
 use glam::{Affine3A, Mat4, Quat, Vec3};
 use wgpu::util::DeviceExt;
 
+use crate::utils;
 use wgpu::StoreOp;
 
 // from cube
@@ -125,7 +126,7 @@ struct Example {
     compute_bind_group: wgpu::BindGroup,
     blit_pipeline: wgpu::RenderPipeline,
     blit_bind_group: wgpu::BindGroup,
-    start_inst: Instant,
+    animation_timer: utils::AnimationTimer,
 }
 
 impl crate::framework::Example for Example {
@@ -385,8 +386,6 @@ impl crate::framework::Example for Example {
 
         queue.submit(Some(encoder.finish()));
 
-        let start_inst = Instant::now();
-
         Example {
             rt_target,
             tlas_package,
@@ -394,7 +393,7 @@ impl crate::framework::Example for Example {
             compute_bind_group,
             blit_pipeline,
             blit_bind_group,
-            start_inst,
+            animation_timer: utils::AnimationTimer::default(),
         }
     }
 
@@ -413,7 +412,7 @@ impl crate::framework::Example for Example {
     fn render(&mut self, view: &wgpu::TextureView, device: &wgpu::Device, queue: &wgpu::Queue) {
         device.push_error_scope(wgpu::ErrorFilter::Validation);
 
-        let anim_time = self.start_inst.elapsed().as_secs_f64() as f32;
+        let anim_time = self.animation_timer.time();
 
         self.tlas_package[0].as_mut().unwrap().transform =
             affine_to_rows(&Affine3A::from_rotation_translation(

examples/features/src/ray_scene/mod.rs

@@ -1,8 +1,9 @@
+use crate::utils;
 use bytemuck::{Pod, Zeroable};
 use glam::{Mat4, Quat, Vec3};
 use std::f32::consts::PI;
 use std::ops::IndexMut;
-use std::{borrow::Cow, future::Future, iter, mem, ops::Range, pin::Pin, task, time::Instant};
+use std::{borrow::Cow, future::Future, iter, mem, ops::Range, pin::Pin, task};
 use wgpu::util::DeviceExt;
 
 // from cube
@@ -310,8 +311,8 @@ struct Example {
     tlas_package: wgpu::TlasPackage,
     pipeline: wgpu::RenderPipeline,
     bind_group: wgpu::BindGroup,
-    start_inst: Instant,
     scene_components: SceneComponents,
+    animation_timer: utils::AnimationTimer,
 }
 
 impl crate::framework::Example for Example {
@@ -434,16 +435,14 @@ impl crate::framework::Example for Example {
             ],
         });
 
-        let start_inst = Instant::now();
-
         Example {
             uniforms,
             uniform_buf,
             tlas_package,
             pipeline,
             bind_group,
-            start_inst,
             scene_components,
+            animation_timer: utils::AnimationTimer::default(),
         }
     }
 
@@ -476,7 +475,7 @@ impl crate::framework::Example for Example {
 
             let side_count = 2;
 
-            let anim_time = self.start_inst.elapsed().as_secs_f64() as f32;
+            let anim_time = self.animation_timer.time();
 
             for x in 0..side_count {
                 for y in 0..side_count {

examples/features/src/ray_shadows/mod.rs

@@ -1,10 +1,12 @@
-use std::{borrow::Cow, future::Future, iter, mem, pin::Pin, task, time::Instant};
+use std::{borrow::Cow, future::Future, iter, mem, pin::Pin, task};
 
 use bytemuck::{Pod, Zeroable};
 use glam::{Mat4, Vec3};
 use wgpu::util::DeviceExt;
 use wgpu::{vertex_attr_array, IndexFormat, VertexBufferLayout};
 
+use crate::utils;
+
 // from cube
 #[repr(C)]
 #[derive(Clone, Copy, Pod, Zeroable)]
@@ -79,7 +81,7 @@ struct Example {
     index_buf: wgpu::Buffer,
     pipeline: wgpu::RenderPipeline,
     bind_group: wgpu::BindGroup,
-    start_inst: Instant,
+    animation_timer: utils::AnimationTimer,
 }
 
 const CAM_LOOK_AT: Vec3 = Vec3::new(0.0, 1.0, -1.5);
@@ -290,7 +292,7 @@ impl crate::framework::Example for Example {
             ],
         });
 
-        let start_inst = Instant::now();
+        let animation_timer = utils::AnimationTimer::default();
 
         Example {
             uniforms,
@@ -299,7 +301,7 @@ impl crate::framework::Example for Example {
             index_buf,
             pipeline,
             bind_group,
-            start_inst,
+            animation_timer,
         }
     }
 
@@ -322,10 +324,9 @@ impl crate::framework::Example for Example {
         const LIGHT_DISTANCE: f32 = 5.0;
         const TIME_SCALE: f32 = -0.2;
         const INITIAL_TIME: f32 = 1.0;
-        let cos = (self.start_inst.elapsed().as_secs_f32() * TIME_SCALE + INITIAL_TIME).cos()
-            * LIGHT_DISTANCE;
-        let sin = (self.start_inst.elapsed().as_secs_f32() * TIME_SCALE + INITIAL_TIME).sin()
-            * LIGHT_DISTANCE;
+        let time = self.animation_timer.time();
+        let cos = (time * TIME_SCALE + INITIAL_TIME).cos() * LIGHT_DISTANCE;
+        let sin = (time * TIME_SCALE + INITIAL_TIME).sin() * LIGHT_DISTANCE;
 
         let mut encoder =
             device.create_command_encoder(&wgpu::CommandEncoderDescriptor { label: None });

examples/features/src/ray_traced_triangle/mod.rs

@@ -1,6 +1,5 @@
 use glam::{Mat4, Vec3};
 use std::mem;
-use std::time::Instant;
 use wgpu::util::{BufferInitDescriptor, DeviceExt};
 use wgpu::{include_wgsl, BufferUsages, IndexFormat, SamplerDescriptor};
 use wgpu::{
@@ -9,6 +8,8 @@ use wgpu::{
     CreateBlasDescriptor, CreateTlasDescriptor, TlasInstance, TlasPackage,
 };
 
+use crate::utils;
+
 struct Example {
     tlas_package: TlasPackage,
     compute_pipeline: wgpu::ComputePipeline,
@@ -16,7 +17,7 @@ struct Example {
     bind_group: wgpu::BindGroup,
     blit_bind_group: wgpu::BindGroup,
     storage_texture: wgpu::Texture,
-    start: Instant,
+    animation_timer: utils::AnimationTimer,
 }
 
 #[repr(C)]
@@ -360,7 +361,7 @@ impl crate::framework::Example for Example {
             bind_group,
             blit_bind_group,
             storage_texture: storage_tex,
-            start: Instant::now(),
+            animation_timer: utils::AnimationTimer::default(),
         }
     }
 
@@ -376,7 +377,7 @@ impl crate::framework::Example for Example {
 
     fn render(&mut self, view: &wgpu::TextureView, device: &wgpu::Device, queue: &wgpu::Queue) {
         self.tlas_package[0].as_mut().unwrap().transform =
-            Mat4::from_rotation_y(self.start.elapsed().as_secs_f32())
+            Mat4::from_rotation_y(self.animation_timer.time())
                 .transpose()
                 .to_cols_array()[..12]
                 .try_into()

examples/features/src/utils.rs

@@ -1,5 +1,6 @@
 #[cfg(not(target_arch = "wasm32"))]
 use std::io::Write;
+use std::time::Instant;
 #[cfg(target_arch = "wasm32")]
 use wasm_bindgen::prelude::*;
 
@@ -264,3 +265,23 @@ pub(crate) async fn get_adapter_with_capabilities_or_from_env(
     );
     adapter
 }
+
+/// A custom timer that only starts counting after the first call to get its time value.
+/// Useful because some examples have animations that would otherwise get started at initialization
+/// leading to random CI fails.
+#[derive(Default)]
+pub struct AnimationTimer {
+    start_time: Option<Instant>,
+}
+
+impl AnimationTimer {
+    pub fn time(&mut self) -> f32 {
+        match self.start_time {
+            None => {
+                self.start_time = Some(Instant::now());
+                0.0
+            }
+            Some(ref instant) => instant.elapsed().as_secs_f32(),
+        }
+    }
+}