Offscreen painting

kernel/include/console.hpp

@@ -19,6 +19,8 @@ namespace stdio {
 void init_console();
 
 struct console {
+    void init();
+
     size_t get_columns() const ;
     size_t get_rows() const ;
 
@@ -26,16 +28,18 @@ struct console {
 
     void wipeout();
 
+    void set_active(bool active);
     void save();
     void restore();
 
 private:
     void next_line();
 
-    size_t current_line = 0;
+    size_t current_line   = 0;
     size_t current_column = 0;
 
-    void* buffer;
+    void* buffer = nullptr;
+    bool active  = false;
 };
 
 } // end of namespace stdio

kernel/include/terminal.hpp

@@ -83,9 +83,6 @@ struct virtual_terminal {
 
     void set_active(bool);
 
-    void save();
-    void restore();
-
     console& get_console();
 
     size_t id;

kernel/include/vesa_console.hpp

@@ -12,11 +12,19 @@
 
 struct vesa_console {
     void init();
-    size_t lines();
-    size_t columns();
+
+    size_t lines() const ;
+    size_t columns() const ;
+
     void clear();
+    void clear(void* buffer);
+
     void scroll_up();
+    void scroll_up(void* buffer);
+
     void print_char(size_t line, size_t column, char c);
+    void print_char(void* buffer, size_t line, size_t column, char c);
+
     void* save(void* buffer);
     void restore(void* buffer);
 };

kernel/src/console.cpp

@@ -35,6 +35,12 @@ void stdio::init_console(){
     }
 }
 
+void stdio::console::init(){
+    if(!text){
+        buffer = vesa::create_buffer();
+    }
+}
+
 size_t stdio::console::get_rows() const {
     if(text){
         return t_console.lines();
@@ -67,7 +73,11 @@ void stdio::console::print(char key){
         if(text){
             t_console.print_char(current_line, current_column, key);
         } else {
-            v_console.print_char(current_line, current_column, key);
+            if(active){
+                v_console.print_char(current_line, current_column, key);
+            } else {
+                v_console.print_char(buffer, current_line, current_column, key);
+            }
         }
 
         ++current_column;
@@ -82,7 +92,11 @@ void stdio::console::wipeout(){
     if(text){
         t_console.clear();
     } else {
-        v_console.clear();
+        if(active){
+            v_console.clear();
+        } else {
+            v_console.clear(buffer);
+        }
     }
 
     current_line = 0;
@@ -101,6 +115,10 @@ void stdio::console::restore(){
     v_console.restore(buffer);
 }
 
+void stdio::console::set_active(bool active){
+    this->active = active;
+}
+
 void stdio::console::next_line(){
     ++current_line;
 
@@ -108,7 +126,11 @@ void stdio::console::next_line(){
         if(text){
             t_console.scroll_up();
         } else {
-            v_console.scroll_up();
+            if(active){
+                v_console.scroll_up();
+            } else {
+                v_console.scroll_up(buffer);
+            }
         }
 
         --current_line;

kernel/src/stdio.cpp

@@ -136,8 +136,11 @@ void stdio::init_terminals(){
         terminal.mouse     = false;
     }
 
+    // Initialize the active terminal
+
     active_terminal = 0;
     terminals[active_terminal].active = true;
+    terminals[active_terminal].get_console().set_active(true);
 }
 
 void stdio::register_devices(){
@@ -162,7 +165,7 @@ void stdio::finalize(){
         terminal.input_thread_pid = input_process.pid;
 
         // Save the initial image of the terminal
-        terminal.save();
+        terminal.get_console().save();
     }
 }
 
@@ -184,8 +187,9 @@ void stdio::switch_terminal(size_t id){
     if(active_terminal != id){
         logging::logf(logging::log_level::TRACE, "stdio: Switch activate virtual terminal %u\n", id);
 
-        terminals[active_terminal].save();
-        terminals[id].restore();
+        // Effectively switch the terminal
+        terminals[active_terminal].set_active(false);
+        terminals[id].set_active(true);
 
         active_terminal = id;
     }

kernel/src/terminal.cpp

@@ -130,12 +130,20 @@ bool stdio::virtual_terminal::is_canonical() const {
     return canonical;
 }
 
-void stdio::virtual_terminal::save(){
-    cons.save();
-}
+void stdio::virtual_terminal::set_active(bool active){
+    if(this->active == active){
+        return;
+    }
 
-void stdio::virtual_terminal::restore(){
-    cons.restore();
+    this->active = active;
+
+    cons.set_active(active);
+
+    if(active){
+        cons.restore();
+    } else {
+        cons.save();
+    }
 }
 
 stdio::console& stdio::virtual_terminal::get_console(){

kernel/src/vesa_console.cpp

@@ -47,11 +47,11 @@ void vesa_console::init() {
     vesa::draw_char(title_left + 24, PADDING + MARGIN, 'R', _color);
 }
 
-size_t vesa_console::lines() {
+size_t vesa_console::lines() const {
     return _lines;
 }
 
-size_t vesa_console::columns() {
+size_t vesa_console::columns() const {
     return _columns;
 }
 
@@ -59,15 +59,28 @@ void vesa_console::clear() {
     vesa::draw_rect(LEFT, TOP, _columns * 8, _lines * 16, vesa::make_color(0, 0, 0));
 }
 
+void vesa_console::clear(void* buffer) {
+    vesa::draw_rect(buffer, LEFT, TOP, _columns * 8, _lines * 16, vesa::make_color(0, 0, 0));
+}
+
 void vesa_console::scroll_up() {
     vesa::move_lines_up(TOP + 16, LEFT, _columns * 8, (_lines - 1) * 16, 16);
     vesa::draw_rect(LEFT, TOP + (_lines - 1) * 16, _columns * 8, 16, vesa::make_color(0, 0, 0));
 }
 
+void vesa_console::scroll_up(void* buffer) {
+    vesa::move_lines_up(buffer, TOP + 16, LEFT, _columns * 8, (_lines - 1) * 16, 16);
+    vesa::draw_rect(buffer, LEFT, TOP + (_lines - 1) * 16, _columns * 8, 16, vesa::make_color(0, 0, 0));
+}
+
 void vesa_console::print_char(size_t line, size_t column, char c) {
     vesa::draw_char(LEFT + 8 * column, TOP + 16 * line, c, _color);
 }
 
+void vesa_console::print_char(void* buffer, size_t line, size_t column, char c) {
+    vesa::draw_char(buffer, LEFT + 8 * column, TOP + 16 * line, c, _color);
+}
+
 void* vesa_console::save(void* buffer) {
     void* buffer32 = static_cast<uint32_t*>(buffer);
     if (!buffer32) {