glsl: Create a field to store fractional varying locations.

Currently, the location of each varying is recorded in ir_variable as
a multiple of the size of a vec4.  In order to pack varyings, we need
to be able to record, e.g. that a vec2 is stored in the second half of
a varying slot rather than the first half.

This patch introduces a field ir_variable::location_frac, which
represents the offset within a vec4 where a varying's value is stored.
Varyings that are not subject to packing will always have a
location_frac value of zero.

Reviewed-by: Eric Anholt <[email protected]>
Reviewed-by: Ian Romanick <[email protected]>

1 files changed, 4 insertions, 2 deletions

diff --git a/src/glsl/linker.cpp b/src/glsl/linker.cpp
index ee6dc2596d0..b13a6aa1ab6 100644
--- a/src/glsl/linker.cpp
+++ b/src/glsl/linker.cpp
@@ -226,10 +226,12 @@ link_invalidate_variable_locations(gl_shader *sh, int input_base,
       if ((var->location >= base) && !var->explicit_location)
          var->location = -1;
 
-      if ((var->location == -1) && !var->explicit_location)
+      if ((var->location == -1) && !var->explicit_location) {
          var->is_unmatched_generic_inout = 1;
-      else
+         var->location_frac = 0;
+      } else {
          var->is_unmatched_generic_inout = 0;
+      }
    }
 }