Add static glTF support (#14557)

Co-authored-by: Lars Mueller <appgurulars@gmx.de>
Co-authored-by: jordan4ibanez <jordan4ibanez@users.noreply.github.com>
Co-authored-by: sfan5 <sfan5@live.de>
Co-authored-by: SmallJoker <SmallJoker@users.noreply.github.com>

irr/include/IMesh.h

@@ -86,6 +86,17 @@ public:
 	mesh buffer. */
 	virtual IMeshBuffer *getMeshBuffer(const video::SMaterial &material) const = 0;
 
+	//! Minetest binds textures (node tiles, object textures) to models.
+	// glTF allows multiple primitives (mesh buffers) to reference the same texture.
+	// This is reflected here: This function gets the texture slot for a mesh buffer.
+	/** \param meshbufNr: Zero based index of the mesh buffer. The maximum value is
+	getMeshBufferCount() - 1;
+	\return number of texture slot to bind to the given mesh buffer */
+	virtual u32 getTextureSlot(u32 meshbufNr) const
+	{
+		return meshbufNr;
+	}
+
 	//! Get an axis aligned bounding box of the mesh.
 	/** \return Bounding box of this mesh. */
 	virtual const core::aabbox3d<f32> &getBoundingBox() const = 0;

irr/include/ISkinnedMesh.h

@@ -199,6 +199,9 @@ public:
 	//! Adds a new meshbuffer to the mesh, access it as last one
 	virtual SSkinMeshBuffer *addMeshBuffer() = 0;
 
+	//! Adds a new meshbuffer to the mesh, access it as last one
+	virtual void addMeshBuffer(SSkinMeshBuffer *meshbuf) = 0;
+
 	//! Adds a new joint to the mesh, access it as last one
 	virtual SJoint *addJoint(SJoint *parent = 0) = 0;
 

irr/include/SMesh.h

@@ -64,6 +64,17 @@ struct SMesh : public IMesh
 		return nullptr;
 	}
 
+	u32 getTextureSlot(u32 meshbufNr) const override
+	{
+		return TextureSlots.at(meshbufNr);
+	}
+
+	void setTextureSlot(u32 meshbufNr, u32 textureSlot)
+	{
+		TextureSlots.at(meshbufNr) = textureSlot;
+	}
+
+
 	//! returns an axis aligned bounding box
 	const core::aabbox3d<f32> &getBoundingBox() const override
 	{
@@ -103,6 +114,7 @@ struct SMesh : public IMesh
 		if (buf) {
 			buf->grab();
 			MeshBuffers.push_back(buf);
+			TextureSlots.push_back(getMeshBufferCount() - 1);
 		}
 	}
 
@@ -122,6 +134,8 @@ struct SMesh : public IMesh
 
 	//! The meshbuffers of this mesh
 	std::vector<IMeshBuffer *> MeshBuffers;
+	//! Mapping from meshbuffer number to bindable texture slot
+	std::vector<u32> TextureSlots;
 
 	//! The bounding box of this mesh
 	core::aabbox3d<f32> BoundingBox;

irr/include/SSkinMeshBuffer.h

@@ -6,6 +6,7 @@
 
 #include "IMeshBuffer.h"
 #include "S3DVertex.h"
+#include "irrArray.h"
 
 namespace irr
 {
@@ -21,10 +22,14 @@ struct SSkinMeshBuffer : public IMeshBuffer
 			PrimitiveType(EPT_TRIANGLES), HWBuffer(nullptr),
 			MappingHint_Vertex(EHM_NEVER), MappingHint_Index(EHM_NEVER),
 			BoundingBoxNeedsRecalculated(true)
+	{}
+
+	//! Constructor for standard vertices
+	SSkinMeshBuffer(std::vector<video::S3DVertex> &&vertices, std::vector<u16> &&indices) :
+			SSkinMeshBuffer()
 	{
-#ifdef _DEBUG
-		setDebugName("SSkinMeshBuffer");
-#endif
+		Vertices_Standard = std::move(vertices);
+		Indices = std::move(indices);
 	}
 
 	//! Get Material of this buffer.

irr/include/irrArray.h

@@ -45,6 +45,10 @@ public:
 	{
 	}
 
+	//! Move constructor
+	array(std::vector<T> &&data) :
+			m_data(std::move(data)), is_sorted(false) {}
+
 	//! Reallocates the array, make it bigger or smaller.
 	/** \param new_size New size of array.
 	\param canShrink Specifies whether the array is reallocated even if

irr/include/irrString.h

@@ -11,7 +11,6 @@
 #include <cstdio>
 #include <cstring>
 #include <cwchar>
-#include <locale>
 
 /* HACK: import these string methods from MT's util/string.h */
 extern std::wstring utf8_to_wide(std::string_view input);
@@ -65,6 +64,7 @@ static inline u32 locale_upper(u32 x)
 template <typename T>
 class string
 {
+	using stl_type = std::basic_string<T>;
 public:
 	typedef T char_type;
 
@@ -79,6 +79,10 @@ public:
 		*this = other;
 	}
 
+	string(const stl_type &str) : str(str) {}
+
+	string(stl_type &&str) : str(std::move(str)) {}
+
 	//! Constructor from other string types
 	template <class B>
 	string(const string<B> &other)
@@ -814,13 +818,6 @@ public:
 	friend size_t wStringToUTF8(stringc &destination, const wchar_t *source);
 
 private:
-	typedef std::basic_string<T> stl_type;
-
-	//! Private constructor
-	string(stl_type &&str) :
-			str(str)
-	{
-	}
 
 	//! strlen wrapper
 	template <typename U>