st/mesa: determine Const.MaxSamples in init_extensions

v2: Check for non-pow2 sample counts as well.

1 files changed, 11 insertions, 0 deletions

diff --git a/src/mesa/state_tracker/st_extensions.c b/src/mesa/state_tracker/st_extensions.c
index b5f6d356eb0..8e900934054 100644
--- a/src/mesa/state_tracker/st_extensions.c
+++ b/src/mesa/state_tracker/st_extensions.c
@@ -228,6 +228,7 @@ void st_init_extensions(struct st_context *st)
 {
    struct pipe_screen *screen = st->pipe->screen;
    struct gl_context *ctx = st->ctx;
+   int i;
 
    /*
     * Extensions that are supported by all Gallium drivers:
@@ -605,6 +606,16 @@ void st_init_extensions(struct st_context *st)
       ctx->Extensions.EXT_packed_float = GL_TRUE;
    }
 
+   /* Maximum sample count. */
+   for (i = 16; i > 0; --i) {
+      if (screen->is_format_supported(screen, PIPE_FORMAT_B8G8R8A8_UNORM,
+                                      PIPE_TEXTURE_2D, i,
+                                      PIPE_BIND_RENDER_TARGET)) {
+         ctx->Const.MaxSamples = i;
+         break;
+      }
+   }
+
    if (screen->get_param(screen, PIPE_CAP_SEAMLESS_CUBE_MAP_PER_TEXTURE)) {
       ctx->Extensions.ARB_seamless_cube_map = GL_TRUE;
       ctx->Extensions.AMD_seamless_cubemap_per_texture = GL_TRUE;