glsl: add gl_SubGroup*ARB builtins

Reviewed-by: Marek Olšák <[email protected]>

1 files changed, 59 insertions, 0 deletions

diff --git a/src/compiler/shader_enums.h b/src/compiler/shader_enums.h
index 98565c80cb8..930d99748e7 100644
--- a/src/compiler/shader_enums.h
+++ b/src/compiler/shader_enums.h
@@ -318,6 +318,65 @@ const char *gl_varying_slot_name(gl_varying_slot slot);
 typedef enum
 {
    /**
+    * \name System values applicable to all shaders
+    */
+   /*@{*/
+
+   /**
+    * Builtin variables added by GL_ARB_shader_ballot.
+    */
+   /*@{*/
+
+   /**
+    * From the GL_ARB_shader-ballot spec:
+    *
+    *    "A sub-group is a collection of invocations which execute in lockstep.
+    *     The variable <gl_SubGroupSizeARB> is the maximum number of
+    *     invocations in a sub-group. The maximum <gl_SubGroupSizeARB>
+    *     supported in this extension is 64."
+    *
+    * The spec defines this as a uniform. However, it's highly unlikely that
+    * implementations actually treat it as a uniform (which is loaded from a
+    * constant buffer). Most likely, this is an implementation-wide constant,
+    * or perhaps something that depends on the shader stage.
+    */
+   SYSTEM_VALUE_SUBGROUP_SIZE,
+
+   /**
+    * From the GL_ARB_shader_ballot spec:
+    *
+    *    "The variable <gl_SubGroupInvocationARB> holds the index of the
+    *     invocation within sub-group. This variable is in the range 0 to
+    *     <gl_SubGroupSizeARB>-1, where <gl_SubGroupSizeARB> is the total
+    *     number of invocations in a sub-group."
+    */
+   SYSTEM_VALUE_SUBGROUP_INVOCATION,
+
+   /**
+    * From the GL_ARB_shader_ballot spec:
+    *
+    *    "The <gl_SubGroup??MaskARB> variables provide a bitmask for all
+    *     invocations, with one bit per invocation starting with the least
+    *     significant bit, according to the following table,
+    *
+    *       variable               equation for bit values
+    *       --------------------   ------------------------------------
+    *       gl_SubGroupEqMaskARB   bit index == gl_SubGroupInvocationARB
+    *       gl_SubGroupGeMaskARB   bit index >= gl_SubGroupInvocationARB
+    *       gl_SubGroupGtMaskARB   bit index >  gl_SubGroupInvocationARB
+    *       gl_SubGroupLeMaskARB   bit index <= gl_SubGroupInvocationARB
+    *       gl_SubGroupLtMaskARB   bit index <  gl_SubGroupInvocationARB
+    */
+   SYSTEM_VALUE_SUBGROUP_EQ_MASK,
+   SYSTEM_VALUE_SUBGROUP_GE_MASK,
+   SYSTEM_VALUE_SUBGROUP_GT_MASK,
+   SYSTEM_VALUE_SUBGROUP_LE_MASK,
+   SYSTEM_VALUE_SUBGROUP_LT_MASK,
+   /*@}*/
+
+   /*@}*/
+
+   /**
     * \name Vertex shader system values
     */
    /*@{*/