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 <[email protected]>
Reviewed-by: Brian Paul <[email protected]>
Reviewed-by: José Fonseca <[email protected]>

2 files changed, 27 insertions, 9 deletions

diff --git a/src/gallium/drivers/llvmpipe/lp_draw_arrays.c b/src/gallium/drivers/llvmpipe/lp_draw_arrays.c
index ae00c49d490..efeca255755 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 fd6f5f7d0da..b18795cdc4f 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;