From 4a2073b20c93036c9215d5ec33e3905246298ffc Mon Sep 17 00:00:00 2001
From: Jon Ringle <jringle@gridpoint.com>
Date: Mon, 18 Mar 2024 20:24:20 -0400
Subject: [PATCH] debug fps: log number of frames rendered in each second

---
 c_src/scenic/comms.c | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/c_src/scenic/comms.c b/c_src/scenic/comms.c
index 62d804f..5321b83 100644
--- a/c_src/scenic/comms.c
+++ b/c_src/scenic/comms.c
@@ -399,6 +399,14 @@ void receive_crash()
 //---------------------------------------------------------
 void render(driver_data_t* p_data)
 {
+  // Setup FPS calc
+  static int64_t start_real = 0;
+  static int64_t time_remaining = -1;
+  static clock_t render_fps = 0;
+  static uint32_t frames = 0;
+
+  clock_t begin_frame = clock();
+
   // prep the id to the root scene
   sid_t id;
   id.p_data = "_root_";
@@ -420,6 +428,27 @@ void render(driver_data_t* p_data)
   }
 
   device_end_render(p_data);
+  clock_t end_frame = clock();
+  clock_t delta_ticks = end_frame - begin_frame;
+
+  if (delta_ticks > 0) {
+    render_fps = CLOCKS_PER_SEC / delta_ticks;
+    // log_debug("render_fps (cpu time): %d", render_fps);
+  }
+
+  frames++;
+
+  int64_t end_real = monotonic_time();
+  int64_t delta_real = (end_real - start_real);
+  start_real = end_real;
+  time_remaining -= delta_real;
+
+  if (time_remaining <= 0) {
+    log_debug("real_fps: %d", frames);
+    start_real = monotonic_time();
+    time_remaining = 1000;
+    frames = 0;
+  }
 
   // all done
   send_ready();