1 files changed, 31 insertions, 0 deletions
diff --git a/src/mesa/main/varray.h b/src/mesa/main/varray.h
index 53e68c89667..1c423200ffd 100644
--- a/src/mesa/main/varray.h
+++ b/src/mesa/main/varray.h
@@ -34,6 +34,37 @@
 struct gl_client_array;
 struct gl_context;
 
+
+/**
+ * Compute the index of the last array element that can be safely accessed in
+ * a vertex array.  We can really only do this when the array lives in a VBO.
+ * The array->_MaxElement field will be updated.
+ * Later in glDrawArrays/Elements/etc we can do some bounds checking.
+ */
+static INLINE void
+_mesa_update_array_max_element(struct gl_client_array *array)
+{
+   assert(array->Enabled);
+
+   if (array->BufferObj->Name) {
+      GLsizeiptrARB offset = (GLsizeiptrARB) array->Ptr;
+      GLsizeiptrARB bufSize = (GLsizeiptrARB) array->BufferObj->Size;
+
+      if (offset < bufSize) {
+	 array->_MaxElement = (bufSize - offset + array->StrideB
+                               - array->_ElementSize) / array->StrideB;
+      }
+      else {
+	 array->_MaxElement = 0;
+      }
+   }
+   else {
+      /* user-space array, no idea how big it is */
+      array->_MaxElement = 2 * 1000 * 1000 * 1000; /* just a big number */
+   }
+}
+
+
 #if _HAVE_FULL_GL
 
 extern void GLAPIENTRY