[cogl/wip/rig: 16/33] texture: make some texture vfuncs optional

[Robert Bragg <rbragg src gnome org>]

commit 0ca9c3b3a5afc5653087e485b790a3093147ac29
Author: Robert Bragg <robert bragg intel com>
Date:   Tue Mar 18 23:11:57 2014 +0000

    texture: make some texture vfuncs optional
    
    This makes some of the texture vfuncs optional to simplify adding new
    texture types.

 cogl/cogl-texture-private.h |    2 +-
 cogl/cogl-texture.c         |   17 +++++++++++++----
 2 files changed, 14 insertions(+), 5 deletions(-)
---
diff --git a/cogl/cogl-texture-private.h b/cogl/cogl-texture-private.h
index 0feaeb0..ecb7173 100644
--- a/cogl/cogl-texture-private.h
+++ b/cogl/cogl-texture-private.h
@@ -44,7 +44,7 @@
 
 typedef struct _CoglTextureVtable     CoglTextureVtable;
 
-/* Encodes three possibiloities result of transforming a quad */
+/* Encodes three possible result of transforming a quad */
 typedef enum {
   /* quad doesn't cross the boundaries of a texture */
   COGL_TRANSFORM_NO_REPEAT,
diff --git a/cogl/cogl-texture.c b/cogl/cogl-texture.c
index c45509b..070a01e 100644
--- a/cogl/cogl-texture.c
+++ b/cogl/cogl-texture.c
@@ -279,7 +279,11 @@ cogl_texture_is_sliced (CoglTexture *texture)
 {
   if (!texture->allocated)
     cogl_texture_allocate (texture, NULL);
-  return texture->vtable->is_sliced (texture);
+
+  if (texture->vtable->is_sliced)
+    return texture->vtable->is_sliced (texture);
+  else
+    return FALSE;
 }
 
 /* If this returns FALSE, that implies _foreach_sub_texture_in_region
@@ -291,7 +295,10 @@ _cogl_texture_can_hardware_repeat (CoglTexture *texture)
 {
   if (!texture->allocated)
     cogl_texture_allocate (texture, NULL);
-  return texture->vtable->can_hardware_repeat (texture);
+  if (texture->vtable->can_hardware_repeat)
+    return texture->vtable->can_hardware_repeat (texture);
+  else
+    return TRUE;
 }
 
 /* NB: You can't use this with textures comprised of multiple sub textures (use
@@ -302,7 +309,8 @@ _cogl_texture_transform_coords_to_gl (CoglTexture *texture,
                                       float *s,
                                       float *t)
 {
-  texture->vtable->transform_coords_to_gl (texture, s, t);
+  if (texture->vtable->transform_coords_to_gl)
+    texture->vtable->transform_coords_to_gl (texture, s, t);
 }
 
 CoglTransformResult
@@ -353,7 +361,8 @@ _cogl_texture_pre_paint (CoglTexture *texture, CoglTexturePrePaintFlags flags)
 void
 _cogl_texture_ensure_non_quad_rendering (CoglTexture *texture)
 {
-  texture->vtable->ensure_non_quad_rendering (texture);
+  if (texture->vtable->ensure_non_quad_rendering)
+    texture->vtable->ensure_non_quad_rendering (texture);
 }
 
 CoglBool