gallium,glsl: Delete PIPE_CAP_VERTEXID_NOBASE and lower_vertex_id.

Every driver uses the nir_lower_system_values path now.

Reviewed-by: Rob Clark <robdclark@chromium.org>
Reviewed-by: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>
Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/18327>

src/mesa/main/consts_exts.h

@@ -697,15 +697,6 @@ struct gl_constants
     */
    GLboolean NativeIntegers;
 
-   /**
-    * Does VertexID count from zero or from base vertex?
-    *
-    * \note
-    * If desktop GLSL 1.30 or GLSL ES 3.00 are not supported, this field is
-    * ignored and need not be set.
-    */
-   bool VertexID_is_zero_based;
-
    /**
     * If the driver supports real 32-bit integers, what integer value should be
     * used for boolean true in uniform uploads?  (Usually 1 or ~0.)

src/mesa/main/context.c

@@ -481,12 +481,6 @@ _mesa_init_constants(struct gl_constants *consts, gl_api api)
 
    consts->GLSLLowerConstArrays = true;
 
-   /* Assume that if GLSL 1.30+ (or GLSL ES 3.00+) is supported that
-    * gl_VertexID is implemented using a native hardware register with OpenGL
-    * semantics.
-    */
-   consts->VertexID_is_zero_based = false;
-
    /* GL_ARB_draw_buffers */
    consts->MaxDrawBuffers = MAX_DRAW_BUFFERS;
 

src/mesa/state_tracker/st_extensions.c

@@ -1210,10 +1210,6 @@ void st_init_extensions(struct pipe_screen *screen,
       if (drv_clip_planes > 1)
          consts->MaxClipPlanes = drv_clip_planes;
 
-      if (screen->get_param(screen, PIPE_CAP_VERTEXID_NOBASE)) {
-         consts->VertexID_is_zero_based = GL_TRUE;
-      }
-
       /* Extensions that either depend on GLSL 1.30 or are a subset thereof. */
       extensions->ARB_conservative_depth = GL_TRUE;
       extensions->ARB_shading_language_packing = GL_TRUE;