Mesa (master): glsl: do not set the 'smooth' qualifier by default on ES shaders

[Nicolai Hähnle]

Module: Mesa
Branch: master
Commit: fcae1a64ec0ef96bf90e473893849213ab9c14dd
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=fcae1a64ec0ef96bf90e473893849213ab9c14dd

Author: Nicolai Hähnle <nicolai.haehnle at amd.com>
Date:   Mon Sep 11 16:40:37 2017 +0200

glsl: do not set the 'smooth' qualifier by default on ES shaders

It leads to surprising states with integer inputs and outputs on
vertex processing stages (e.g. geometry stages). Instead, rely on the
driver to choose smooth interpolation by default.

We still allow varyings to match when one stage declares it as smooth
and the other declares it without interpolation qualifiers.

Reviewed-by: Marek Olšák <marek.olsak at amd.com>
Tested-by: Dieter Nützel <Dieter at nuetzel-hh.de>

---

 src/compiler/glsl/ast_to_hir.cpp    | 11 -----------
 src/compiler/glsl/link_varyings.cpp | 17 ++++++++++++++++-
 src/mesa/main/shader_query.cpp      |  8 +++++++-
 3 files changed, 23 insertions(+), 13 deletions(-)

diff --git a/src/compiler/glsl/ast_to_hir.cpp b/src/compiler/glsl/ast_to_hir.cpp
index c46454956d..1999e68158 100644
--- a/src/compiler/glsl/ast_to_hir.cpp
+++ b/src/compiler/glsl/ast_to_hir.cpp
@@ -3126,17 +3126,6 @@ interpret_interpolation_qualifier(const struct ast_type_qualifier *qual,
       interpolation = INTERP_MODE_NOPERSPECTIVE;
    else if (qual->flags.q.smooth)
       interpolation = INTERP_MODE_SMOOTH;
-   else if (state->es_shader &&
-            ((mode == ir_var_shader_in &&
-              state->stage != MESA_SHADER_VERTEX) ||
-             (mode == ir_var_shader_out &&
-              state->stage != MESA_SHADER_FRAGMENT)))
-      /* Section 4.3.9 (Interpolation) of the GLSL ES 3.00 spec says:
-       *
-       *    "When no interpolation qualifier is present, smooth interpolation
-       *    is used."
-       */
-      interpolation = INTERP_MODE_SMOOTH;
    else
       interpolation = INTERP_MODE_NONE;
 
diff --git a/src/compiler/glsl/link_varyings.cpp b/src/compiler/glsl/link_varyings.cpp
index 656bf79ca9..ed3bf41687 100644
--- a/src/compiler/glsl/link_varyings.cpp
+++ b/src/compiler/glsl/link_varyings.cpp
@@ -325,8 +325,23 @@ cross_validate_types_and_qualifiers(struct gl_shader_program *prog,
     *     "It is a link-time error if, within the same stage, the interpolation
     *     qualifiers of variables of the same name do not match.
     *
+    * Section 4.3.9 (Interpolation) of the GLSL ES 3.00 spec says:
+    *
+    *    "When no interpolation qualifier is present, smooth interpolation
+    *    is used."
+    *
+    * So we match variables where one is smooth and the other has no explicit
+    * qualifier.
     */
-   if (input->data.interpolation != output->data.interpolation &&
+   unsigned input_interpolation = input->data.interpolation;
+   unsigned output_interpolation = output->data.interpolation;
+   if (prog->IsES) {
+      if (input_interpolation == INTERP_MODE_NONE)
+         input_interpolation = INTERP_MODE_SMOOTH;
+      if (output_interpolation == INTERP_MODE_NONE)
+         output_interpolation = INTERP_MODE_SMOOTH;
+   }
+   if (input_interpolation != output_interpolation &&
        prog->data->Version < 440) {
       linker_error(prog,
                    "%s shader output `%s' specifies %s "
diff --git a/src/mesa/main/shader_query.cpp b/src/mesa/main/shader_query.cpp
index 64e68b4a26..6712bb45fb 100644
--- a/src/mesa/main/shader_query.cpp
+++ b/src/mesa/main/shader_query.cpp
@@ -1634,7 +1634,13 @@ validate_io(struct gl_program *producer, struct gl_program *consumer)
        * Note that location mismatches are detected by the loops above that
        * find the producer variable that goes with the consumer variable.
        */
-      if (producer_var->interpolation != consumer_var->interpolation) {
+      unsigned producer_interpolation = producer_var->interpolation;
+      unsigned consumer_interpolation = consumer_var->interpolation;
+      if (producer_interpolation == INTERP_MODE_NONE)
+         producer_interpolation = INTERP_MODE_SMOOTH;
+      if (consumer_interpolation == INTERP_MODE_NONE)
+         consumer_interpolation = INTERP_MODE_SMOOTH;
+      if (producer_interpolation != consumer_interpolation) {
          valid = false;
          goto out;
       }