Implement placeholder assets

* Placeholder textures
* Placeholder meshes
* Placeholder material

This PR is the first step towards implementing https://github.com/godotengine/godot-proposals/issues/2756
It adds an asset type that uses no resources, which can be used to replace the existing ones on export for using on the upcoming server export.

8 files changed, 90 insertions, 0 deletions

diff --git a/doc/classes/PlaceholderCubemap.xml b/doc/classes/PlaceholderCubemap.xml
new file mode 100644
index 0000000000..3617c6ac2c
--- /dev/null
+++ b/doc/classes/PlaceholderCubemap.xml
@@ -0,0 +1,9 @@
+<?xml version="1.0" encoding="UTF-8" ?>
+<class name="PlaceholderCubemap" inherits="PlaceholderTextureLayered" version="4.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="../class.xsd">
+	<brief_description>
+	</brief_description>
+	<description>
+	</description>
+	<tutorials>
+	</tutorials>
+</class>
diff --git a/doc/classes/PlaceholderCubemapArray.xml b/doc/classes/PlaceholderCubemapArray.xml
new file mode 100644
index 0000000000..1fcf1e7795
--- /dev/null
+++ b/doc/classes/PlaceholderCubemapArray.xml
@@ -0,0 +1,9 @@
+<?xml version="1.0" encoding="UTF-8" ?>
+<class name="PlaceholderCubemapArray" inherits="PlaceholderTextureLayered" version="4.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="../class.xsd">
+	<brief_description>
+	</brief_description>
+	<description>
+	</description>
+	<tutorials>
+	</tutorials>
+</class>
diff --git a/doc/classes/PlaceholderMaterial.xml b/doc/classes/PlaceholderMaterial.xml
new file mode 100644
index 0000000000..c66641d81c
--- /dev/null
+++ b/doc/classes/PlaceholderMaterial.xml
@@ -0,0 +1,9 @@
+<?xml version="1.0" encoding="UTF-8" ?>
+<class name="PlaceholderMaterial" inherits="Material" version="4.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="../class.xsd">
+	<brief_description>
+	</brief_description>
+	<description>
+	</description>
+	<tutorials>
+	</tutorials>
+</class>
diff --git a/doc/classes/PlaceholderMesh.xml b/doc/classes/PlaceholderMesh.xml
new file mode 100644
index 0000000000..cc688816b6
--- /dev/null
+++ b/doc/classes/PlaceholderMesh.xml
@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="UTF-8" ?>
+<class name="PlaceholderMesh" inherits="Mesh" version="4.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="../class.xsd">
+	<brief_description>
+	</brief_description>
+	<description>
+	</description>
+	<tutorials>
+	</tutorials>
+	<members>
+		<member name="aabb" type="AABB" setter="set_aabb" getter="get_aabb" default="AABB(0, 0, 0, 0, 0, 0)">
+		</member>
+	</members>
+</class>
diff --git a/doc/classes/PlaceholderTexture2D.xml b/doc/classes/PlaceholderTexture2D.xml
new file mode 100644
index 0000000000..76e575265b
--- /dev/null
+++ b/doc/classes/PlaceholderTexture2D.xml
@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="UTF-8" ?>
+<class name="PlaceholderTexture2D" inherits="Texture2D" version="4.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="../class.xsd">
+	<brief_description>
+	</brief_description>
+	<description>
+	</description>
+	<tutorials>
+	</tutorials>
+	<members>
+		<member name="size" type="Vector2" setter="set_size" getter="get_size" default="Vector2(1, 1)">
+		</member>
+	</members>
+</class>
diff --git a/doc/classes/PlaceholderTexture2DArray.xml b/doc/classes/PlaceholderTexture2DArray.xml
new file mode 100644
index 0000000000..a502e5d334
--- /dev/null
+++ b/doc/classes/PlaceholderTexture2DArray.xml
@@ -0,0 +1,9 @@
+<?xml version="1.0" encoding="UTF-8" ?>
+<class name="PlaceholderTexture2DArray" inherits="PlaceholderTextureLayered" version="4.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="../class.xsd">
+	<brief_description>
+	</brief_description>
+	<description>
+	</description>
+	<tutorials>
+	</tutorials>
+</class>
diff --git a/doc/classes/PlaceholderTexture3D.xml b/doc/classes/PlaceholderTexture3D.xml
new file mode 100644
index 0000000000..d31e538307
--- /dev/null
+++ b/doc/classes/PlaceholderTexture3D.xml
@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="UTF-8" ?>
+<class name="PlaceholderTexture3D" inherits="Texture3D" version="4.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="../class.xsd">
+	<brief_description>
+	</brief_description>
+	<description>
+	</description>
+	<tutorials>
+	</tutorials>
+	<members>
+		<member name="size" type="Vector3i" setter="set_size" getter="get_size" default="Vector3i(1, 1, 1)">
+		</member>
+	</members>
+</class>
diff --git a/doc/classes/PlaceholderTextureLayered.xml b/doc/classes/PlaceholderTextureLayered.xml
new file mode 100644
index 0000000000..39af08473a
--- /dev/null
+++ b/doc/classes/PlaceholderTextureLayered.xml
@@ -0,0 +1,15 @@
+<?xml version="1.0" encoding="UTF-8" ?>
+<class name="PlaceholderTextureLayered" inherits="TextureLayered" version="4.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="../class.xsd">
+	<brief_description>
+	</brief_description>
+	<description>
+	</description>
+	<tutorials>
+	</tutorials>
+	<members>
+		<member name="layers" type="int" setter="set_layers" getter="get_layers" default="1">
+		</member>
+		<member name="size" type="Vector2i" setter="set_size" getter="get_size" default="Vector2i(1, 1)">
+		</member>
+	</members>
+</class>