[Mesa-dev] [PATCH] i965: Fix the passthrough TCS for isolines.

[Kenneth Graunke]

We weren't setting up several of the uniform values for the patch
header, so we'd crash when uploading push constants.  We at least
need to initialize them to zero.  We also had the isoline parameters
reversed, so it would also render incorrectly (if it didn't crash).

Fixes a new Piglit test(*) (isoline-no-tcs), as well as crashes in
GL44-CTS.tessellation_shader.single.max_patch_vertices.

(*) https://lists.freedesktop.org/archives/piglit/2016-May/019866.html

Signed-off-by: Kenneth Graunke <kenneth at whitecape.org>
Cc: mesa-stable at lists.freedesktop.org
---
 src/mesa/drivers/dri/i965/brw_tcs.c | 19 ++++++++++++-------
 1 file changed, 12 insertions(+), 7 deletions(-)

diff --git a/src/mesa/drivers/dri/i965/brw_tcs.c b/src/mesa/drivers/dri/i965/brw_tcs.c
index 9589fa5..9374a42 100644
--- a/src/mesa/drivers/dri/i965/brw_tcs.c
+++ b/src/mesa/drivers/dri/i965/brw_tcs.c
@@ -227,19 +227,24 @@ brw_codegen_tcs_prog(struct brw_context *brw,
        */
       const float **param = (const float **) prog_data.base.base.param;
       static float zero = 0.0f;
-      for (int i = 0; i < 4; i++) {
-         param[7 - i] = &ctx->TessCtrlProgram.patch_default_outer_level[i];
-      }
+      for (int i = 0; i < 8; i++)
+         param[i] = &zero;
 
       if (key->tes_primitive_mode == GL_QUADS) {
+         for (int i = 0; i < 4; i++)
+            param[7 - i] = &ctx->TessCtrlProgram.patch_default_outer_level[i];
+
          param[3] = &ctx->TessCtrlProgram.patch_default_inner_level[0];
          param[2] = &ctx->TessCtrlProgram.patch_default_inner_level[1];
-         param[1] = &zero;
-         param[0] = &zero;
       } else if (key->tes_primitive_mode == GL_TRIANGLES) {
+         for (int i = 0; i < 3; i++)
+            param[7 - i] = &ctx->TessCtrlProgram.patch_default_outer_level[i];
+
          param[4] = &ctx->TessCtrlProgram.patch_default_inner_level[0];
-         for (int i = 0; i < 4; i++)
-            param[i] = &zero;
+      } else {
+         assert(key->tes_primitive_mode == GL_ISOLINES);
+         param[7] = &ctx->TessCtrlProgram.patch_default_outer_level[1];
+         param[6] = &ctx->TessCtrlProgram.patch_default_outer_level[0];
       }
    }
 
-- 
2.8.2