From caff84753a1e3c8962afb4c387ea5ae95316f990 Mon Sep 17 00:00:00 2001
From: Lephenixnoir <sebastien.michelland@protonmail.com>
Date: Sat, 28 Oct 2023 19:58:13 +0200
Subject: [PATCH] azur: use flexible C++ functions for main loop

---
 azur/include/azur/azur.h       | 10 ++++----
 azur/include/azur/gl/shaders.h |  1 +
 azur/src/gl/init.cpp           | 43 ++++++++++++++++++++--------------
 3 files changed, 30 insertions(+), 24 deletions(-)

diff --git a/azur/include/azur/azur.h b/azur/include/azur/azur.h
index ca78650..44ef769 100644
--- a/azur/include/azur/azur.h
+++ b/azur/include/azur/azur.h
@@ -4,7 +4,7 @@
 
 #pragma once
 #include <azur/defs.h>
-AZUR_BEGIN_DECLS
+#include <functional>
 
 /* azur_init(): Initialize the engine's subsystems.
 
@@ -47,9 +47,9 @@ int azur_init(char const *title, int window_width, int window_height);
 
    The main loop stops whenever update() returns non-zero. */
 int azur_main_loop(
-   void (*render)(void), int render_fps,
-   int (*update)(void), int update_ups,
-   int flags);
+    std::function<void(void)> const &render, int render_fps,
+    std::function<int(void)> const &update, int update_ups,
+    int flags);
 
 /* Render loop is synchronized with display refresh. */
 #define AZUR_MAIN_LOOP_VSYNC       0x01
@@ -69,5 +69,3 @@ int azur_main_loop(
 SDL_Window *azur_sdl_window(void);
 
 #endif /* AZUR_TOOLKIT_SDL */
-
-AZUR_END_DECLS
diff --git a/azur/include/azur/gl/shaders.h b/azur/include/azur/gl/shaders.h
index 2a49dbd..79c963b 100644
--- a/azur/include/azur/gl/shaders.h
+++ b/azur/include/azur/gl/shaders.h
@@ -44,6 +44,7 @@
 #pragma once
 #include <azur/gl/gl.h>
 #include <glm/glm.hpp>
+#include <string.h>
 #include <string>
 #include <vector>
 #include <map>
diff --git a/azur/src/gl/init.cpp b/azur/src/gl/init.cpp
index ff1b378..77b7738 100644
--- a/azur/src/gl/init.cpp
+++ b/azur/src/gl/init.cpp
@@ -146,8 +146,8 @@ static double ml_time = 0.0;
 #include <emscripten/html5.h>
 
 struct params {
-    void (*render)(void);
-    int (*update)(void);
+    std::function<void(void)> const &render;
+    std::function<int(void)> const &update;
     bool tied, started;
 };
 
@@ -155,36 +155,43 @@ static void nop(void)
 {
 }
 
+static std::function<int(void)> const *update_int = nullptr;
+static void update_void(void)
+{
+    (*update_int)();
+}
+
 static EM_BOOL frame(double time, void *data)
 {
     struct params *params = static_cast<struct params *>(data);
 
     if(params->tied && params->started)
-        if(params->update) params->update();
+        params->update();
 
-    if(params->render) params->render();
+    params->render();
     params->started = true;
 
     return EM_TRUE;
 }
 
 int azur_main_loop(
-    void (*render)(void), int render_fps,
-    int (*update)(void), int update_ups,
+    std::function<void(void)> const &render, int render_fps,
+    std::function<int(void)> const &update, int update_ups,
     int flags)
 {
-    static struct params p;
-    p.render = render;
-    p.update = update;
-    p.tied = flags & AZUR_MAIN_LOOP_TIED;
-    p.started = false;
+    static struct params p = {
+        .render = render,
+        .update = update,
+        .tied = (flags & AZUR_MAIN_LOOP_TIED) != 0,
+        .started = false,
+    };
 
     (void)render_fps;
     emscripten_request_animation_frame_loop(frame, &p);
 
     if(!(flags & AZUR_MAIN_LOOP_TIED)) {
-        void (*update_v)(void) = (void (*)(void))update;
-        emscripten_set_main_loop(update_v, update_ups, true);
+        update_int = &update;
+        emscripten_set_main_loop(update_void, update_ups, true);
     }
     else {
         /* Even if no update is requested, we want emscripten to simulate an
@@ -231,8 +238,8 @@ static int filter_event(void *userdata, SDL_Event *event)
 }
 
 int azur_main_loop(
-    void (*render)(void), int render_fps,
-    int (*update)(void), int update_ups,
+    std::function<void(void)> const &render, int render_fps,
+    std::function<int(void)> const &update, int update_ups,
     int flags)
 {
     /* Register an event to wake up SDL_WaitEvent() on timer interrupts */
@@ -261,7 +268,7 @@ int azur_main_loop(
     while(1) {
         if(update_tick && !(flags & AZUR_MAIN_LOOP_TIED)) {
             update_tick = 0;
-            if(update && update()) break;
+            if(update()) break;
         }
 
         /* When vsync is enabled, render() is indirectly blocking so we just
@@ -271,9 +278,9 @@ int azur_main_loop(
 
             /* Tied renders and updates */
             if(started && (flags & AZUR_MAIN_LOOP_TIED)) {
-                if(update && update()) break;
+                if(update()) break;
             }
-            if(render) render();
+            render();
             started = true;
         }