vrend: add support for stencil texturing.

This should fix stencil drawpixels if the host supports
stencil texturing.

src/virgl_hw.h

@@ -112,6 +112,8 @@ enum virgl_formats {
    VIRGL_FORMAT_B10G10R10A2_UNORM       = 131,
    VIRGL_FORMAT_R8G8B8X8_UNORM          = 134,
    VIRGL_FORMAT_B4G4R4X4_UNORM          = 135,
+   VIRGL_FORMAT_X24S8_UINT              = 136,
+   VIRGL_FORMAT_S8X24_UINT              = 137,
    VIRGL_FORMAT_B2G3R3_UNORM            = 139,
 
    VIRGL_FORMAT_L16A16_UNORM            = 140,

src/vrend_renderer.c

@@ -107,6 +107,7 @@ struct global_renderer_state {
    bool have_bit_encoding;
    bool have_vertex_attrib_binding;
    bool have_tf2;
+   bool have_stencil_texturing;
 
    /* these appeared broken on at least one driver */
    bool use_explicit_locations;
@@ -1930,6 +1931,14 @@ void vrend_set_single_sampler_view(struct vrend_context *ctx,
                   view->depth_texture_mode = GL_RED;
                }
             }
+            if (vrend_state.have_stencil_texturing) {
+               const struct util_format_description *desc = util_format_description(view->format);
+               if (!util_format_has_depth(desc)) {
+                  glTexParameteri(view->texture->target, GL_DEPTH_STENCIL_TEXTURE_MODE, GL_STENCIL_INDEX);
+               } else {
+                  glTexParameteri(view->texture->target, GL_DEPTH_STENCIL_TEXTURE_MODE, GL_DEPTH_COMPONENT);
+               }
+            }
          }
 
          if (view->cur_base != (view->val1 & 0xff)) {
@@ -3853,6 +3862,8 @@ int vrend_renderer_init(struct vrend_if_cbs *cbs, uint32_t flags)
    if (gl_ver >= 40 || epoxy_has_gl_extension("GL_ARB_transform_feedback2"))
       vrend_state.have_tf2 = true;
 
+   if (epoxy_has_gl_extension("GL_ARB_stencil_texturing"))
+      vrend_state.have_stencil_texturing = true;
    if (epoxy_has_gl_extension("GL_EXT_framebuffer_multisample") && epoxy_has_gl_extension("GL_ARB_texture_multisample")) {
       vrend_state.have_multisample = true;
       if (epoxy_has_gl_extension("GL_EXT_framebuffer_multisample_blit_scaled"))