[Mesa-dev] [PATCH] glsl: Raise a link error for non-SSO ES programs with a TES but no TCS.

[Kenneth Graunke]

OpenGL allows the TCS to be missing and supplies an implicit passthrough
shader, but OpenGL ES does not.

One open question is how to handle this for ARB_ES3_2_compatibility.
This patch raises the link error for all ES shading language programs,
but it might make sense to base it on the API.  The approach taken in
this patch is more restrictive, but should still allow any valid ES
programs to work in GL.

Signed-off-by: Kenneth Graunke <kenneth at whitecape.org>
---
 src/compiler/glsl/linker.cpp | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/src/compiler/glsl/linker.cpp b/src/compiler/glsl/linker.cpp
index b6f8bc4212e..9e68c6e2d71 100644
--- a/src/compiler/glsl/linker.cpp
+++ b/src/compiler/glsl/linker.cpp
@@ -4743,6 +4743,16 @@ link_shaders(struct gl_context *ctx, struct gl_shader_program *prog)
                       "tessellation evaluation shader\n");
          goto done;
       }
+
+      if (prog->IsES) {
+         if (num_shaders[MESA_SHADER_TESS_EVAL] > 0 &&
+             num_shaders[MESA_SHADER_TESS_CTRL] == 0) {
+            linker_error(prog, "GLSL ES requires non-separable programs "
+                         "containing a tessellation evaluation shader to also "
+                         "be linked with a tessellation control shader\n");
+            goto done;
+         }
+      }
    }
 
    /* Compute shaders have additional restrictions. */
-- 
2.11.1