[Mesa-dev] [RFC PATCH 10/56] mesa: Generalize sso stage interleaving check for tess

[Chris Forbes]

Signed-off-by: Chris Forbes <chrisf at ijw.co.nz>
---
 src/mesa/main/pipelineobj.c | 53 +++++++++++++++++++++++++++++++--------------
 1 file changed, 37 insertions(+), 16 deletions(-)

diff --git a/src/mesa/main/pipelineobj.c b/src/mesa/main/pipelineobj.c
index c902107..b91289e 100644
--- a/src/mesa/main/pipelineobj.c
+++ b/src/mesa/main/pipelineobj.c
@@ -662,6 +662,38 @@ program_stages_all_active(struct gl_pipeline_object *pipe,
    return status;
 }
 
+static bool
+program_stages_interleaved_illegally(struct gl_pipeline_object *pipe)
+{
+   struct gl_shader_program *prev = NULL;
+   unsigned i, j;
+
+   /* Look for programs bound to stages: A -> B -> A, with
+    * any intervening sequence of unrelated programs or
+    * empty stages
+    */
+
+   for (i = 0; i < MESA_SHADER_STAGES; i++) {
+      /* Empty stages anywhere in the pipe are OK */
+      if (!pipe->CurrentProgram[i])
+         continue;
+
+      if (prev && pipe->CurrentProgram[i] != prev) {
+         /* We've seen an A -> B transition; look at the rest of
+          * the pipe to see if we ever see A again.
+          */
+         for (j = i + 1; j < MESA_SHADER_STAGES; j++) {
+            if (pipe->CurrentProgram[j] == prev)
+               return true;
+         }
+      }
+
+      prev = pipe->CurrentProgram[i];
+   }
+
+   return false;
+}
+
 extern GLboolean
 _mesa_validate_program_pipeline(struct gl_context* ctx,
                                 struct gl_pipeline_object *pipe,
@@ -714,22 +746,11 @@ _mesa_validate_program_pipeline(struct gl_context* ctx,
     * Without Tesselation, the only case where this can occur is the geometry
     * shader between the fragment shader and vertex shader.
     */
-   if (pipe->CurrentProgram[MESA_SHADER_GEOMETRY]
-       && pipe->CurrentProgram[MESA_SHADER_FRAGMENT]
-       && pipe->CurrentProgram[MESA_SHADER_VERTEX]) {
-      if (pipe->CurrentProgram[MESA_SHADER_VERTEX]->Name == pipe->CurrentProgram[MESA_SHADER_FRAGMENT]->Name &&
-          pipe->CurrentProgram[MESA_SHADER_GEOMETRY]->Name != pipe->CurrentProgram[MESA_SHADER_VERTEX]->Name) {
-         pipe->InfoLog =
-            ralloc_asprintf(pipe,
-                            "Program %d is active for geometry stage between "
-                            "two stages for which another program %d is "
-                            "active",
-                            pipe->CurrentProgram[MESA_SHADER_GEOMETRY]->Name,
-                            pipe->CurrentProgram[MESA_SHADER_VERTEX]->Name);
-         goto err;
-      }
-
-      /* XXX tess */
+   if (program_stages_interleaved_illegally(pipe)) {
+      pipe->InfoLog = ralloc_strdup(pipe, "Program is active for multiple shader"
+                                          "stages with an intervening stage provided"
+                                          "by another program");
+      goto err;
    }
 
    /* Section 2.11.11 (Shader Execution), subheading "Validation," of the
-- 
2.1.0