POC coroutine impl

nob.c

@@ -75,7 +75,7 @@ bool build_plug_cxx(bool force, Nob_Cmd *cmd, const char *source_path, const cha
 
     if (force || rebuild_is_needed) {
         cxx(cmd);
-        nob_cmd_append(cmd, "-fPIC", "-shared", "-Wl,--no-undefined");
+        nob_cmd_append(cmd, "-fPIC", "-shared", "-Wl,--no-undefined", "-fcoroutines", "-std=c++20");
         nob_cmd_append(cmd, "-o", output_path);
         nob_cmd_append(cmd, source_path);
         libs(cmd);
@@ -129,6 +129,7 @@ int main(int argc, char **argv)
     if (!build_plug_c(force, &cmd, PLUGS_DIR"squares/plug.c", BUILD_DIR"libsquare.so")) return 1;
     if (!build_plug_c(force, &cmd, PLUGS_DIR"bezier/plug.c", BUILD_DIR"libbezier.so")) return 1;
     if (!build_plug_cxx(force, &cmd, PLUGS_DIR"cpp/plug.cpp", BUILD_DIR"libcpp.so")) return 1;
+    if (!build_plug_cxx(force, &cmd, PLUGS_DIR"cpp_async/plug.cpp", BUILD_DIR"libcpp_async.so")) return 1;
     {
         const char *output_path = BUILD_DIR"libc3";
         const char *source_paths[] = {

plugs/cpp_async/plug.cpp

@@ -0,0 +1,178 @@
+#include <assert.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <coroutine>
+#include <vector>
+#include <memory>
+
+#include <raylib.h>
+#include <raymath.h>
+#include "env.h"
+#include "interpolators.h"
+#include "plug.h"
+
+#define SQUARE_SIZE 20
+
+#define AWAIT(task) do { \
+    auto __t = (task); \
+    while (!__t.done()) { __t(); co_yield 0; } \
+  } while (0)
+
+struct promise;
+
+struct Task : std::coroutine_handle<promise>
+{
+    using promise_type = ::promise;
+};
+
+struct promise
+{
+    Task get_return_object() { return {Task::from_promise(*this)}; }
+    std::suspend_always initial_suspend() noexcept { return {}; }
+    std::suspend_always final_suspend() noexcept { return {}; }
+    void return_void() {}
+    void unhandled_exception() {}
+    std::suspend_always yield_value(int /* dummy */)
+    {
+        return {};
+    }
+};
+
+#define FONT_SIZE 68
+
+typedef struct {
+    size_t size;
+    Task task;
+    Vector2 position1;
+    Vector2 position2;
+    Vector2 position3;
+} Plug;
+
+static Plug *p;
+
+static void load_assets(void)
+{
+}
+
+static void unload_assets(void)
+{
+}
+
+static Task move(Vector2 &position, Vector2 direction, size_t n)
+{
+  for (size_t i = 0; i < n; ++i)
+  {
+    position = Vector2Add(position, direction);
+    co_yield 0;
+  }
+}
+
+static Task move2(Vector2 &position, Vector2 direction1, size_t n1, Vector2 direction2, size_t n2)
+{
+  AWAIT(move(position, direction1, n1));
+  printf("move 1 done\n");
+  AWAIT(move(position, direction2, n2));
+}
+
+static Task combine(std::vector<Task> tasks)
+{
+  while (true)
+  {
+    bool ran = false;
+    for (auto &task : tasks)
+    {
+      if (!task.done())
+      {
+        ran = true;
+        task();
+      }
+    }
+    if (!ran)
+      break;
+    co_yield 0;
+  }
+}
+
+extern "C" {
+
+#define PLUG(name, ret, ...) ret name(__VA_ARGS__);
+LIST_OF_PLUGS
+#undef PLUG
+
+void plug_reset(void)
+{
+    p->position1 = {0, 0};
+    p->position2 = {300, 0};
+    p->position3 = {100, 300};
+    p->task = combine({ move(p->position1, {0.1, 0}, 300), move(p->position2, {0, 0.1}, 300), move2(p->position3, {0, 0.5}, 100, {0.5, 0}, 200) });
+}
+
+void plug_init(void)
+{
+    p = (Plug*)malloc(sizeof(*p));
+    assert(p != NULL);
+    memset(p, 0, sizeof(*p));
+    p->size = sizeof(*p);
+
+    load_assets();
+    plug_reset();
+}
+
+void *plug_pre_reload(void)
+{
+    unload_assets();
+    return p;
+}
+
+void plug_post_reload(void *state)
+{
+    p = (Plug*)state;
+    if (p->size < sizeof(*p)) {
+        TraceLog(LOG_INFO, "Migrating plug state schema %zu bytes -> %zu bytes", p->size, sizeof(*p));
+        p = (Plug*)realloc(p, sizeof(*p));
+        p->size = sizeof(*p);
+    }
+
+    load_assets();
+}
+
+void plug_update(Env env)
+{
+    if (!p->task.done())
+      p->task();
+
+    Color background_color = ColorFromHSV(0, 0, 0.05);
+    Color foreground_color = ColorFromHSV(0, 0, 0.95);
+
+    ClearBackground(background_color);
+
+    Rectangle boundary = {
+        .x = p->position1.x,
+        .y = p->position1.y,
+        .width = SQUARE_SIZE,
+        .height = SQUARE_SIZE,
+    };
+    DrawRectangleRec(boundary, foreground_color);
+    boundary = {
+        .x = p->position2.x,
+        .y = p->position2.y,
+        .width = SQUARE_SIZE,
+        .height = SQUARE_SIZE,
+    };
+    DrawRectangleRec(boundary, foreground_color);
+    boundary = {
+        .x = p->position3.x,
+        .y = p->position3.y,
+        .width = SQUARE_SIZE,
+        .height = SQUARE_SIZE,
+    };
+    DrawRectangleRec(boundary, foreground_color);
+}
+
+bool plug_finished(void)
+{
+    return p->task.done();
+}
+
+}