gallium: add new properties for clip and cull distance usage

The TGSI usage mask can't be used, because these are declared as an output
array of 2 elements.

Reviewed-by: Ilia Mirkin <imirkin@alum.mit.edu>
Reviewed-by: Brian Paul <brianp@vmware.com>

src/gallium/auxiliary/tgsi/tgsi_strings.c

@@ -137,6 +137,8 @@ const char *tgsi_property_names[TGSI_PROPERTY_COUNT] =
    "TES_SPACING",
    "TES_VERTEX_ORDER_CW",
    "TES_POINT_MODE",
+   "NUM_CLIPDIST_ENABLED",
+   "NUM_CULLDIST_ENABLED",
 };
 
 const char *tgsi_return_type_names[TGSI_RETURN_TYPE_COUNT] =

src/gallium/docs/source/tgsi.rst

@@ -3126,6 +3126,16 @@ TES_POINT_MODE
 If set to a non-zero value, this turns on point mode for the tessellator,
 which means that points will be generated instead of primitives.
 
+NUM_CLIPDIST_ENABLED
+""""""""""""""""
+
+How many clip distance scalar outputs are enabled.
+
+NUM_CULLDIST_ENABLED
+""""""""""""""""
+
+How many cull distance scalar outputs are enabled.
+
 
 Texture Sampling and Texture Formats
 ------------------------------------

src/gallium/include/pipe/p_shader_tokens.h

@@ -267,7 +267,9 @@ union tgsi_immediate_data
 #define TGSI_PROPERTY_TES_SPACING            12
 #define TGSI_PROPERTY_TES_VERTEX_ORDER_CW    13
 #define TGSI_PROPERTY_TES_POINT_MODE         14
-#define TGSI_PROPERTY_COUNT                  15
+#define TGSI_PROPERTY_NUM_CLIPDIST_ENABLED   15
+#define TGSI_PROPERTY_NUM_CULLDIST_ENABLED   16
+#define TGSI_PROPERTY_COUNT                  17
 
 struct tgsi_property {
    unsigned Type         : 4;  /**< TGSI_TOKEN_TYPE_PROPERTY */