i965/vs: add support for emitting gl_ClipVertex

Removes the special-case suppression of gl_ClipVertex in the VUE map.

Also calculate vertex outcodes for user clip planes based on
gl_ClipVertex if written; otherwise gl_Position.

Signed-off-by: Chris Forbes <[email protected]>
Reviewed-by: Paul Berry <[email protected]>
Reviewed-by: Kenneth Graunke <[email protected]>

2 files changed, 3 insertions, 7 deletions

diff --git a/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp b/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp
index b2f8f009db9..33c1b2483c4 100644
--- a/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp
+++ b/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp
@@ -2567,8 +2567,10 @@ vec4_visitor::emit_psiz_and_flags(struct brw_reg reg)
       current_annotation = "Clipping flags";
       for (i = 0; i < key->nr_userclip_plane_consts; i++) {
 	 vec4_instruction *inst;
+         gl_varying_slot slot = (prog_data->vue_map.slots_valid & VARYING_BIT_CLIP_VERTEX)
+            ? VARYING_SLOT_CLIP_VERTEX : VARYING_SLOT_POS;
 
-	 inst = emit(DP4(dst_null_f(), src_reg(output_reg[VARYING_SLOT_POS]),
+	 inst = emit(DP4(dst_null_f(), src_reg(output_reg[slot]),
                          src_reg(this->userplane[i])));
 	 inst->conditional_mod = BRW_CONDITIONAL_L;
 
diff --git a/src/mesa/drivers/dri/i965/brw_vs.c b/src/mesa/drivers/dri/i965/brw_vs.c
index 6eb916ea4c6..720325dec5c 100644
--- a/src/mesa/drivers/dri/i965/brw_vs.c
+++ b/src/mesa/drivers/dri/i965/brw_vs.c
@@ -63,12 +63,6 @@ brw_compute_vue_map(struct brw_context *brw, struct brw_vue_map *vue_map,
 {
    const struct intel_context *intel = &brw->intel;
 
-   /* Prior to Gen6, don't assign a slot for VARYING_SLOT_CLIP_VERTEX, since
-    * it is unsupported.
-    */
-   if (intel->gen < 6)
-      slots_valid &= ~VARYING_BIT_CLIP_VERTEX;
-
    vue_map->slots_valid = slots_valid;
    int i;