3 files changed, 54 insertions, 1 deletions

diff --git a/src/mesa/drivers/dri/common/dri_util.c b/src/mesa/drivers/dri/common/dri_util.c
index 0bce77ea9c7..fd2eca715c3 100644
--- a/src/mesa/drivers/dri/common/dri_util.c
+++ b/src/mesa/drivers/dri/common/dri_util.c
@@ -873,3 +873,18 @@ const __DRIimageDriverExtension driImageDriverExtension = {
     .getAPIMask                 = driGetAPIMask,
     .createContextAttribs       = driCreateContextAttribs,
 };
+
+/* swrast copy sub buffer entrypoint. */
+static void driCopySubBuffer(__DRIdrawable *pdp, int x, int y,
+                             int w, int h)
+{
+    assert(pdp->driScreenPriv->swrast_loader);
+
+    pdp->driScreenPriv->driver->CopySubBuffer(pdp, x, y, w, h);
+}
+
+/* for swrast only */
+const __DRIcopySubBufferExtension driCopySubBufferExtension = {
+   { __DRI_COPY_SUB_BUFFER, 1 },
+   .copySubBuffer = driCopySubBuffer,
+};
diff --git a/src/mesa/drivers/dri/common/dri_util.h b/src/mesa/drivers/dri/common/dri_util.h
index 79a8564ad51..4cfa75dd3e4 100644
--- a/src/mesa/drivers/dri/common/dri_util.h
+++ b/src/mesa/drivers/dri/common/dri_util.h
@@ -66,7 +66,7 @@ extern const __DRIcoreExtension driCoreExtension;
 extern const __DRIswrastExtension driSWRastExtension;
 extern const __DRIdri2Extension driDRI2Extension;
 extern const __DRI2configQueryExtension dri2ConfigQueryExtension;
-
+extern const __DRIcopySubBufferExtension driCopySubBufferExtension;
 /**
  * Driver callback functions.
  *
@@ -115,6 +115,9 @@ struct __DriverAPIRec {
                                     int width, int height);
 
     void (*ReleaseBuffer) (__DRIscreen *screenPrivate, __DRIbuffer *buffer);
+
+    void (*CopySubBuffer)(__DRIdrawable *driDrawPriv, int x, int y,
+                          int w, int h);
 };
 
 extern const struct __DriverAPIRec driDriverAPI;
diff --git a/src/mesa/drivers/dri/swrast/swrast.c b/src/mesa/drivers/dri/swrast/swrast.c
index 0e1c530b39d..7eed5a418cb 100644
--- a/src/mesa/drivers/dri/swrast/swrast.c
+++ b/src/mesa/drivers/dri/swrast/swrast.c
@@ -820,6 +820,39 @@ dri_unbind_context(__DRIcontext * cPriv)
     return GL_TRUE;
 }
 
+static void
+dri_copy_sub_buffer(__DRIdrawable *dPriv, int x, int y,
+                    int w, int h)
+{
+    __DRIscreen *sPriv = dPriv->driScreenPriv;
+    void *data;
+    int iy;
+    struct dri_drawable *drawable = dri_drawable(dPriv);
+    struct gl_framebuffer *fb;
+    struct dri_swrast_renderbuffer *frontrb, *backrb;
+
+    TRACE;
+
+    fb = &drawable->Base;
+
+    frontrb =
+	dri_swrast_renderbuffer(fb->Attachment[BUFFER_FRONT_LEFT].Renderbuffer);
+    backrb =
+	dri_swrast_renderbuffer(fb->Attachment[BUFFER_BACK_LEFT].Renderbuffer);
+
+    /* check for signle-buffered */
+    if (backrb == NULL)
+       return;
+
+    iy = frontrb->Base.Base.Height - y - h;
+    data = (char *)backrb->Base.Buffer + (iy * backrb->pitch) + (x * ((backrb->bpp + 7) / 8));
+    sPriv->swrast_loader->putImage2(dPriv, __DRI_SWRAST_IMAGE_OP_SWAP,
+                                    x, iy, w, h,
+                                    frontrb->pitch,
+                                    data,
+                                    dPriv->loaderPrivate);
+}
+
 
 static const struct __DriverAPIRec swrast_driver_api = {
     .InitScreen = dri_init_screen,
@@ -831,6 +864,7 @@ static const struct __DriverAPIRec swrast_driver_api = {
     .SwapBuffers = dri_swap_buffers,
     .MakeCurrent = dri_make_current,
     .UnbindContext = dri_unbind_context,
+    .CopySubBuffer = dri_copy_sub_buffer,
 };
 
 static const struct __DRIDriverVtableExtensionRec swrast_vtable = {
@@ -841,6 +875,7 @@ static const struct __DRIDriverVtableExtensionRec swrast_vtable = {
 static const __DRIextension *swrast_driver_extensions[] = {
     &driCoreExtension.base,
     &driSWRastExtension.base,
+    &driCopySubBufferExtension.base,
     &swrast_vtable.base,
     NULL
 };