X-Git-Url: http://git.tdb.fi/?a=blobdiff_plain;f=source%2Ftexturecube.h;h=0d23884f1458626b954f2a6badd871d38ff9026f;hb=2157e9320c60d561208dfdf6034e9a06781c9f30;hp=c8e18a11df59adfc123db32460999a5ad90acba8;hpb=70153a4e27eeebc7e0a91de122f45eff6296cb71;p=libs%2Fgl.git

diff --git a/source/texturecube.h b/source/texturecube.h
index c8e18a11..0d23884f 100644
--- a/source/texturecube.h
+++ b/source/texturecube.h
@@ -4,6 +4,7 @@
 #include "datatype.h"
 #include "pixelformat.h"
 #include "texture.h"
+#include "vector.h"
 
 namespace Msp {
 namespace GL {
@@ -21,8 +22,10 @@ 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.  The face is first selected according to the largest coordinate,
-and the remaining two coordinates are used to sample the face image.
+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.
 
 All faces of a cube map texture must be allocated for it to be usable.
 
@@ -35,6 +38,8 @@ private:
 	unsigned size;
 	unsigned allocated;
 
+	static Vector3 directions[6];
+
 public:
 	TextureCube();
 
@@ -62,6 +67,23 @@ public:
 	unsigned get_size() const { return size; }
 private:
 	unsigned get_level_size(unsigned);
+
+public:
+	/** Translates indices into face constants.  Valid indices are between 0
+	and 5, inclusive. */
+	static TextureCubeFace enumerate_faces(unsigned);
+
+	/** Returns a vector pointing out of the face. */
+	static const Vector3 &get_face_direction(TextureCubeFace);
+
+	/** Returns a vector in the direction of the s axis of the face. */
+	static const Vector3 &get_s_direction(TextureCubeFace);
+
+	/** 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. */
+	Vector3 get_texel_direction(TextureCubeFace, unsigned, unsigned);
 };
 
 } // namespace GL