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, 37 insertions, 2 deletions

diff --git a/src/gallium/state_trackers/dri/drisw.c b/src/gallium/state_trackers/dri/drisw.c
index 4ec6992..753c59d 100644
--- a/src/gallium/state_trackers/dri/drisw.c
+++ b/src/gallium/state_trackers/dri/drisw.c
@@ -95,6 +95,21 @@ get_image(__DRIdrawable *dPriv, int x, int y, int width, int height, void *data)
                     data, dPriv->loaderPrivate);
 }
 
+static inline void
+get_image2(__DRIdrawable *dPriv, int x, int y, int width, int height, int stride, void *data)
+{
+   __DRIscreen *sPriv = dPriv->driScreenPriv;
+   const __DRIswrastLoaderExtension *loader = sPriv->swrast_loader;
+
+   /* getImage2 support is only in version 3 or newer */
+   if (loader->base.version < 3)
+      return;
+
+   loader->getImage2(dPriv,
+                     x, y, width, height, stride,
+                     data, dPriv->loaderPrivate);
+}
+
 static void
 drisw_update_drawable_info(struct dri_drawable *drawable)
 {
@@ -105,6 +120,18 @@ drisw_update_drawable_info(struct dri_drawable *drawable)
 }
 
 static void
+drisw_get_image(struct dri_drawable *drawable,
+                int x, int y, unsigned width, unsigned height, unsigned stride,
+                void *data)
+{
+   __DRIdrawable *dPriv = drawable->dPriv;
+   int draw_x, draw_y, draw_w, draw_h;
+
+   get_drawable_info(dPriv, &draw_x, &draw_y, &draw_w, &draw_h);
+   get_image2(dPriv, x, y, draw_w, draw_h, stride, data);
+}
+
+static void
 drisw_put_image(struct dri_drawable *drawable,
                 void *data, unsigned width, unsigned height)
 {
@@ -236,6 +263,7 @@ drisw_allocate_textures(struct dri_context *stctx,
                         unsigned count)
 {
    struct dri_screen *screen = dri_screen(drawable->sPriv);
+   const __DRIswrastLoaderExtension *loader = drawable->dPriv->driScreenPriv->swrast_loader;
    struct pipe_resource templ;
    unsigned width, height;
    boolean resized;
@@ -281,8 +309,14 @@ drisw_allocate_textures(struct dri_context *stctx,
       templ.format = format;
       templ.bind = bind;
 
-      drawable->textures[statts[i]] =
-         screen->base.screen->resource_create(screen->base.screen, &templ);
+      if (statts[i] == ST_ATTACHMENT_FRONT_LEFT &&
+          screen->base.screen->resource_create_front &&
+          loader->base.version >= 3) {
+         drawable->textures[statts[i]] =
+            screen->base.screen->resource_create_front(screen->base.screen, &templ, (const void *)drawable);
+      } else
+         drawable->textures[statts[i]] =
+            screen->base.screen->resource_create(screen->base.screen, &templ);
    }
 
    drawable->old_w = width;
@@ -338,6 +372,7 @@ static const __DRIextension *drisw_screen_extensions[] = {
 };
 
 static struct drisw_loader_funcs drisw_lf = {
+   .get_image = drisw_get_image,
    .put_image = drisw_put_image,
    .put_image2 = drisw_put_image2
 };