[Mesa-dev] [PATCH] st/mesa: allow glDrawElements to work with GL_SELECT feedback

[Ilia Mirkin]

Not sure if this ever worked, but the current logic for setting the
min/max index is definitely wrong for indexed draws. While we're at it,
bring in all the usual logic from the non-indirect drawing path.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=109086
Signed-off-by: Ilia Mirkin <imirkin at alum.mit.edu>
---

This makes it more or less mirror st_draw_vbo. As the comment in the
code says, would be nice to refactor, but ... meh.

Note that I haven't tested any of the interactions with additional
features, like primitive restart or instancing or any of that. However I
don't think that this would make things *worse*.

 src/mesa/state_tracker/st_draw_feedback.c | 61 +++++++++++++++--------
 1 file changed, 39 insertions(+), 22 deletions(-)

diff --git a/src/mesa/state_tracker/st_draw_feedback.c b/src/mesa/state_tracker/st_draw_feedback.c
index 6ec6d5c16f4..49fdecf7e38 100644
--- a/src/mesa/state_tracker/st_draw_feedback.c
+++ b/src/mesa/state_tracker/st_draw_feedback.c
@@ -84,27 +84,6 @@ set_feedback_vertex_format(struct gl_context *ctx)
 }
 
 
-/**
- * Helper for drawing current vertex arrays.
- */
-static void
-draw_arrays(struct draw_context *draw, unsigned mode,
-            unsigned start, unsigned count)
-{
-   struct pipe_draw_info info;
-
-   util_draw_init_info(&info);
-
-   info.mode = mode;
-   info.start = start;
-   info.count = count;
-   info.min_index = start;
-   info.max_index = start + count - 1;
-
-   draw_vbo(draw, &info);
-}
-
-
 /**
  * Called by VBO to draw arrays when in selection or feedback mode and
  * to implement glRasterPos.
@@ -136,10 +115,18 @@ st_feedback_draw_vbo(struct gl_context *ctx,
    struct pipe_transfer *ib_transfer = NULL;
    GLuint i;
    const void *mapped_indices = NULL;
+   struct pipe_draw_info info;
 
    if (!draw)
       return;
 
+   /* Initialize pipe_draw_info. */
+   info.primitive_restart = false;
+   info.vertices_per_patch = ctx->TessCtrlProgram.patch_vertices;
+   info.indirect = NULL;
+   info.count_from_stream_output = NULL;
+   info.restart_index = 0;
+
    st_flush_bitmap_cache(st);
    st_invalidate_readpix_cache(st);
 
@@ -213,9 +200,23 @@ st_feedback_draw_vbo(struct gl_context *ctx,
          mapped_indices = ib->ptr;
       }
 
+      info.index_size = ib->index_size;
+      info.min_index = min_index;
+      info.max_index = max_index;
+      info.has_user_indices = true;
+      info.index.user = mapped_indices;
+
       draw_set_indexes(draw,
                        (ubyte *) mapped_indices,
                        index_size, ~0);
+
+      if (ctx->Array._PrimitiveRestart) {
+         info.primitive_restart = true;
+         info.restart_index = _mesa_primitive_restart_index(ctx, info.index_size);
+      }
+   } else {
+      info.index_size = 0;
+      info.has_user_indices = false;
    }
 
    /* set the constant buffer */
@@ -226,7 +227,23 @@ st_feedback_draw_vbo(struct gl_context *ctx,
 
    /* draw here */
    for (i = 0; i < nr_prims; i++) {
-      draw_arrays(draw, prims[i].mode, start + prims[i].start, prims[i].count);
+      info.count = prims[i].count;
+
+      if (!info.count)
+         continue;
+
+      info.mode = prims[i].mode;
+      info.start = start + prims[i].start;
+      info.start_instance = prims[i].base_instance;
+      info.instance_count = prims[i].num_instances;
+      info.index_bias = prims[i].basevertex;
+      info.drawid = prims[i].draw_id;
+      if (!ib) {
+         info.min_index = info.start;
+         info.max_index = info.start + info.count - 1;
+      }
+
+      draw_vbo(draw, &info);
    }
 
 
-- 
2.18.1