virgl: implement set_min_samples

This allows us to implement glMinSampleShading correctly, which up
until now just got ignored.

Signed-off-by: Erik Faye-Lund <erik.faye-lund@collabora.com>
Reviewed-by: Dave Airlie <airlied@redhat.com>

src/gallium/drivers/virgl/virgl_context.c

@@ -844,6 +844,17 @@ static void virgl_set_sample_mask(struct pipe_context *ctx,
    virgl_encoder_set_sample_mask(vctx, sample_mask);
 }
 
+static void virgl_set_min_samples(struct pipe_context *ctx,
+                                 unsigned min_samples)
+{
+   struct virgl_context *vctx = virgl_context(ctx);
+   struct virgl_screen *rs = virgl_screen(ctx->screen);
+
+   if (!(rs->caps.caps.v2.capability_bits & VIRGL_CAP_SET_MIN_SAMPLES))
+      return;
+   virgl_encoder_set_min_samples(vctx, min_samples);
+}
+
 static void virgl_set_clip_state(struct pipe_context *ctx,
                                 const struct pipe_clip_state *clip)
 {
@@ -1025,6 +1036,7 @@ struct pipe_context *virgl_context_create(struct pipe_screen *pscreen,
    vctx->base.set_polygon_stipple = virgl_set_polygon_stipple;
    vctx->base.set_scissor_states = virgl_set_scissor_states;
    vctx->base.set_sample_mask = virgl_set_sample_mask;
+   vctx->base.set_min_samples = virgl_set_min_samples;
    vctx->base.set_stencil_ref = virgl_set_stencil_ref;
    vctx->base.set_clip_state = virgl_set_clip_state;
 

src/gallium/drivers/virgl/virgl_encode.c

@@ -726,6 +726,13 @@ void virgl_encoder_set_sample_mask(struct virgl_context *ctx,
    virgl_encoder_write_dword(ctx->cbuf, sample_mask);
 }
 
+void virgl_encoder_set_min_samples(struct virgl_context *ctx,
+                                  unsigned min_samples)
+{
+   virgl_encoder_write_cmd_dword(ctx, VIRGL_CMD0(VIRGL_CCMD_SET_MIN_SAMPLES, 0, VIRGL_SET_MIN_SAMPLES_SIZE));
+   virgl_encoder_write_dword(ctx->cbuf, min_samples);
+}
+
 void virgl_encoder_set_clip_state(struct virgl_context *ctx,
                                  const struct pipe_clip_state *clip)
 {

src/gallium/drivers/virgl/virgl_encode.h

@@ -211,6 +211,9 @@ void virgl_encoder_set_polygon_stipple(struct virgl_context *ctx,
 void virgl_encoder_set_sample_mask(struct virgl_context *ctx,
                                   unsigned sample_mask);
 
+void virgl_encoder_set_min_samples(struct virgl_context *ctx,
+                                  unsigned min_samples);
+
 void virgl_encoder_set_clip_state(struct virgl_context *ctx,
                                  const struct pipe_clip_state *clip);
 

src/gallium/drivers/virgl/virgl_hw.h

@@ -201,6 +201,7 @@ enum virgl_formats {
 #define VIRGL_CAP_NONE 0
 #define VIRGL_CAP_TGSI_INVARIANT       (1 << 0)
 #define VIRGL_CAP_TEXTURE_VIEW         (1 << 1)
+#define VIRGL_CAP_SET_MIN_SAMPLES      (1 << 2)
 
 #define VIRGL_BIND_DEPTH_STENCIL (1 << 0)
 #define VIRGL_BIND_RENDER_TARGET (1 << 1)

src/gallium/drivers/virgl/virgl_protocol.h

@@ -85,6 +85,7 @@ enum virgl_context_cmd {
    VIRGL_CCMD_BIND_SHADER,
 
    VIRGL_CCMD_SET_TESS_STATE,
+   VIRGL_CCMD_SET_MIN_SAMPLES,
 };
 
 /*
@@ -486,4 +487,8 @@ enum virgl_context_cmd {
 /* tess state */
 #define VIRGL_TESS_STATE_SIZE 6
 
+/* set min samples */
+#define VIRGL_SET_MIN_SAMPLES_SIZE 1
+#define VIRGL_SET_MIN_SAMPLES_MASK 1
+
 #endif