mesa: create _mesa_bind_buffer_range_xfb() helper

Reviewed-by: Iago Toral Quiroga <itoral@igalia.com>
Tested-by: Dieter Nützel <Dieter@nuetzel-hh.de>

src/mesa/main/transformfeedback.h

@@ -150,6 +150,26 @@ _mesa_set_transform_feedback_binding(struct gl_context *ctx,
       bufObj->UsageHistory |= USAGE_TRANSFORM_FEEDBACK_BUFFER;
 }
 
+static inline void
+_mesa_bind_buffer_range_xfb(struct gl_context *ctx,
+                            struct gl_transform_feedback_object *obj,
+                            GLuint index, struct gl_buffer_object *bufObj,
+                            GLintptr offset, GLsizeiptr size)
+{
+   /* Note: no need to FLUSH_VERTICES or flag NewTransformFeedback, because
+    * transform feedback buffers can't be changed while transform feedback is
+    * active.
+    */
+
+   /* The general binding point */
+   _mesa_reference_buffer_object(ctx,
+                                 &ctx->TransformFeedback.CurrentBuffer,
+                                 bufObj);
+
+   /* The per-attribute binding point */
+   _mesa_set_transform_feedback_binding(ctx, obj, index, bufObj, offset, size);
+}
+
 /*** GL_ARB_direct_state_access ***/
 
 extern void GLAPIENTRY