feat(lua): implemented coroutines for scripts + wait()

core/src/objects/script.cpp

@@ -1,4 +1,5 @@
 #include "script.h"
+#include "common.h"
 #include "logger.h"
 #include "objects/base/instance.h"
 #include "objects/base/member.h"
@@ -7,17 +8,23 @@
 #include "objects/datamodel.h"
 #include "datatypes/ref.h"
 #include "lua.h"
+#include <luajit-2.1/lauxlib.h>
 #include <luajit-2.1/lua.h>
+#include <memory>
+
+int script_wait(lua_State*);
 
 Script::Script(): Instance(&TYPE) {
-    source = "print \"Hello, world!\"";
+    source = "print \"Hello, world!\"\nwait(1)print \"Wait success! :D\"";
 }
 
 Script::~Script() {
 }
 
 void Script::Run() {
-    lua_State* L = dataModel().value()->GetService<ScriptContext>()->state;
+    std::shared_ptr<ScriptContext> scriptContext = dataModel().value()->GetService<ScriptContext>();
+
+    lua_State* L = scriptContext->state;
 
     // Create thread
     this->thread = lua_newthread(L);
@@ -34,6 +41,11 @@ void Script::Run() {
     Data::InstanceRef(dataModel().value()->GetService<Workspace>()).PushLuaValue(Lt);
     lua_rawset(Lt, -3);
 
+    lua_pushstring(Lt, "wait");
+    lua_pushlightuserdata(Lt, scriptContext.get());
+    lua_pushcclosure(Lt, script_wait, 1);
+    lua_rawset(Lt, -3);
+
     lua_pop(Lt, 1); // _G
 
     // Load source and push onto thread stack as function ptr
@@ -51,3 +63,13 @@ void Script::Run() {
 void Script::Stop() {
     // TODO:
 }
+
+int script_wait(lua_State* L) {
+    ScriptContext* scriptContext = (ScriptContext*)lua_touserdata(L, lua_upvalueindex(1));
+    float secs = luaL_checknumber(L, 1);
+
+    scriptContext->PushThreadSleep(L, secs);
+
+    // Yield
+    return lua_yield(L, 0);
+}

core/src/objects/script/scriptcontext.cpp

@@ -1,12 +1,14 @@
 #include "scriptcontext.h"
 #include "datatypes/cframe.h"
-#include "datatypes/meta.h"
+#include "datatypes/color3.h"
 #include "datatypes/vector.h"
 #include "logger.h"
+#include "timeutil.h"
 #include <cstdint>
-#include <luajit-2.1/lauxlib.h>
+#include <ctime>
+#include <chrono>
 #include <luajit-2.1/lua.h>
-#include <luajit-2.1/lualib.h>
+#include "lua.h"
 
 static int g_print(lua_State*);
 static int g_require(lua_State*);
@@ -62,8 +64,70 @@ void ScriptContext::InitService() {
         lua_rawset(state, -3);
     }
 
-    lua_pop(state, 1);
+    lua_pop(state, 1); // _G
 
+    lua_getregistry(state);
+    
+    lua_pushstring(state, "__sleepingThreads");
+    lua_newtable(state);
+    lua_rawset(state, -3);
+
+    lua_pop(state, -1); // registry
+}
+
+void ScriptContext::PushThreadSleep(lua_State* thread, float delay) {
+    // A thread is allowed to sleep multiple times at once, though this is a very edge-case scenario
+
+    SleepingThread sleep;
+    sleep.thread = thread;
+    sleep.timeYieldedWhen = tu_clock_micros();
+    sleep.targetTimeMicros = tu_clock_micros() + delay * 1'000'000;
+
+    sleepingThreads.push_back(sleep);
+
+    // Add to registry so it doesn't get GC'd
+
+    // https://stackoverflow.com/a/17138663/16255372
+    lua_getregistry(state); // registry
+    lua_pushstring(state, "__sleepingThreads");
+    lua_rawget(state, -2); // table
+
+    lua_pushthread(thread); // key
+    lua_xmove(thread, state, 1);
+    lua_pushboolean(state, true); // value
+    lua_rawset(state, -3); // set
+
+    lua_pop(state, 2); // pop table and registry
+}
+
+void ScriptContext::RunSleepingThreads() {
+    for (int i = 0; i < sleepingThreads.size();) {
+        bool deleted = false;
+
+        SleepingThread sleep = sleepingThreads[i];
+        if (tu_clock_micros() >= sleep.targetTimeMicros) {
+            // Time args
+            lua_pushnumber(sleep.thread, float(tu_clock_micros() - sleep.timeYieldedWhen) / 1'000'000);
+            lua_pushnumber(sleep.thread, float(tu_clock_micros()) / 1'000'000);
+            lua_resume(sleep.thread, 2);
+
+            // Remove thread
+            sleepingThreads.erase(sleepingThreads.begin() + i);
+
+            // Erase from registry
+            lua_getregistry(state); // registry
+            lua_pushstring(state, "__sleepingThreads");
+            lua_rawget(state, -2); // table
+            
+            lua_pushthread(sleep.thread); // key
+            lua_xmove(sleep.thread, state, 1);
+            lua_pushnil(state);
+            lua_rawset(state, -3); // set
+        }
+
+        if (!deleted)
+            i++;
+    }
 }
 
 // https://www.lua.org/source/5.1/lbaselib.c.html

core/src/objects/script/scriptcontext.h

@@ -3,9 +3,19 @@
 #include "objects/annotation.h"
 #include "objects/base/service.h"
 #include "lua.h"
+#include <vector>
+
+struct SleepingThread {
+    lua_State* thread;
+    uint64_t timeYieldedWhen;
+    uint64_t targetTimeMicros;
+    bool active = true;
+};
 
 class DEF_INST_SERVICE ScriptContext : public Service {
     AUTOGEN_PREAMBLE
+
+    std::vector<SleepingThread> sleepingThreads;
 protected:
     void InitService() override;
     bool initialized = false;
@@ -15,6 +25,8 @@ public:
     ~ScriptContext();
 
     lua_State* state;
+    void PushThreadSleep(lua_State* thread, float delay);
+    void RunSleepingThreads();
 
     static inline std::shared_ptr<Instance> Create() { return std::make_shared<ScriptContext>(); };
 };

core/src/timeutil.cpp

@@ -0,0 +1,12 @@
+#include "timeutil.h"
+
+#include <chrono>
+
+tu_time_t TIME_STARTED_MICROS = std::chrono::time_point_cast<std::chrono::microseconds>(std::chrono::high_resolution_clock::now()).time_since_epoch().count();
+
+
+tu_time_t tu_clock_micros() {
+    tu_time_t now = std::chrono::time_point_cast<std::chrono::microseconds>(std::chrono::high_resolution_clock::now()).time_since_epoch().count();;
+
+    return now - TIME_STARTED_MICROS;
+}

core/src/timeutil.h

@@ -0,0 +1,8 @@
+#pragma once
+
+#include <cstdint>
+
+typedef uint64_t tu_time_t;
+
+// Provides a high-accuracy time since the program started in microseconds (via std::chrono)
+tu_time_t tu_clock_micros();

editor/placedocument.cpp

@@ -4,6 +4,7 @@
 #include "mainwindow.h"
 #include "objects/joint/snap.h"
 #include "objects/script.h"
+#include "objects/script/scriptcontext.h"
 #include "rendering/surface.h"
 #include <cstdio>
 #include <memory>
@@ -67,6 +68,7 @@ void PlaceDocument::timerEvent(QTimerEvent* evt) {
         gWorkspace()->PhysicsStep(deltaTime);
     placeWidget->repaint();
     placeWidget->updateCycle();
+    gDataModel->GetService<ScriptContext>()->RunSleepingThreads();
 }