virgl: Add a tweak to set the value for emulated queries of GL_SAMPLES_PASSED

On GLES hosts GL_SAMPLES_PASSED is emulated by GL_ANY_SAMPLES_PASSED which returns a boolen.
With this tweak the value that is returned if any sample passed can be set. This
may be of iterest when an application decides whether some geometry is rendered based
on an amount of visibility and not just a binary desicion. virgelrenderer sets a default
of 1024 on th host.

v2: Remove reference from virgl and correct description (Emil)
v3: Send the tweak binary encoded instead of using strings (Gurchetan)

Signed-off-by: Gert Wollny <[email protected]>
Reviewed-by: Gurchetan Singh <[email protected]>

1 files changed, 5 insertions, 0 deletions

diff --git a/src/gallium/drivers/virgl/virgl_screen.c b/src/gallium/drivers/virgl/virgl_screen.c
index e96a10ffbc7..be684dbf3c1 100644
--- a/src/gallium/drivers/virgl/virgl_screen.c
+++ b/src/gallium/drivers/virgl/virgl_screen.c
@@ -856,6 +856,8 @@ virgl_create_screen(struct virgl_winsys *vws, const struct pipe_screen_config *c
 
    const char *VIRGL_GLES_EMULATE_BGRA = "gles_emulate_bgra";
    const char *VIRGL_GLES_APPLY_BGRA_DEST_SWIZZLE = "gles_apply_bgra_dest_swizzle";
+   const char *VIRGL_GLES_SAMPLES_PASSED_VALUE = "gles_samples_passed_value";
+
    if (!screen)
       return NULL;
 
@@ -866,7 +868,10 @@ virgl_create_screen(struct virgl_winsys *vws, const struct pipe_screen_config *c
             driQueryOptionb(config->options, VIRGL_GLES_EMULATE_BGRA);
       screen->tweak_gles_apply_bgra_dest_swizzle =
             driQueryOptionb(config->options, VIRGL_GLES_APPLY_BGRA_DEST_SWIZZLE);
+      screen->tweak_gles_tf3_value =
+            driQueryOptioni(config->options, VIRGL_GLES_SAMPLES_PASSED_VALUE);
    }
+
    screen->vws = vws;
    screen->base.get_name = virgl_get_name;
    screen->base.get_vendor = virgl_get_vendor;