feat: hot reload and draw text example

main.cpp

@@ -1,9 +1,22 @@
-#include "raylib.h"
-#include <angelscript.h>
-#include <scriptstdstring.h>
-#include <cassert>
 #include <iostream>
-#include <string>
+#include <filesystem>
+#include <chrono>
+#include <thread>
+#include "raylib.h"
+#include "angelscript.h"
+#include "scriptstdstring.h"
+#include <fstream>
+#include <sstream>
+#include <assert.h>
+namespace fs = std::filesystem;
+
+asIScriptEngine* engine = nullptr;
+std::string scriptFile = "scripts/test.as";
+std::time_t lastWriteTime = 0;
+
+// Cached script functions
+asIScriptFunction* updateFunc = nullptr;
+asIScriptFunction* drawFunc = nullptr;
 
 // -------------------------
 // Functions exposed to AngelScript
@@ -12,6 +25,19 @@ void Print(const std::string &msg) {
     std::cout << "[Script] " << msg << std::endl;
 }
 
+Color ColorFromUInt(unsigned int c) {
+    Color col;
+    col.r = (c >> 24) & 0xFF;
+    col.g = (c >> 16) & 0xFF;
+    col.b = (c >> 8) & 0xFF;
+    col.a = c & 0xFF;
+    return col;
+}
+
+void AS_DrawText(const std::string &text, int x, int y, int fontSize, unsigned int color) {
+    DrawText(text.c_str(), x, y, fontSize, ColorFromUInt(color));
+}
+
 // -------------------------
 // AngelScript message callback
 // -------------------------
@@ -19,6 +45,74 @@ void AngelScriptMessageCallback(const asSMessageInfo* msg, void* param) {
     std::cout << msg->section << " (" << msg->row << "): " << msg->message << std::endl;
 }
 
+// -------------------------
+// Utility to read script files
+// -------------------------
+std::string ReadFile(const std::string &filename) {
+    std::ifstream file(filename);
+    if (!file) return "";
+    std::stringstream ss;
+    ss << file.rdbuf();
+    return ss.str();
+}
+
+// -------------------------
+// Compile script and cache Update/Draw
+// -------------------------
+bool compileScript(const std::string& filename) {
+    engine->GarbageCollect();
+    asIScriptModule* mod = engine->GetModule("main", asGM_ALWAYS_CREATE);
+
+    std::string code = ReadFile(filename);
+    if (code.empty()) {
+        std::cerr << "Failed to read script file: " << filename << "\n";
+        return false;
+    }
+
+    int r = mod->AddScriptSection(filename.c_str(), code.c_str());
+    if (r < 0) return false;
+
+    r = mod->Build();
+    if (r < 0) return false;
+
+    // Cache Update(float dt) and Draw() functions if they exist
+    updateFunc = mod->GetFunctionByName("Update");
+    drawFunc = mod->GetFunctionByName("Draw");
+
+    std::cout << "Script compiled and cached: " << filename << "\n";
+    return true;
+}
+
+// -------------------------
+// Hot reload check
+// -------------------------
+void checkHotReload() {
+    auto ftime = fs::last_write_time(scriptFile);
+    auto sctp = std::chrono::time_point_cast<std::chrono::system_clock::duration>(ftime - fs::file_time_type::clock::now() + std::chrono::system_clock::now());
+    std::time_t t = std::chrono::system_clock::to_time_t(sctp);
+    if (t != lastWriteTime) {
+        lastWriteTime = t;
+        compileScript(scriptFile);
+    }
+}
+
+// -------------------------
+// Call a cached script function
+// -------------------------
+void callScriptFunction(asIScriptFunction* func, float dt = 0.0f) {
+    if (!func) return;
+
+    asIScriptContext* ctx = engine->CreateContext();
+    ctx->Prepare(func);
+
+    if (func->GetParamCount() == 1) {
+        ctx->SetArgFloat(0, dt);
+    }
+
+    ctx->Execute();
+    ctx->Release();
+}
+
 // -------------------------
 // Main
 // -------------------------
@@ -28,45 +122,41 @@ int main() {
     SetTargetFPS(60);
 
     // Initialize AngelScript
-    asIScriptEngine* engine = asCreateScriptEngine();
+    engine = asCreateScriptEngine();
     assert(engine);
 
     RegisterStdString(engine);
+    engine->RegisterGlobalFunction("void DrawText(const string &in, int, int, int, uint)",
+                                   asFUNCTION(AS_DrawText), asCALL_CDECL);
 
-    // Register the message callback
     int r = engine->SetMessageCallback(asFUNCTION(AngelScriptMessageCallback), nullptr, asCALL_CDECL);
     assert(r >= 0);
 
-    // Register the Print function for scripts
     r = engine->RegisterGlobalFunction("void Print(const string &in)", asFUNCTION(Print), asCALL_CDECL);
     assert(r >= 0);
 
-    // Create a module and add a simple script
-    asIScriptModule* mod = engine->GetModule("Game", asGM_ALWAYS_CREATE);
-    const char* scriptCode =
-        "void main() { "
-        "   Print('Hello from AngelScript!'); "
-        "}";
-    mod->AddScriptSection("test", scriptCode);
-    r = mod->Build();
-    if (r < 0) std::cerr << "Failed to build script.\n";
-
-    // Prepare and execute the script
-    asIScriptFunction* func = mod->GetFunctionByDecl("void main()");
-    asIScriptContext* ctx = engine->CreateContext();
-    ctx->Prepare(func);
-    ctx->Execute();
-    ctx->Release();
+    compileScript(scriptFile);
 
     // Main loop
     while (!WindowShouldClose()) {
+        float dt = GetFrameTime();
+
+        checkHotReload();
+
+        callScriptFunction(updateFunc, dt);
+
         BeginDrawing();
         ClearBackground(RAYWHITE);
-        DrawText("Raylib + AngelScript running!", 180, 280, 20, DARKGRAY);
+
+        DrawText("Modify scripts/test.as to hot-reload!", 50, 50, 20, DARKGRAY);
+
+        callScriptFunction(drawFunc);
+
         EndDrawing();
+
+        std::this_thread::sleep_for(std::chrono::milliseconds(10));
     }
 
-    // Clean up
     CloseWindow();
-    engine->Release();
+    engine->ShutDownAndRelease();
 }