From c26ddeef4dd231e7fb6a58d2c421623b4c1c3b57 Mon Sep 17 00:00:00 2001
From: Cyberarm <matthewlikesrobots@gmail.com>
Date: Thu, 20 Apr 2023 16:08:59 -0500
Subject: [PATCH] Refactored CyberarmEngine::Stats to track data for last N
 frames

---
 .../opengl/renderer/renderer.rb               | 13 ++-
 lib/cyberarm_engine/stats.rb                  | 91 +++++++++++++++++--
 lib/cyberarm_engine/ui/elements/container.rb  |  4 +-
 lib/cyberarm_engine/ui/gui_state.rb           |  7 ++
 lib/cyberarm_engine/window.rb                 | 25 ++++-
 5 files changed, 123 insertions(+), 17 deletions(-)

diff --git a/lib/cyberarm_engine/opengl/renderer/renderer.rb b/lib/cyberarm_engine/opengl/renderer/renderer.rb
index 3e58575..1575d51 100644
--- a/lib/cyberarm_engine/opengl/renderer/renderer.rb
+++ b/lib/cyberarm_engine/opengl/renderer/renderer.rb
@@ -8,8 +8,19 @@ module CyberarmEngine
     end
 
     def draw(camera, lights, entities)
+      Stats.frame.start_timing(:opengl_renderer)
+
+      Stats.frame.start_timing(:opengl_model_renderer)
       @opengl_renderer.render(camera, lights, entities)
-      @bounding_box_renderer.render(entities) if @show_bounding_boxes
+      Stats.frame.end_timing(:opengl_model_renderer)
+
+      if @show_bounding_boxes
+        Stats.frame.start_timing(:opengl_boundingbox_renderer)
+        @bounding_box_renderer.render(entities)
+        Stats.frame.end_timing(:opengl_boundingbox_renderer)
+      end
+
+      Stats.frame.end_timing(:opengl_renderer)
     end
 
     def canvas_size_changed
diff --git a/lib/cyberarm_engine/stats.rb b/lib/cyberarm_engine/stats.rb
index 459c296..3dbb8d7 100644
--- a/lib/cyberarm_engine/stats.rb
+++ b/lib/cyberarm_engine/stats.rb
@@ -1,20 +1,91 @@
 module CyberarmEngine
   class Stats
-    @@hash = {
-      gui_recalculations_last_frame: 0
-    }
+    @frames = []
+    @frame_index = -1
+    @max_frame_history = 1024
 
-    def self.get(key)
-      @@hash.dig(key)
+    def self.new_frame
+      if @frames.size < @max_frame_history
+        @frames << Frame.new
+      else
+        @frames[@frame_index] = Frame.new
+      end
     end
 
-    def self.increment(key, n)
-      @@hash[key] += n
+    def self.frame
+      @frames[@frame_index]
     end
 
-    def self.clear
-      @@hash.each do |key, _value|
-        @@hash[key] = 0
+    def self.end_frame
+      frame&.complete
+
+      @frame_index += 1
+      @frame_index %= @max_frame_history
+    end
+
+    def self.frames
+      if @frames.size < @max_frame_history
+        @frames
+      else
+        @frames.rotate(@frame_index - (@max_frame_history - (@frames.size - 1)))
+      end
+    end
+
+    def self.frame_index
+      @frame_index
+    end
+
+    def self.max_frame_history
+      @max_frame_history
+    end
+
+    class Frame
+      Timing = Struct.new(:start_time, :end_time, :duration)
+
+      attr_reader :frame_timing, :counters, :timings
+      def initialize
+        @frame_timing = Timing.new(start_time: Gosu.milliseconds, end_time: -1, duration: -1)
+
+        @counters = {
+          gui_recalculations: 0
+        }
+
+        @timings = {}
+      end
+
+      def increment(key, number = 1)
+        @counters[key] ||= 0
+        @counters[key] += number
+      end
+
+      def start_timing(key)
+        raise "key must be a symbol!" unless key.is_a?(Symbol)
+        warn "Only one timing per key per frame. (Timing for #{key.inspect} already exists!)" if @timings[key]
+
+        @timings[key] = Timing.new(start_time: Gosu.milliseconds, end_time: -1, duration: -1)
+      end
+
+      def end_timing(key)
+        timing = @timings[key]
+
+        warn "Timing #{key.inspect} already ended!" if timing.end_time != -1
+
+        timing.end_time = Gosu.milliseconds
+        timing.duration = timing.end_time - timing.start_time
+      end
+
+      def complete
+        @frame_timing.end_time = Gosu.milliseconds
+        @frame_timing.duration = @frame_timing.end_time - @frame_timing.start_time
+
+        # Lock data structures
+        @frame_timing.freeze
+        @counters.freeze
+        @timings.freeze
+      end
+
+      def complete?
+        @frame_timing.duration != -1
       end
     end
   end
diff --git a/lib/cyberarm_engine/ui/elements/container.rb b/lib/cyberarm_engine/ui/elements/container.rb
index c06bdfa..11603f5 100644
--- a/lib/cyberarm_engine/ui/elements/container.rb
+++ b/lib/cyberarm_engine/ui/elements/container.rb
@@ -118,7 +118,7 @@ module CyberarmEngine
 
         return unless visible?
 
-        Stats.increment(:gui_recalculations_last_frame, 1)
+        Stats.frame.increment(:gui_recalculations)
 
         stylize
 
@@ -176,7 +176,7 @@ module CyberarmEngine
           child.recalculate
           child.reposition # TODO: Implement top,bottom,left,center, and right positioning
 
-          Stats.increment(:gui_recalculations_last_frame, 1)
+          Stats.frame.increment(:gui_recalculations)
 
           child.element_visible = child.x >= @x - child.width && child.x <= @x + width &&
                                   child.y >= @y - child.height && child.y <= @y + height
diff --git a/lib/cyberarm_engine/ui/gui_state.rb b/lib/cyberarm_engine/ui/gui_state.rb
index d4455f8..6802f43 100644
--- a/lib/cyberarm_engine/ui/gui_state.rb
+++ b/lib/cyberarm_engine/ui/gui_state.rb
@@ -79,16 +79,23 @@ module CyberarmEngine
 
     def update
       if @pending_recalculate_request
+        Stats.frame.start_timing(:gui_recalculate)
         @root_container.recalculate
         @root_container.recalculate
         @root_container.recalculate
 
         @pending_recalculate_request = false
+
+        Stats.frame.end_timing(:gui_recalculate)
       end
 
+      Stats.frame.start_timing(:gui_element_recalculate_requests)
+
       @pending_element_recalculate_requests.each(&:recalculate)
       @pending_element_recalculate_requests.clear
 
+      Stats.frame.end_timing(:gui_element_recalculate_requests)
+
       if @pending_focus_request
         @pending_focus_request = false
 
diff --git a/lib/cyberarm_engine/window.rb b/lib/cyberarm_engine/window.rb
index f76833e..ab3cadd 100644
--- a/lib/cyberarm_engine/window.rb
+++ b/lib/cyberarm_engine/window.rb
@@ -8,14 +8,14 @@ module CyberarmEngine
 
     attr_accessor :show_cursor
     attr_writer :exit_on_opengl_error
-    attr_reader :last_frame_time, :states
+    attr_reader :last_frame_time, :delta_time, :states
 
     def self.now
       Gosu.milliseconds
     end
 
     def self.dt
-      instance.last_frame_time / 1000.0
+      instance.dt
     end
 
     def self.instance=(window)
@@ -37,6 +37,7 @@ module CyberarmEngine
 
       @last_frame_time = Gosu.milliseconds - 1
       @current_frame_time = Gosu.milliseconds
+      @delta_time = @last_frame_time
       self.caption = "CyberarmEngine #{CyberarmEngine::VERSION} #{Gosu.user_languages.join(', ')}"
 
       @states = []
@@ -50,16 +51,32 @@ module CyberarmEngine
     end
 
     def draw
+      Stats.frame.start_timing(:draw)
+
       current_state&.draw
+
+      Stats.frame.end_timing(:draw)
+      Stats.frame.start_timing(:interframe_sleep)
     end
 
     def update
-      Stats.clear
+      # Gosu calls update() then (optionally) draw(),
+      # so always end last frame and start next frame when update() is called.
+      Stats.frame&.end_timing(:interframe_sleep)
+      Stats.end_frame
 
-      current_state&.update
+      Stats.new_frame
+
+      @delta_time = (Gosu.milliseconds - @current_frame_time) * 0.001
 
       @last_frame_time = Gosu.milliseconds - @current_frame_time
       @current_frame_time = Gosu.milliseconds
+
+      Stats.frame.start_timing(:update)
+      current_state&.update
+      Stats.frame.end_timing(:update)
+
+      Stats.frame.start_timing(:interframe_sleep) unless needs_redraw?
     end
 
     def needs_cursor?