tessellation: add protocol support for set tess state. (v2)

This passes the default tessellation factors from the guest to
the host.

v2: fix warnings

Tested-by: Elie Tournier <elie.tournier@collabora.com>
Reviewed-by: Elie Tournier <elie.tournier@collabora.com>
Tested-by: Jakob Bornecrantz <jakob@collabora.com>

src/virgl_protocol.h

@@ -83,6 +83,7 @@ enum virgl_context_cmd {
    VIRGL_CCMD_CREATE_SUB_CTX,
    VIRGL_CCMD_DESTROY_SUB_CTX,
    VIRGL_CCMD_BIND_SHADER,
+   VIRGL_CCMD_SET_TESS_STATE,
 };
 
 /*
@@ -481,4 +482,7 @@ enum virgl_context_cmd {
 #define VIRGL_BIND_SHADER_HANDLE 1
 #define VIRGL_BIND_SHADER_TYPE 2
 
+/* tess state */
+#define VIRGL_TESS_STATE_SIZE 6
+
 #endif

src/vrend_decode.c

@@ -1050,6 +1050,22 @@ static int vrend_decode_bind_shader(struct vrend_decode_ctx *ctx, int length)
    return 0;
 }
 
+static int vrend_decode_set_tess_state(struct vrend_decode_ctx *ctx,
+				       int length)
+{
+   float tess_factors[6];
+   int i;
+
+   if (length != VIRGL_TESS_STATE_SIZE)
+      return EINVAL;
+
+   for (i = 0; i < 6; i++) {
+      tess_factors[i] = uif(get_buf_entry(ctx, i + 1));
+   }
+   vrend_set_tess_state(ctx->grctx, tess_factors);
+   return 0;
+}
+
 static int vrend_decode_set_streamout_targets(struct vrend_decode_ctx *ctx,
                                               uint16_t length)
 {
@@ -1272,6 +1288,9 @@ int vrend_decode_block(uint32_t ctx_id, uint32_t *block, int ndw)
       case VIRGL_CCMD_BIND_SHADER:
          ret = vrend_decode_bind_shader(gdctx, len);
          break;
+      case VIRGL_CCMD_SET_TESS_STATE:
+         ret = vrend_decode_set_tess_state(gdctx, len);
+         break;
       default:
          ret = EINVAL;
       }

src/vrend_renderer.c

@@ -5791,6 +5791,14 @@ void vrend_set_sample_mask(UNUSED struct vrend_context *ctx, unsigned sample_mas
    glSampleMaski(0, sample_mask);
 }
 
+void vrend_set_tess_state(UNUSED struct vrend_context *ctx, const float tess_factors[6])
+{
+   if (vrend_state.have_tessellation) {
+      glPatchParameterfv(GL_PATCH_DEFAULT_OUTER_LEVEL, tess_factors);
+      glPatchParameterfv(GL_PATCH_DEFAULT_INNER_LEVEL, &tess_factors[4]);
+   }
+}
+
 static void vrend_hw_emit_streamout_targets(UNUSED struct vrend_context *ctx, struct vrend_streamout_object *so_obj)
 {
    uint i;

src/vrend_renderer.h

@@ -276,6 +276,8 @@ void vrend_set_uniform_buffer(struct vrend_context *ctx, uint32_t shader,
                               uint32_t index, uint32_t offset, uint32_t length,
                               uint32_t res_handle);
 
+void vrend_set_tess_state(struct vrend_context *ctx, const float tess_factors[6]);
+
 void vrend_renderer_fini(void);
 
 int vrend_decode_block(uint32_t ctx_id, uint32_t *block, int ndw);