mesa/st: Tie depth_clamp lowering into the FS

v1 implemented by Erik Faye-Lund <[email protected]>
v2: Use different call for FS
v3: Use file scope defined depth_range_state

Signed-off-by: Gert Wollny <[email protected]>
Reviewed-by: Reviewed-by: Marek Olšák <[email protected]>

3 files changed, 18 insertions, 0 deletions

diff --git a/src/mesa/state_tracker/st_atom_shader.c b/src/mesa/state_tracker/st_atom_shader.c
index 97abe72d3ef..a10cc21021c 100644
--- a/src/mesa/state_tracker/st_atom_shader.c
+++ b/src/mesa/state_tracker/st_atom_shader.c
@@ -131,6 +131,11 @@ st_update_fp( struct st_context *st )
          st->ctx->Multisample.MinSampleShadingValue *
          _mesa_geometric_samples(st->ctx->DrawBuffer) > 1;
 
+      key.lower_depth_clamp =
+         st->clamp_frag_depth_in_shader &&
+         (st->ctx->Transform.DepthClampNear ||
+          st->ctx->Transform.DepthClampFar);
+
       if (stfp->ati_fs) {
          key.fog = st->ctx->Fog._PackedEnabledMode;
 
diff --git a/src/mesa/state_tracker/st_program.c b/src/mesa/state_tracker/st_program.c
index 23e9f15cd60..fa7552b2592 100644
--- a/src/mesa/state_tracker/st_program.c
+++ b/src/mesa/state_tracker/st_program.c
@@ -1365,6 +1365,16 @@ st_create_fp_variant(struct st_context *st,
       }
    }
 
+   if (key->lower_depth_clamp) {
+      unsigned depth_range_const = _mesa_add_state_reference(params, depth_range_state);
+
+      const struct tgsi_token *tokens;
+      tokens = st_tgsi_lower_depth_clamp_fs(tgsi.tokens, depth_range_const);
+      if (tgsi.tokens != stfp->tgsi.tokens)
+         tgsi_free_tokens(tgsi.tokens);
+      tgsi.tokens = tokens;
+   }
+
    if (ST_DEBUG & DEBUG_TGSI) {
       tgsi_dump(tgsi.tokens, 0);
       debug_printf("\n");
diff --git a/src/mesa/state_tracker/st_program.h b/src/mesa/state_tracker/st_program.h
index ef55fe33320..eefa340e5cb 100644
--- a/src/mesa/state_tracker/st_program.h
+++ b/src/mesa/state_tracker/st_program.h
@@ -123,6 +123,9 @@ struct st_fp_variant_key
    /** needed for ATI_fragment_shader */
    GLuint fog:2;
 
+   /** for ARB_depth_clamp */
+   GLuint lower_depth_clamp:1;
+
    /** needed for ATI_fragment_shader */
    char texture_targets[MAX_NUM_FRAGMENT_REGISTERS_ATI];