draw: fixup draw_find_shader_output

draw_find_shader_output like most of the code in draw used to
depend on position always being at output slot 0. which meant
that any other attribute being at 0 could signify an error.
unfortunately position can be at any of the output slots, thus
other attributes can occupy slot 0 and we need to mark the ones
which were not found by something else. This commit changes
draw_find_shader_output so that it returns -1 if it can't
find the given attribute and adjust the code that depended
on it returning >0 whenever it correctly found an attrib.

Signed-off-by: Zack Rusin <[email protected]>
Reviewed-by: José Fonseca<[email protected]>
Reviewed-by: Brian Paul <[email protected]>
Reviewed-by: Roland Scheidegger <[email protected]>

1 files changed, 1 insertions, 1 deletions

diff --git a/src/gallium/auxiliary/draw/draw_vertex.h b/src/gallium/auxiliary/draw/draw_vertex.h
index c87c3d84ce2..9e10ada1a59 100644
--- a/src/gallium/auxiliary/draw/draw_vertex.h
+++ b/src/gallium/auxiliary/draw/draw_vertex.h
@@ -125,7 +125,7 @@ static INLINE uint
 draw_emit_vertex_attr(struct vertex_info *vinfo,
                       enum attrib_emit emit, 
                       enum interp_mode interp, /* only used by softpipe??? */
-                      uint src_index)
+                      int src_index)
 {
    const uint n = vinfo->num_attribs;
    assert(n < Elements(vinfo->attrib));