From b85a3cbce35bf67d746c57d979236e511a2b2627 Mon Sep 17 00:00:00 2001
From: Hendrik Brucker <hendrik.brucker@mail.de>
Date: Tue, 22 Nov 2022 13:25:54 +0800
Subject: [PATCH] Add Gradient resource preview generator

Co-Authored-By: Haoyu Qiu <timothyqiu32@gmail.com>
---
 editor/editor_node.cpp                    |  1 +
 editor/editor_resource_picker.cpp         |  2 +-
 editor/plugins/editor_preview_plugins.cpp | 29 +++++++++++++++++++++++
 editor/plugins/editor_preview_plugins.h   | 11 +++++++++
 4 files changed, 42 insertions(+), 1 deletion(-)

diff --git a/editor/editor_node.cpp b/editor/editor_node.cpp
index 2c5ec6cae..a2d0e0541 100644
--- a/editor/editor_node.cpp
+++ b/editor/editor_node.cpp
@@ -6971,6 +6971,7 @@ EditorNode::EditorNode() {
 	resource_preview->add_preview_generator(Ref<EditorMeshPreviewPlugin>(memnew(EditorMeshPreviewPlugin)));
 	resource_preview->add_preview_generator(Ref<EditorBitmapPreviewPlugin>(memnew(EditorBitmapPreviewPlugin)));
 	resource_preview->add_preview_generator(Ref<EditorFontPreviewPlugin>(memnew(EditorFontPreviewPlugin)));
+	resource_preview->add_preview_generator(Ref<EditorGradientPreviewPlugin>(memnew(EditorGradientPreviewPlugin)));
 
 	{
 		Ref<SpatialMaterialConversionPlugin> spatial_mat_convert;
diff --git a/editor/editor_resource_picker.cpp b/editor/editor_resource_picker.cpp
index 2855e70ef..0ee81ef3b 100644
--- a/editor/editor_resource_picker.cpp
+++ b/editor/editor_resource_picker.cpp
@@ -118,7 +118,7 @@ void EditorResourcePicker::_update_resource_preview(const String &p_path, const
 	if (p_preview.is_valid()) {
 		preview_rect->set_margin(MARGIN_LEFT, assign_button->get_icon()->get_width() + assign_button->get_theme_stylebox("normal")->get_default_margin(MARGIN_LEFT) + get_theme_constant("hseparation", "Button"));
 
-		if (type == "GradientTexture") {
+		if (type == "GradientTexture" || type == "Gradient") {
 			preview_rect->set_stretch_mode(TextureRect::STRETCH_SCALE);
 			assign_button->set_custom_minimum_size(Size2(1, 1));
 		} else {
diff --git a/editor/plugins/editor_preview_plugins.cpp b/editor/plugins/editor_preview_plugins.cpp
index 07171a860..1c16dcbda 100644
--- a/editor/plugins/editor_preview_plugins.cpp
+++ b/editor/plugins/editor_preview_plugins.cpp
@@ -956,3 +956,32 @@ EditorFontPreviewPlugin::~EditorFontPreviewPlugin() {
 	RS::get_singleton()->free(canvas);
 	RS::get_singleton()->free(viewport);
 }
+
+///////////////////////////////////////////////////////////////////////////
+
+static const real_t GRADIENT_PREVIEW_TEXTURE_SCALE_FACTOR = 4.0;
+
+bool EditorGradientPreviewPlugin::handles(const String &p_type) const {
+	return ClassDB::is_parent_class(p_type, "Gradient");
+}
+
+bool EditorGradientPreviewPlugin::generate_small_preview_automatically() const {
+	return true;
+}
+
+Ref<Texture> EditorGradientPreviewPlugin::generate(const Ref<Resource> &p_from, const Size2 &p_size) const {
+	Ref<Gradient> gradient = p_from;
+	if (gradient.is_valid()) {
+		Ref<GradientTexture> ptex = Ref<GradientTexture>(memnew(GradientTexture));
+		ptex->set_width(p_size.width * GRADIENT_PREVIEW_TEXTURE_SCALE_FACTOR * EDSCALE);
+		ptex->set_gradient(gradient);
+
+		Ref<ImageTexture> image = Ref<ImageTexture>(memnew(ImageTexture));
+		image->create_from_image(ptex->get_data());
+		return image;
+	}
+	return Ref<Texture>();
+}
+
+EditorGradientPreviewPlugin::EditorGradientPreviewPlugin() {
+}
diff --git a/editor/plugins/editor_preview_plugins.h b/editor/plugins/editor_preview_plugins.h
index 46d475a61..df3137e48 100644
--- a/editor/plugins/editor_preview_plugins.h
+++ b/editor/plugins/editor_preview_plugins.h
@@ -183,3 +183,14 @@ public:
 	~EditorFontPreviewPlugin();
 };
 #endif // EDITORPREVIEWPLUGINS_H
+class EditorGradientPreviewPlugin : public EditorResourcePreviewGenerator {
+	GDCLASS(EditorGradientPreviewPlugin, EditorResourcePreviewGenerator);
+
+public:
+	virtual bool handles(const String &p_type) const;
+	virtual bool generate_small_preview_automatically() const;
+	virtual Ref<Texture> generate(const Ref<Resource> &p_from, const Size2 &p_size) const;
+
+	EditorGradientPreviewPlugin();
+};
+