i965/fs: Change brw_wm_prog_data::urb_read_length to num_varying_inputs.

On gen4-5, the FS stage reads varying inputs from URB entries that
were output by the SF thread, where each register stores the
interpolation setup for two components of a vec4, therefore the FS
urb_read_length is twice the number of FS input varyings.  On gen6+,
varying inputs are directly deposited in the FS payload by the SF/SBE
fixed function logic, so urb_read_length is irrelevant.

However, in future patches, it will be nice to be able to consult
brw_wm_prog_data to determine how many varying inputs the FS expects
(rather than inferring it from gl_program::InputsRead).  So instead of
storing urb_read_length, we simply store num_varying_inputs in
brw_wm_prog_data.  On gen4-5, we multiply this by 2 to recover the URB
read length.

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>

1 files changed, 1 insertions, 1 deletions

diff --git a/src/mesa/drivers/dri/i965/brw_context.h b/src/mesa/drivers/dri/i965/brw_context.h
index 988e9fb..b9c9f50 100644
--- a/src/mesa/drivers/dri/i965/brw_context.h
+++ b/src/mesa/drivers/dri/i965/brw_context.h
@@ -314,7 +314,7 @@ struct brw_shader {
  */
 struct brw_wm_prog_data {
    GLuint curb_read_length;
-   GLuint urb_read_length;
+   GLuint num_varying_inputs;
 
    GLuint first_curbe_grf;
    GLuint first_curbe_grf_16;