cogl-texture: List texture subclass types rather than hardcoding them

Instead of having a hardcoded series of if-statements in
cogl_is_texture to determine which types should appear as texture
subclasses, they are now stored in a GSList attached to the Cogl
context. The list is amended to using a new cogl_texture_register_type
function. There is a convenience macro called COGL_TEXTURE_DEFINE
which uses COGL_HANDLE_DEFINE_WITH_CODE to register the texture type
when the _get_type() function is first called.

cogl/cogl-atlas-texture.c

@@ -72,7 +72,7 @@
 
 static void _cogl_atlas_texture_free (CoglAtlasTexture *sub_tex);
 
-COGL_HANDLE_DEFINE (AtlasTexture, atlas_texture);
+COGL_TEXTURE_DEFINE (AtlasTexture, atlas_texture);
 
 static const CoglTextureVtable cogl_atlas_texture_vtable;
 

cogl/cogl-context.c

@@ -65,6 +65,8 @@ cogl_create_context (void)
   _context->feature_flags_private = 0;
   _context->features_cached = FALSE;
 
+  _context->texture_types = NULL;
+
   /* Initialise the driver specific state */
   /* TODO: combine these two into one function */
   _cogl_create_context_driver (_context);
@@ -251,6 +253,8 @@ _cogl_destroy_context (void)
   _cogl_bitmask_destroy (&_context->temp_bitmask);
   _cogl_bitmask_destroy (&_context->texcoord_arrays_to_disable);
 
+  g_slist_free (_context->texture_types);
+
   g_free (_context);
 }
 

cogl/cogl-context.h

@@ -162,6 +162,10 @@ typedef struct
   CoglMaterialProgramType current_use_program_type;
   GLuint                  current_gl_program;
 
+  /* List of types that will be considered a subclass of CoglTexture in
+     cogl_is_texture */
+  GSList           *texture_types;
+
   CoglContextDriver drv;
 } CoglContext;
 

cogl/cogl-sub-texture.c

@@ -42,7 +42,7 @@
 
 static void _cogl_sub_texture_free (CoglSubTexture *sub_tex);
 
-COGL_HANDLE_DEFINE (SubTexture, sub_texture);
+COGL_TEXTURE_DEFINE (SubTexture, sub_texture);
 
 static const CoglTextureVtable cogl_sub_texture_vtable;
 

cogl/cogl-texture-2d-sliced.c

@@ -50,7 +50,7 @@
 
 static void _cogl_texture_2d_sliced_free (CoglTexture2DSliced *tex_2ds);
 
-COGL_HANDLE_DEFINE (Texture2DSliced, texture_2d_sliced);
+COGL_TEXTURE_DEFINE (Texture2DSliced, texture_2d_sliced);
 
 static const CoglTextureVtable cogl_texture_2d_sliced_vtable;
 

cogl/cogl-texture-2d.c

@@ -44,7 +44,7 @@
 
 static void _cogl_texture_2d_free (CoglTexture2D *tex_2d);
 
-COGL_HANDLE_DEFINE (Texture2D, texture_2d);
+COGL_TEXTURE_DEFINE (Texture2D, texture_2d);
 
 static const CoglTextureVtable cogl_texture_2d_vtable;
 

cogl/cogl-texture-private.h

@@ -142,6 +142,17 @@ typedef enum _CoglTextureChangeFlags
 void
 _cogl_texture_free (CoglTexture *texture);
 
+/* This is used to register a type to the list of handle types that
+   will be considered a texture in cogl_is_texture() */
+void
+_cogl_texture_register_texture_type (GQuark type);
+
+#define COGL_TEXTURE_DEFINE(TypeName, type_name)                        \
+  COGL_HANDLE_DEFINE_WITH_CODE                                          \
+  (TypeName, type_name,                                                 \
+   _cogl_texture_register_texture_type (_cogl_handle_                   \
+                                        ## type_name ## _get_type ()))
+
 void
 _cogl_texture_foreach_sub_texture_in_region (CoglHandle handle,
                                              float virtual_tx_1,

cogl/cogl-texture.c

@@ -59,18 +59,31 @@
  * abstract class manually.
  */
 
+void
+_cogl_texture_register_texture_type (GQuark type)
+{
+  _COGL_GET_CONTEXT (ctxt, NO_RETVAL);
+
+  ctxt->texture_types = g_slist_prepend (ctxt->texture_types,
+                                         GINT_TO_POINTER (type));
+}
+
 gboolean
 cogl_is_texture (CoglHandle handle)
 {
   CoglHandleObject *obj = (CoglHandleObject *)handle;
+  GSList *l;
+
+  _COGL_GET_CONTEXT (ctxt, FALSE);
 
   if (handle == COGL_INVALID_HANDLE)
     return FALSE;
 
-  return (obj->klass->type == _cogl_handle_texture_2d_get_type () ||
-          obj->klass->type == _cogl_handle_atlas_texture_get_type () ||
-          obj->klass->type == _cogl_handle_texture_2d_sliced_get_type () ||
-          obj->klass->type == _cogl_handle_sub_texture_get_type ());
+  for (l = ctxt->texture_types; l; l = l->next)
+    if (GPOINTER_TO_INT (l->data) == obj->klass->type)
+      return TRUE;
+
+  return FALSE;
 }
 
 CoglHandle