From 89823ab617af3bb299b411aa707448872407ab83 Mon Sep 17 00:00:00 2001
From: Emil Ernerfeldt <emilernerfeldt@gmail.com>
Date: Wed, 29 Apr 2020 07:20:27 +0200
Subject: [PATCH] Print frame times for glium and wasm excluding painting

---
 emigui_glium/src/painter.rs |  1 +
 example_glium/src/main.rs   | 21 +++++++++++++++++++++
 example_wasm/src/lib.rs     | 18 +++++++++++-------
 3 files changed, 33 insertions(+), 7 deletions(-)

diff --git a/emigui_glium/src/painter.rs b/emigui_glium/src/painter.rs
index 6c7b77de..1d19148a 100644
--- a/emigui_glium/src/painter.rs
+++ b/emigui_glium/src/painter.rs
@@ -226,6 +226,7 @@ impl Painter {
         target.finish().unwrap();
     }
 
+    #[inline(never)] // Easier profiling
     fn paint_batch(
         &mut self,
         target: &mut Frame,
diff --git a/example_glium/src/main.rs b/example_glium/src/main.rs
index 67319af8..3e15fbcb 100644
--- a/example_glium/src/main.rs
+++ b/example_glium/src/main.rs
@@ -43,6 +43,8 @@ fn main() {
 
     let mut frame_start = Instant::now();
 
+    let mut frame_times = std::collections::VecDeque::new();
+
     let mut example_app = ExampleApp::default();
 
     while running {
@@ -73,6 +75,19 @@ fn main() {
             running = false;
         }
 
+        let mean_frame_time = if frame_times.is_empty() {
+            0.0
+        } else {
+            frame_times.iter().sum::<f64>() / (frame_times.len() as f64)
+        };
+        region.add(
+            label!(
+                "Frame time: {:.1} ms (excludes painting)",
+                1e3 * mean_frame_time
+            )
+            .text_style(TextStyle::Monospace),
+        );
+
         // TODO: Make it even simpler to show a window
 
         Window::new("Examples")
@@ -90,6 +105,12 @@ fn main() {
             });
 
         let (output, paint_batches) = emigui.end_frame();
+
+        frame_times.push_back((Instant::now() - emigui_start).as_secs_f64());
+        while frame_times.len() > 30 {
+            frame_times.pop_front();
+        }
+
         painter.paint_batches(&display, paint_batches, emigui.texture());
 
         let cursor = match output.cursor_icon {
diff --git a/example_wasm/src/lib.rs b/example_wasm/src/lib.rs
index 9aebdde6..31e9f3e0 100644
--- a/example_wasm/src/lib.rs
+++ b/example_wasm/src/lib.rs
@@ -73,8 +73,11 @@ impl State {
             self.frame_times.iter().sum::<f64>() / (self.frame_times.len() as f64)
         };
         region.add(
-            label!("Total CPU usage: {:.1} ms", 1e3 * mean_frame_time)
-                .text_style(TextStyle::Monospace),
+            label!(
+                "Frame time: {:.1} ms (excludes painting)",
+                1e3 * mean_frame_time
+            )
+            .text_style(TextStyle::Monospace),
         );
 
         // TODO: Make it even simpler to show a window
@@ -95,6 +98,12 @@ impl State {
 
         let bg_color = srgba(0, 0, 0, 0); // Use background css color.
         let (output, batches) = self.emigui.end_frame();
+
+        self.frame_times.push_back(now_sec() - everything_start);
+        while self.frame_times.len() > 30 {
+            self.frame_times.pop_front();
+        }
+
         self.webgl_painter.paint_batches(
             bg_color,
             batches,
@@ -102,11 +111,6 @@ impl State {
             pixels_per_point,
         )?;
 
-        self.frame_times.push_back(now_sec() - everything_start);
-        while self.frame_times.len() > 30 {
-            self.frame_times.pop_front();
-        }
-
         Ok(output)
     }
 }