+ dest->_Complete = src->_Complete;
+ COPY_4V(dest->Swizzle, src->Swizzle);
+ dest->_Swizzle = src->_Swizzle;
+}
+
+
+/**
+ * Check if the given texture object is valid by examining its Target field.
+ * For debugging only.
+ */
+static GLboolean
+valid_texture_object(const struct gl_texture_object *tex)
+{
+ switch (tex->Target) {
+ case 0:
+ case GL_TEXTURE_1D:
+ case GL_TEXTURE_2D:
+ case GL_TEXTURE_3D:
+ case GL_TEXTURE_CUBE_MAP_ARB:
+ case GL_TEXTURE_RECTANGLE_NV:
+ case GL_TEXTURE_1D_ARRAY_EXT:
+ case GL_TEXTURE_2D_ARRAY_EXT:
+ return GL_TRUE;
+ case 0x99:
+ _mesa_problem(NULL, "invalid reference to a deleted texture object");
+ return GL_FALSE;
+ default:
+ _mesa_problem(NULL, "invalid texture object Target value");
+ return GL_FALSE;
+ }
+}
+
+
+/**
+ * Reference (or unreference) a texture object.
+ * If '*ptr', decrement *ptr's refcount (and delete if it becomes zero).
+ * If 'tex' is non-null, increment its refcount.
+ */
+void
+_mesa_reference_texobj(struct gl_texture_object **ptr,
+ struct gl_texture_object *tex)
+{
+ assert(ptr);
+ if (*ptr == tex) {
+ /* no change */
+ return;
+ }
+
+ if (*ptr) {
+ /* Unreference the old texture */
+ GLboolean deleteFlag = GL_FALSE;
+ struct gl_texture_object *oldTex = *ptr;
+
+ assert(valid_texture_object(oldTex));
+
+ _glthread_LOCK_MUTEX(oldTex->Mutex);
+ ASSERT(oldTex->RefCount > 0);
+ oldTex->RefCount--;
+
+ deleteFlag = (oldTex->RefCount == 0);
+ _glthread_UNLOCK_MUTEX(oldTex->Mutex);
+
+ if (deleteFlag) {
+ GET_CURRENT_CONTEXT(ctx);
+ if (ctx)
+ ctx->Driver.DeleteTexture(ctx, oldTex);
+ else
+ _mesa_problem(NULL, "Unable to delete texture, no context");
+ }
+
+ *ptr = NULL;
+ }
+ assert(!*ptr);
+
+ if (tex) {
+ /* reference new texture */
+ assert(valid_texture_object(tex));
+ _glthread_LOCK_MUTEX(tex->Mutex);
+ if (tex->RefCount == 0) {
+ /* this texture's being deleted (look just above) */
+ /* Not sure this can every really happen. Warn if it does. */
+ _mesa_problem(NULL, "referencing deleted texture object");
+ *ptr = NULL;
+ }
+ else {
+ tex->RefCount++;
+ *ptr = tex;
+ }
+ _glthread_UNLOCK_MUTEX(tex->Mutex);
+ }