added an assertion to help debug broken stencil readback

diff --git a/src/mesa/drivers/dri/r200/r200_span.c b/src/mesa/drivers/dri/r200/r200_span.c
index 898ff61e76a4b6422f3bf5cd13c3e967a8440542..9f910ebaccaec0910886b82066007d3eb680706d 100644 (file)
--- a/src/mesa/drivers/dri/r200/r200_span.c
+++ b/src/mesa/drivers/dri/r200/r200_span.c
@@ -80,13 +80,15 @@ WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 
 #define LOCAL_DEPTH_VARS                                               \
    r200ContextPtr rmesa = R200_CONTEXT(ctx);                           \
+   r200ScreenPtr r200Screen = rmesa->r200Screen;                       \
    __DRIscreenPrivate *sPriv = rmesa->dri.screen;                      \
    __DRIdrawablePrivate *dPriv = rmesa->dri.drawable;                  \
    driRenderbuffer *drb = (driRenderbuffer *) rb;                      \
    GLuint height = dPriv->h;                                           \
    GLuint xo = dPriv->x;                                               \
    GLuint yo = dPriv->y;                                               \
-   char *buf = (char *)(sPriv->pFB + drb->offset);
+   char *buf = (char *)(sPriv->pFB + drb->offset);                     \
+   assert(drb->offset == r200Screen->depthOffset);
 
 #define LOCAL_STENCIL_VARS     LOCAL_DEPTH_VARS