intel: Use GL_FRONT_AND_BACK for stencil clearing.

This comes from a radeon-rewrite fallback fix, but may also fix stencil
clear failure when the polygon winding mode is flipped.
(cherry picked from commit d866abeffc7e4a29736fa35fb8ac09c3a28a44d6)

diff --git a/src/mesa/drivers/dri/intel/intel_clear.c b/src/mesa/drivers/dri/intel/intel_clear.c
index eb0d890..488db2c 100644 (file)
--- a/src/mesa/drivers/dri/intel/intel_clear.c
+++ b/src/mesa/drivers/dri/intel/intel_clear.c
@@ -256,7 +256,8 @@ intel_clear_tris(GLcontext *ctx, GLbitfield mask)
       if (this_mask & BUFFER_BIT_STENCIL) {
         _mesa_Enable(GL_STENCIL_TEST);
         _mesa_StencilOp(GL_REPLACE, GL_REPLACE, GL_REPLACE);
-        _mesa_StencilFuncSeparate(GL_FRONT, GL_ALWAYS, ctx->Stencil.Clear,
+        _mesa_StencilFuncSeparate(GL_FRONT_AND_BACK, GL_ALWAYS,
+                                  ctx->Stencil.Clear,
                                   ctx->Stencil.WriteMask[0]);
       } else {
         _mesa_Disable(GL_STENCIL_TEST);