X-Git-Url: http://git.tdb.fi/?a=blobdiff_plain;f=source%2Ftexture2d.h;h=35346e0091e2bbc8a24bf827bec4a96d921cbbd8;hb=edd2a01b3c696df8630ac6a97e9b55a95fe7e112;hp=05fbbce2e80b6362e576077ca4fe019311576f46;hpb=48d253c9f19c04c6940bfc932a78c51ea24e2e75;p=libs%2Fgl.git

diff --git a/source/texture2d.h b/source/texture2d.h
index 05fbbce2..35346e00 100644
--- a/source/texture2d.h
+++ b/source/texture2d.h
@@ -11,12 +11,14 @@ namespace Msp {
 namespace GL {
 
 /**
-Two-dimensional texture class.  This is the most common type of texture.
+Two-dimensional texture.  Consists of an array of texels in the shape of a
+rectangle.  Texture coordinate have a principal range of [0, 1].  This is the
+most common type of texture.
 */
 class Texture2D: public Texture
 {
 public:
-	class Loader: public Texture::Loader
+	class Loader: public Msp::DataFile::DerivedObjectLoader<Texture2D, Texture::Loader>
 	{
 	public:
 		Loader(Texture2D &);
@@ -36,39 +38,38 @@ private:
 public:
 	Texture2D();
 
-	/**
-	Defines the texture storage.  This function may only be successfully called
-	once.
-	*/
+	/** Defines storage structure for the texture.  Must be called before an
+	image can be uploaded.  Once storage is defined, it can't be changed. */
 	void storage(PixelFormat fmt, unsigned wd, unsigned ht);
 
-	/** Allocates texture storage.  If storage has already been allocated, this
-	function does nothing. */
+	/** Allocates storage for the texture.  The contents are initially
+	undefined.  If storage has already been allocated, does nothing. */
 	void allocate(unsigned level);
 	
-	/** Uploads an image to the texture.  storage() must have been called prior to
-	this, and the image must have dimensions conforming to the specified
-	storage.  For level>0, mipmapping rules apply to the image dimensions. */
+	/** Uploads an image to the texture.  Storage must be defined beforehand.
+	The image data must have dimensions and format compatible with the defined
+	storage. */
 	void image(unsigned level, PixelFormat fmt, DataType type, const void *data);
 
-	/**
-	Uploads a sub-image into the texture.  Unlike full image upload, there are
-	no constraints on the size of the sub-image.
-	*/
-	void sub_image(unsigned level, int x, int y, unsigned wd, unsigned ht, PixelFormat fmt, DataType type, const void *data);
+	/** Updates a rectangular region of the texture.  Storage must be defined
+	and allocated beforehand.  The update region must be fully inside the
+	texture. */
+	void sub_image(unsigned level, int x, int y, unsigned wd, unsigned ht,
+		PixelFormat fmt, DataType type, const void *data);
 
-	/**
-	Loads an image from a file and uploads it to the texture.  If storage() has
-	not been called, the storage format will be set to match the loaded image.
-	*/
+	/** Loads an image from a file and uploads it to the texture.  If storage
+	has not been defined, it will be set to match the loaded image.  Otherwise
+	the image must be compatible with the defined storage. */
 	void load_image(const std::string &fn);
 
+private:
+	void image(const Graphics::Image &);
+
+public:
 	unsigned get_width() const  { return width; }
 	unsigned get_height() const { return height; }
 
 private:
-	void image(const Graphics::Image &);
-	void require_storage();
 	void get_level_size(unsigned, unsigned &, unsigned &);
 };