i965: add software fallback for conformant 3D textures and GL_CLAMP

The i965 hardware cannot do GL_CLAMP behavior on textures; an earlier
commit forced a software fallback if strict conformance was required
(i.e. the INTEL_STRICT_CONFORMANCE environment variable was set) and
2D textures were used, but it was somewhat flawed - it could trigger
the software fallback even if 2D textures weren't enabled, as long
as one texture unit was enabled.

This fixes that, and adds software fallback for GL_CLAMP behavior with
1D and 3D textures.

It also adds support for a particular setting of the INTEL_STRICT_CONFORMANCE
environment variable, which forces software fallbacks to be taken *all*
the time.  This is helpful with debugging.  The value is:
   export INTEL_STRICT_CONFORMANCE=2

1 files changed, 6 insertions, 1 deletions

diff --git a/src/mesa/drivers/dri/intel/intel_context.h b/src/mesa/drivers/dri/intel/intel_context.h
index 18dc43c4a4..f2ecb9eb27 100644
--- a/src/mesa/drivers/dri/intel/intel_context.h
+++ b/src/mesa/drivers/dri/intel/intel_context.h
@@ -229,7 +229,12 @@ struct intel_context
    GLboolean hw_stipple;
    GLboolean depth_buffer_is_float;
    GLboolean no_rast;
-   GLboolean strict_conformance;
+
+   /* 0 - nonconformant, best performance;
+    * 1 - fallback to sw for known conformance bugs
+    * 2 - always fallback to sw
+    */
+   GLuint conformance_mode;
 
    /* State for intelvb.c and inteltris.c.
     */