feat(term): make cursor hollow when un-focused

Closes #29.

addons/godot_xterm/editor_plugins/terminal/editor_terminal.gd

@@ -22,9 +22,6 @@ func _ready():
 	if not editor_settings:
 		return
 
-	add_theme_stylebox_override("normal", get_theme_stylebox("normal", "Tree"))
-	add_theme_stylebox_override("focus", get_theme_stylebox("focus", "Tree"))
-
 	# Get colors from TextEdit theme. Created using the default (Adaptive) theme
 	# for reference, but will probably cause strange results if using another theme
 	# better to use a dedicated terminal theme, rather than relying on this.

addons/godot_xterm/native/src/terminal.cpp

@@ -209,6 +209,7 @@ void Terminal::_notification(int what)
 	case NOTIFICATION_FOCUS_ENTER:
 	case NOTIFICATION_FOCUS_EXIT:
 	{
+		set_shader_parameters("has_focus", has_focus());
 		refresh();
 		break;
 	}
@@ -275,6 +276,9 @@ int Terminal::_draw_cb(struct tsm_screen *con,
 		attr_flags |= AttrFlag::INVERSE;
 	if (attr->blink)
 		attr_flags |= AttrFlag::BLINK;
+	if (term->cursor_position.x == posx && term->cursor_position.y == posy) {
+		attr_flags |= AttrFlag::CURSOR;
+	}
 
 	// Collect colors.
 	Color fgcol = std::min(attr->fccode, (int8_t)TSM_COLOR_FOREGROUND) >= 0
@@ -471,22 +475,26 @@ void Terminal::update_sizes(bool force)
 	attr_image = Image::create(std::max(cols, 1u), std::max(rows, 1u), false, Image::FORMAT_L8);
 	attr_texture->set_image(attr_image);
 
-	update_shader_parameters(back_material);
-	update_shader_parameters(fore_material);
+	set_shader_parameters();
 
 	if (force || prev_cols != cols || prev_rows != rows)
 		emit_signal("size_changed", Vector2i(cols, rows));
 
 	refresh();
 }
 
-void Terminal::update_shader_parameters(Ref<ShaderMaterial> material)
+void Terminal::set_shader_parameters(const String &param, const Variant &value)
 {
-	material->set_shader_parameter("cols", cols);
-	material->set_shader_parameter("rows", rows);
-	material->set_shader_parameter("size", size);
-	material->set_shader_parameter("cell_size", cell_size);
-	material->set_shader_parameter("grid_size", Vector2(cols * cell_size.x, rows * cell_size.y));
+	if (param.is_empty()) {
+		set_shader_parameters("cols", cols);
+		set_shader_parameters("rows", rows);
+		set_shader_parameters("size", size);
+		set_shader_parameters("cell_size", cell_size);
+		set_shader_parameters("grid_size", Vector2(cols * cell_size.x, rows * cell_size.y));
+	} else {
+		back_material->set_shader_parameter(param, value);
+		fore_material->set_shader_parameter(param, value);
+	}
 }
 
 void Terminal::initialize_rendering() {
@@ -614,6 +622,7 @@ void Terminal::draw_screen() {
 	}
 
 	rs->canvas_item_clear(char_canvas_item);
+	cursor_position = tsm_screen_get_flags(screen) & TSM_SCREEN_HIDE_CURSOR ? Vector2i(-1, -1) : get_cursor_pos();
 	framebuffer_age = tsm_screen_draw(screen, Terminal::_draw_cb, this);
 	attr_texture->update(attr_image);
 	back_texture->update(back_image);
@@ -752,8 +761,7 @@ void Terminal::set_inverse_mode(const int mode) {
 	inverse_mode = static_cast<InverseMode>(mode);
 
 	bool inverse_enabled = inverse_mode == InverseMode::INVERSE_MODE_INVERT;
-	back_material->set_shader_parameter("inverse_enabled", inverse_enabled);
-	fore_material->set_shader_parameter("inverse_enabled", inverse_enabled);
+	set_shader_parameters("inverse_enabled", inverse_enabled);
 
 	refresh();
 }

addons/godot_xterm/native/src/terminal.h

@@ -42,6 +42,7 @@ namespace godot
     {
       INVERSE = 1 << 0,
       BLINK = 1 << 1,
+      CURSOR = 1 << 2,
     };
 
     enum InverseMode {
@@ -130,6 +131,7 @@ namespace godot
     double font_offset;
     Vector2 size;
     Vector2 cell_size;
+    Vector2i cursor_position;
 
     Ref<Image> attr_image;
     Ref<ImageTexture> attr_texture;
@@ -157,7 +159,7 @@ namespace godot
     void initialize_rendering();
     void update_theme();
     void update_sizes(bool force = false);
-    void update_shader_parameters(Ref<ShaderMaterial> material);
+    void set_shader_parameters(const String &name = "", const Variant &value = nullptr);
     bool redraw_requested = false;
     void _on_frame_post_draw();
     void draw_screen();

addons/godot_xterm/shaders/common.gdshaderinc

@@ -3,6 +3,7 @@
 
 #define FLAG_INVERSE 1 << 0
 #define FLAG_BLINK 1 << 1
+#define FLAG_CURSOR 1 << 2
 
 #define transparent vec4(0)
 
@@ -14,6 +15,7 @@ uniform vec2 grid_size;
 
 uniform sampler2D attributes;
 uniform bool inverse_enabled = true;
+uniform bool has_focus = false;
 
 #ifdef BACKGROUND
 uniform vec4 background_color;
@@ -48,17 +50,21 @@ void fragment() {
 		color = texture(TEXTURE, UV);
 #endif
 
-		if (has_attribute(sample_uv, FLAG_INVERSE) && inverse_enabled) {
+		bool unfocused_cursor = !has_focus && has_attribute(sample_uv, FLAG_CURSOR);
+
 #ifdef BACKGROUND
+		if (has_attribute(sample_uv, FLAG_INVERSE) && inverse_enabled) {
 			vec4 bg_color = textureLod(screen_texture, SCREEN_UV, 0.0);
 			vec4 target_color;
 			target_color.a = color.a + (1.0 - color.a) * bg_color.a;
 			target_color.rgb = 1.0 / target_color.a * (color.a * color.rgb + (1.0 - color.a) * bg_color.a * bg_color.rgb);
-#else
-			vec4 target_color = color;
-#endif
 			color = vec4(1.0 - target_color.rgb, target_color.a);
 		}
+#else
+		if (has_attribute(sample_uv, FLAG_INVERSE) && inverse_enabled && !unfocused_cursor) {
+			color.rgb = vec3(1.0 - color.rgb);
+		}
+#endif
 
 #ifdef FOREGROUND
 		if (has_attribute(sample_uv, FLAG_BLINK)) {
@@ -70,9 +76,18 @@ void fragment() {
         }
 #endif
 
-#if defined(FOREGROUND) || defined(BACKGROUND)
-		COLOR = color;
+#ifdef BACKGROUND
+		if (unfocused_cursor) {
+		    // Draw hollow cursor when not focused.
+		    bool isBorderX = (UV.x * size.x - float(cell_x) * cell_size.x) < 1.0 || (float(cell_x + 1) * cell_size.x - UV.x * size.x) < 1.0;
+		    bool isBorderY = (UV.y * size.y - float(cell_y) * cell_size.y) < 1.0 || (float(cell_y + 1) * cell_size.y - UV.y * size.y) < 1.0;
+		    if (!isBorderX && !isBorderY) {
+				color = transparent;
+		    }
+		}
 #endif
+
+		COLOR = color;
 	} else { // Outside the grid.
 		COLOR = transparent;
 	}

test/visual_regression/test_visual_regression.gd

@@ -51,6 +51,16 @@ class TestVisualRegression:
 		await wait_frames(30)
 		assert_match("empty")
 
+	func test_empty_focused():
+		subject.grab_focus()
+		await wait_frames(30)
+		assert_match("empty_focused")
+
+	func test_hollow_cursor():
+		subject.write("W\b")
+		await wait_frames(30)
+		assert_match("hollow_cursor")
+
 	func test_default_theme():
 		# Print every background color.
 		for i in range(8):