gallium/st: add pipe_context::generate_mipmap()

This patch adds a new interface to support hardware mipmap generation.
PIPE_CAP_GENERATE_MIPMAP is added to allow a driver to specify
if this new interface is supported; if not supported, the state tracker will
fallback to mipmap generation by rendering/texturing.

v2: add PIPE_CAP_GENERATE_MIPMAP to the disabled section for all drivers
v3: add format to the generate_mipmap interface to allow mipmap generation
    using a format other than the resource format
v4: fix return type of trace_context_generate_mipmap()

Reviewed-by: Brian Paul <[email protected]>
Reviewed-by: Roland Scheidegger <[email protected]>
Reviewed-by: Jose Fonseca <[email protected]>

1 files changed, 12 insertions, 5 deletions

diff --git a/src/mesa/state_tracker/st_gen_mipmap.c b/src/mesa/state_tracker/st_gen_mipmap.c
index b3700406df0..3e6c0a73bc7 100644
--- a/src/mesa/state_tracker/st_gen_mipmap.c
+++ b/src/mesa/state_tracker/st_gen_mipmap.c
@@ -149,12 +149,19 @@ st_generate_mipmap(struct gl_context *ctx, GLenum target,
       last_layer = util_max_layer(pt, baseLevel);
    }
 
-   /* Try to generate the mipmap by rendering/texturing.  If that fails,
-    * use the software fallback.
+   /* First see if the driver supports hardware mipmap generation,
+    * if not then generate the mipmap by rendering/texturing.
+    * If that fails, use the software fallback.
     */
-   if (!util_gen_mipmap(st->pipe, pt, pt->format, baseLevel, lastLevel,
-                        first_layer, last_layer, PIPE_TEX_FILTER_LINEAR)) {
-      _mesa_generate_mipmap(ctx, target, texObj);
+   if (!st->pipe->screen->get_param(st->pipe->screen,
+                                    PIPE_CAP_GENERATE_MIPMAP) ||
+       !st->pipe->generate_mipmap(st->pipe, pt, pt->format, baseLevel,
+                                  lastLevel, first_layer, last_layer)) {
+
+      if (!util_gen_mipmap(st->pipe, pt, pt->format, baseLevel, lastLevel,
+                           first_layer, last_layer, PIPE_TEX_FILTER_LINEAR)) {
+         _mesa_generate_mipmap(ctx, target, texObj);
+      }
    }
 
    /* Fill in the Mesa gl_texture_image fields */