[GTK3] Implement tilemap scrolling rect

gtk3/main.c

@@ -26,7 +26,8 @@ static bool paused = false;
 static bool underclock_down = false, rewind_down = false, do_rewind = false, rewind_paused = false, turbo_down = false;
 static double clock_mutliplier = 1.0;
 static char *battery_save_path_ptr;
-static Rect rect;
+static Rect viewport = {0};
+static Rect scrollRect = {0};
 static bool vram_viewer_visible = false;
 static bool running = true;
 
@@ -673,8 +674,8 @@ static gboolean on_draw_fallback(GtkWidget *widget, cairo_t *cr, gpointer data)
 		cairo_format_stride_for_width(CAIRO_FORMAT_RGB24, screen_width)
 	);
 
-	cairo_translate(cr, rect.x, rect.y);
+	cairo_translate(cr, viewport.x, viewport.y);
-	cairo_scale(cr, rect.w / screen_width, rect.h / screen_height);
+	cairo_scale(cr, viewport.w / screen_width, viewport.h / screen_height);
 	cairo_set_source_surface(cr, surface, 0, 0);
 	cairo_pattern_set_filter(cairo_get_source(cr), CAIRO_FILTER_NEAREST);
 	cairo_paint(cr);
@@ -790,6 +791,29 @@ static gboolean on_draw_vram_viewer_tilemap(GtkWidget *widget, cairo_t *cr, gpoi
 		cairo_stroke(cr);
 	}
 
+	if (gtk_toggle_button_get_active(gtkget(GTK_TOGGLE_BUTTON, "vram_viewer_tilemap_toggle_scrolling_button"))) {
+		cairo_rectangle(cr, 0, 0, width, height);
+
+		for (unsigned x = 0; x < 2; x++) {
+			for (unsigned y = 0; y < 2; y++) {
+				Rect rect = scrollRect;
+				rect.x -= 256 * x;
+				rect.y += 256 * y;
+
+				cairo_rectangle(cr, rect.x, rect.y, rect.w, rect.h);
+			}
+		}
+
+		cairo_set_fill_rule(cr, CAIRO_FILL_RULE_EVEN_ODD);
+		cairo_set_line_width(cr, 2);
+		cairo_set_line_join(cr, CAIRO_LINE_JOIN_ROUND);
+		cairo_set_source_rgba(cr, 0.2, 0.2, 0.2, 0.5);
+		cairo_fill_preserve(cr);
+		cairo_clip_preserve(cr);
+		cairo_set_source_rgba(cr, 0.0, 0.0, 0.0, 0.6);
+		cairo_stroke(cr);
+	}
+
 	return FALSE;
 }
 
@@ -889,7 +913,7 @@ static void render_texture(void *pixels,  void *previous) {
 	glClearColor(0, 0, 0, 1);
 	glClear(GL_COLOR_BUFFER_BIT);
 	
-	render_bitmap_with_shader(&shader, _pixels, previous, GB_get_screen_width(&gb), GB_get_screen_height(&gb), rect.x, rect.y, rect.w, rect.h);
+	render_bitmap_with_shader(&shader, _pixels, previous, GB_get_screen_width(&gb), GB_get_screen_height(&gb), viewport.x, viewport.y, viewport.w, viewport.h);
 }
 
 static void update_viewport(void) {
@@ -918,14 +942,14 @@ static void update_viewport(void) {
 	unsigned new_width  = x_factor * GB_get_screen_width(&gb);
 	unsigned new_height = y_factor * GB_get_screen_height(&gb);
 
-	rect = (Rect){
+	viewport = (Rect){
 		(win_width - new_width) / 2,
 		(win_height - new_height) / 2,
 		new_width,
 		new_height
 	};
 
-	if (!fallback_canvas) glViewport(rect.x, rect.y, rect.w, rect.h);
+	if (!fallback_canvas) glViewport(viewport.x, viewport.y, viewport.w, viewport.h);
 }
 
 static void update_window_geometry() {
@@ -990,6 +1014,12 @@ static void vblank(GB_gameboy_t *gb) {
 		GB_draw_tileset(gb, tileset_buffer, GB_PALETTE_NONE, 0);
 		GB_draw_tilemap(gb, tilemap_buffer, GB_PALETTE_AUTO, 0, GB_MAP_AUTO, GB_TILESET_AUTO);
 
+		scrollRect = (Rect){
+			GB_read_memory(gb, 0xFF00 | GB_IO_SCX),
+			GB_read_memory(gb, 0xFF00 | GB_IO_SCY),
+			160, 144
+		};
+
 		// Queue a redraw of the VRAM viewer
 		gtk_widget_queue_draw(GTK_WIDGET(vram_viewer));
 	}

gtk3/resources/ui/window.ui

@@ -1353,7 +1353,7 @@ Maximilian Mader https://github.com/max-m</property>
                       </packing>
                     </child>
                     <child>
-                      <object class="GtkToggleButton" id="vram_viewer_tilemap_toggle_scrolling">
+                      <object class="GtkToggleButton" id="vram_viewer_tilemap_toggle_scrolling_button">
                         <property name="label" translatable="yes">Scrolling</property>
                         <property name="visible">True</property>
                         <property name="can_focus">True</property>
@@ -1401,6 +1401,10 @@ Maximilian Mader https://github.com/max-m</property>
                     <property name="visible">True</property>
                     <property name="app_paintable">True</property>
                     <property name="can_focus">False</property>
+                    <property name="halign">start</property>
+                    <property name="valign">start</property>
+                    <property name="hexpand">False</property>
+                    <property name="vexpand">False</property>
                   </object>
                   <packing>
                     <property name="expand">True</property>