From 6ad898877d5d34209770970adbea8509f6fe5be8 Mon Sep 17 00:00:00 2001
From: lotaviods <l.otavio9099@gmail.com>
Date: Mon, 16 Mar 2026 01:11:29 -0300
Subject: [PATCH] fix: add dynamic window resize support

---
 Minecraft.Client/Minecraft.cpp                | 23 +++++++++++++++++--
 Minecraft.Client/Minecraft.h                  |  2 ++
 .../Platform/Common/UI/UIController.h         |  1 +
 .../Platform/Linux/Linux_Minecraft.cpp        |  5 ++++
 Minecraft.Client/Rendering/GameRenderer.cpp   |  9 ++++++--
 5 files changed, 36 insertions(+), 4 deletions(-)

diff --git a/Minecraft.Client/Minecraft.cpp b/Minecraft.Client/Minecraft.cpp
index 5d804d22d..698e0b6a3 100644
--- a/Minecraft.Client/Minecraft.cpp
+++ b/Minecraft.Client/Minecraft.cpp
@@ -2254,14 +2254,33 @@ void Minecraft::pauseGame() {
     //    setScreen(new PauseScreen());	// 4J - TODO put back in
 }
 
+bool Minecraft::pollResize() {
+    int fbw, fbh;
+    RenderManager.GetFramebufferSize(fbw, fbh);
+    if (fbw != width_phys || fbh != height_phys) {
+        resize(fbw, fbh);
+        return true;
+    }
+    return false;
+}
+
 void Minecraft::resize(int width, int height) {
     if (width <= 0) width = 1;
     if (height <= 0) height = 1;
-    this->width = width;
+    // 4jcraft: store physical framebuffer size and adjust logical width
+    // for non-widescreen aspect ratio to fix UI scaling.
+    this->width_phys = width;
+    this->height_phys = height;
+    if (RenderManager.IsWidescreen()) {
+        this->width = width;
+    } else {
+        this->width = (width * 3) / 4;
+    }
     this->height = height;
 
     if (screen != NULL) {
-        ScreenSizeCalculator ssc(options, width, height);
+        // 4jcraft: use adjusted logical width instead of raw width for correct screen size calculation.
+        ScreenSizeCalculator ssc(options, this->width, height);
         int screenWidth = ssc.getWidth();
         int screenHeight = ssc.getHeight();
         //        screen->init(this, screenWidth, screenHeight);	// 4J -
diff --git a/Minecraft.Client/Minecraft.h b/Minecraft.Client/Minecraft.h
index 8493675f7..07b4c1a3b 100644
--- a/Minecraft.Client/Minecraft.h
+++ b/Minecraft.Client/Minecraft.h
@@ -264,6 +264,8 @@ public:
 
     void pauseGame();
     //    void toggleFullScreen();	// 4J - removed
+    bool pollResize();
+
 private:
     void resize(int width, int height);
 
diff --git a/Minecraft.Client/Platform/Common/UI/UIController.h b/Minecraft.Client/Platform/Common/UI/UIController.h
index 707e7de1a..936e8c077 100644
--- a/Minecraft.Client/Platform/Common/UI/UIController.h
+++ b/Minecraft.Client/Platform/Common/UI/UIController.h
@@ -218,6 +218,7 @@ public:
 	// RENDERING
 	float getScreenWidth() { return m_fScreenWidth; }
 	float getScreenHeight() { return m_fScreenHeight; }
+	void setScreenSize(S32 w, S32 h) { m_fScreenWidth = (float)w; m_fScreenHeight = (float)h; }
 
 	virtual void render() = 0;
 	void getRenderDimensions(C4JRender::eViewportType viewport, S32 &width, S32 &height);
diff --git a/Minecraft.Client/Platform/Linux/Linux_Minecraft.cpp b/Minecraft.Client/Platform/Linux/Linux_Minecraft.cpp
index 7d16d9af0..b62da92d7 100644
--- a/Minecraft.Client/Platform/Linux/Linux_Minecraft.cpp
+++ b/Minecraft.Client/Platform/Linux/Linux_Minecraft.cpp
@@ -905,6 +905,11 @@ return -1;
     app.InitialiseTips();
     while (!RenderManager.ShouldClose()) {
         RenderManager.StartFrame();
+        if (pMinecraft->pollResize()) {
+            int fbw, fbh;
+            RenderManager.GetFramebufferSize(fbw, fbh);
+            ui.setScreenSize(fbw, fbh);
+        }
         app.UpdateTime();
         PIXBeginNamedEvent(0, "Input manager tick");
         InputManager.Tick();
diff --git a/Minecraft.Client/Rendering/GameRenderer.cpp b/Minecraft.Client/Rendering/GameRenderer.cpp
index 6b0d32724..532319318 100644
--- a/Minecraft.Client/Rendering/GameRenderer.cpp
+++ b/Minecraft.Client/Rendering/GameRenderer.cpp
@@ -1046,7 +1046,9 @@ void GameRenderer::render(float a, bool bFirst) {
         int fbw, fbh;
         RenderManager.GetFramebufferSize(fbw, fbh);
         glViewport(0, 0, fbw, fbh);
-        ScreenSizeCalculator ssc(mc->options, mc->width, mc->height);
+        // 4jcraft: use framebuffer dimensions for ScreenSizeCalculator so the
+        // title screen GUI coordinates match the actual viewport size.
+        ScreenSizeCalculator ssc(mc->options, fbw, fbh);
         int screenWidth = ssc.getWidth();
         int screenHeight = ssc.getHeight();
         int xMouse = Mouse::getX() * screenWidth / fbw;
@@ -1819,7 +1821,10 @@ void GameRenderer::renderSnowAndRain(float a) {
 void GameRenderer::setupGuiScreen(int forceScale /*=-1*/) {
     int fbw, fbh;
     RenderManager.GetFramebufferSize(fbw, fbh);
-    ScreenSizeCalculator ssc(mc->options, mc->width, mc->height, forceScale);
+
+    // 4jcraft: use actual framebuffer dimensions instead of mc->width/height
+    // to ensure GUI scales correctly after a window resize.
+    ScreenSizeCalculator ssc(mc->options, fbw, fbh, forceScale);
 
     glClear(GL_DEPTH_BUFFER_BIT);
     glMatrixMode(GL_PROJECTION);