u_blitter: add support for saving vertex buffers

Currently r300g does not save vertex buffer on blitter calls.

It gets away with it because the current Mesa state tracker usually
resets vertex buffers on every draw calls.

However, this is wrong.

nvfx won't be lucky because it needs to use the blitter inside draw
calls.

src/gallium/auxiliary/util/u_blitter.c

@@ -132,6 +132,7 @@ struct blitter_context *util_blitter_create(struct pipe_context *pipe)
    ctx->blitter.saved_fb_state.nr_cbufs = ~0;
    ctx->blitter.saved_num_sampler_views = ~0;
    ctx->blitter.saved_num_sampler_states = ~0;
+   ctx->blitter.saved_num_vertex_buffers = ~0;
 
    /* blend state objects */
    memset(&blend, 0, sizeof(blend));
@@ -318,6 +319,13 @@ static void blitter_restore_CSOs(struct blitter_context_priv *ctx)
                                        ctx->blitter.saved_sampler_views);
       ctx->blitter.saved_num_sampler_views = ~0;
    }
+
+   if (ctx->blitter.saved_num_vertex_buffers != ~0) {
+      pipe->set_vertex_buffers(pipe,
+                                       ctx->blitter.saved_num_vertex_buffers,
+                                       ctx->blitter.saved_vertex_buffers);
+      ctx->blitter.saved_num_vertex_buffers = ~0;
+   }
 }
 
 static void blitter_set_rectangle(struct blitter_context_priv *ctx,

src/gallium/auxiliary/util/u_blitter.h

@@ -57,6 +57,9 @@ struct blitter_context
 
    int saved_num_sampler_views;
    struct pipe_sampler_view *saved_sampler_views[PIPE_MAX_SAMPLERS];
+
+   int saved_num_vertex_buffers;
+   struct pipe_vertex_buffer saved_vertex_buffers[PIPE_MAX_ATTRIBS];
 };
 
 /**
@@ -255,6 +258,19 @@ util_blitter_save_fragment_sampler_views(struct blitter_context *blitter,
           num_views * sizeof(struct pipe_sampler_view *));
 }
 
+static INLINE void
+util_blitter_save_vertex_buffers(struct blitter_context *blitter,
+                                         int num_vertex_buffers,
+                                         struct pipe_vertex_buffer *vertex_buffers)
+{
+   assert(num_vertex_buffers <= Elements(blitter->saved_vertex_buffers));
+
+   blitter->saved_num_vertex_buffers = num_vertex_buffers;
+   memcpy(blitter->saved_vertex_buffers,
+          vertex_buffers,
+          num_vertex_buffers * sizeof(struct pipe_vertex_buffer));
+}
+
 #ifdef __cplusplus
 }
 #endif