don't crash in RasterPos if feedback not implemented yet

diff --git a/src/mesa/state_tracker/st_cb_rasterpos.c b/src/mesa/state_tracker/st_cb_rasterpos.c
index 661d155e6da20dad135ba008a02ece9a396df5da..13580e400bd8806d1428626ddaac388e20d7ba0f 100644 (file)
--- a/src/mesa/state_tracker/st_cb_rasterpos.c
+++ b/src/mesa/state_tracker/st_cb_rasterpos.c
@@ -101,7 +101,8 @@ setup_feedback(GLcontext *ctx)
       feedback.num_attribs++;
    }
 
-   pipe->set_feedback_state(pipe, &feedback);
+   if (pipe->set_feedback_state)
+      pipe->set_feedback_state(pipe, &feedback);
 }
 
 
@@ -294,7 +295,8 @@ st_RasterPos(GLcontext *ctx, const GLfloat v[4])
       pipe->winsys->buffer_data(pipe->winsys, fb_buf.buffer,
                                 fb_buf.size,
                                 NULL); /* data */
-      pipe->set_feedback_buffer(pipe, 0, &fb_buf);
+      if (pipe->set_feedback_buffer)
+         pipe->set_feedback_buffer(pipe, 0, &fb_buf);
    }
 
 
@@ -347,7 +349,8 @@ st_RasterPos(GLcontext *ctx, const GLfloat v[4])
    pipe->winsys->buffer_reference(pipe->winsys, &fb_buf.buffer, NULL);
 
    /* restore pipe state */
-   pipe->set_feedback_state(pipe, &st->state.feedback);
+   if (pipe->set_feedback_state)
+      pipe->set_feedback_state(pipe, &st->state.feedback);
 }