Add basic timer query support.

Inaccurate on macOS.

Cargo.lock

@@ -169,6 +169,9 @@ dependencies = [
  "pathfinder_svg 0.1.0",
  "rayon 1.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "sdl2 0.32.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.84 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_derive 1.0.84 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde_json 1.0.37 (registry+https://github.com/rust-lang/crates.io-index)",
  "usvg 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -321,6 +324,11 @@ dependencies = [
  "adler32 1.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "itoa"
+version = "0.4.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "jemalloc-sys"
 version = "0.1.8"
@@ -798,6 +806,11 @@ dependencies = [
  "semver 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "ryu"
+version = "0.2.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "safe-transmute"
 version = "0.10.1"
@@ -867,6 +880,16 @@ dependencies = [
  "syn 0.15.24 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "serde_json"
+version = "1.0.37"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "itoa 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "ryu 0.2.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "serde 1.0.84 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "simplecss"
 version = "0.1.0"
@@ -1130,6 +1153,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum image 0.19.0 (registry+https://github.com/rust-lang/crates.io-index)" = "ebdff791af04e30089bde8ad2a632b86af433b40c04db8d70ad4b21487db7a6a"
 "checksum image 0.21.0 (registry+https://github.com/rust-lang/crates.io-index)" = "52fb0666a1273dac46f9725aa4859bcd5595fc3554cf3495051b4de8db745e7d"
 "checksum inflate 0.4.4 (registry+https://github.com/rust-lang/crates.io-index)" = "84c683bde2d8413b8f1be3e459c30e4817672b6e7a31d9212b0323154e76eba7"
+"checksum itoa 0.4.3 (registry+https://github.com/rust-lang/crates.io-index)" = "1306f3464951f30e30d12373d31c79fbd52d236e5e896fd92f96ec7babbbe60b"
 "checksum jemalloc-sys 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)" = "bfc62c8e50e381768ce8ee0428ee53741929f7ebd73e4d83f669bcf7693e00ae"
 "checksum jemallocator 0.1.9 (registry+https://github.com/rust-lang/crates.io-index)" = "9f0cd42ac65f758063fea55126b0148b1ce0a6354ff78e07a4d6806bc65c4ab3"
 "checksum jpeg-decoder 0.1.15 (registry+https://github.com/rust-lang/crates.io-index)" = "c8b7d43206b34b3f94ea9445174bda196e772049b9bddbc620c9d29b2d20110d"
@@ -1181,6 +1205,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum regex-syntax 0.6.4 (registry+https://github.com/rust-lang/crates.io-index)" = "4e47a2ed29da7a9e1960e1639e7a982e6edc6d49be308a3b02daf511504a16d1"
 "checksum roxmltree 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)" = "02660467d0c2da1b6276042501aee6e15ec5b8ff59423243f185b294cd53acf3"
 "checksum rustc_version 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)" = "138e3e0acb6c9fb258b19b67cb8abd63c00679d2851805ea151465464fe9030a"
+"checksum ryu 0.2.7 (registry+https://github.com/rust-lang/crates.io-index)" = "eb9e9b8cde282a9fe6a42dd4681319bfb63f121b8a8ee9439c6f4107e58a46f7"
 "checksum safe-transmute 0.10.1 (registry+https://github.com/rust-lang/crates.io-index)" = "9604873ffe1980bc1f179103704a65c8aca141c248d9e52b7af95ff10578166e"
 "checksum safemem 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)" = "8dca453248a96cb0749e36ccdfe2b0b4e54a61bfef89fb97ec621eb8e0a93dd9"
 "checksum scoped_threadpool 0.1.9 (registry+https://github.com/rust-lang/crates.io-index)" = "1d51f5df5af43ab3f1360b429fa5e0152ac5ce8c0bd6485cae490332e96846a8"
@@ -1191,6 +1216,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum semver-parser 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)" = "388a1df253eca08550bef6c72392cfe7c30914bf41df5269b68cbd6ff8f570a3"
 "checksum serde 1.0.84 (registry+https://github.com/rust-lang/crates.io-index)" = "0e732ed5a5592c17d961555e3b552985baf98d50ce418b7b655f31f6ba7eb1b7"
 "checksum serde_derive 1.0.84 (registry+https://github.com/rust-lang/crates.io-index)" = "b4d6115a3ca25c224e409185325afc16a0d5aaaabc15c42b09587d6f1ba39a5b"
+"checksum serde_json 1.0.37 (registry+https://github.com/rust-lang/crates.io-index)" = "4b90a9fbe1211e57d3e1c15670f1cb00802988fb23a1a4aad7a2b63544f1920e"
 "checksum simplecss 0.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "135685097a85a64067df36e28a243e94a94f76d829087ce0be34eeb014260c0e"
 "checksum siphasher 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)" = "0b8de496cf83d4ed58b6be86c3a275b8602f6ffe98d3024a869e124147a9a3ac"
 "checksum slab 0.4.1 (registry+https://github.com/rust-lang/crates.io-index)" = "5f9776d6b986f77b35c6cf846c11ad986ff128fe0b2b63a3628e3755e8d3102d"

demo3/src/debug_text.rs

@@ -31,7 +31,7 @@ const DEBUG_FONT_VERTEX_SIZE:  GLint = 8;
 const DEBUG_SOLID_VERTEX_SIZE: GLint = 4;
 
 const WINDOW_WIDTH: i16 = 400;
-const WINDOW_HEIGHT: i16 = LINE_HEIGHT * 2 + PADDING + 3;
+const WINDOW_HEIGHT: i16 = LINE_HEIGHT * 3 + PADDING + 3;
 const PADDING: i16 = 12;
 const FONT_ASCENT: i16 = 28;
 const LINE_HEIGHT: i16 = 42;
@@ -112,7 +112,10 @@ impl DebugRenderer {
         self.framebuffer_size = *window_size;
     }
 
-    pub fn draw(&self, prepare_time: Duration, tile_time: Duration) {
+    pub fn draw(&self,
+                prepare_time: Duration,
+                tile_time: Duration,
+                rendering_time: Option<Duration>) {
         let window_rect =
             Rect::new(Point2D::new(self.framebuffer_size.width as i16 - PADDING - WINDOW_WIDTH,
                                    self.framebuffer_size.height as i16 - PADDING - WINDOW_HEIGHT),
@@ -124,6 +127,12 @@ impl DebugRenderer {
         self.draw_text(&format!("Tiling: {:.3} ms", duration_ms(tile_time)),
                        &Point2D::new(window_rect.origin.x + PADDING,
                                      window_rect.origin.y + PADDING + FONT_ASCENT + LINE_HEIGHT));
+        if let Some(rendering_time) = rendering_time {
+            self.draw_text(&format!("Rendering: {:.3} ms", duration_ms(rendering_time)),
+                           &Point2D::new(
+                               window_rect.origin.x + PADDING,
+                               window_rect.origin.y + PADDING + FONT_ASCENT + LINE_HEIGHT * 2));
+        }
     }
 
     fn draw_solid_rect(&self, rect: &Rect<i16>, color: ColorU) {

demo3/src/device.rs

@@ -373,3 +373,59 @@ impl Texture {
         }
     }
 }
+
+pub struct TimerQuery {
+    gl_query: GLuint,
+}
+
+impl Drop for TimerQuery {
+    #[inline]
+    fn drop(&mut self) {
+        unsafe {
+            gl::DeleteQueries(1, &mut self.gl_query);
+        }
+    }
+}
+
+impl TimerQuery {
+    #[inline]
+    pub fn new() -> TimerQuery {
+        let mut query = TimerQuery { gl_query: 0 };
+        unsafe {
+            gl::GenQueries(1, &mut query.gl_query);
+        }
+        query
+    }
+
+    #[inline]
+    pub fn begin(&self) {
+        unsafe {
+            gl::BeginQuery(gl::TIME_ELAPSED, self.gl_query);
+        }
+    }
+
+    #[inline]
+    pub fn end(&self) {
+        unsafe {
+            gl::EndQuery(gl::TIME_ELAPSED);
+        }
+    }
+
+    #[inline]
+    pub fn is_available(&self) -> bool {
+        unsafe {
+            let mut result = 0;
+            gl::GetQueryObjectiv(self.gl_query, gl::QUERY_RESULT_AVAILABLE, &mut result);
+            result != gl::FALSE as GLint
+        }
+    }
+
+    #[inline]
+    pub fn get(&self) -> u64 {
+        unsafe {
+            let mut result = 0;
+            gl::GetQueryObjectui64v(self.gl_query, gl::QUERY_RESULT, &mut result);
+            result
+        }
+    }
+}

demo3/src/main.rs

@@ -13,7 +13,7 @@ extern crate serde_derive;
 
 use crate::debug_text::DebugRenderer;
 use crate::device::{Buffer, BufferTarget, BufferUploadMode, Framebuffer, Program, Texture};
-use crate::device::{Uniform, VertexAttr};
+use crate::device::{TimerQuery, Uniform, VertexAttr};
 use clap::{App, Arg};
 use euclid::{Point2D, Rect, Size2D};
 use gl::types::{GLfloat, GLint, GLuint};
@@ -31,8 +31,9 @@ use rayon::ThreadPoolBuilder;
 use sdl2::event::Event;
 use sdl2::keyboard::Keycode;
 use sdl2::video::GLProfile;
+use std::collections::VecDeque;
 use std::f32::consts::FRAC_PI_4;
-use std::time::Instant;
+use std::time::{Duration, Instant};
 use std::path::PathBuf;
 use usvg::{Options as UsvgOptions, Tree};
 
@@ -152,7 +153,8 @@ fn main() {
             gl::Clear(gl::COLOR_BUFFER_BIT);
             renderer.render_scene(&built_scene);
 
-            renderer.debug_renderer.draw(elapsed_prepare_time, elapsed_tile_time);
+            let rendering_time = renderer.shift_timer_query();
+            renderer.debug_renderer.draw(elapsed_prepare_time, elapsed_tile_time, rendering_time);
         }
 
         window.gl_swap_window();
@@ -311,6 +313,9 @@ struct Renderer {
     mask_framebuffer: Framebuffer,
     fill_colors_texture: Texture,
 
+    pending_timer_queries: VecDeque<TimerQuery>,
+    free_timer_queries: Vec<TimerQuery>,
+
     debug_renderer: DebugRenderer,
 
     main_framebuffer_size: Size2D<u32>,
@@ -355,6 +360,9 @@ impl Renderer {
             mask_framebuffer,
             fill_colors_texture,
 
+            pending_timer_queries: VecDeque::new(),
+            free_timer_queries: vec![],
+
             debug_renderer,
 
             main_framebuffer_size: *main_framebuffer_size,
@@ -362,6 +370,9 @@ impl Renderer {
     }
 
     fn render_scene(&mut self, built_scene: &BuiltScene) {
+        let timer_query = self.free_timer_queries.pop().unwrap_or_else(|| TimerQuery::new());
+        timer_query.begin();
+
         self.upload_shaders(&built_scene.shaders);
 
         self.upload_solid_tiles(&built_scene.solid_tiles);
@@ -372,6 +383,20 @@ impl Renderer {
             self.draw_batch_fills(batch);
             self.draw_batch_mask_tiles(batch);
         }
+
+        timer_query.end();
+        self.pending_timer_queries.push_back(timer_query);
+    }
+
+    fn shift_timer_query(&mut self) -> Option<Duration> {
+        let query = self.pending_timer_queries.front()?;
+        if !query.is_available() {
+            return None
+        }
+        let query = self.pending_timer_queries.pop_front().unwrap();
+        let result = Duration::from_nanos(query.get());
+        self.free_timer_queries.push(query);
+        Some(result)
     }
 
     fn upload_shaders(&mut self, shaders: &[ObjectShader]) {