[Fix] Regression bugs with scrolling and auto-scrolling

client/src/terminal.cpp

@@ -20,7 +20,7 @@ Terminal::Terminal(GameState* game_state)
 
 Terminal::~Terminal(void) {}
 
-void Terminal::update(void) {
+void Terminal::update(int content_width, int content_height) {
 
 }
 
@@ -92,7 +92,8 @@ void Terminal::_on_ret_press(void) {
   _game_state->send_network_command(_session_id, command);
 }
 
-void Terminal::handle_input(SDL_Event* event, int window_x, int window_y, int window_gl_y) {
+void Terminal::handle_input(SDL_Event* event, int window_x, int window_y, int window_gl_y,
+                            int content_width, int content_height) {
   /* Pass input to TextView; if true, RET was pressed. */
   if(event->type == SDL_EVENT_KEY_DOWN) {
     switch(event->key.key) {
@@ -114,10 +115,10 @@ void Terminal::handle_input(SDL_Event* event, int window_x, int window_y, int wi
         }
         break;
       default:
-        if(_input_view->handle_event(event)) { _on_ret_press(); }
+        if(_input_view->handle_event(event, content_height)) { _on_ret_press(); }
     }
   } else {
-    if(_input_view->handle_event(event)) { _on_ret_press(); }
+    if(_input_view->handle_event(event, content_height)) { _on_ret_press(); }
   }
 }
 

client/src/terminal.h

@@ -17,8 +17,9 @@ public:
   Terminal(GameState* game_state);
   ~Terminal(void);
 
-  void update(void) override;
+  void update(int content_width, int content_height) override;
-  void handle_input(SDL_Event* event, int window_x, int window_y, int window_gl_y) override;
+  void handle_input(SDL_Event* event, int window_x, int window_y, int window_gl_y,
+                    int content_width, int content_height) override;
   void render(const RenderContext& context, int x, int y_screen, int y_gl,
               int width, int height) override;
   void scroll(int amount, int content_height) override;

client/src/ui/editor.cpp

@@ -29,11 +29,12 @@ Editor::Editor(const std::string& filename)
 
 Editor::~Editor(void) {}
 
-void Editor::update(void) {
+void Editor::update(int content_width, int content_height) {
   /* Nothing to do yet. */
 }
 
-void Editor::handle_input(SDL_Event* event, int window_x, int window_y, int window_gl_y) {
+void Editor::handle_input(SDL_Event* event, int window_x, int window_y, int window_gl_y,
+                          int content_width, int content_height) {
   if(!event) return;
 
   _menu_bar->handle_event(event, window_x, window_y);
@@ -44,7 +45,7 @@ void Editor::handle_input(SDL_Event* event, int window_x, int window_y, int wind
     /* C-S pressed, create a save action. */
     _pending_action = { ActionType::WRITE_FILE, _filename, _buffer.get_text() };
   } else {
-    _view->handle_event(event);
+    _view->handle_event(event, content_height);
   }
 }
 
@@ -59,6 +60,8 @@ void Editor::render(const RenderContext& context, int x, int y_screen, int y_gl,
   _menu_bar->render_bar_bg(context.ui_renderer, x, y_screen, width);
   context.ui_renderer->flush_shapes();
 
+  context.ui_renderer->enable_scissor(x, y_gl, width, content_height);
+
   /* Pass 2: Main text view. */
   context.ui_renderer->begin_text();
   _view->render_text_content(context.ui_renderer, _theme, x, content_y, width, content_height);
@@ -71,6 +74,8 @@ void Editor::render(const RenderContext& context, int x, int y_screen, int y_gl,
     context.ui_renderer->flush_shapes();
   }
 
+  context.ui_renderer->disable_scissor();
+
   /* Pass 4: Menu bar text and dropdown. */
   context.ui_renderer->begin_text();
   _menu_bar->render_bar_text(context.ui_renderer, x, y_screen, width);

client/src/ui/editor.h

@@ -25,8 +25,9 @@ public:
   Editor(const std::string& filename);
   ~Editor(void) override;
 
-  void update(void) override;
+  void update(int content_width, int content_height) override;
-  void handle_input(SDL_Event* event, int window_x, int window_y, int window_gl_y) override;
+  void handle_input(SDL_Event* event, int window_x, int window_y, int window_gl_y,
+                    int content_widht, int content_heigth) override;
   void render(const RenderContext& context, int x, int y_screen, int y_gl,
               int width, int height) override;
   void scroll(int amount, int content_height) override;

client/src/ui/i_window_content.h

@@ -8,8 +8,9 @@
 class IWindowContent {
 public:
   virtual ~IWindowContent(void) = default;
-  virtual void update(void) = 0;
+  virtual void update(int content_width, int content_height) = 0;
-  virtual void handle_input(SDL_Event* event, int window_x, int window_y, int window_gl_y) = 0;
+  virtual void handle_input(SDL_Event* event, int window_x, int window_y, int window_gl_y,
+                            int content_width, int content_height) = 0;
   virtual void render(const RenderContext& context, int x, int y_screen, int y_gl,
                       int width, int height) = 0;
   virtual void scroll(int amount, int content_height) = 0;

client/src/ui/text_view.cpp

@@ -22,17 +22,19 @@ TextView::TextView(TextBuffer* buffer, bool handle_ret, bool show_line_numbers,
   };
 }
 
-TextView::~TextView(void) {}
+TextView::~TextView(void) = default;
 
-bool TextView::handle_event(SDL_Event* event) {
+bool TextView::handle_event(SDL_Event* event, int content_height) {
   if(!_buffer) return false;
 
   if(event->type == SDL_EVENT_TEXT_INPUT) {
     _buffer->insert_char(event->text.text[0]);
+    _ensure_cursor_visible(content_height);
   } else if(event->type == SDL_EVENT_KEY_DOWN) {
     switch(event->key.key) {
       case SDLK_BACKSPACE:
         _buffer->backspace();
+        _ensure_cursor_visible(content_height);
         break;
       case SDLK_RETURN:
         /*
@@ -43,22 +45,28 @@ bool TextView::handle_event(SDL_Event* event) {
         if(_handle_ret) {
           _buffer->newline();
         }
+        _ensure_cursor_visible(content_height);
         return true;
         break;
       case SDLK_LEFT:
         _buffer->move_cursor(-1,0);
+        _ensure_cursor_visible(content_height);
         break;
       case SDLK_RIGHT:
         _buffer->move_cursor(1,0);
+        _ensure_cursor_visible(content_height);
         break;
       case SDLK_UP:
         _buffer->move_cursor(0,-1);
+        _ensure_cursor_visible(content_height);
         break;
       case SDLK_DOWN:
         _buffer->move_cursor(0,1);
+        _ensure_cursor_visible(content_height);
         break;
       case SDLK_HOME:
         _buffer->move_cursor_home();
+        _ensure_cursor_visible(content_height);
         break;
       case SDLK_END:
         _buffer->move_cursor_end();
@@ -77,8 +85,13 @@ void TextView::scroll(int amount, int content_height) {
     _scroll_offset = 0;
   }
   float line_height = 20.0f;
-  int visible_lines = content_height / line_height;
+  int visible_lines = static_cast<int>(content_height / line_height)-1;
   int max_scroll = _buffer->get_line_count() - visible_lines;
+  /* Allow one extra scroll step if content is larger than visible area. */
+  if(_buffer->get_line_count() > visible_lines) max_scroll += 1;
+  if(max_scroll < 0) {
+    max_scroll = 0;
+  }
   if(max_scroll < 0) max_scroll = 0;
   if(_scroll_offset > max_scroll) {
     _scroll_offset = max_scroll;
@@ -168,7 +181,7 @@ void TextView::render_text_content(UIRenderer* ui_renderer, const SyntaxTheme& t
      * Culling: If the top of the current line is already below the bottom of the
      * view, we can stop rendering completely.
      */
-    if(current_y > y + height) {
+    if(current_y >= y + height) {
       break;
     }
 
@@ -218,3 +231,20 @@ void TextView::render_cursor(UIRenderer* ui_renderer, const SyntaxTheme& theme,
     ui_renderer->draw_rect(cursor_x, cursor_y, 2, line_height, theme.normal);
   }
 }
+
+void TextView::_ensure_cursor_visible(int content_height) {
+  Point cursor_pos = _buffer->get_cursor_pos();
+  float line_height = 20.0f;
+  int visible_lines = static_cast<int>(content_height / line_height)-1;
+
+  /* If cursor above current scroll view, scroll up. */
+  if(cursor_pos.row < _scroll_offset) {
+    _scroll_offset = cursor_pos.row;
+  } else if(cursor_pos.row >= _scroll_offset + visible_lines) {
+    /* Below, scroll down. */
+    _scroll_offset = cursor_pos.row - visible_lines+1;
+  }
+
+  /* Re-clamp scroll offset to ensure it's within valid bounds. */
+  scroll(0, content_height);
+}

client/src/ui/text_view.h

@@ -29,7 +29,7 @@ public:
   TextView(TextBuffer* buffer, bool handle_ret, bool show_line_numbers, bool syntax_highlighting);
   ~TextView(void);
 
-  bool handle_event(SDL_Event* event);
+  bool handle_event(SDL_Event* event, int content_height);
   void scroll(int amount, int content_height);
   void render_text_content(UIRenderer* ui_renderer, const SyntaxTheme& theme,
                            int x, int y, int width, int height);
@@ -37,6 +37,7 @@ public:
                      int x, int y, int width, int height);
 
 private:
+  void _ensure_cursor_visible(int content_height);
   std::vector<Token> _tokenize_line(const std::string& line);
 
   TextBuffer* _buffer;

client/src/ui/ui_renderer.cpp

@@ -1,3 +1,5 @@
+#include <GL/glew.h>
+
 #include "ui_renderer.h"
 #include "gfx/shape_renderer.h"
 #include "gfx/txt_renderer.h"
@@ -51,3 +53,12 @@ void UIRenderer::flush_shapes(void) {
 TextRenderer* UIRenderer::get_text_renderer(void) {
   return _txt_renderer;
 }
+
+void UIRenderer::enable_scissor(int x, int y, int width, int height) {
+  glEnable(GL_SCISSOR_TEST);
+  glScissor(x, y, width, height);
+}
+
+void UIRenderer::disable_scissor(void) {
+  glDisable(GL_SCISSOR_TEST);
+}

client/src/ui/ui_renderer.h

@@ -26,6 +26,9 @@ public:
   /* Expose underlying text renderer for things like width calculation. */
   TextRenderer* get_text_renderer(void);
 
+  void enable_scissor(int x, int y, int width, int height);
+  void disable_scissor(void);
+
 private:
   ShapeRenderer*  _shape_renderer;
   TextRenderer*   _txt_renderer;

client/src/ui/ui_window.cpp

@@ -129,9 +129,10 @@ void UIWindow::render(const RenderContext& context) {
   if(_content) {
     int content_screen_y = _y + title_bar_height;
     int content_height = _height - title_bar_height;
+    int content_width = _width;
     /* Got to pass GL y-coord for scissor box to work correctly. */
     int content_gl_y = context.screen_height - content_screen_y - content_height;
-    _content->render(context, _x, content_screen_y, content_gl_y, _width, content_height);
+    _content->render(context, _x, content_screen_y, content_gl_y, content_width, content_height);
   }
 }
 
@@ -215,7 +216,9 @@ void UIWindow::handle_event(SDL_Event* event, int screen_width,
   }
   if(_content) {
     int y_gl = screen_height - _y - _height;
-    _content->handle_input(event, _x, _y, y_gl);
+    int content_height = _height - title_bar_height;
+    int content_width = _width;
+    _content->handle_input(event, _x, _y, y_gl, content_width, content_height);
   }
 }