gallium/swrast: fix front buffer blitting. (v2)

So I've known this was broken before, cogl has a workaround
for it from what I know, but with the gallium based swrast
drivers BlitFramebuffer from back to front or vice-versa
was pretty broken.

The legacy swrast driver tracks when a front buffer is used
and does the get/put images when it is mapped/unmapped,
so this patch attempts to add the same functionality to the
gallium drivers.

It creates a new context interface to denote when a front
buffer is being created, and passes a private pointer to it,
this pointer is then used to decide on map/unmap if the
contents should be updated from the real frontbuffer using
get/put image.

This is primarily to make gtk's gl code work, the only
thing I've tested so far is the glarea test from
https://github.com/ebassi/glarea-example.git

v2: bump extension version,
check extension version before calling get image. (Ian)

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=91930

Cc: <mesa-stable@lists.freedesktop.org>
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 14 insertions, 4 deletions

diff --git a/src/gallium/drivers/softpipe/sp_texture.c b/src/gallium/drivers/softpipe/sp_texture.c
index e1ea5df..3347f5f 100644
--- a/src/gallium/drivers/softpipe/sp_texture.c
+++ b/src/gallium/drivers/softpipe/sp_texture.c
@@ -127,7 +127,8 @@ softpipe_can_create_resource(struct pipe_screen *screen,
  */
 static boolean
 softpipe_displaytarget_layout(struct pipe_screen *screen,
-                              struct softpipe_resource *spr)
+                              struct softpipe_resource *spr,
+                              const void *map_front_private)
 {
    struct sw_winsys *winsys = softpipe_screen(screen)->winsys;
 
@@ -139,6 +140,7 @@ softpipe_displaytarget_layout(struct pipe_screen *screen,
                                           spr->base.width0, 
                                           spr->base.height0,
                                           64,
+                                          map_front_private,
                                           &spr->stride[0] );
 
    return spr->dt != NULL;
@@ -149,8 +151,9 @@ softpipe_displaytarget_layout(struct pipe_screen *screen,
  * Create new pipe_resource given the template information.
  */
 static struct pipe_resource *
-softpipe_resource_create(struct pipe_screen *screen,
-                         const struct pipe_resource *templat)
+softpipe_resource_create_front(struct pipe_screen *screen,
+                               const struct pipe_resource *templat,
+                               const void *map_front_private)
 {
    struct softpipe_resource *spr = CALLOC_STRUCT(softpipe_resource);
    if (!spr)
@@ -169,7 +172,7 @@ softpipe_resource_create(struct pipe_screen *screen,
    if (spr->base.bind & (PIPE_BIND_DISPLAY_TARGET |
 			 PIPE_BIND_SCANOUT |
 			 PIPE_BIND_SHARED)) {
-      if (!softpipe_displaytarget_layout(screen, spr))
+      if (!softpipe_displaytarget_layout(screen, spr, map_front_private))
          goto fail;
    }
    else {
@@ -184,6 +187,12 @@ softpipe_resource_create(struct pipe_screen *screen,
    return NULL;
 }
 
+static struct pipe_resource *
+softpipe_resource_create(struct pipe_screen *screen,
+                         const struct pipe_resource *templat)
+{
+   return softpipe_resource_create_front(screen, templat, NULL);
+}
 
 static void
 softpipe_resource_destroy(struct pipe_screen *pscreen,
@@ -514,6 +523,7 @@ void
 softpipe_init_screen_texture_funcs(struct pipe_screen *screen)
 {
    screen->resource_create = softpipe_resource_create;
+   screen->resource_create_front = softpipe_resource_create_front;
    screen->resource_destroy = softpipe_resource_destroy;
    screen->resource_from_handle = softpipe_resource_from_handle;
    screen->resource_get_handle = softpipe_resource_get_handle;