draw/llvmpipe: allow independent so attachments to the vs

When geometry shaders are present, one needs to be able to create
an empty geometry shader with stream output that needs to be
resolved later and attached to the currently bound vertex shader.
Lets add support for it to llvmpipe and draw. draw allows attaching
independent stream output info to any vertex shader and llvmpipe
resolves at draw time which vertex shader the given empty geometry
shader should be linked to.

Signed-off-by: Zack Rusin <zackr@vmware.com>
Reviewed-by: Brian Paul <brianp@vmware.com>
Reviewed-by: José Fonseca <jfonseca@vmware.com>

6 files changed, 43 insertions, 23 deletions

diff --git a/src/gallium/auxiliary/draw/draw_context.c b/src/gallium/auxiliary/draw/draw_context.c
index bb56f1b..2fb9bac 100644
--- a/src/gallium/auxiliary/draw/draw_context.c
+++ b/src/gallium/auxiliary/draw/draw_context.c
@@ -735,15 +735,6 @@ draw_set_mapped_so_targets(struct draw_context *draw,
 }
 
 void
-draw_set_so_state(struct draw_context *draw,
-                  struct pipe_stream_output_info *state)
-{
-   memcpy(&draw->so.state,
-          state,
-          sizeof(struct pipe_stream_output_info));
-}
-
-void
 draw_set_sampler_views(struct draw_context *draw,
                        unsigned shader_stage,
                        struct pipe_sampler_view **views,
diff --git a/src/gallium/auxiliary/draw/draw_context.h b/src/gallium/auxiliary/draw/draw_context.h
index 426fd44..1d25b7f 100644
--- a/src/gallium/auxiliary/draw/draw_context.h
+++ b/src/gallium/auxiliary/draw/draw_context.h
@@ -171,6 +171,9 @@ void draw_bind_vertex_shader(struct draw_context *draw,
                              struct draw_vertex_shader *dvs);
 void draw_delete_vertex_shader(struct draw_context *draw,
                                struct draw_vertex_shader *dvs);
+void draw_vs_attach_so(struct draw_vertex_shader *dvs,
+                       const struct pipe_stream_output_info *info);
+void draw_vs_reset_so(struct draw_vertex_shader *dvs);
 
 
 /*
@@ -226,10 +229,6 @@ draw_set_mapped_so_targets(struct draw_context *draw,
                            int num_targets,
                            struct draw_so_target *targets[PIPE_MAX_SO_BUFFERS]);
 
-void
-draw_set_so_state(struct draw_context *draw,
-                  struct pipe_stream_output_info *state);
-
 
 /***********************************************************************
  * draw_pt.c 
diff --git a/src/gallium/auxiliary/draw/draw_private.h b/src/gallium/auxiliary/draw/draw_private.h
index 5063c3c..757ed26 100644
--- a/src/gallium/auxiliary/draw/draw_private.h
+++ b/src/gallium/auxiliary/draw/draw_private.h
@@ -279,7 +279,6 @@ struct draw_context
 
    /** Stream output (vertex feedback) state */
    struct {
-      struct pipe_stream_output_info state;
       struct draw_so_target *targets[PIPE_MAX_SO_BUFFERS];
       uint num_targets;
    } so;
diff --git a/src/gallium/auxiliary/draw/draw_vs.c b/src/gallium/auxiliary/draw/draw_vs.c
index 266cca7..afec376 100644
--- a/src/gallium/auxiliary/draw/draw_vs.c
+++ b/src/gallium/auxiliary/draw/draw_vs.c
@@ -245,3 +245,16 @@ draw_vs_get_emit( struct draw_context *draw,
    
    return draw->vs.emit;
 }
+
+void
+draw_vs_attach_so(struct draw_vertex_shader *dvs,
+                  const struct pipe_stream_output_info *info)
+{
+   dvs->state.stream_output = *info;
+}
+
+void
+draw_vs_reset_so(struct draw_vertex_shader *dvs)
+{
+   memset(&dvs->state.stream_output, 0, sizeof(dvs->state.stream_output));
+}
diff --git a/src/gallium/drivers/llvmpipe/lp_draw_arrays.c b/src/gallium/drivers/llvmpipe/lp_draw_arrays.c
index ae00c49..efeca25 100644
--- a/src/gallium/drivers/llvmpipe/lp_draw_arrays.c
+++ b/src/gallium/drivers/llvmpipe/lp_draw_arrays.c
@@ -101,6 +101,13 @@ llvmpipe_draw_vbo(struct pipe_context *pipe, const struct pipe_draw_info *info)
    llvmpipe_prepare_geometry_sampling(lp,
                                       lp->num_sampler_views[PIPE_SHADER_GEOMETRY],
                                       lp->sampler_views[PIPE_SHADER_GEOMETRY]);
+   if (lp->gs && !lp->gs->shader.tokens) {
+      /* we have an empty geometry shader with stream output, so
+         attach the stream output info to the current vertex shader */
+      if (lp->vs) {
+         draw_vs_attach_so(lp->vs->draw_data, &lp->gs->shader.stream_output);
+      }
+   }
 
    /* draw! */
    draw_vbo(draw, info);
@@ -116,6 +123,14 @@ llvmpipe_draw_vbo(struct pipe_context *pipe, const struct pipe_draw_info *info)
    }
    draw_set_mapped_so_targets(draw, 0, NULL);
 
+   if (lp->gs && !lp->gs->shader.tokens) {
+      /* we have attached stream output to the vs for rendering,
+         now lets reset it */
+      if (lp->vs) {
+         draw_vs_reset_so(lp->vs->draw_data);
+      }
+   }
+   
    llvmpipe_cleanup_vertex_sampling(lp);
    llvmpipe_cleanup_geometry_sampling(lp);
 
diff --git a/src/gallium/drivers/llvmpipe/lp_state_gs.c b/src/gallium/drivers/llvmpipe/lp_state_gs.c
index fd6f5f7..b18795c 100644
--- a/src/gallium/drivers/llvmpipe/lp_state_gs.c
+++ b/src/gallium/drivers/llvmpipe/lp_state_gs.c
@@ -53,15 +53,18 @@ llvmpipe_create_gs_state(struct pipe_context *pipe,
    if (0)
       tgsi_dump(templ->tokens, 0);
 
-   /* copy shader tokens, the ones passed in will go away.
-    */
-   state->shader.tokens = tgsi_dup_tokens(templ->tokens);
-   if (state->shader.tokens == NULL)
-      goto fail;
-
-   state->draw_data = draw_create_geometry_shader(llvmpipe->draw, templ);
-   if (state->draw_data == NULL)
-      goto fail;
+   /* copy stream output info */
+   state->shader = *templ;
+   if (templ->tokens) {
+      /* copy shader tokens, the ones passed in will go away. */
+      state->shader.tokens = tgsi_dup_tokens(templ->tokens);
+      if (state->shader.tokens == NULL)
+         goto fail;
+
+      state->draw_data = draw_create_geometry_shader(llvmpipe->draw, templ);
+      if (state->draw_data == NULL)
+         goto fail;
+   }
 
    return state;