[Mesa-dev] [PATCH] glsl: Drop the ES requirement that VS outputs must be flat qualified.

[Kenneth Graunke]

Several conformance tests violate this requirement:

ES31-CTS.core.tessellation_shader.max_patch_vertices
ES31-CTS.core.tessellation_shader.tessellation_control_to_tessellation_evaluation.data_pass_through

I submitted a merge request to fix the conformance tests, but Khronos
opted to drop this GLSL ES specific requirement in favor of making flat
qualification of VS outputs optional, matching modern desktop GL.

Note that there are 7 Piglit tests which enforce this rule:
tests/spec/glsl-es-3.00/compiler/interpolation/qualifiers/*nonflat*
These would regress, but I've sent a Piglit patch to delete them.

Bugzilla: https://cvs.khronos.org/bugzilla/show_bug.cgi?id=15465#c7
Signed-off-by: Kenneth Graunke <kenneth at whitecape.org>
---
 src/compiler/glsl/ast_to_hir.cpp | 12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

See also:
https://lists.freedesktop.org/archives/piglit/2016-October/020959.html

diff --git a/src/compiler/glsl/ast_to_hir.cpp b/src/compiler/glsl/ast_to_hir.cpp
index 2ad97d9..8e76cd8 100644
--- a/src/compiler/glsl/ast_to_hir.cpp
+++ b/src/compiler/glsl/ast_to_hir.cpp
@@ -2972,14 +2972,10 @@ validate_interpolation_qualifier(struct _mesa_glsl_parse_state *state,
    if (state->is_version(130, 300)
        && var_type->contains_integer()
        && interpolation != INTERP_MODE_FLAT
-       && ((state->stage == MESA_SHADER_FRAGMENT && mode == ir_var_shader_in)
-           || (state->stage == MESA_SHADER_VERTEX && mode == ir_var_shader_out
-               && state->es_shader))) {
-      const char *shader_var_type = (state->stage == MESA_SHADER_VERTEX) ?
-         "vertex output" : "fragment input";
-      _mesa_glsl_error(loc, state, "if a %s is (or contains) "
-                       "an integer, then it must be qualified with 'flat'",
-                       shader_var_type);
+       && state->stage == MESA_SHADER_FRAGMENT
+       && mode == ir_var_shader_in) {
+      _mesa_glsl_error(loc, state, "if a fragment input is (or contains) "
+                       "an integer, then it must be qualified with 'flat'");
    }
 
    /* Double fragment inputs must be qualified with 'flat'.
-- 
2.10.0