From 494ea78610c267f34c231c7ace9b98f4d87a6f99 Mon Sep 17 00:00:00 2001
From: Yuri Roubinski <chaosus89@gmail.com>
Date: Sun, 25 Aug 2019 09:22:09 +0300
Subject: [PATCH] Small performance fix for preview in visual shader

---
 .../plugins/visual_shader_editor_plugin.cpp   | 22 ++++++++++---------
 editor/plugins/visual_shader_editor_plugin.h  |  1 +
 2 files changed, 13 insertions(+), 10 deletions(-)

diff --git a/editor/plugins/visual_shader_editor_plugin.cpp b/editor/plugins/visual_shader_editor_plugin.cpp
index 0bfe366a6d5..55ff3fc3ddb 100644
--- a/editor/plugins/visual_shader_editor_plugin.cpp
+++ b/editor/plugins/visual_shader_editor_plugin.cpp
@@ -2058,16 +2058,20 @@ void VisualShaderEditor::_show_preview_text() {
 	preview_showed = !preview_showed;
 	preview_vbox->set_visible(preview_showed);
 	if (preview_showed) {
-		if (shader_error) {
-			error_text->set_visible(true);
-		} else {
-			error_text->set_visible(false);
+		if (pending_update_preview) {
+			_update_preview();
+			pending_update_preview = false;
 		}
 	}
 }
 
 void VisualShaderEditor::_update_preview() {
 
+	if (!preview_showed) {
+		pending_update_preview = true;
+		return;
+	}
+
 	String code = visual_shader->get_code();
 
 	preview_text->set_text(code);
@@ -2081,16 +2085,13 @@ void VisualShaderEditor::_update_preview() {
 	}
 	if (err != OK) {
 		preview_text->set_line_as_marked(sl.get_error_line() - 1, true);
-		if (preview_showed) {
-			error_text->set_visible(true);
-		}
+		error_text->set_visible(true);
+
 		String text = "error(" + itos(sl.get_error_line()) + "): " + sl.get_error_text();
 		error_text->set_text(text);
 		shader_error = true;
 	} else {
-		if (preview_showed) {
-			error_text->set_visible(false);
-		}
+		error_text->set_visible(false);
 		shader_error = false;
 	}
 }
@@ -2163,6 +2164,7 @@ VisualShaderEditor::VisualShaderEditor() {
 	ShaderLanguage::get_keyword_list(&keyword_list);
 
 	preview_showed = false;
+	pending_update_preview = false;
 	shader_error = false;
 
 	to_node = -1;
diff --git a/editor/plugins/visual_shader_editor_plugin.h b/editor/plugins/visual_shader_editor_plugin.h
index 5be214f9a99..a2e9516a6eb 100644
--- a/editor/plugins/visual_shader_editor_plugin.h
+++ b/editor/plugins/visual_shader_editor_plugin.h
@@ -70,6 +70,7 @@ class VisualShaderEditor : public VBoxContainer {
 	PanelContainer *error_panel;
 	Label *error_label;
 
+	bool pending_update_preview;
 	bool shader_error;
 	VBoxContainer *preview_vbox;
 	TextEdit *preview_text;