Enforce data hiding

Moved texturevariant_s into texturevariant.c as there is no need
to expose its internal structure.

doomsday/engine/portable/include/texturevariant.h

@@ -21,8 +21,8 @@
  * Boston, MA  02110-1301  USA
  */
 
-#ifndef LIBDENG_GL_TEXTUREVARIANT_H
-#define LIBDENG_GL_TEXTUREVARIANT_H
+#ifndef LIBDENG_REFRESH_TEXTUREVARIANT_H
+#define LIBDENG_REFRESH_TEXTUREVARIANT_H
 
 #include "texturevariantspecification.h"
 
@@ -36,31 +36,16 @@ struct texture_s;
 #define TVF_IS_UPLOADED         0x2 /// Texture has been uploaded to GL.
 /**@}*/
 
-typedef struct texturevariant_s {
-    /// Superior Texture of which this is a derivative.
-    struct texture_s* _generalCase;
-
-    /// @see textureVariantFlags
-    int _flags;
-
-    /// Name of the associated GL texture object.
-    DGLuint _glName;
-
-    /// Prepared coordinates for the bottom right of the texture minus border.
-    float _s, _t;
-
-    /// Specification used to derive this variant.
-    texturevariantspecification_t* _spec;
-} texturevariant_t;
+struct texturevariant_s; // The texturevariant instance (opaque).
+typedef struct texturevariant_s texturevariant_t;
 
 /**
  * @param generalCase  Texture from which this variant is derived.
- * @param glName  GL-name of the associated texture object.
  * @param spec  Specification used to derive this variant. Ownership of
  *      specifcation is NOT given to the resultant TextureVariant
  */
 texturevariant_t* TextureVariant_New(struct texture_s* generalCase,
-    DGLuint glName, texturevariantspecification_t* spec);
+    texturevariantspecification_t* spec);
 
 void TextureVariant_Delete(texturevariant_t* tex);
 
@@ -84,4 +69,4 @@ void TextureVariant_SetCoords(texturevariant_t* tex, float s, float t);
 DGLuint TextureVariant_GLName(const texturevariant_t* tex);
 void TextureVariant_SetGLName(texturevariant_t* tex, DGLuint glName);
 
-#endif /* LIBDENG_GL_TEXTUREVARIANT_H */
+#endif /* LIBDENG_REFRESH_TEXTUREVARIANT_H */

doomsday/engine/portable/src/gl_texmanager.c

@@ -3207,7 +3207,8 @@ static texturevariant_t* tryLoadImageAndPrepareVariant(texture_t* tex,
     if(!variant)
     {
         DGLuint newGLName = GL_GetReservedTextureName();
-        variant = TextureVariant_New(tex, newGLName, spec);
+        variant = TextureVariant_New(tex, spec);
+        TextureVariant_SetGLName(variant, newGLName);
         Texture_AddVariant(tex, variant);
     }
     // Are we re-preparing a released texture?

doomsday/engine/portable/src/texturevariant.c

@@ -28,22 +28,44 @@
 #include "texture.h"
 #include "texturevariant.h"
 
+struct texturevariant_s {
+    /// Superior Texture of which this is a derivative.
+    struct texture_s* _generalCase;
+
+    /// @see textureVariantFlags
+    int _flags;
+
+    /// Name of the associated GL texture object.
+    DGLuint _glName;
+
+    /// Prepared coordinates for the bottom right of the texture minus border.
+    float _s, _t;
+
+    /// Specification used to derive this variant.
+    texturevariantspecification_t* _spec;
+};
+
 texturevariant_t* TextureVariant_New(texture_t* generalCase,
-    DGLuint glName, texturevariantspecification_t* spec)
+    texturevariantspecification_t* spec)
 {
-    assert(generalCase && spec);
-    {
-    texturevariant_t* tex = tex = (texturevariant_t*) malloc(sizeof(*tex));
-    if(NULL == tex)
+    texturevariant_t* tex;
+
+    if(!generalCase)
+        Con_Error("TextureVariant::New: Attempted with invalid generalCase reference (=NULL).");
+    if(!spec)
+        Con_Error("TextureVariant::New: Attempted with invalid spec reference (=NULL).");
+
+    tex = (texturevariant_t*) malloc(sizeof(*tex));
+    if(!tex)
         Con_Error("TextureVariant::Construct: Failed on allocation of %lu bytes for "
             "new TextureVariant.", (unsigned long) sizeof(*tex));
+
     tex->_generalCase = generalCase;
     tex->_spec = spec;
     tex->_flags = 0;
     tex->_s = tex->_t = 0;
-    tex->_glName = glName;
+    tex->_glName = 0;
     return tex;
-    }
 }
 
 void TextureVariant_Delete(texturevariant_t* tex)