Implement support for array textures in GL driver

note: feature detection was not implemented in the legacy driver, but the code itself probably works.

irr/include/EDriverFeatures.h

@@ -132,6 +132,9 @@ enum E_VIDEO_DRIVER_FEATURE
 	//! Support for multisample textures.
 	EVDF_TEXTURE_MULTISAMPLE,
 
+	//! Support for 2D array textures.
+	EVDF_TEXTURE_2D_ARRAY,
+
 	//! Only used for counting the elements of this enum
 	EVDF_COUNT
 };

irr/include/ITexture.h

@@ -129,7 +129,10 @@ enum E_TEXTURE_TYPE
 	ETT_2D_MS,
 
 	//! Cubemap texture.
-	ETT_CUBEMAP
+	ETT_CUBEMAP,
+
+	//! 2D array texture
+	ETT_2D_ARRAY
 };
 
 //! Interface of a Video Driver dependent Texture.

irr/include/IVideoDriver.h

@@ -232,6 +232,15 @@ public:
 	information. */
 	virtual ITexture *addTexture(const io::path &name, IImage *image) = 0;
 
+	/**
+	 * Creates an array texture from IImages.
+	 * @param name A name for the texture.
+	 * @param images Pointer to array of images
+	 * @param count Number of images (must be at least 1)
+	 * @return Pointer to the newly created texture
+	 */
+	virtual ITexture *addArrayTexture(const io::path &name, IImage **images, u32 count) = 0;
+
 	//! Creates a cubemap texture from loaded IImages.
 	/** \param name A name for the texture. Later calls of getTexture() with this name will return this texture.
 	The name can _not_ be empty.