add avg dt

imgui.ini

@@ -8,7 +8,7 @@ Size=1152,1414
 
 [Window][main]
 Pos=0,0
-Size=1775,680
+Size=1777,680
 
 [Window][Hex View]
 Pos=91,62

src/app_state.h

@@ -1,9 +1,18 @@
+struct Delta_Time_Accum {
+  f32 *base;
+  u16 count;
+  u16 max;
+  u16 start;
+};
+
 struct App_State {
   Window_Data win_data;
   User_Input user_input;
   RNTuple_Info rntinfo;
   Viewer_Settings vsettings;
 
+  Delta_Time_Accum delta_time_accum;
+
   FILE *inspected_file;
   u8   *inspected_fmem;
   u64   inspected_file_size;

src/mainloop.cpp

@@ -1,3 +1,37 @@
+internal 
+void glfw_error_callback(i32 error, const char *description) {
+	fprintf(stderr, "GLFW error %d: %s\n", error, description);
+}
+
+internal 
+GLFWwindow *init_glfw(i32 desired_win_width, i32 desired_win_height)
+{
+	glfwSetErrorCallback(glfw_error_callback);
+	glfwInit();
+	glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 4);
+	// glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
+	glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
+	glfwWindowHint(GLFW_DOUBLEBUFFER, GLFW_TRUE);
+	glfwWindowHint(GLFW_RESIZABLE, GLFW_TRUE);
+	glfwWindowHint(GLFW_DECORATED, GLFW_TRUE);
+	glfwWindowHint(GLFW_DEPTH_BITS, 32);
+#ifndef NDEBUG
+	glfwWindowHint(GLFW_OPENGL_DEBUG_CONTEXT, true);
+#endif
+
+	GLFWwindow *window = glfwCreateWindow(
+			desired_win_width, desired_win_height,
+			"RNTuple Viewer",
+			nullptr,
+			nullptr
+			);
+
+	glfwMakeContextCurrent(window);
+	//glfwSetFramebufferSizeCallback(window, resize_keep_ratio);
+
+	return window;
+}
+
 internal
 void monitor_key(GLFWwindow *window, u16 *key_state, i32 glfw_key, Input_Key haru_key) {
 	u16& state = key_state[haru_key];
@@ -25,15 +59,19 @@ void monitor_mouse_btn(GLFWwindow *window, u16 *mouse_btn_state, i32 glfw_btn, M
 internal 
 void run_main_loop(GLFWwindow *window, Arena *arena, App_State &app)
 {
-  f32 delta_time;
+  f32 delta_time_ms;
   chr::time_point last_saved_time = chr::high_resolution_clock::now();
 
+  app.delta_time_accum.max = 100;
+  app.delta_time_accum.base = arena_push_array<f32>(arena, app.delta_time_accum.max);
+  
   b8 running = true;
   while (running) {
 		chr::time_point frame_start = chr::high_resolution_clock::now();
 		u64 time_since_prev_frame_us = chr::duration_cast<chr::microseconds>(frame_start - last_saved_time).count();
-		delta_time = time_since_prev_frame_us * 0.000'001f;
+		delta_time_ms = time_since_prev_frame_us * 0.001f;
 		last_saved_time = frame_start;
+		accum_dt_ms(app.delta_time_accum, delta_time_ms);
 
 		glfwPollEvents();
 
@@ -92,7 +130,7 @@ void run_main_loop(GLFWwindow *window, Arena *arena, App_State &app)
 			monitor_mouse_btn(window, mouse_btn_state, GLFW_MOUSE_BUTTON_RIGHT, MOUSE_BTN_RIGHT);
 		}
 
-		update_and_render(arena, app, delta_time);
+		update_and_render(arena, app, delta_time_ms);
 
 		ImGui::Render();
 		ImGui_ImplOpenGL3_RenderDrawData(ImGui::GetDrawData());

src/render.cpp

@@ -1,11 +1,35 @@
+internal
+void accum_dt_ms(Delta_Time_Accum &accum, f32 dt)
+{
+	if (accum.count < accum.max) {
+		assert(accum.start == 0);
+		accum.base[accum.count++] = dt;
+	} else {
+		accum.base[accum.start++] = dt;
+		if (accum.start == accum.max)
+			accum.start = 0;
+	}
+}
+
+internal
+f32 calc_avg_dt_ms(const Delta_Time_Accum &accum)
+{
+	f32 res = 0;
+	for (u16 idx = 0; idx < accum.count; ++idx)
+		res += accum.base[idx];
+	if (accum.count) res /= accum.count;
+	return res;
+}
+
 internal
 u32 mem_edit_bg_color_fn(const u8 *data, u64 off, const void *user_data)
 {
   const App_State *app = reinterpret_cast<const App_State *>(user_data);
+  const RNTuple_Info &rinfo = app->rntinfo;
 
 #define COL(c) (ImColor((c)[0], (c)[1], (c)[2]))
-  if (app->rntinfo.header.start <= off && off <= app->rntinfo.header.end()) return COL(app->vsettings.col_header);
+  if (rinfo.header.start <= off && off <= rinfo.header.end()) return COL(app->vsettings.col_header);
-  if (app->rntinfo.footer.start <= off && off <= app->rntinfo.footer.end()) return COL(app->vsettings.col_footer);
+  if (rinfo.footer.start <= off && off <= rinfo.footer.end()) return COL(app->vsettings.col_footer);
 #undef COL
 
   return IM_COL32(0, 0, 0, 0);
@@ -23,6 +47,7 @@ MemoryEditor make_memory_editor(const App_State &app)
   return mem_edit;
 }
 
+internal
 Viewer_Settings make_viewer_settings()
 {
   Viewer_Settings settings {};
@@ -34,9 +59,9 @@ Viewer_Settings make_viewer_settings()
 }
 
 internal
-void update_and_render(Arena *arena, App_State &app, f32 delta_time)
+void update_and_render(Arena *arena, App_State &app, f32 delta_time_ms)
 {
-  (void)delta_time;
+  (void)delta_time_ms;
   
   ImGui::SetNextWindowPos({ 0, 0 });
   ImGui::SetNextWindowSize({ (f32)app.win_data.width, (f32)app.win_data.height });
@@ -55,10 +80,28 @@ void update_and_render(Arena *arena, App_State &app, f32 delta_time)
   
   const auto main_win_flags = ImGuiWindowFlags_NoResize | ImGuiWindowFlags_NoTitleBar | ImGuiWindowFlags_NoDecoration;
   if (ImGui::Begin("main", nullptr, main_win_flags)) {
-    ImGui::Text("Inspecting RNTuple '%s' (%s)", app.ntpl_name, 
+        
-                (const char *)rntuple_description(scratch.arena, app.rntinfo.anchor));
+    String8 ntpl_desc = rntuple_description(scratch.arena, app.rntinfo.anchor);
+    ImGui::Text("Inspecting RNTuple '%s' (%s)", app.ntpl_name, ntpl_desc.c());
+
+    // Draw avg delta time
+    {
+      ImGui::SameLine();
+
+      f32 avg_dt = calc_avg_dt_ms(app.delta_time_accum);
+      String8 dt_txt = push_str8f(scratch.arena, "avg dt: %.1f", avg_dt);
+
+      f32 pos_x = (ImGui::GetCursorPosX() + ImGui::GetColumnWidth() - ImGui::CalcTextSize(dt_txt.c()).x 
+        - ImGui::GetScrollX() - 2 * ImGui::GetStyle().ItemSpacing.x);
+      if (pos_x > ImGui::GetCursorPosX())
+        ImGui::SetCursorPosX(pos_x);
+
+      ImGui::Text("%s", dt_txt.c());
+    }
+
     ImGui::Separator();
 
+    // Draw main content
     {
       static MemoryEditor mem_edit = make_memory_editor(app);
       ImGui::BeginTable("Hex View", 2);

src/rntviewer.cpp

@@ -55,40 +55,6 @@ b8 init_imgui(GLFWwindow* window) {
 	return true;
 }
 
-internal 
-void glfw_error_callback(i32 error, const char *description) {
-	fprintf(stderr, "GLFW error %d: %s\n", error, description);
-}
-
-internal 
-GLFWwindow* init_glfw(i32 desired_win_width, i32 desired_win_height)
-{
-	glfwSetErrorCallback(glfw_error_callback);
-	glfwInit();
-	glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 4);
-	// glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
-	glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
-	glfwWindowHint(GLFW_DOUBLEBUFFER, GLFW_TRUE);
-	glfwWindowHint(GLFW_RESIZABLE, GLFW_TRUE);
-	glfwWindowHint(GLFW_DECORATED, GLFW_TRUE);
-	glfwWindowHint(GLFW_DEPTH_BITS, 32);
-#ifndef NDEBUG
-	glfwWindowHint(GLFW_OPENGL_DEBUG_CONTEXT, true);
-#endif
-
-	GLFWwindow *window = glfwCreateWindow(
-			desired_win_width, desired_win_height,
-			"RNTuple Viewer",
-			nullptr,
-			nullptr
-			);
-
-	glfwMakeContextCurrent(window);
-	//glfwSetFramebufferSizeCallback(window, resize_keep_ratio);
-
-	return window;
-}
-
 internal
 void app_cleanup(App_State &app)
 {

src/str.h

@@ -2,9 +2,7 @@ struct String8 {
   u8* str;
   u64 size;
 
-  operator const char *() const {
+  const char *c() const { return reinterpret_cast<const char *>(str); }
-    return (const char *)str;
-  }
 };
 
 #define str8(s) String8((u8*)(s), sizeof(s) - 1)