Update and improve documentation

[libs/gl.git] / source / core / texturecube.h

diff --git a/source/core/texturecube.h b/source/core/texturecube.h
index e738ab53beba296520c3d130744a82b8b3e4208c..aa43c9da0a97ca084bd2690fd1f1e7b2dae35b13 100644 (file)
--- a/source/core/texturecube.h
+++ b/source/core/texturecube.h
@@ -19,16 +19,13 @@ enum TextureCubeFace
 };
 
 /**
-Cube map texture, consisting of six square faces.  All of the faces must be of
-the same size.  A cube map texture is addressed by three-dimensional texture
-coordinates, with a principal range of [-1, 1].  The face is first selected
-according to the largest coordinate, and the remaining two coordinates are used
-to sample the face image.  The images are oriented so that the cross product of
-the s and t axes will point into the cube.
+Cube map texture, consisting of six square faces.
 
-All faces of a cube map texture must be allocated for it to be usable.
-
-Requires OpenGL version 1.3.
+A cube map texture is addressed by three-dimensional texture coordinates.  The
+coordinate vector is projected on the unit cube, with the largest coordinate
+selecting the face and the remaining two used to sample from the face image.
+The images are oriented so that the cross product of the s and t axes will
+point into the cube.
 */
 class TextureCube: public TextureCubeBackend
 {
@@ -58,25 +55,27 @@ private:
        static const unsigned orientations[12];
 
 public:
-       /** Defines storage structure for the texture.  If lv is zero, the number
-       of mipmap levels is automatically determined from storage dimensions.
-
-       Must be called before an image can be uploaded.  Once storage is defined,
-       it can't be changed. */
-       void storage(PixelFormat fmt, unsigned size, unsigned lv = 0);
+       /** Sets storage format and dimensions and allocates memory for the texture.
+       If lv is zero, a complete mipmap pyramid is automatically created.  Storage
+       cannot be changed once set. */
+       void storage(PixelFormat, unsigned size, unsigned lv = 0);
 
-       /** Updates the contents of a face.  Storage must be defined beforehand.
-       The image data must have dimensions and format matching the defined
-       storage. */
-       void image(TextureCubeFace face, unsigned level, const void *data);
+       /** Replaces contents of a single face.  Allocated storage must exist.  The
+       image data is interpreted according to the storage format and must have size
+       matching the selected mipmap level. */
+       void image(TextureCubeFace, unsigned level, const void *);
 
-       /** Updates a rectangular region of a face.  Storage must be defined
-       beforehand.  The image data must be in a format mathing the defined storage
-       and the update region must be fully inside the face. */
-       void sub_image(TextureCubeFace face, unsigned level, int x, int y, unsigned w, unsigned h, const void *data);
+       /** Replaces a rectangular region of a face.  Allocated storage must exist.
+       The image data is interpreted according to the storage format and the region
+       must be fully inside the face. */
+       void sub_image(TextureCubeFace, unsigned level, int x, int y, unsigned w, unsigned h, const void *);
 
        void image(TextureCubeFace, const Graphics::Image &);
 
+       /** Sets the texture's contents from an image.  The image is treated as a
+       stack of square layers and its height must be six times its width.  If
+       storage has not been allocated yet, it will be set to match the image.
+       Otherwise the image must be compatible with the existing storage. */
        virtual void image(const Graphics::Image &, unsigned = 0);
 
        unsigned get_size() const { return size; }
@@ -94,7 +93,7 @@ public:
        /** Returns a vector in the direction of the t axis of the face. */
        static const Vector3 &get_t_direction(TextureCubeFace);
 
-       /** Returns a vector pointing to the center a texel. */
+       /** Returns a vector pointing to the center of a texel. */
        Vector3 get_texel_direction(TextureCubeFace, unsigned, unsigned);
 
        virtual AsyncLoader *load(IO::Seekable &, const Resources * = 0) { return 0; }