From 75a920041208f09c3565006012378c5677a32468 Mon Sep 17 00:00:00 2001
From: Guillaume Chereau <guillaume@noctua-software.com>
Date: Fri, 5 Jan 2024 15:22:20 +0800
Subject: [PATCH] Allow to detach and move the windows

Still a bit experimental.
---
 src/gui.cpp   | 11 ++++++++---
 src/gui.h     |  4 +++-
 src/gui/app.c | 31 +++++++++++++++++++++++++------
 3 files changed, 36 insertions(+), 10 deletions(-)

diff --git a/src/gui.cpp b/src/gui.cpp
index 97468809a..a061f8da2 100644
--- a/src/gui.cpp
+++ b/src/gui.cpp
@@ -656,15 +656,16 @@ void gui_row_end(void)
     gui->item_size = 0;
 }
 
-void gui_window_begin(const char *label, float x, float y, float w, float h)
+void gui_window_begin(const char *label, float x, float y, float w, float h,
+                      bool *moved)
 {
     ImGuiWindowFlags flags =
         ImGuiWindowFlags_NoTitleBar | ImGuiWindowFlags_NoResize |
-        ImGuiWindowFlags_NoMove | //  ImGuiWindowFlags_AlwaysAutoResize |
         ImGuiWindowFlags_NoDecoration;
     float max_h;
 
-    ImGui::SetNextWindowPos(ImVec2(x, y));
+    ImGui::SetNextWindowPos(ImVec2(x, y),
+            moved == NULL ? ImGuiCond_Always : ImGuiCond_Appearing);
     ImGui::SetNextWindowSize(ImVec2(w, h));
     if (h == 0) {
         max_h = ImGui::GetMainViewport()->Size.y - y;
@@ -672,6 +673,10 @@ void gui_window_begin(const char *label, float x, float y, float w, float h)
                 ImVec2(0, 0), ImVec2(FLT_MAX, max_h));
     }
     ImGui::Begin(label, NULL, flags);
+
+    if (moved != NULL) {
+        *moved = ImGui::GetWindowPos() != ImVec2(x, y);
+    }
 }
 
 void gui_window_end(void)
diff --git a/src/gui.h b/src/gui.h
index f65028715..b972cdfcf 100644
--- a/src/gui.h
+++ b/src/gui.h
@@ -35,7 +35,9 @@
 #   define GUI_PANEL_WIDTH_LARGE 400
 #endif
 
-void gui_window_begin(const char *label, float x, float y, float w, float h);
+void gui_window_begin(const char *label, float x, float y, float w, float h,
+                      bool *moved);
+
 void gui_window_end(void);
 
 bool gui_want_capture_mouse(void);
diff --git a/src/gui/app.c b/src/gui/app.c
index 333ff3a13..971cfc9d2 100644
--- a/src/gui/app.c
+++ b/src/gui/app.c
@@ -53,10 +53,11 @@ void gui_debug_panel(void);
 void gui_export_panel(void);
 bool gui_rotation_bar(void);
 
-static const struct {
+static struct {
     const char *name;
     int icon;
     void (*fn)(void);
+    bool detached;
 } PANELS[] = {
     {NULL},
     {"Tools", ICON_TOOLS, gui_tools_panel},
@@ -99,6 +100,9 @@ static void render_left_panel(void)
 void gui_app(void)
 {
     float x = 0, y = 0;
+    bool moved;
+    const char *name;
+    int i;
 
     goxel.show_export_viewport = false;
 
@@ -117,24 +121,39 @@ void gui_app(void)
         y = ITEM_HEIGHT + 2;
     }
 
-    gui_window_begin("Top Bar", x, y, 0, 0);
+    gui_window_begin("Top Bar", x, y, 0, 0, NULL);
     gui_top_bar();
     gui_window_end();
 
     y += ICON_HEIGHT + 28;
-    gui_window_begin("Left Bar", x, y, 0, 0);
+    gui_window_begin("Left Bar", x, y, 0, 0, NULL);
     render_left_panel();
     gui_window_end();
 
     if (goxel.gui.current_panel) {
         x += ICON_HEIGHT + 28;
-        gui_window_begin("Controls", x, y, goxel.gui.panel_width, 0);
-
-        if (gui_panel_header(PANELS[goxel.gui.current_panel].name))
+        name = PANELS[goxel.gui.current_panel].name;
+        gui_window_begin(name, x, y, goxel.gui.panel_width, 0, &moved);
+        if (gui_panel_header(name))
             goxel.gui.current_panel = 0;
         else
             PANELS[goxel.gui.current_panel].fn();
+        gui_window_end();
 
+        if (moved) {
+            PANELS[goxel.gui.current_panel].detached = true;
+            goxel.gui.current_panel = 0;
+        }
+    }
+
+    for (i = 0; i < ARRAY_SIZE(PANELS); i++) {
+        if (!PANELS[i].detached) continue;
+        name = PANELS[i].name;
+        gui_window_begin(name, 0, 0, goxel.gui.panel_width, 0, &moved);
+        if (gui_panel_header(name)) {
+            PANELS[i].detached = false;
+        }
+        PANELS[i].fn();
         gui_window_end();
     }